Recently, Lam et al. [1] concluded that patients with macular pucker and foveoschisis had a higher risk of postoperative macular oedema. Since only 5/17 cases had baseline fluorescein angiography it is unclear how they distinguished foveoschisis due to tangential traction, versus cystoid macular edema (CME). Is it possible that postoperative CME was recurrent and not new? In our experience, resolution of foveoschisis takes much longer than the relatively swift resolution in 25% and partial resolution in 68.8% of cases at 1 month, so perhaps CME was a confounding factor. Indeed, Figure 3 appears more like exudative cyst than ‘foveoschisis’.
Previous studies [2] found that nearly half of patients with macular pucker had multiple centers of retinal contraction which were associated with a higher prevalence of intraretinal cysts and greater macular thickening. Was en face OCT performed to determine the number of contraction centers and its relationship to foveoschisis as well as outcomes of surgery? Additionally, anomalous PVD with vitreoschisis [3] and vitreo-papillary adhesion [4] may be important in the pathogenesis of macular pucker. Did the authors correlate these with foveoschisis and postoperative outcomes?
There was no significant difference in postoperative visual acuity (VA) between the foveoschisis and control groups, but this may not be the best outcome measure in macular pucker surgery. Studies [5] have shown that quantifying contrast sensitivity fu...
Recently, Lam et al. [1] concluded that patients with macular pucker and foveoschisis had a higher risk of postoperative macular oedema. Since only 5/17 cases had baseline fluorescein angiography it is unclear how they distinguished foveoschisis due to tangential traction, versus cystoid macular edema (CME). Is it possible that postoperative CME was recurrent and not new? In our experience, resolution of foveoschisis takes much longer than the relatively swift resolution in 25% and partial resolution in 68.8% of cases at 1 month, so perhaps CME was a confounding factor. Indeed, Figure 3 appears more like exudative cyst than ‘foveoschisis’.
Previous studies [2] found that nearly half of patients with macular pucker had multiple centers of retinal contraction which were associated with a higher prevalence of intraretinal cysts and greater macular thickening. Was en face OCT performed to determine the number of contraction centers and its relationship to foveoschisis as well as outcomes of surgery? Additionally, anomalous PVD with vitreoschisis [3] and vitreo-papillary adhesion [4] may be important in the pathogenesis of macular pucker. Did the authors correlate these with foveoschisis and postoperative outcomes?
There was no significant difference in postoperative visual acuity (VA) between the foveoschisis and control groups, but this may not be the best outcome measure in macular pucker surgery. Studies [5] have shown that quantifying contrast sensitivity function (CSF), distortions (3-D Threshold Amsler Grid), and 3-D macular volume (as opposed to 2-D central thickness) more completely characterizes the benefits of surgery. Specifically, VA, CSF, and macular thickness all improved (34%, 35%, 33%, respectively; P<0.001 for each) postoperatively, but did not normalize relative to control (fellow) eyes. [5] In fact, only the Distortions Index (92% improved, P<0.01) and macular volume normalized, demonstrating the discriminating power and sensitivity of these outcome measures of surgical success. What is not known, however, is the relationship to ‘foveoschisis’.
References
1. Lam M, Philippakis E, Gaudric A, Tadayoni R, Couturier A. Postoperative outcomes of idiopathic epiretinal membrane associated with foveoschisis. Br J Ophthalmol. 2021 Feb 17:bjophthalmol-2020-317982. doi: 10.1136/bjophthalmol-2020-317982. Epub ahead of print. PMID: 33597194.
2. Gupta P, Sadun AA, Sebag J. Multifocal retinal contraction in macular pucker analyzed by combined optical coherence tomography/scanning laser ophthalmoscopy. Retina. 2008 Mar;28(3):447-52.
3. Gupta P, Yee KM, Garcia P, Rosen RB, Parikh J, Hageman GS, Sadun AA, Sebag J. Vitreoschisis in macular diseases. Br J Ophthalmol. 2011 Mar;95(3):376-80.
4. Wang MY, Nguyen D, Hindoyan N, Sadun AA, Sebag J. Vitreo-papillary adhesion in macular hole and macular pucker. Retina. 2009 May;29(5):644-50.
5. Nguyen JH, Yee KM, Sadun AA, Sebag J. Quantifying Visual Dysfunction and the Response to Surgery in Macular Pucker. Ophthalmology. 2016 Jul;123(7):1500-10.
In their review and meta-analysis, Hedengran and coworkers1 report no relative therapeutic benefit of preservative-free (PF) therapies over benzalkonium chloride (BAK)-preserved ones. Should the costlier PF medications therefore be abandoned, or should we question this conclusion?
Ten of the 16 comparative trials analysed were of short duration, (between 15 and 90 days), the longest taking 6 months. Once-a-day medication was used in each trial, yet the dose response curve for BAK toxicity shows that each additional drop of BAK-containing medication doubles the likelihood of lissamine green corneal staining2 and increases the risk of early failure of glaucoma surgery.3 BAK toxicity is slow in onset increasing over time, due to its continual accumulation within ocular tissues.3 Thus, inconsistencies between experimental studies, which document the harmful effects of BAK and clinical trials, which do not, likely relate to the timing, dosing and duration of glaucoma therapy.4 Two to 12 week trials comparing BAK with alternatively preserved eyedrops, or PF formulations have shown no convincing differences in ocular tolerability, yet the benefits from switching from once-a-day preserved to PF therapy, accrue several months later.4 Longer term transition to alternatively preserved, or PF formulations improves tolerability, and there is good evidence that substituting PF tafluprost for BAK-containing latanoprost significantly improves tolerability.3 So sh...
In their review and meta-analysis, Hedengran and coworkers1 report no relative therapeutic benefit of preservative-free (PF) therapies over benzalkonium chloride (BAK)-preserved ones. Should the costlier PF medications therefore be abandoned, or should we question this conclusion?
Ten of the 16 comparative trials analysed were of short duration, (between 15 and 90 days), the longest taking 6 months. Once-a-day medication was used in each trial, yet the dose response curve for BAK toxicity shows that each additional drop of BAK-containing medication doubles the likelihood of lissamine green corneal staining2 and increases the risk of early failure of glaucoma surgery.3 BAK toxicity is slow in onset increasing over time, due to its continual accumulation within ocular tissues.3 Thus, inconsistencies between experimental studies, which document the harmful effects of BAK and clinical trials, which do not, likely relate to the timing, dosing and duration of glaucoma therapy.4 Two to 12 week trials comparing BAK with alternatively preserved eyedrops, or PF formulations have shown no convincing differences in ocular tolerability, yet the benefits from switching from once-a-day preserved to PF therapy, accrue several months later.4 Longer term transition to alternatively preserved, or PF formulations improves tolerability, and there is good evidence that substituting PF tafluprost for BAK-containing latanoprost significantly improves tolerability.3 So short duration studies are unlikely to reveal substantive differences.4
Several methodological issues within this systematic review merit consideration. First, there is no protocol registration, which questions its transparency. Such protocols safeguard against biased post hoc decisions in review methods, such as selective outcome reporting. Second, there is no flow diagram presenting the process of report selection. Third, cross-over trials were considered as parallel in this meta-analysis, leading to a unit-of-analysis error, which should be avoided. Appropriate unbiased methodology does exist to impute within-patient differences to incorporate cross-over trials into a meta-analysis.5 Fourth, there was no risk-of-bias assessment across studies, such as a funnel plot and an asymmetry test, to elicit evidence of publication bias. A risk-of-bias in individual studies’ evaluation was performed utilizing an old Cochrane tool. Recently, a revised Cochrane risk-of-bias tool (the RoB 2.0) for randomized trials has been introduced, and is now the preferred option.6 Last but not least every meta-analysis should include the GRADE approach for grading the strength and quality of evidence.
Unfortunately, this review and most published literature focus on mild glaucoma therapy-related ocular surface disease (GTR-OSD). The dosing and number of IOP-lowering medications needed for glaucoma control increase with disease duration so studies to determine the optimal formulations needed to avert longer term moderate/severe GTR-OSD are sorely needed.3 We agree with the authors’ statement that the “study lengths are short, especially in the context of BAK-preserved eyedrop use often being lifelong”, but are unable to accept the conclusion that BAK-containing and PF medications do not differ with respect to tolerability and therapy outcome.
Anastasios G. Konstas1, Gábor Holló2, Andreas Katsanos3, Konstadinos G. Boboridis1, Anna-Bettina Haidich4, Gordon N. Dutton5.
1: 1st and 3rd University Departments of Ophthalmology, Aristotle University of Thessaloniki, Thessaloniki, Greece;
2: Tutkimusz Ltd and Eye Center, Prima Medica Health Centers, Budapest, Hungary;
3: Ophthalmology Department, University of Ioannina, Ioannina, Greece;
4: Department of Hygiene, Social-Preventive Medicine & Medical Statistics, School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece;
5: Department of Ophthalmology, Caledonian University, Glasgow, UK.
Correspondence to: Anastasios G. Konstas, 1st and 3rd University Departments of Ophthalmology, Aristotle University of Thessaloniki, Thessaloniki, Greece; email: agkonstas@gmail.com
References
1. Hedengran A, Steensberg AT, Virgili G, Azuara-Blanco A, Kolko M. Efficacy and safety evaluation of benzalkonium chloride preserved eye-drops compared with alternatively preserved and preservative-free eye-drops in the treatment of glaucoma: a systematic review and meta-analysis. Br J Ophthalmol 2020;104:1512-18.
2. Leung EW, Medeiros FA, Weinreb RN. Prevalence of ocular surface disease in glaucoma patients. J Glaucoma 2008;17:350–5.
3. Konstas AGP, Labbe A, Katsanos A et al. The treatment of glaucoma using topical preservative-free agents: an evaluation of safety and tolerability. Expert Opin Drug Saf 2021;20:453-66.
4. Rasmussen CA, Kaufman PL, Kiland JA. Benzalkonium chloride and glaucoma. J Ocul Pharmacol Ther 2014;30:163–9.
5. Elbourne DR, Altman DG, Higgins JP et al. Meta-analyses involving cross-over trials: methodological issues. Int J Epidemiol 2002;31:140-9.
6. Sterne JAC, Savović J, Page MJ et al. RoB 2: a revised tool for assessing risk of bias in randomised trials. BMJ 2019;366:l4898.
In your interesting paper dealing with the incidence of rhegmatogenous retinal detachment in France, you report the highest incidence rate so far together with Gout et al 1. It is almost twice as high as the incidence found in our area 2. You also report that this incidence was highest in Guadeloupe (28.30±2.74 per 100000 population) and lowest in French Guiana (15.51±3.50 per 100000 population).
Peters 3 investigated the incidence of RRD in black people and found that it was much lower (0.46/100,000 inhabitants) than in whites. Foos et al. 4 also found that there were no differences in the number of breaks or the proportion/ percentage of vitreous detachments between black and white people, suggesting a stronger adherence in their retinal pigmentary epithelium in the former. Given the fact that black subjects present higher levels of melanin, they have greater resistance against solar radiation, in the same way that they present a lower incidence of non-melanoma skin cancer due to this protective factor 5. Similarly, there is a lower risk of RRD in very dark-colored iris 6 subjects, possibly due to the same reason, as a smaller amount of solar radiation, which has been found to be associated with RRD 7 enters the eye. Taking into account that 70-90% of the population in the French Antilles are mulattoes or creoles (source: indexmundi.com), the lower incidence detected in this geographical location is not surprising. However, we encourage the authors to investigate...
In your interesting paper dealing with the incidence of rhegmatogenous retinal detachment in France, you report the highest incidence rate so far together with Gout et al 1. It is almost twice as high as the incidence found in our area 2. You also report that this incidence was highest in Guadeloupe (28.30±2.74 per 100000 population) and lowest in French Guiana (15.51±3.50 per 100000 population).
Peters 3 investigated the incidence of RRD in black people and found that it was much lower (0.46/100,000 inhabitants) than in whites. Foos et al. 4 also found that there were no differences in the number of breaks or the proportion/ percentage of vitreous detachments between black and white people, suggesting a stronger adherence in their retinal pigmentary epithelium in the former. Given the fact that black subjects present higher levels of melanin, they have greater resistance against solar radiation, in the same way that they present a lower incidence of non-melanoma skin cancer due to this protective factor 5. Similarly, there is a lower risk of RRD in very dark-colored iris 6 subjects, possibly due to the same reason, as a smaller amount of solar radiation, which has been found to be associated with RRD 7 enters the eye. Taking into account that 70-90% of the population in the French Antilles are mulattoes or creoles (source: indexmundi.com), the lower incidence detected in this geographical location is not surprising. However, we encourage the authors to investigate the reasons why this is not so in Guadeloupe as it might provide valuable information as to the factors influencing retinal detachment incidence in this region and globally.
1. Gout I, Mellington F, Tah V, Sarhan M, Rokerya S, Goldacre M, et al. Retinal Detachment - An Update of the Disease and Its Epidemiology - A Discussion Based on Research and Clinical Experience at the Prince Charles Eye Unit, Windsor, England, Advances in Ophthalmology 2012; 341-356
2. Sevillano C, Viso E, Moreira-Martínez S, Blanco MJ, Parafita-Fernández A, Sampil M, Gude F. Incidence and epidemiological characteristics of rhegmatogenous retinal detachment in Northwestern Spain.. Eye (Lond). 2021 Jan 8. doi: 10.1038/s41433-020-01200-7
3. Peters AL. Retinal detachment in black South Africans. S Afr Med J. 1995 Mar;85(3):158–9.
4. Foos RY, Simons KB, Wheeler NC. Comparison of lesions predisposing to rhegmatogenous retinal detachment by race of subjects. Am J Ophthalmol. 1983 Nov;96(5):644–9
5. Fajuyigbe D, Young AR. The impact of skin colour on human photobiological responses. Pigment Cell Melanoma Res. 2016 Nov;29(6): 607–18.
6. Risk factors for idiopathic rhegmatogenous retinal detachment. The Eye Disease Case Control Study Group. Am J Epidemiol. 1993 Apr;137(7):749–57.
7. Sevillano C, Viso E, Moreira-Martínez S, Blanco MJ, Gude F. Rhegmatogenous retinal detachment and solar radiation in northwestern Spain. Ophthalmologica 2020;243(1):51-57.
We read with interest the recent article by Evans et al regarding outcomes in randomised control trial of multifocal lenses in cataract surgery, and their case for development of a core outcome set.1 We wholeheartedly agree that a set of core outcomes would be hugely beneficial to multifocal intraocular lens (MIOL) studies, as there is such variation in multifocal studies currently. This has been commented on by previous Cochrane reviews2 yet there remains no consensus. Such variability makes meaningful comparison between studies difficult.
Evans’ suggests that the minimum data collected in MIOL studies should be unaided and corrected distance and near LogMAR acuity and contrast sensitivity. Also, the use of a questionnaire for patient reported outcomes that must include questions relating to spectacle independence and halos/glare.
Whilst we agree with the above measures, we feel that perhaps such a minimum data set may be insufficient particularly as it fails to address intermediate vision. We would recommend the inclusion of a defocus profile that covers distance, intermediate and near ranges. In addition, a standardised method of defocus measurement3 and analysis.4 This could be used as an adjunct to conventional visual acuity testing or indeed as a replacement. MIOLs have different add powers and light distribution profiles; consequently the choice of testing distance for near and intermediate acuity measures has a profound impact on results and hence may n...
We read with interest the recent article by Evans et al regarding outcomes in randomised control trial of multifocal lenses in cataract surgery, and their case for development of a core outcome set.1 We wholeheartedly agree that a set of core outcomes would be hugely beneficial to multifocal intraocular lens (MIOL) studies, as there is such variation in multifocal studies currently. This has been commented on by previous Cochrane reviews2 yet there remains no consensus. Such variability makes meaningful comparison between studies difficult.
Evans’ suggests that the minimum data collected in MIOL studies should be unaided and corrected distance and near LogMAR acuity and contrast sensitivity. Also, the use of a questionnaire for patient reported outcomes that must include questions relating to spectacle independence and halos/glare.
Whilst we agree with the above measures, we feel that perhaps such a minimum data set may be insufficient particularly as it fails to address intermediate vision. We would recommend the inclusion of a defocus profile that covers distance, intermediate and near ranges. In addition, a standardised method of defocus measurement3 and analysis.4 This could be used as an adjunct to conventional visual acuity testing or indeed as a replacement. MIOLs have different add powers and light distribution profiles; consequently the choice of testing distance for near and intermediate acuity measures has a profound impact on results and hence may not reflect visual function accurately. The use of a defocus curve is more robust to the variations between lenses and provides vital information for clinicians looking to assess the performance of the MIOL.
Finally, Evans suggests a post-operative interval of 6-18 months, and we entirely support the need for a long-term follow-up interval, yet feel it is beneficial to include a short-term follow-up also (<6 months) to allow for comparison and documentation of changes to measures, such as contrast sensitivity, which have been shown to improve with time5
References
1. Evans JR, de Silva SR, Ziaei M, Kirthi V, Leyland MD. Outcomes in randomised controlled trials of multifocal lenses in cataract surgery: the case for development of a core outcome set. Br J Ophthalmol. 2020;104(10):1345-1349.
2. de Silva SR, Evans JR, Kirthi V, Ziaei M, Leyland M. Multifocal versus monofocal intraocular lenses after cataract extraction. Cochrane Database Syst Rev. 2016;12:CD003169.
3. Gupta N, Wolffsohn JS, Naroo SA. Optimizing measurement of subjective amplitude of accommodation with defocus curves. J Cataract Refract Surg. 2008;34(8):1329-1338.
4. Buckhurst PJ, Wolffsohn JS, Naroo SA, et al. Multifocal intraocular lens differentiation using defocus curves. Invest Ophthalmol Vis Sci. 2012;53(7):3920-3926.
5. Law EM, Aggarwal RK, Buckhurst H, et al. Visual function and subjective perception of vision after bilateral implantation of monofocal and multifocal IOLs: a randomized controlled trial. J Cataract Refract Surg. 2020;46(7):1020-1029.
Chua et al,[1] used the UK Biobank to identify an association between higher levels of air pollution and increased odds of age-related macular degeneration (AMD). We hypothesize that exposure to high levels of the air pollutant, lead, before 2000, while gasoline contained lead, may play a role in this observed relationship.
Lead is a toxic heavy metal pollutant that can accumulate in various tissues in the body, including the retina and bones.[2] Lead exposure can induce inflammation and oxidative stress, processes that can be harmful for the eye.[2]
Various studies have indicated a link between lead exposure and AMD. An autopsy study reported 50% higher lead levels in AMD-affected eyes than controls’ eyes.[2] A doubling of blood lead levels (BLL) in the Beaver Dam Offspring Study was associated with 60% greater risk of 5-year incident AMD.[3] Analyses of a nationally representative Korean survey found 25% higher odds of late AMD per 1 μg/dl increase in BLL.[4]
In the late 1970s, mean BLLs were 12 μg/dl higher than today, primarily due to exposure from leaded gasoline.[5] BLLs were even higher among those living close to major roads. Once inhaled, lead can deposit in bones, with a half-life of up to 49 years.[5] While the concentration of lead in air decreased dramatically after lead was removed from gasoline, the lead that has accumulated in bones is slowly released, resulting in persistent endogenous exposure which may negativel...
Chua et al,[1] used the UK Biobank to identify an association between higher levels of air pollution and increased odds of age-related macular degeneration (AMD). We hypothesize that exposure to high levels of the air pollutant, lead, before 2000, while gasoline contained lead, may play a role in this observed relationship.
Lead is a toxic heavy metal pollutant that can accumulate in various tissues in the body, including the retina and bones.[2] Lead exposure can induce inflammation and oxidative stress, processes that can be harmful for the eye.[2]
Various studies have indicated a link between lead exposure and AMD. An autopsy study reported 50% higher lead levels in AMD-affected eyes than controls’ eyes.[2] A doubling of blood lead levels (BLL) in the Beaver Dam Offspring Study was associated with 60% greater risk of 5-year incident AMD.[3] Analyses of a nationally representative Korean survey found 25% higher odds of late AMD per 1 μg/dl increase in BLL.[4]
In the late 1970s, mean BLLs were 12 μg/dl higher than today, primarily due to exposure from leaded gasoline.[5] BLLs were even higher among those living close to major roads. Once inhaled, lead can deposit in bones, with a half-life of up to 49 years.[5] While the concentration of lead in air decreased dramatically after lead was removed from gasoline, the lead that has accumulated in bones is slowly released, resulting in persistent endogenous exposure which may negatively impact AMD.[5]
Future investigations into AMD would benefit from attempts to untangle the contribution of historic lead exposure from current PM2.5 and NOx exposure. Possible strategies include assessment of subjects’ bone lead levels and the use of historic regional air lead pollution data, in conjunction with current air pollutant information. Clarity on the relative contribution of lead versus other pollutants may inform future interventions.
References:
1. Chua SYL, Warwick A, Peto T, et al. Association of ambient air pollution with age-related macular degeneration and retinal thickness in UK Biobank, Br J Ophthalmol 2021.
2. Erie JC, Good JA, Butz JA. Excess lead in the neural retina in age-related macular degeneration, Am J Ophthalmol 2009;148:890-4.
3. Cruickshanks KJ. Generational Differences in Lifetime Exposure to Lead and the Decreasing Incidence of Age-Related Macular Degeneration—Reply, JAMA ophthalmol 2018;136:958-9.
4. Park SJ, Lee JH, Woo SJ, et al. Five heavy metallic elements and age-related macular degeneration: Korean National Health and Nutrition Examination Survey, 2008–2011, Ophthalmology 2015;122:129-37.
5. Fuller-Thomson E, Deng Z. Could lifetime lead exposure play a role in limbic-predominant age-related TDP-43 encephalopathy (LATE)? J Alzheimer's Dis 2020;73:455-9.
Reply to the comment on: “Influence of corneal guttae and nuclear cataract on contrast sensitivity”
We thank Sanjay V Patel for the comments. Patients with Fuchs endothelial corneal dystrophy (FECD) are known to have reduced contrast sensitivity due to corneal edema and guttae. Before the introduction of endothelial keratoplasty, penetrating keratoplasty had been performed mainly in patients with advanced FECD and clinically significant corneal edema. However, as endothelial keratoplasty procedures such as Descemet membrane endothelial keratoplasty can bring excellent visual acuity outcomes, surgery can be performed earlier and even in cases without any clinical corneal edema. Therefore, it has become even more important to detect the causes of visual impairment in patients with FECD. In our retrospective study, we enrolled FECD patients with >5 mm of confluent guttae and no corneal edema (modified Krachmer grade 5). When analyzed by Scheimpflug tomography, our FECD patients showed no difference in the central corneal thickness and corneal volume when compared to the control group of cataract patients without any corneal pathologies.1 Recently, Sun et al. presented a new method to detect subclinical corneal edema in patients with FECD.2,3 The authors analyzed three Scheimpflug tomography pachymetry map and posterior elevation map patterns to detect subclinical edema in FECD patients: loss of regular isopachs, displacement of the thinnest point of the cornea, and...
Reply to the comment on: “Influence of corneal guttae and nuclear cataract on contrast sensitivity”
We thank Sanjay V Patel for the comments. Patients with Fuchs endothelial corneal dystrophy (FECD) are known to have reduced contrast sensitivity due to corneal edema and guttae. Before the introduction of endothelial keratoplasty, penetrating keratoplasty had been performed mainly in patients with advanced FECD and clinically significant corneal edema. However, as endothelial keratoplasty procedures such as Descemet membrane endothelial keratoplasty can bring excellent visual acuity outcomes, surgery can be performed earlier and even in cases without any clinical corneal edema. Therefore, it has become even more important to detect the causes of visual impairment in patients with FECD. In our retrospective study, we enrolled FECD patients with >5 mm of confluent guttae and no corneal edema (modified Krachmer grade 5). When analyzed by Scheimpflug tomography, our FECD patients showed no difference in the central corneal thickness and corneal volume when compared to the control group of cataract patients without any corneal pathologies.1 Recently, Sun et al. presented a new method to detect subclinical corneal edema in patients with FECD.2,3 The authors analyzed three Scheimpflug tomography pachymetry map and posterior elevation map patterns to detect subclinical edema in FECD patients: loss of regular isopachs, displacement of the thinnest point of the cornea, and presence of posterior surface depression may help identify subclinical corneal edema more accurately in patients with FECD. In our study, the loss of regular isopachs (12/25 [48%] vs. 4/25 [16%]), the displacement of the thinnest point of the cornea (11/25 [44%] vs. 1/25 [4%]), and the posterior surface depression (13/25 [52%] vs. 8/25 [32%]) could be found more frequently in FECD patients, than in the control group without corneal pathology. Eleven of the 25 FECD patients (44%) met at least two of the three criteria, implying the presence of a subclinical corneal edema. However, the preoperative MARS letter contrast sensitivity of these 11 patients (contrast sensitivity: 0.98 ± 0.13 logCS) did not show any statistically significant difference compared to that of the other 14 FECD patients (contrast sensitivity: 1.02 ± 0.09 logCS; p=0.47) in whom the aforementioned criteria were not met. Interestingly, two of the three criteria were also met in 4 cases (16%) of the control group. Indeed, future studies should also include the analysis of these patterns when assessing the contrast sensitivity in FECD patients.
1Augustin VA, Weller JM, Kruse FE, Tourtas T. Influence of corneal guttae and nuclear cataract on contrast sensitivity. Br J Ophthalmol 2020.
2Sun SY, Wacker K, Baratz KH, Patel SV. Determining Subclinical Edema in Fuchs Endothelial Corneal Dystrophy. Revised Classification using Scheimpflug Tomography for Preoperative Assessment. Ophthalmology 2019;126:195-204.
3Patel SV, Hodge DO, Treichel EJ, Spiegel MR, Baratz KH. Predicting the Prognosis of Fuchs Endothelial Corneal Dystrophy by using Scheimpflug Tomography. Ophthalmology 2020;127:315-323.
I read with interest the paper by Gagrani and colleagues, regarding the self-characterisation of visual field loss by glaucoma patients, and the development of an app to allow this to be measured.1
The study helps to further understand the experience of glaucoma patients. Their experimental results support the view that patients experience their visual field defects as blur rather than 'black holes'. Hu et al found the most common subjective symptoms in glaucoma were "needing more light" (57%) and "blurry vision" (55%).2 In the study by Gagrani et al., subjects were able to modify both dimness and blur, though in practice they did not choose to use the dimness response at all.
It is possible that differences in the measurement tools might potentially influence these findings. For example, patients may have found the dim response more difficult to use.
The potential for this app to allow patients to better understand and self-pictoralise their visual disability is poignant and important. It will be interesting to see whether this novel approach yields similar results when replicated in future.
References
1. Gagrani M, Ndulue J, Anderson D, Kedar S, Gulati V, Shepherd J, et al. What do patients with glaucoma see: a novel iPad app to improve glaucoma patient awareness of visual field loss. Br J Ophthalmol. 2020 Nov 20.
2. Hu CX, Zangalli C, Hsieh M, et al. What do patients with glaucoma see? Visual symptoms...
I read with interest the paper by Gagrani and colleagues, regarding the self-characterisation of visual field loss by glaucoma patients, and the development of an app to allow this to be measured.1
The study helps to further understand the experience of glaucoma patients. Their experimental results support the view that patients experience their visual field defects as blur rather than 'black holes'. Hu et al found the most common subjective symptoms in glaucoma were "needing more light" (57%) and "blurry vision" (55%).2 In the study by Gagrani et al., subjects were able to modify both dimness and blur, though in practice they did not choose to use the dimness response at all.
It is possible that differences in the measurement tools might potentially influence these findings. For example, patients may have found the dim response more difficult to use.
The potential for this app to allow patients to better understand and self-pictoralise their visual disability is poignant and important. It will be interesting to see whether this novel approach yields similar results when replicated in future.
References
1. Gagrani M, Ndulue J, Anderson D, Kedar S, Gulati V, Shepherd J, et al. What do patients with glaucoma see: a novel iPad app to improve glaucoma patient awareness of visual field loss. Br J Ophthalmol. 2020 Nov 20.
2. Hu CX, Zangalli C, Hsieh M, et al. What do patients with glaucoma see? Visual symptoms reported by patients with glaucoma. Am J Med Sci 2014;348:403–9.
Luzia Diegues Silva MD1, Albert Santos MD1, Flávio Eduardo Hirai MD. Ph.D1, Norma Allemann MD1,2, Adriana Berezovsky Ph.D1, Solange Rios Salomão Ph.D1, Paulo Ricardo Chaves de Oliveira MD1, Gabriel Costa de Andrade MD1, Andre Maia MD1, Luciene Barbosa de Sousa MD1, Lauro Augusto de Oliveira MD. Ph.D.1,*
1 Department of Ophthalmology and Visual Sciences, Federal University of São Paulo, Brazil
2 Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, USA
Corresponding author: Lauro Augusto de Oliveira
Dear Editor,
We read with interest the comments about our article by Anchouche and associates.
We agree with the authors that B-scan ultrasonography is widely accepted as the gold-standard preoperative imaging modality used to assess the posterior segment in eyes with severe and dense anterior segment opacities and it has been proven to be a useful tool in the preoperative evaluation of Kpro candidates. We also agree that it is safer, cheaper and a less invasive procedure when compared to VE. However, this image modality offers mostly anatomical information and less functional prognosis prediction when compared to direct visualization of the posterior segment achieved with VE.[1]
We are aware and agree with the authors’ concern regarding the invasive nature, the risk of elevated intraocular pressure, and cataract formation as discussed in our work. However, as it is clearly described in our manuscript,...
Luzia Diegues Silva MD1, Albert Santos MD1, Flávio Eduardo Hirai MD. Ph.D1, Norma Allemann MD1,2, Adriana Berezovsky Ph.D1, Solange Rios Salomão Ph.D1, Paulo Ricardo Chaves de Oliveira MD1, Gabriel Costa de Andrade MD1, Andre Maia MD1, Luciene Barbosa de Sousa MD1, Lauro Augusto de Oliveira MD. Ph.D.1,*
1 Department of Ophthalmology and Visual Sciences, Federal University of São Paulo, Brazil
2 Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, USA
Corresponding author: Lauro Augusto de Oliveira
Dear Editor,
We read with interest the comments about our article by Anchouche and associates.
We agree with the authors that B-scan ultrasonography is widely accepted as the gold-standard preoperative imaging modality used to assess the posterior segment in eyes with severe and dense anterior segment opacities and it has been proven to be a useful tool in the preoperative evaluation of Kpro candidates. We also agree that it is safer, cheaper and a less invasive procedure when compared to VE. However, this image modality offers mostly anatomical information and less functional prognosis prediction when compared to direct visualization of the posterior segment achieved with VE.[1]
We are aware and agree with the authors’ concern regarding the invasive nature, the risk of elevated intraocular pressure, and cataract formation as discussed in our work. However, as it is clearly described in our manuscript, the VE test was performed perioperatively and did not hinder the surgical decision to proceed with KPro surgery. There was no additional anesthesia risk. Cataract formation was not a concern in this scenario because all Kpro candidates in our series would have their lens removed.
The study does have limitations such as the sample size. But this series allowed for an overall better understanding of the endoscopic findings and their usefulness, particularly with the comparative metrics between the preoperative data and postoperative results.
Optimizing the use of keratoprosthesis as an alternative for corneal blindness is challenging in contexts in which the device is not available or affordable. This is a difficult decision faced by surgeons daily, especially in limited-resource settings such as ours. We will continue to investigate strategies for predicting prognosis to allow us to be more precise in the selection of treatment. We agree with the authors that our findings should not be over-generalized. Ideally one cannot deny keratoprosthesis implantation based on unfavourable findings noted on videoendoscopy, but regarding prognostication, we would counsel these patients on potential visual outcomes.
1. Farias CC, Ozturk HE, Albini TA, et al. Use of intraocular video endoscopic examination in the preoperative evaluation of keratoprosthesis surgery to assess visual potential. Am J Ophthalmol 2014;158:80-6.
We were intrigued by the study by Yang et al[1] recently published in the British Journal of Ophthalmology. They conducted a detailed analysis of the fundus screening results of 5606 infants over 5 years in tertiary neonatal intensive care units (NICUs) in four medical centres in Shanghai, China. They found the detection rate of retinopathy of prematurity (ROP)to be 15.9%, and the detection rate of type 1 ROP (1.1%) was lower than that previously reported. The mean gestational age (GA) and birth weight (BW) of infants with ROP have also decreased. Therefore, they suggest modifying the criteria of Chinese ROP screening to GA <32 weeks or BW <1600 g. Application of these criteria to the studied cohort yielded a 98.4% sensitivity, with the infants requiring fundus screening reduced by 43.2%. Therefore, these criteria would reduce medical costs significantly. This is of great significance to the screening and treatment of ROP in China, which has a huge population and regional medical resource imbalances.
However, the study also had issues that need further discussion. First, the patient cohort was not a continuous population-based cohort, and the authors did not clearly state the specific criteria for screening. Therefore, the rate could be the detection rate rather than the true incidence. In addition, the development and general conditions of these patients from NICUs are significantly different from those of the general population. Therefore, although it was a r...
We were intrigued by the study by Yang et al[1] recently published in the British Journal of Ophthalmology. They conducted a detailed analysis of the fundus screening results of 5606 infants over 5 years in tertiary neonatal intensive care units (NICUs) in four medical centres in Shanghai, China. They found the detection rate of retinopathy of prematurity (ROP)to be 15.9%, and the detection rate of type 1 ROP (1.1%) was lower than that previously reported. The mean gestational age (GA) and birth weight (BW) of infants with ROP have also decreased. Therefore, they suggest modifying the criteria of Chinese ROP screening to GA <32 weeks or BW <1600 g. Application of these criteria to the studied cohort yielded a 98.4% sensitivity, with the infants requiring fundus screening reduced by 43.2%. Therefore, these criteria would reduce medical costs significantly. This is of great significance to the screening and treatment of ROP in China, which has a huge population and regional medical resource imbalances.
However, the study also had issues that need further discussion. First, the patient cohort was not a continuous population-based cohort, and the authors did not clearly state the specific criteria for screening. Therefore, the rate could be the detection rate rather than the true incidence. In addition, the development and general conditions of these patients from NICUs are significantly different from those of the general population. Therefore, although it was a relatively representative multi-centre study, these results may not fully represent the incidence in the whole region. More population-based studies on ROP screening in a wider area could supplement and enrich the data of this study, which would provide a more comprehensive and clearer assessment of the incidence of ROP in Shanghai and China.
Second, this was a retrospective study. The authors mentioned that the results could be used as a reliable basis to improve the ROP screening guideline in China, which is insufficiently rigorous. Recent reports show that more mature infants and those with a higher BW are also at risk of developing severe ROP in developing countries [2, 3]. Dou et al [4] reported 20 cases of stage 5 ROP in north-western China, among whom 2 had GA >34 weeks and 4 had BW >2000 g. A prospective study in two medical centres in Shanghai found that if their criteria (GA ≤33 weeks or BW ≤1750 g) were adopted, any infant with ROP who needed treatment would be identified, and the number of infants needing examinations could be reduced by 16.9%[5]. If further prospective observations were conducted to examine the criteria recommended in this study (GA <32 weeks or BW <1600 g) and take the current guideline as a control, it would be more convincing.
Finally, many paediatric patients are referred to Shanghai from neighbouring areas. The investigators did not specify whether the infants were first screened in their medical centres or other hospitals. Therefore, the selection bias of the study could not be evaluated, which weakened the credibility of the results. If the authors could further explain the source and regional distribution of the participants, the results would be more convincing.
Liang Wang, Zifeng Zhang, Manhong Li, Yusheng Wang
Department of Ophthalmology, Eye Institute of Chinese PLA, Xijing Hospital, Fourth Military Medical University, Xi’an 710032, China
Correspondence to Zifeng Zhang, Department of Ophthalmology, Eye Institute of Chinese PLA, Xijing Hospital, Fourth Military Medical University, Xi’an 710032, China; Email: zzffmmu@163.com; Yusheng Wang, Department of Ophthalmology, Eye Institute of Chinese PLA, Xijing Hospital, Fourth Military Medical University, Xi’an 710032, China; Email: wangys003@126.com
Funding Grants from the National Natural Science Foundation of China (81770936)
References
1 Yang Q, Zhou X, Ni Y, et al. Optimised retinopathy of prematurity screening guideline in China based on a 5-year cohort study. Br J Ophthalmol, doi: 1136/bjophthalmol-2020-316401
2 Zhang Z, Li M, Wang Y, et al. Analysis of retinopathy of prematurity with birth weight higher than 2 kg in Xi'an area. Chin J Ophthalmol 2014;50:184-8.
3 Chen Y, Li X. Characteristics of severe retinopathy of prematurity patients in China: a repeat of the first epidemic? Br J Ophthalmol 2006;90:268-71.
4 Dou G, Li M, Zhang Z, et al. Demographic profile and ocular characteristics of stage 5 retinopathy of prematurity at a referral center in Northwest China: implications for implementation. BMC Ophthalmol 2018;18. doi: 10.1186/s12886-018-0975-z
5 Xu Y, Zhou X, Zhang Q, et al. Screening for retinopathy of prematurity in China: a neonatal units-based prospective study. Invest Ophthalmol Vis Sci 2013;54:8229-36
We read with interest the study by Silva and colleagues.[1] The authors investigate the prognostic potential of B-scan ultrasonography, visual electrophysiology and perioperative videoendoscopy (VE) for 13 patients undergoing keratoprosthesis (KPro) surgery and identified perioperative intraocular VE as a predictor of functional visual outcome at 1-year follow-up.[1] While we find this study interesting, we would like to caution against the interpretation and over-generalization of the findings reported therein.
Negative predictive value (NPV) was as defined as the number of patients with abnormal VE findings and subsequent unsatisfactory visual acuity over all patients with unfavourable VE. The authors report a NPV of 50% in 10 patients. By contrast, they report a positive predictive value (PPV) of 100% for this test.[1] Although a high PPV, as reported by the authors, is of great importance when deciding which patients are appropriate KPro candidates preoperatively, once the patient is undergoing surgery, we believe identifying patients at highest risk of poor visual outcome using NPV is more clinically relevant. The small sample size of 10 patients with a low prevalence of patients with unsatisfactory post-operative visual acuity, and NPV of 50% are important limitations of this study. From these findings, we are unable to justify VE's clinical benefit to the surgeon and their patient at the time of surgery. This is especially true give...
We read with interest the study by Silva and colleagues.[1] The authors investigate the prognostic potential of B-scan ultrasonography, visual electrophysiology and perioperative videoendoscopy (VE) for 13 patients undergoing keratoprosthesis (KPro) surgery and identified perioperative intraocular VE as a predictor of functional visual outcome at 1-year follow-up.[1] While we find this study interesting, we would like to caution against the interpretation and over-generalization of the findings reported therein.
Negative predictive value (NPV) was as defined as the number of patients with abnormal VE findings and subsequent unsatisfactory visual acuity over all patients with unfavourable VE. The authors report a NPV of 50% in 10 patients. By contrast, they report a positive predictive value (PPV) of 100% for this test.[1] Although a high PPV, as reported by the authors, is of great importance when deciding which patients are appropriate KPro candidates preoperatively, once the patient is undergoing surgery, we believe identifying patients at highest risk of poor visual outcome using NPV is more clinically relevant. The small sample size of 10 patients with a low prevalence of patients with unsatisfactory post-operative visual acuity, and NPV of 50% are important limitations of this study. From these findings, we are unable to justify VE's clinical benefit to the surgeon and their patient at the time of surgery. This is especially true given the invasive nature, cost and associated complications of this ancillary test. In addition to the risk of elevated intraocular pressure and cataract formation as outlined by the authors, the use of perioperative VE increases the risk of iatrogenic retinal tears, vitreous hemorrhage, and wound leaks,[2] not to mention the risk of retrobulbar anaesthesia,[3] all of which are morbid complications in KPro eyes. Moreover, 23% of the patient cohort (n=3) were excluded from analysis due to technical issues relating to perioperative VE. This highlights the additional challenges this ancillary test may present to the surgeon and their team.
Although prognosticating the visual outcomes of KPro and identifying which patients are at highest risk of KPro failure remain important areas of research and discussion, we believe the data presented by the authors are insufficient to position VE as a predictive perioperative ancillary test and urge readers to consider the associated risks to the patient and medical costs to the healthcare system. B-scan ultrasonography is widely accepted as the gold-standard preoperative imaging modality used to assess the posterior segment in eyes with severe and dense anterior segment opacities.[4] After reading this study, we believe that B-scan ultrasonography remains the method of choice for KPro preoperative evaluations.
References:
1. Silva, L. D. et al. B-scan ultrasound, visual electrophysiology and perioperative videoendoscopy for predicting functional results in keratoprosthesis candidates. Br. J. Ophthalmol. (2020).
2. Nagiel, A. et al. VISUAL AND ANATOMIC OUTCOMES OF PEDIATRIC ENDOSCOPIC VITRECTOMY IN 326 CASES. Retina (2020).
3. Hamilton, R. C. A discourse on the complications of retrobulbar and peribulbar blockade. Can. J. Ophthalmol. (2000).
4. Williamson, S. L. & Cortina, M. S. Boston type 1 keratoprosthesis from patient selection through postoperative management: A review for the keratoprosthetic surgeon. Clinical Ophthalmology (2016).
Recently, Lam et al. [1] concluded that patients with macular pucker and foveoschisis had a higher risk of postoperative macular oedema. Since only 5/17 cases had baseline fluorescein angiography it is unclear how they distinguished foveoschisis due to tangential traction, versus cystoid macular edema (CME). Is it possible that postoperative CME was recurrent and not new? In our experience, resolution of foveoschisis takes much longer than the relatively swift resolution in 25% and partial resolution in 68.8% of cases at 1 month, so perhaps CME was a confounding factor. Indeed, Figure 3 appears more like exudative cyst than ‘foveoschisis’.
Previous studies [2] found that nearly half of patients with macular pucker had multiple centers of retinal contraction which were associated with a higher prevalence of intraretinal cysts and greater macular thickening. Was en face OCT performed to determine the number of contraction centers and its relationship to foveoschisis as well as outcomes of surgery? Additionally, anomalous PVD with vitreoschisis [3] and vitreo-papillary adhesion [4] may be important in the pathogenesis of macular pucker. Did the authors correlate these with foveoschisis and postoperative outcomes?
There was no significant difference in postoperative visual acuity (VA) between the foveoschisis and control groups, but this may not be the best outcome measure in macular pucker surgery. Studies [5] have shown that quantifying contrast sensitivity fu...
Show MoreDear Editor,
In their review and meta-analysis, Hedengran and coworkers1 report no relative therapeutic benefit of preservative-free (PF) therapies over benzalkonium chloride (BAK)-preserved ones. Should the costlier PF medications therefore be abandoned, or should we question this conclusion?
Show MoreTen of the 16 comparative trials analysed were of short duration, (between 15 and 90 days), the longest taking 6 months. Once-a-day medication was used in each trial, yet the dose response curve for BAK toxicity shows that each additional drop of BAK-containing medication doubles the likelihood of lissamine green corneal staining2 and increases the risk of early failure of glaucoma surgery.3 BAK toxicity is slow in onset increasing over time, due to its continual accumulation within ocular tissues.3 Thus, inconsistencies between experimental studies, which document the harmful effects of BAK and clinical trials, which do not, likely relate to the timing, dosing and duration of glaucoma therapy.4 Two to 12 week trials comparing BAK with alternatively preserved eyedrops, or PF formulations have shown no convincing differences in ocular tolerability, yet the benefits from switching from once-a-day preserved to PF therapy, accrue several months later.4 Longer term transition to alternatively preserved, or PF formulations improves tolerability, and there is good evidence that substituting PF tafluprost for BAK-containing latanoprost significantly improves tolerability.3 So sh...
In your interesting paper dealing with the incidence of rhegmatogenous retinal detachment in France, you report the highest incidence rate so far together with Gout et al 1. It is almost twice as high as the incidence found in our area 2. You also report that this incidence was highest in Guadeloupe (28.30±2.74 per 100000 population) and lowest in French Guiana (15.51±3.50 per 100000 population).
Peters 3 investigated the incidence of RRD in black people and found that it was much lower (0.46/100,000 inhabitants) than in whites. Foos et al. 4 also found that there were no differences in the number of breaks or the proportion/ percentage of vitreous detachments between black and white people, suggesting a stronger adherence in their retinal pigmentary epithelium in the former. Given the fact that black subjects present higher levels of melanin, they have greater resistance against solar radiation, in the same way that they present a lower incidence of non-melanoma skin cancer due to this protective factor 5. Similarly, there is a lower risk of RRD in very dark-colored iris 6 subjects, possibly due to the same reason, as a smaller amount of solar radiation, which has been found to be associated with RRD 7 enters the eye. Taking into account that 70-90% of the population in the French Antilles are mulattoes or creoles (source: indexmundi.com), the lower incidence detected in this geographical location is not surprising. However, we encourage the authors to investigate...
Show MoreWe read with interest the recent article by Evans et al regarding outcomes in randomised control trial of multifocal lenses in cataract surgery, and their case for development of a core outcome set.1 We wholeheartedly agree that a set of core outcomes would be hugely beneficial to multifocal intraocular lens (MIOL) studies, as there is such variation in multifocal studies currently. This has been commented on by previous Cochrane reviews2 yet there remains no consensus. Such variability makes meaningful comparison between studies difficult.
Show MoreEvans’ suggests that the minimum data collected in MIOL studies should be unaided and corrected distance and near LogMAR acuity and contrast sensitivity. Also, the use of a questionnaire for patient reported outcomes that must include questions relating to spectacle independence and halos/glare.
Whilst we agree with the above measures, we feel that perhaps such a minimum data set may be insufficient particularly as it fails to address intermediate vision. We would recommend the inclusion of a defocus profile that covers distance, intermediate and near ranges. In addition, a standardised method of defocus measurement3 and analysis.4 This could be used as an adjunct to conventional visual acuity testing or indeed as a replacement. MIOLs have different add powers and light distribution profiles; consequently the choice of testing distance for near and intermediate acuity measures has a profound impact on results and hence may n...
Dear Editor,
Chua et al,[1] used the UK Biobank to identify an association between higher levels of air pollution and increased odds of age-related macular degeneration (AMD). We hypothesize that exposure to high levels of the air pollutant, lead, before 2000, while gasoline contained lead, may play a role in this observed relationship.
Lead is a toxic heavy metal pollutant that can accumulate in various tissues in the body, including the retina and bones.[2] Lead exposure can induce inflammation and oxidative stress, processes that can be harmful for the eye.[2]
Various studies have indicated a link between lead exposure and AMD. An autopsy study reported 50% higher lead levels in AMD-affected eyes than controls’ eyes.[2] A doubling of blood lead levels (BLL) in the Beaver Dam Offspring Study was associated with 60% greater risk of 5-year incident AMD.[3] Analyses of a nationally representative Korean survey found 25% higher odds of late AMD per 1 μg/dl increase in BLL.[4]
In the late 1970s, mean BLLs were 12 μg/dl higher than today, primarily due to exposure from leaded gasoline.[5] BLLs were even higher among those living close to major roads. Once inhaled, lead can deposit in bones, with a half-life of up to 49 years.[5] While the concentration of lead in air decreased dramatically after lead was removed from gasoline, the lead that has accumulated in bones is slowly released, resulting in persistent endogenous exposure which may negativel...
Show MoreReply to the comment on: “Influence of corneal guttae and nuclear cataract on contrast sensitivity”
We thank Sanjay V Patel for the comments. Patients with Fuchs endothelial corneal dystrophy (FECD) are known to have reduced contrast sensitivity due to corneal edema and guttae. Before the introduction of endothelial keratoplasty, penetrating keratoplasty had been performed mainly in patients with advanced FECD and clinically significant corneal edema. However, as endothelial keratoplasty procedures such as Descemet membrane endothelial keratoplasty can bring excellent visual acuity outcomes, surgery can be performed earlier and even in cases without any clinical corneal edema. Therefore, it has become even more important to detect the causes of visual impairment in patients with FECD. In our retrospective study, we enrolled FECD patients with >5 mm of confluent guttae and no corneal edema (modified Krachmer grade 5). When analyzed by Scheimpflug tomography, our FECD patients showed no difference in the central corneal thickness and corneal volume when compared to the control group of cataract patients without any corneal pathologies.1 Recently, Sun et al. presented a new method to detect subclinical corneal edema in patients with FECD.2,3 The authors analyzed three Scheimpflug tomography pachymetry map and posterior elevation map patterns to detect subclinical edema in FECD patients: loss of regular isopachs, displacement of the thinnest point of the cornea, and...
Show MoreI read with interest the paper by Gagrani and colleagues, regarding the self-characterisation of visual field loss by glaucoma patients, and the development of an app to allow this to be measured.1
The study helps to further understand the experience of glaucoma patients. Their experimental results support the view that patients experience their visual field defects as blur rather than 'black holes'. Hu et al found the most common subjective symptoms in glaucoma were "needing more light" (57%) and "blurry vision" (55%).2 In the study by Gagrani et al., subjects were able to modify both dimness and blur, though in practice they did not choose to use the dimness response at all.
It is possible that differences in the measurement tools might potentially influence these findings. For example, patients may have found the dim response more difficult to use.
The potential for this app to allow patients to better understand and self-pictoralise their visual disability is poignant and important. It will be interesting to see whether this novel approach yields similar results when replicated in future.
References
Show More1. Gagrani M, Ndulue J, Anderson D, Kedar S, Gulati V, Shepherd J, et al. What do patients with glaucoma see: a novel iPad app to improve glaucoma patient awareness of visual field loss. Br J Ophthalmol. 2020 Nov 20.
2. Hu CX, Zangalli C, Hsieh M, et al. What do patients with glaucoma see? Visual symptoms...
Luzia Diegues Silva MD1, Albert Santos MD1, Flávio Eduardo Hirai MD. Ph.D1, Norma Allemann MD1,2, Adriana Berezovsky Ph.D1, Solange Rios Salomão Ph.D1, Paulo Ricardo Chaves de Oliveira MD1, Gabriel Costa de Andrade MD1, Andre Maia MD1, Luciene Barbosa de Sousa MD1, Lauro Augusto de Oliveira MD. Ph.D.1,*
1 Department of Ophthalmology and Visual Sciences, Federal University of São Paulo, Brazil
2 Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, USA
Corresponding author: Lauro Augusto de Oliveira
Dear Editor,
We read with interest the comments about our article by Anchouche and associates.
We agree with the authors that B-scan ultrasonography is widely accepted as the gold-standard preoperative imaging modality used to assess the posterior segment in eyes with severe and dense anterior segment opacities and it has been proven to be a useful tool in the preoperative evaluation of Kpro candidates. We also agree that it is safer, cheaper and a less invasive procedure when compared to VE. However, this image modality offers mostly anatomical information and less functional prognosis prediction when compared to direct visualization of the posterior segment achieved with VE.[1]
We are aware and agree with the authors’ concern regarding the invasive nature, the risk of elevated intraocular pressure, and cataract formation as discussed in our work. However, as it is clearly described in our manuscript,...
Show MoreWe were intrigued by the study by Yang et al[1] recently published in the British Journal of Ophthalmology. They conducted a detailed analysis of the fundus screening results of 5606 infants over 5 years in tertiary neonatal intensive care units (NICUs) in four medical centres in Shanghai, China. They found the detection rate of retinopathy of prematurity (ROP)to be 15.9%, and the detection rate of type 1 ROP (1.1%) was lower than that previously reported. The mean gestational age (GA) and birth weight (BW) of infants with ROP have also decreased. Therefore, they suggest modifying the criteria of Chinese ROP screening to GA <32 weeks or BW <1600 g. Application of these criteria to the studied cohort yielded a 98.4% sensitivity, with the infants requiring fundus screening reduced by 43.2%. Therefore, these criteria would reduce medical costs significantly. This is of great significance to the screening and treatment of ROP in China, which has a huge population and regional medical resource imbalances.
Show MoreHowever, the study also had issues that need further discussion. First, the patient cohort was not a continuous population-based cohort, and the authors did not clearly state the specific criteria for screening. Therefore, the rate could be the detection rate rather than the true incidence. In addition, the development and general conditions of these patients from NICUs are significantly different from those of the general population. Therefore, although it was a r...
Dear Editor,
We read with interest the study by Silva and colleagues.[1] The authors investigate the prognostic potential of B-scan ultrasonography, visual electrophysiology and perioperative videoendoscopy (VE) for 13 patients undergoing keratoprosthesis (KPro) surgery and identified perioperative intraocular VE as a predictor of functional visual outcome at 1-year follow-up.[1] While we find this study interesting, we would like to caution against the interpretation and over-generalization of the findings reported therein.
Negative predictive value (NPV) was as defined as the number of patients with abnormal VE findings and subsequent unsatisfactory visual acuity over all patients with unfavourable VE. The authors report a NPV of 50% in 10 patients. By contrast, they report a positive predictive value (PPV) of 100% for this test.[1] Although a high PPV, as reported by the authors, is of great importance when deciding which patients are appropriate KPro candidates preoperatively, once the patient is undergoing surgery, we believe identifying patients at highest risk of poor visual outcome using NPV is more clinically relevant. The small sample size of 10 patients with a low prevalence of patients with unsatisfactory post-operative visual acuity, and NPV of 50% are important limitations of this study. From these findings, we are unable to justify VE's clinical benefit to the surgeon and their patient at the time of surgery. This is especially true give...
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