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).
Kruglyakova, et al recently published an excellent paper about visually pertinent correlation of optic nerve hypoplasia (ONH) with intra-operative photographic measurements1. We recently reported similar findings without subjecting children to general anesthesia if ultra-widefield imaging (OPTOS; Dunfermline, UK) is available2. We agree that a MD/DD ratio greater than 3.22 (≥3.51) is consistent with clinical optic nerve hypoplasia but our direct measure of horizontal optic nerve size was even more predictive utilizing our definition of logMAR for pediatric and low vision patients3. Instead of starting from the temporal edge of the optic nerve to determine MD (macula-disk) distance, we found the center of the optic nerve more uniform. In addition, we have also noted a worrisome relationship between ONH and threshold retinopathy of prematurity4 and wonder if the authors also found any association between the two common pediatric blinding conditions ONH and ROP?
References:
1. Kruglyakova J, Garcia-Filion P, Nelson M, Borchert M. Orbital MRI versus fundus photography in the diagnosis of optic nerve hypoplasia and prediction of vision. Br J Ophthalmol. 2020;104(10):1458-1461.
2. Arnold AW, Eller AM, Smith KA, Grendahl RL, Winkle RK, Arnold RW. Direct nerve size determination and prevalent optic nerve hypoplasia in Alaska. Clin Ophthalmol. 2020;14:491—499.
3. Arnold RW. Digital values for alpha acuities. JPOS. 2020:In Press.
4. Arnold RW. Opti...
Kruglyakova, et al recently published an excellent paper about visually pertinent correlation of optic nerve hypoplasia (ONH) with intra-operative photographic measurements1. We recently reported similar findings without subjecting children to general anesthesia if ultra-widefield imaging (OPTOS; Dunfermline, UK) is available2. We agree that a MD/DD ratio greater than 3.22 (≥3.51) is consistent with clinical optic nerve hypoplasia but our direct measure of horizontal optic nerve size was even more predictive utilizing our definition of logMAR for pediatric and low vision patients3. Instead of starting from the temporal edge of the optic nerve to determine MD (macula-disk) distance, we found the center of the optic nerve more uniform. In addition, we have also noted a worrisome relationship between ONH and threshold retinopathy of prematurity4 and wonder if the authors also found any association between the two common pediatric blinding conditions ONH and ROP?
References:
1. Kruglyakova J, Garcia-Filion P, Nelson M, Borchert M. Orbital MRI versus fundus photography in the diagnosis of optic nerve hypoplasia and prediction of vision. Br J Ophthalmol. 2020;104(10):1458-1461.
2. Arnold AW, Eller AM, Smith KA, Grendahl RL, Winkle RK, Arnold RW. Direct nerve size determination and prevalent optic nerve hypoplasia in Alaska. Clin Ophthalmol. 2020;14:491—499.
3. Arnold RW. Digital values for alpha acuities. JPOS. 2020:In Press.
4. Arnold RW. Optic nerve hypoplasia potentiates retinopathy of prematurity. J Pediatr Ophthalmol Strabismus. 2008;45(4):247-249.
McCann et al. reported factors of the associations with intraocular pressure (IOP) and circumpapillary retinal nerve fibre layer (cRNFL) thickness (1). Increased IOP and reduced cRNFL were associated with increased age, myopic refractive error, male sex and hypertension. In addition, Alzheimer's disease was associated with thinner average global cRNFL, and Parkinson's disease (PD) and current smoking status were associated with thicker average global cRNFL, and I present recent information regarding their study in patients with PD.
Murueta-Goyena et al. reported the association between the changes of retinal thickness and their predictive value as biomarkers of disease progression in idiopathic PD (2). The authors used macular ganglion-inner plexiform layer complex (mGCIPL) and peripapillary retinal nerve fiber layer (pRNFL) thickness reduction rates, and the Montreal Cognitive Assessment (MoCA) questionnaire was also applied. The adjusted relative risks of lower parafoveal mGCIPL and pRNFL thickness at baseline for an increased risk of cognitive decline at 3 years significantly increased. This means that reduced retinal thickness is a risk factor of cognitive impairment in patients with PD. McCann et al. did not evaluate cRNFL in PD patients with cognitive impairment, and I suppose that progression of cognitive impairment in patients with PD might accelerate reduction of average global cRNFL.
Second, Sung et al. also investigated the association be...
McCann et al. reported factors of the associations with intraocular pressure (IOP) and circumpapillary retinal nerve fibre layer (cRNFL) thickness (1). Increased IOP and reduced cRNFL were associated with increased age, myopic refractive error, male sex and hypertension. In addition, Alzheimer's disease was associated with thinner average global cRNFL, and Parkinson's disease (PD) and current smoking status were associated with thicker average global cRNFL, and I present recent information regarding their study in patients with PD.
Murueta-Goyena et al. reported the association between the changes of retinal thickness and their predictive value as biomarkers of disease progression in idiopathic PD (2). The authors used macular ganglion-inner plexiform layer complex (mGCIPL) and peripapillary retinal nerve fiber layer (pRNFL) thickness reduction rates, and the Montreal Cognitive Assessment (MoCA) questionnaire was also applied. The adjusted relative risks of lower parafoveal mGCIPL and pRNFL thickness at baseline for an increased risk of cognitive decline at 3 years significantly increased. This means that reduced retinal thickness is a risk factor of cognitive impairment in patients with PD. McCann et al. did not evaluate cRNFL in PD patients with cognitive impairment, and I suppose that progression of cognitive impairment in patients with PD might accelerate reduction of average global cRNFL.
Second, Sung et al. also investigated the association between retinal thinning and cognitive impairment in patients with PD (3). There were significant reductions in the thickness of average, temporal, and inferior pRNFL and overall mGCIPL in patients with PD, and the MoCA score was significantly associated with mGCIPL thinning. As the thinning of the mGCIPL was also significantly associated with the volumetric parameters of some brain structures, the relationship between retinal thickness and brain structures in patients with PD should be comprehensively evaluated with special reference to the level of cognitive impairment.
Finally, Matlach et al. reported that thinning of some retinal layers of the ipsilateral eye was observed in the most-affected body side of PD patients (4). In addition, thickness of pRNFL and mGCIPL did not correlate to the severity of PD. As Murueta-Goyena et al. reported that there was no significant association between retinal thickness and motor deterioration (2), the discrepancy in the relationship of cognitive decline and motor deterioration with retinal thickness might be related to the lack of relationship between retinal thickness and the severity of PD.
References
1. McCann P, Hogg R, Wright DM, et al. Intraocular pressure and circumpapillary retinal nerve fibre layer thickness in the Northern Ireland Cohort for the Longitudinal Study of Ageing (NICOLA): distributions and associations. Br J Ophthalmol. 2020 Jul 30 doi: 10.1136/bjophthalmol-2020-316499 [Epub ahead of print]
2. Murueta-Goyena A, Del Pino R, Galdós M, et al. Retinal thickness predicts the risk of cognitive decline in Parkinson's disease. Ann Neurol 2020 Oct 24 doi: 10.1002/ana.25944 [Epub ahead of print]
3. Sung MS, Choi SM, Kim J, et al. Inner retinal thinning as a biomarker for cognitive impairment in de novo Parkinson's disease. Sci Rep 2019;9:11832.
4. Matlach J, Wagner M, Malzahn U, et al. Retinal changes in Parkinson's disease and glaucoma. Parkinsonism Relat Disord 2018 Nov;56:41-46.
I read the interesting manuscript entitled “Effect of a formulated eye drop with Leptospermum spp honey on tear film properties”. Authors have compared a formulated eye drop made of honey and regular lubricant drops finding some advantages of the honey eye drop. While the natural honey mainly composed of sugars, the beneficial effect might merely related to these simple carbohydrates. If authors have decided to find any effect, peculiarly attributed to the honey, they might design a control group with similar composition of simple carbohydrates to disclose the unclouded actual effect of the honey. On the other side, there might be some possible complications of promoting such agents as proved treatments, that have been already in use as alternative home made remedies; we have reported a case of Acanthamoeba keratitis using non-sterile honey eye drop (1).
1. Peyman A, Pourazizi M, Peyman M, Kianersi F. Natural Honey-Induced Acanthamoeba keratitis. Middle East Afr J Ophthalmol. 2020 Jan 29;26(4):243-245. doi: 10.4103/meajo.MEAJO_56_18. PMID: 32153338; PMCID: PMC7034153.
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.
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...
Show MoreKruglyakova, et al recently published an excellent paper about visually pertinent correlation of optic nerve hypoplasia (ONH) with intra-operative photographic measurements1. We recently reported similar findings without subjecting children to general anesthesia if ultra-widefield imaging (OPTOS; Dunfermline, UK) is available2. We agree that a MD/DD ratio greater than 3.22 (≥3.51) is consistent with clinical optic nerve hypoplasia but our direct measure of horizontal optic nerve size was even more predictive utilizing our definition of logMAR for pediatric and low vision patients3. Instead of starting from the temporal edge of the optic nerve to determine MD (macula-disk) distance, we found the center of the optic nerve more uniform. In addition, we have also noted a worrisome relationship between ONH and threshold retinopathy of prematurity4 and wonder if the authors also found any association between the two common pediatric blinding conditions ONH and ROP?
References:
Show More1. Kruglyakova J, Garcia-Filion P, Nelson M, Borchert M. Orbital MRI versus fundus photography in the diagnosis of optic nerve hypoplasia and prediction of vision. Br J Ophthalmol. 2020;104(10):1458-1461.
2. Arnold AW, Eller AM, Smith KA, Grendahl RL, Winkle RK, Arnold RW. Direct nerve size determination and prevalent optic nerve hypoplasia in Alaska. Clin Ophthalmol. 2020;14:491—499.
3. Arnold RW. Digital values for alpha acuities. JPOS. 2020:In Press.
4. Arnold RW. Opti...
McCann et al. reported factors of the associations with intraocular pressure (IOP) and circumpapillary retinal nerve fibre layer (cRNFL) thickness (1). Increased IOP and reduced cRNFL were associated with increased age, myopic refractive error, male sex and hypertension. In addition, Alzheimer's disease was associated with thinner average global cRNFL, and Parkinson's disease (PD) and current smoking status were associated with thicker average global cRNFL, and I present recent information regarding their study in patients with PD.
Murueta-Goyena et al. reported the association between the changes of retinal thickness and their predictive value as biomarkers of disease progression in idiopathic PD (2). The authors used macular ganglion-inner plexiform layer complex (mGCIPL) and peripapillary retinal nerve fiber layer (pRNFL) thickness reduction rates, and the Montreal Cognitive Assessment (MoCA) questionnaire was also applied. The adjusted relative risks of lower parafoveal mGCIPL and pRNFL thickness at baseline for an increased risk of cognitive decline at 3 years significantly increased. This means that reduced retinal thickness is a risk factor of cognitive impairment in patients with PD. McCann et al. did not evaluate cRNFL in PD patients with cognitive impairment, and I suppose that progression of cognitive impairment in patients with PD might accelerate reduction of average global cRNFL.
Second, Sung et al. also investigated the association be...
Show MoreI read the interesting manuscript entitled “Effect of a formulated eye drop with Leptospermum spp honey on tear film properties”. Authors have compared a formulated eye drop made of honey and regular lubricant drops finding some advantages of the honey eye drop. While the natural honey mainly composed of sugars, the beneficial effect might merely related to these simple carbohydrates. If authors have decided to find any effect, peculiarly attributed to the honey, they might design a control group with similar composition of simple carbohydrates to disclose the unclouded actual effect of the honey. On the other side, there might be some possible complications of promoting such agents as proved treatments, that have been already in use as alternative home made remedies; we have reported a case of Acanthamoeba keratitis using non-sterile honey eye drop (1).
1. Peyman A, Pourazizi M, Peyman M, Kianersi F. Natural Honey-Induced Acanthamoeba keratitis. Middle East Afr J Ophthalmol. 2020 Jan 29;26(4):243-245. doi: 10.4103/meajo.MEAJO_56_18. PMID: 32153338; PMCID: PMC7034153.
Pages