We read the article published by Chaudhary, et al (1) with great interest and laud them on the quality and design of their study. Primary congenital blindness (PCG) poses a challenge to clinicians, both in terms of diagnosis, and treatment. (2)
We would like to bring to the authors’ notice a similar study conducted in 2017 (3) of 230 eyes of 121 PCG patients having undergone a primary CTT. This study differed from the present study in the fact that it had a longer average follow-up period of 28.87 years with a more concentrated follow-up range of 21.5-38 years. There were also two main differences in the findings of the two studies.
Contrary to the results in the present study where the infants with PCG fared better than the neonates (48.9% >6/60), the previous study found that 76.3% newborns with PCG had a vision better than 6/60. Additionally, the previous study, found visual acuity to be better than 6/60 in a greater proportion of patients (76.1%) at the last follow-up, as compared to the proportion in the study by Chaudhary et al (55.3%). Applying the WHO recommendation of measuring vision in the better eye, (4) the results improved to 89.3% in the study by Sood et al. (3)
A possible reason for these disparities between the studies could be the difference in presentation times of the patients and the study inclusion criteria. While the present study reports late presentation, over half of the patients (53%) in the earlier pub...
We read the article published by Chaudhary, et al (1) with great interest and laud them on the quality and design of their study. Primary congenital blindness (PCG) poses a challenge to clinicians, both in terms of diagnosis, and treatment. (2)
We would like to bring to the authors’ notice a similar study conducted in 2017 (3) of 230 eyes of 121 PCG patients having undergone a primary CTT. This study differed from the present study in the fact that it had a longer average follow-up period of 28.87 years with a more concentrated follow-up range of 21.5-38 years. There were also two main differences in the findings of the two studies.
Contrary to the results in the present study where the infants with PCG fared better than the neonates (48.9% >6/60), the previous study found that 76.3% newborns with PCG had a vision better than 6/60. Additionally, the previous study, found visual acuity to be better than 6/60 in a greater proportion of patients (76.1%) at the last follow-up, as compared to the proportion in the study by Chaudhary et al (55.3%). Applying the WHO recommendation of measuring vision in the better eye, (4) the results improved to 89.3% in the study by Sood et al. (3)
A possible reason for these disparities between the studies could be the difference in presentation times of the patients and the study inclusion criteria. While the present study reports late presentation, over half of the patients (53%) in the earlier publication were operated before they reached 28 days of age. Further, the present study only includes patients with enlarged corneal diameter (>12mm) and pre-surgery IOP of 22mmHg, whereas our study had 31.74% patients with corneal diameter between 10-12mm and 0.87% patients with IOP less than 20mmHg. The former constituted 42.1% of the patients with visual acuity better than 6/60, while the latter constituted 0% of the same.
The authors of the present study also conducted an in-depth analysis of causes behind poor visual outcomes, whereas the previous study focused only on three pre-determined factors, with only one in common with the present study. Needless to say, both studies add considerably to existing literature, bolstered in their endeavour by their large sample size, a rarity by itself in studies reporting long-term outcomes in PCG patients.
References:
1. Chaudhary RS, Gupta A, Sharma A, et al Long-term functional outcomes of different subtypes of primary congenital glaucoma British Journal of Ophthalmology Published Online First: 23 December 2019. doi: 10.1136/bjophthalmol-2019-315131
2. Mandal AK, Chakrabarti D. Update on congenital glaucoma. Indian J Ophthalmol 2011;59, Suppl S1:148-57
3. Sood D, Rathore A, Sood I, Singh G, Sood NN. Long-term outcome of combined trabeculotomy-trabeculectomy by a single surgeon in patients with primary congenital glaucoma. Eye (Lond). 2018;32(2):426–432. doi:10.1038/eye.2017.207
4. World Health Organization. Change the Definition of Blindness; 2020. Available at: http://www.who.int/blindness/Change%20the %20Definition%20of%20Blindness.pdf. [Accessed on 04 May 2020].
ACKNOWLEDGEMENT: The authors would like to thank Dr Shalinder Sabherwal for his review of the manuscript for this Letter in Response.
We read with interest the post-hoc study by Waldstein and colleagues concerning the impact of posterior vitreous detachment (PVD) on the efficacy of anti-VEGF treatment in neovascular age-related macular degeneration (AMD). However, the reliability of spectral-domain optical coherence tomography (SD-OCT) in confirming PVD status, upon which the findings of this study are dependent, is questionable.[1, 2] In particular, OCT is poor at distinguishing between fully attached vitreous and complete PVD.
Hwang et al recently reported limited sensitivity of SD-OCT in detecting complete PVD when compared to clinical findings at the time of vitrectomy.[1] It was found that among patients awaiting vitrectomy, OCT diagnosis of complete PVD (based on the absence of visible posterior vitreous cortex or a premacular bursa on SD-OCT) had a positive predictive value of just 53% when compared to intra-operative findings.
PVD remains a clinical diagnosis that is based on the identification of the posterior hyaloid membrane (PHM), a diaphanous, wrinkled film observable during biomicroscopic examination. The Weiss ring which it incorporates is a more variable and less reliable confirmatory sign of PHM detachment from the optic nerve head. The visible PHM is a consistent clinical finding in patients with PVD and correlates histopathologically with a type IV collagen basement membrane which begins life attached to the retina as the internal limiting membrane.[3...
We read with interest the post-hoc study by Waldstein and colleagues concerning the impact of posterior vitreous detachment (PVD) on the efficacy of anti-VEGF treatment in neovascular age-related macular degeneration (AMD). However, the reliability of spectral-domain optical coherence tomography (SD-OCT) in confirming PVD status, upon which the findings of this study are dependent, is questionable.[1, 2] In particular, OCT is poor at distinguishing between fully attached vitreous and complete PVD.
Hwang et al recently reported limited sensitivity of SD-OCT in detecting complete PVD when compared to clinical findings at the time of vitrectomy.[1] It was found that among patients awaiting vitrectomy, OCT diagnosis of complete PVD (based on the absence of visible posterior vitreous cortex or a premacular bursa on SD-OCT) had a positive predictive value of just 53% when compared to intra-operative findings.
PVD remains a clinical diagnosis that is based on the identification of the posterior hyaloid membrane (PHM), a diaphanous, wrinkled film observable during biomicroscopic examination. The Weiss ring which it incorporates is a more variable and less reliable confirmatory sign of PHM detachment from the optic nerve head. The visible PHM is a consistent clinical finding in patients with PVD and correlates histopathologically with a type IV collagen basement membrane which begins life attached to the retina as the internal limiting membrane.[3-5]
We would be interested to learn whether the baseline evaluation of the patients in the reported study included a clinical assessment of PVD status and whether clinical separation of the posterior hyaloid membrane correlated with response to anti-VEGF therapy. We agree with the authors that there is evidence that PVD status may significantly impact the response of neovascular AMD to anti-VEGF therapy but SD-OCT must be combined with meticulous clinical slit-lamp examination to reliably determine the true status of the posterior hyaloid membrane.
1 Hwang ES, Kraker JA, Griffin KJ, et al. Accuracy of spectral-domain OCT of the macula for detection of complete posterior vitreous detachment. Ophthalmol Retina 2020;4(2):148-153.
2 Kičová N, Bertelmann T, Irle S, et al. Evaluation of a posterior vitreous detachment: a comparison of biomicroscopy, B-scan ultrasonography and optical coherence tomography to surgical findings with chromodissection. Acta Ophthalmol 2012;90(4):e264-268.
3 Snead MP, Snead DR, James S, et al. Clinicopathological changes at the vitreoretinal junction: posterior vitreous detachment. Eye (Lond) 2008;22(10):1257–1262.
4 Snead MP, Snead DRJ, Richards AJ, et al. Clinical, histological and ultrastructural studies of the posterior hyaloid membrane. Eye (Lond) 2002;16(4),447-453.
5 Fincham GS, James S, Spickett C, et al. Posterior vitreous detachment and the posterior hyaloid membrane. Ophthalmology 2018;125(2):227-236.
Tabandeh and colleagues[1] presented a contrarian viewpoint on the redundancy of scleral-depressed vitreous base shaving: a procedure we have come to take for granted during vitrectomy for retinal detachment (RD). Their excellent outcomes are great news for trainee surgeons, as lens touch is likely during meticulous base dissection in phakic eyes. Sutureless micro-incision vitreous surgery is indeed more secure with residual peripheral vitreous, which plugs the sclerotomy leaks. The authors’ attribution of their high success rate to circumferential laser photocoagulation is validated by a randomized clinical trial.[2] The cases with residual silicone oil (13/89; 15%) should however not be included in the anatomical success; a significant percentage of them re-detach after oil removal.[3]
The optional use of scleral buckle in this study is confusing. The authors have not specified the choice of buckle (most probably an encircling belt-buckle). Vitreous base-shaving is critical to anatomical success when no encirclage is used.[3] The authors reported no additional benefit from buckling, though it was preferentially performed for complex detachments. We therefore do not have clarity about the one moot issue this study could settle: whether vitrectomy sans base-shaving is good enough for simple RD at least. A recent study suggested that anterior dissection is essential in the presence of posteriorly inserted vitreous base.[4] Did the authors observe this vitreous config...
Tabandeh and colleagues[1] presented a contrarian viewpoint on the redundancy of scleral-depressed vitreous base shaving: a procedure we have come to take for granted during vitrectomy for retinal detachment (RD). Their excellent outcomes are great news for trainee surgeons, as lens touch is likely during meticulous base dissection in phakic eyes. Sutureless micro-incision vitreous surgery is indeed more secure with residual peripheral vitreous, which plugs the sclerotomy leaks. The authors’ attribution of their high success rate to circumferential laser photocoagulation is validated by a randomized clinical trial.[2] The cases with residual silicone oil (13/89; 15%) should however not be included in the anatomical success; a significant percentage of them re-detach after oil removal.[3]
The optional use of scleral buckle in this study is confusing. The authors have not specified the choice of buckle (most probably an encircling belt-buckle). Vitreous base-shaving is critical to anatomical success when no encirclage is used.[3] The authors reported no additional benefit from buckling, though it was preferentially performed for complex detachments. We therefore do not have clarity about the one moot issue this study could settle: whether vitrectomy sans base-shaving is good enough for simple RD at least. A recent study suggested that anterior dissection is essential in the presence of posteriorly inserted vitreous base.[4] Did the authors observe this vitreous configuration and its effect in any of their cases?
The study included 14 giant retinal tears (GRT), and reported 93% single-surgery success rate. It is important to know the size of GRTs, presence/severity of PVR, need for encirclage, concomitant lens removal, and the nature of postoperative tamponade. These details are necessary to replicate the excellent outcomes without vitreous base-shaving, considered non-negotiable in a GRT.[5]
REFERENCES
1. Tabandeh H, London NJS, Boyer DS, et al. Outcomes of small-gauge vitreoretinal surgery without scleral-depressed shaving of the vitreous base in the era of wide-angle viewing systems. Br J Ophthalmol 2019;103:1765-8.
2. Avitabile T, Longo A, Lentini G, et al. Retinal detachment after silicone oil removal is prevented by 360° laser treatment. Br J Ophthalmol 2008;92:1479-82.
3. Teke MY, Balikoglu-Yilmaz M, Yuksekkaya P, et al. Surgical outcomes and incidence of retinal redetachment in cases with complicated retinal detachment after silicone oil removal: univariate and multiple risk factors analysis. Retina 2014;34:1926-38.
4. Sohn EH, Strohbehn A, Stryjewski T, et al. Posteriorly inserted vitreous base: preoperative characteristics, intraoperative findings, and outcomes after vitrectomy. Retina 2020;40:943-50.
5. Shunmugam M, Ang GS, Lois N. Giant retinal tears. Surv Ophthalmol 2014;59:192-216.
Dr. Portabella reviewed the stability of 345 consecutive cases of scleral-sutured posterior chamber IOLs retrospectively.1 In discussing sutured scleral-fixated IOLs several main points must be considered: 1) type of suture utilized; 2) length of follow-up; 3) multiple surgeons or single surgeon; 4) type of knot utilized; and 5) reoperation rate.
This paper by Portabella et al.1 involved use of Prolene (polypropylene) or Mersilene sutures, follow-up with a maximum of 10 years, multiple surgeons, a knot with a single loop through the sclera and around the haptic, and a reoperation rate of 7.2%. The Vote et al study2 reviewed 61 eyes with Prolene sutures, follow-up with a maximum of 10.6 years, multiple surgeons, variable knots, and an extremely high rate of redislocation of 26.2%, which they postulated was due to suture breakage. This high rate of redislocation has not been confirmed in any other study.3,4
A recent study by Kokame et al3 involved 118 eyes utilizing 10-0 Prolene sutures, a single surgeon, follow-up of up to 24.75 years, a knot with two sutures - one secured to the haptic by a cow-hitch and the other to the sclera with both sutures tied together in a single knot under a scleral flap, and a broken suture rate of 0.5% (1/214 fixation sutures). The maximum follow-up of 24.75 years with stable fixation strongly supports the stability of 10-0 Prolene. Higher rates of redislocations of sutured scleral-fixated IOLs can be due to multiple surgeo...
Dr. Portabella reviewed the stability of 345 consecutive cases of scleral-sutured posterior chamber IOLs retrospectively.1 In discussing sutured scleral-fixated IOLs several main points must be considered: 1) type of suture utilized; 2) length of follow-up; 3) multiple surgeons or single surgeon; 4) type of knot utilized; and 5) reoperation rate.
This paper by Portabella et al.1 involved use of Prolene (polypropylene) or Mersilene sutures, follow-up with a maximum of 10 years, multiple surgeons, a knot with a single loop through the sclera and around the haptic, and a reoperation rate of 7.2%. The Vote et al study2 reviewed 61 eyes with Prolene sutures, follow-up with a maximum of 10.6 years, multiple surgeons, variable knots, and an extremely high rate of redislocation of 26.2%, which they postulated was due to suture breakage. This high rate of redislocation has not been confirmed in any other study.3,4
A recent study by Kokame et al3 involved 118 eyes utilizing 10-0 Prolene sutures, a single surgeon, follow-up of up to 24.75 years, a knot with two sutures - one secured to the haptic by a cow-hitch and the other to the sclera with both sutures tied together in a single knot under a scleral flap, and a broken suture rate of 0.5% (1/214 fixation sutures). The maximum follow-up of 24.75 years with stable fixation strongly supports the stability of 10-0 Prolene. Higher rates of redislocations of sutured scleral-fixated IOLs can be due to multiple surgeons inexperienced with secure knot tying with the slippery Prolene suture, and knot integrity of a single loop around the haptic through the sclera with one suture knot creating the scleral fixation. Histopathologic studies of 10-0 Prolene sutures do not show evidence of cracking, wrinkling, flaking, or degradation of 10-0 Prolene sutures 10.5 years after placement.5
Gregg T Kokame MD MMM
Chief of Ophthalmology
University of Hawaii School of Medicine
Honolulu, Hawaii, USA
References:
1. Portabella M, Nadal J, Alarex de Toledo J et al. Long-term outcome of scleral-sutured posterior chamber intraocular lens: a case series. Br J Ophthalmol 2020;104:712-717. Doi: 10.1136/brjophthalmol-2019-314054.
2. Vote BJ, Tranos P, Bunce C, Charteris DG, Da Cruz L. Long term outcome of combined pars plana vitrectomy and scleral fixated posterior chamber intraocular lens implantation. Am J Ophthalmol 2006; 141(2):308-312. doi:10.1016/j.ajo.2005.09.012
3. Kokame GT, Yanagihara RT, Shantha JG, Kaneko KN, Long Term Outcome of Pars Plana Vitrectomy and Sutured Scleral-Fixated Posterior Chamber Intraocular Lens Implantation or Repositioning, American Journal of Ophthalmology 2018 May;189:10-16. doi: 10.1016/j.ajo.2018.01.034
4. Bading G, Hillenkamp J, Sachs HG, Gabel VP, Framme C. Long-term safety and functional outcome of combined pars plana vitrectomy and scleral-fixated sutured posterior chamber lens implantation. Am J Ophthalmol 2007;144(3):371–377. doi: 10.1016/j.ajo.2007.05.014.
5. Parekh P, Green WR, Stark WJ, Akpek EK. Subluxation of suture-fixated posterior chamber intraocular lenses a clinicopathologic study. Ophthalmology 2007;114(2):232-237.
Dear Editor,
We have read the clinical case report entitled “Ocular manifestations of a patient hospitalized with a new coronavirus disease confirmed in 2019” by Chen L, et al.1 We congratulate the authors for this important work and wish to share our comment concerning the retinal findings. The authors indicated that Spectral-domain optical coherence tomography (SD-OCT) imaging was normal in both eyes. However, we would like to highlight the presence of hyper-reflective focal points at the level of the internal plexiform layer (IPL) and the ganglion cell layer (GCL). The report later published by Marinho PM, et al. in Lancet on May 12, 2020 "Retinal findings in patients with COVID-19" described the presence of focal hyperreflective dots at the IPL and GCL levels in all patients (24 eyes of 12 patients), which was the first report of SD-OCT retinal abnormalities in patients with COVID 19.2 We compared the two SD-OCT images published by Chen L, et al. to those published by Marinho PM, et al. All images were reviewed by two different retina specialists (NM, RTJH), and our analysis was strongly consistent. We have implemented the algorithm using the Python script3 to adjust the size and resolution of the images, and flipped the C by Marinho PM, et al. using fovea as the reference to obtain comparable images. We overlaid the images published by Chen L, et al. with those published by Marinho PM, et al. We were able to demonstrate that the hyperreflective lesions...
Dear Editor,
We have read the clinical case report entitled “Ocular manifestations of a patient hospitalized with a new coronavirus disease confirmed in 2019” by Chen L, et al.1 We congratulate the authors for this important work and wish to share our comment concerning the retinal findings. The authors indicated that Spectral-domain optical coherence tomography (SD-OCT) imaging was normal in both eyes. However, we would like to highlight the presence of hyper-reflective focal points at the level of the internal plexiform layer (IPL) and the ganglion cell layer (GCL). The report later published by Marinho PM, et al. in Lancet on May 12, 2020 "Retinal findings in patients with COVID-19" described the presence of focal hyperreflective dots at the IPL and GCL levels in all patients (24 eyes of 12 patients), which was the first report of SD-OCT retinal abnormalities in patients with COVID 19.2 We compared the two SD-OCT images published by Chen L, et al. to those published by Marinho PM, et al. All images were reviewed by two different retina specialists (NM, RTJH), and our analysis was strongly consistent. We have implemented the algorithm using the Python script3 to adjust the size and resolution of the images, and flipped the C by Marinho PM, et al. using fovea as the reference to obtain comparable images. We overlaid the images published by Chen L, et al. with those published by Marinho PM, et al. We were able to demonstrate that the hyperreflective lesions in both images co-localized in the IPL and GCL layers. This indicates that the hyperreflective foci that we observed in the OCT images by Chen L, et al. are correlating with the retinal findings described by Marinho PM, et al.
References
1. Chen L, Liu M, Zhang Z, et al. Ocular manifestations of a hospitalised patient with confirmed 2019 novel coronavirus disease. Br J Ophthalmol. 2020;104:748‐51.
2. Marinho PM, Marcos AAA, Romano AC, Nascimento H, Belfort R Jr. Retinal findings in patients with COVID-19. Lancet. 2020;395(10237):1610. doi:10.1016/S0140-6736(20)31014-X
3. Späth H. Fitting affine and orthogonal transformations between two
sets of points. Mathematical Communications. 2004;9: 27-34
At the outset, we would like to congratulate the authors for determining the presence of the viral RNA over time in conjunctival specimens of a patient with COVID-19, which was much needed.
The clinical course of viral conjunctivitis is self-limiting. Usually only supportive treatments like cold compress, artificial tears and topical steroids are given. The time duration taken for symptoms to subside without treatment ranges from 4-6 days to 2-3 weeks, depending upon the type of disease.[1] Clinical studies regarding the usage of antivirals for conjunctivitis reveal that they were effective only for DNA viruses and was not free of toxicity.[2]
In the case report regarding ocular manifestation of patient with 2019 novel corona virus disease,[3] the ocular symptoms of patient resolved after 5 days of its onset and the author claims it to be possibly due to treatment with ribavirin eye drops. As Corona virus is a RNA virus, we believe that antiviral therapy would have been limited use. Adequate corneal tissue levels of antiviral agents are achieved by both topical and systemic administration.[4] If antiviral therapy was the reason for improvement of ocular symptoms, the patient was on three oral antiviral drugs (Umifenovir, lopinavir and ritonavir) in addition to topical ribavirin. Therefore, attributing only topical ribavirin for curing ocular symptoms may not be appropriate with the limited evidence.
The authors also had mentioned that sterile synthetic f...
At the outset, we would like to congratulate the authors for determining the presence of the viral RNA over time in conjunctival specimens of a patient with COVID-19, which was much needed.
The clinical course of viral conjunctivitis is self-limiting. Usually only supportive treatments like cold compress, artificial tears and topical steroids are given. The time duration taken for symptoms to subside without treatment ranges from 4-6 days to 2-3 weeks, depending upon the type of disease.[1] Clinical studies regarding the usage of antivirals for conjunctivitis reveal that they were effective only for DNA viruses and was not free of toxicity.[2]
In the case report regarding ocular manifestation of patient with 2019 novel corona virus disease,[3] the ocular symptoms of patient resolved after 5 days of its onset and the author claims it to be possibly due to treatment with ribavirin eye drops. As Corona virus is a RNA virus, we believe that antiviral therapy would have been limited use. Adequate corneal tissue levels of antiviral agents are achieved by both topical and systemic administration.[4] If antiviral therapy was the reason for improvement of ocular symptoms, the patient was on three oral antiviral drugs (Umifenovir, lopinavir and ritonavir) in addition to topical ribavirin. Therefore, attributing only topical ribavirin for curing ocular symptoms may not be appropriate with the limited evidence.
The authors also had mentioned that sterile synthetic fibre swab was used for conjunctival swabs. It would be better if additional details regarding the material of swab stick and the technique were mentioned. This will also help other researchers for precise isolation and detection of the virus. Moreover, authors have mentioned a study by Xia et al, where out of 30 patients only one patients swab had come positive.[5] This highlights the skill in the authors technique.
Reference:
1 Bialasiewicz A. Adenoviral Keratoconjunctivitis. Sultan Qaboos Univ Med J 2007;7:15–23.
2 Skevaki CL, Galani IE, Pararas MV, et al. Treatment of viral conjunctivitis with antiviral drugs. Drugs 2011;71:331–47. doi:10.2165/11585330-000000000-00000
3 Chen L, Liu M, Zhang Z, et al. Ocular manifestations of a hospitalised patient with confirmed 2019 novel coronavirus disease. Br J Ophthalmol Published Online First: 7 April 2020. doi:10.1136/bjophthalmol-2020-316304
4 Dias C, Nashed Y, Atluri H, et al. Ocular penetration of acyclovir and its peptide prodrugs valacyclovir and val-valacyclovir following systemic administration in rabbits: An evaluation using ocular microdialysis and LC-MS. Curr Eye Res 2002;25:243–52. doi:10.1076/ceyr.25.4.243.13488
5 Xia J, Tong J, Liu M, et al. Evaluation of coronavirus in tears and conjunctival secretions of patients with SARS-CoV-2 infection. J Med Virol Published Online First: 26 February 2020. doi:10.1002/jmv.25725
Synopsis:
Applying Pearson r to assesses the repeatability of a test is a methodologic mistake which leads to misinterpretation.
Repeatability of automated leakage quantification and microaneurysm identification utilising an analysis platform for ultra-widefield fluorescein angiography. Avoid misinterpretation
Dear editor, We were interested to read the paper by Jiang A et al. published in Apr 2020 edition of the Br J Ophthalmol.1 Ultra-wide field fluorescein angiography (UWFA) provides unique opportunities for panretinal assessment of retinal diseases. The objective quantification of UWFA features is a labour-intensive manual process, limiting its utility. The authors aimed to assesses the consistency/repeatability of an automated assessment platform for the characterization of retinal vascular features, quantification of microaneurysms (MA) and leakage foci in UWFA images. For each eye, two arteriovenous-phase images and two late-phase images were selected. Automated assessment was performed for retinal vascular features, MA identification and leakage segmentation. Panretinal and zonal assessment of metrics was performed. The authors mentioned a significant correlation between paired time points for retinal vessel area and vessel length on early images (Pearson r=0.92, p<0.0001; Pearson r=0.94, p<0.0001) and late images (Pearson r=0.92, p<0.0001; Pearson r=0.92, p<0.0001, respectively). Panretinal and zonal MA counts demonst...
Synopsis:
Applying Pearson r to assesses the repeatability of a test is a methodologic mistake which leads to misinterpretation.
Repeatability of automated leakage quantification and microaneurysm identification utilising an analysis platform for ultra-widefield fluorescein angiography. Avoid misinterpretation
Dear editor, We were interested to read the paper by Jiang A et al. published in Apr 2020 edition of the Br J Ophthalmol.1 Ultra-wide field fluorescein angiography (UWFA) provides unique opportunities for panretinal assessment of retinal diseases. The objective quantification of UWFA features is a labour-intensive manual process, limiting its utility. The authors aimed to assesses the consistency/repeatability of an automated assessment platform for the characterization of retinal vascular features, quantification of microaneurysms (MA) and leakage foci in UWFA images. For each eye, two arteriovenous-phase images and two late-phase images were selected. Automated assessment was performed for retinal vascular features, MA identification and leakage segmentation. Panretinal and zonal assessment of metrics was performed. The authors mentioned a significant correlation between paired time points for retinal vessel area and vessel length on early images (Pearson r=0.92, p<0.0001; Pearson r=0.94, p<0.0001) and late images (Pearson r=0.92, p<0.0001; Pearson r=0.92, p<0.0001, respectively). Panretinal and zonal MA counts demonstrated high repeatability between images (all p<0.0001). The automated MA algorithm demonstrated a high level of precision/repeatability across multiple metrics. Panretinal MA count demonstrated high repeatability between images (Pearson r=0.94, p<0.0001).
We want to congratulate the authors for this successful article, and make some contributions. Reproducibility (repeatability or reliability) can be evaluated by various statistical tests, such as Pearson r which is one of the common errors in reliability analysis. Pearson r only evaluates the linearity between two continuous variables. Any shift in the location and/or scale of a regression line leading to non-reproducibility cannot be detected by Pearson correlation coefficients (Fig. 1). 2 It is important to know that the mean value of a quantitative variable can be similar in absolute value; however, to assess reproducibility, the Pearson is not an appropriate test. Because the Pearson correlation coefficient can only assess linear association between two quantitative variables. It means, it is possible to have linear association between two variables with no reliability at al. 2 Therefore, for quantitative variables, the Intraclass Correlation Coefficient (ICCC) is one of the appropriate statistical tests for evaluating precision/repeatability. Moreover, in repeatability analysis, the approach should be individual-based, rather than global average. Pearson r cannot cover this approach. Briefly, to assess reliability, for quantitative variables, the Intraclass Correlation Coefficient (ICCC) and Bland-Altman plot are suggested. 2-6 Authors concluded that This automated algorithm demonstrated very strong intrastudy correlation between paired time points in the same phases of the angiogram for quantifying retinal vascular characteristics, MA count and leakage parameters in UWFA images. Such conclusion may be due to inappropriate use of statistical test which ultimately leads to a misleading message. So, due to inappropriate use of statistical tests (Pearson r) there may be a high level of uncertainty for their conclusion.
KEYWORDS: diagnostic tests/investigation; imaging; retina
Contributors: SS and FG drafted and revised the manuscript. SS provided conception for the project. All authors provided significant effort in the interpretation, reviewing the manuscript, final approval of the
manuscript and agreed to be accountable for all aspects of the work.
Funding: None
Competing interests: SS and FG have no competing interest
Patient consent for publication: Not required.
Ethics approval: N/A
Data availability statement: N/A.
References:
1 Jiang A, Srivastava S, Figueiredo N, et al. Repeatability of automated leakage quantification and microaneurysm identification utilising an analysis platform for ultra-widefield fluorescein angiography. Br J Ophthalmol. 2020;104:500-503.
2 Szklo M, Nieto FJ. Epidemiology beyond the basics. 3rd ed. Manhattan: Jones and Bartlett Publisher, United State, 2014.
3 Sabour S. Reproducibility of semi-automatic coronary plaque quantification in coronary CT angiography with sub-mSv radiation dose; common mistakes. J Cardiovasc Comput Tomogr. 2016; 10:21-2.
4 Sabour S. Reproducibility of the external surface position in left-breast DIBH radiotherapy with spirometer-based monitoring: methodological mistake. J Appl Clin Med Phys. 2014;15:4909.
5 Sabour S. Reliability of automatic vibratory equipment for ultrasonic strain measurement of the median nerve: common mistake. Ultrasound Med Biol. 2015; 41:1119-20.
6 Sabour S, Ghassemi F. Accuracy, validity, and reliability of the infrared optical head tracker (IOHT). Invest Ophthalmol Vis Sci. 2012;53:4776.
Figure 1: Cases when Pearson correlation coefficient fails to detect non reproducibility
Optic disc drusen pose a diagnostic challenge when trying to differentiate between papilloedema and pseudopapilloedema.1 Dahlman-Noor et al highlight the importance of a structured history when evaluating children with optic nerve head (ONH) swelling. The authors recommend a future study to explore the diagnostic accuracy of an algorithm published by the Royal College of Paediatrics and Child Health (RCPCH) which details key features of the history (e.g. headache, vomiting, visual symptoms) that should trigger neuroimaging.2
As part of a prospective study of children referred to our regional paediatric ophthalmology service for assessment for ONH swelling, we implemented this algorithm. 122 children under 16 years of age were assessed from 1st January to 31st December 2018. 93% (113/122) had optic disc drusen, 4% (5/122) had normal optic discs, and 3% (4/122) had papilloedema. Two cases of papilloedema were caused by idiopathic intracranial hypertension (IIH) and two by venous sinus thrombosis.
Of the 118 patients with drusen or normal discs, only one fulfilled the RCPCH criteria for neuroimaging: a 14-year-old girl with persistent headaches and vomiting. Neuroimaging and lumbar puncture were unremarkable, and her symptoms were ultimately attributed to migraine.
For the four patients with papilloedema, the algorithm-derived questions would have triggered neuroimaging in three cases. This yields a specificity of 99% but a sensitivity of only...
Optic disc drusen pose a diagnostic challenge when trying to differentiate between papilloedema and pseudopapilloedema.1 Dahlman-Noor et al highlight the importance of a structured history when evaluating children with optic nerve head (ONH) swelling. The authors recommend a future study to explore the diagnostic accuracy of an algorithm published by the Royal College of Paediatrics and Child Health (RCPCH) which details key features of the history (e.g. headache, vomiting, visual symptoms) that should trigger neuroimaging.2
As part of a prospective study of children referred to our regional paediatric ophthalmology service for assessment for ONH swelling, we implemented this algorithm. 122 children under 16 years of age were assessed from 1st January to 31st December 2018. 93% (113/122) had optic disc drusen, 4% (5/122) had normal optic discs, and 3% (4/122) had papilloedema. Two cases of papilloedema were caused by idiopathic intracranial hypertension (IIH) and two by venous sinus thrombosis.
Of the 118 patients with drusen or normal discs, only one fulfilled the RCPCH criteria for neuroimaging: a 14-year-old girl with persistent headaches and vomiting. Neuroimaging and lumbar puncture were unremarkable, and her symptoms were ultimately attributed to migraine.
For the four patients with papilloedema, the algorithm-derived questions would have triggered neuroimaging in three cases. This yields a specificity of 99% but a sensitivity of only 75%.
One patient with IIH did not fulfil the criteria for neuroimaging. This 13-year-old girl was asymptomatic despite having marked bilateral optic disc swelling and raised intracranial pressure. The ONH abnormalities were identified on routine optometric examination.
The high specificity of the RCPCH algorithm indicates that when the screening questions are positive, it is likely that a child has intracranial pathology and neuroimaging is justified. However, in our cohort, the sensitivity was insufficient for the algorithm to act as a screening tool in isolation.
1. Chang MY, Velez FG, Demer JL, et al. Accuracy of Diagnostic Imaging Modalities for Classifying Pediatric Eyes as Papilledema Versus Pseudopapilledema. Ophthalmology. 2017;124(12):1839-1848.
2. Walker D, Grundy R, Kennedy C et al. The diagnosis of brain tumours in children. www.rcph.ac.uk/bpp.
We thank S N Gillan et al for their original study investigating the influence of medical student career aims on ophthalmic surgical simulator performance. The authors reported no association between medical student interest in pursuing an ophthalmic career and microsurgical task performance.
The authors recruited subjects from the medical student division of the ‘Moorfields Academy’ and deemed these subjects as students with career interests in ophthalmology. However, we suggest that a more accurate measure in determining ophthalmic career interest would be whether these students had undertaken the ‘Duke Elder exam’, an annual national undergraduate prize examination in ophthalmology, and the only specialty-specific prize examination in the UK. We believe that undertaking the ‘Duke Elder exam’ and the preparation that this involves demonstrates commitment to the ophthalmic specialty more than being a member of the ‘Moorfields Academy’. Almost 30% of candidates ranked in the top 20 in this exam eventually pursue an ophthalmic career [1].
Moreover, as the ‘Duke Elder exam’ can be taken multiple times during the course of a medical degree, it would have been particularly interesting to examine the correlation between the frequency that this exam had been taken with microsurgical task performance. However, we would also like to state that a proportion of the subjects in this study have likely undertaken the ‘Duke Elder exam’. Finally, using the ‘Duke Elder exam’...
We thank S N Gillan et al for their original study investigating the influence of medical student career aims on ophthalmic surgical simulator performance. The authors reported no association between medical student interest in pursuing an ophthalmic career and microsurgical task performance.
The authors recruited subjects from the medical student division of the ‘Moorfields Academy’ and deemed these subjects as students with career interests in ophthalmology. However, we suggest that a more accurate measure in determining ophthalmic career interest would be whether these students had undertaken the ‘Duke Elder exam’, an annual national undergraduate prize examination in ophthalmology, and the only specialty-specific prize examination in the UK. We believe that undertaking the ‘Duke Elder exam’ and the preparation that this involves demonstrates commitment to the ophthalmic specialty more than being a member of the ‘Moorfields Academy’. Almost 30% of candidates ranked in the top 20 in this exam eventually pursue an ophthalmic career [1].
Moreover, as the ‘Duke Elder exam’ can be taken multiple times during the course of a medical degree, it would have been particularly interesting to examine the correlation between the frequency that this exam had been taken with microsurgical task performance. However, we would also like to state that a proportion of the subjects in this study have likely undertaken the ‘Duke Elder exam’. Finally, using the ‘Duke Elder exam’ as a determinant of ophthalmic career interest would provide scope to undertake a multi-centre study instead of the authors’ single-centre study as the exam is undertaken by medical students from various universities across the UK.
Regardless, we thank the authors for their insightful prospective cohort study and for highlighting the potential downsides to using the EyeSi Simulator as an assessment tool for entry into ophthalmic specialty training.
REFERENCE
1. L Joshi, V A Shanmuganathan, R L Kneebone, W Amoaku. Performance in the Duke-Elder ophthalmology undergraduate prize examination and future careers in ophthalmology. Eye (Lond). 2011 Aug;25(8):1027-1033.
To,
The editor
We would like to congratulate and highly appreciate Ha et al. for this simple and innovative study on ‘Changes in intraocular pressure during reading or writing on smartphones in patients with normal tension glaucoma’. However, we have few queries and seek your kind attention.
First, out of 38 trabeculectomised eyes, 12 were not using any anti-glaucoma medications whereas remaining was on some antiglaucoma medications. An overall analysis was done including all trabeculectomised eyes. However, we think, it would have been better analyzed if the authors had compared eyes with or without antiglaucoma medications separately. We are interested to know the pattern of intraocular pressure (IOP) fluctuation in eyes with trabeculectomy not using any antiglaucoma medications.
Second, in this present study, no control group was included.
Third, it was established that there is circadian pattern of IOP change in normal tension glaucoma patients. Therefore, we are interested to know whether IOP was measured in all patients at the same time of day or was it measured at different times of the day.
References
1. Ha A, Kim Y K, Kim J et al. Changes in intraocular pressure during reading or writing on smartphones in patients with normal-tension glaucoma. Br J Ophthalmol. 2019; Sep314467doi.org/10.1136/bjophthalmol-2019-314467
2. Lee Y R, Kook M S, Joe S G et al. Circadian (24- hour) pattern of intraocular pressure and visual...
To,
The editor
We would like to congratulate and highly appreciate Ha et al. for this simple and innovative study on ‘Changes in intraocular pressure during reading or writing on smartphones in patients with normal tension glaucoma’. However, we have few queries and seek your kind attention.
First, out of 38 trabeculectomised eyes, 12 were not using any anti-glaucoma medications whereas remaining was on some antiglaucoma medications. An overall analysis was done including all trabeculectomised eyes. However, we think, it would have been better analyzed if the authors had compared eyes with or without antiglaucoma medications separately. We are interested to know the pattern of intraocular pressure (IOP) fluctuation in eyes with trabeculectomy not using any antiglaucoma medications.
Second, in this present study, no control group was included.
Third, it was established that there is circadian pattern of IOP change in normal tension glaucoma patients. Therefore, we are interested to know whether IOP was measured in all patients at the same time of day or was it measured at different times of the day.
References
1. Ha A, Kim Y K, Kim J et al. Changes in intraocular pressure during reading or writing on smartphones in patients with normal-tension glaucoma. Br J Ophthalmol. 2019; Sep314467doi.org/10.1136/bjophthalmol-2019-314467
2. Lee Y R, Kook M S, Joe S G et al. Circadian (24- hour) pattern of intraocular pressure and visual field damage in eyes with normal tension glaucoma. Investigative Ophthalmology and visual science February 2012, vol. 53, 881-887.doi:10.1167/iovs.11-7846
Dear Editor,
We read the article published by Chaudhary, et al (1) with great interest and laud them on the quality and design of their study. Primary congenital blindness (PCG) poses a challenge to clinicians, both in terms of diagnosis, and treatment. (2)
We would like to bring to the authors’ notice a similar study conducted in 2017 (3) of 230 eyes of 121 PCG patients having undergone a primary CTT. This study differed from the present study in the fact that it had a longer average follow-up period of 28.87 years with a more concentrated follow-up range of 21.5-38 years. There were also two main differences in the findings of the two studies.
Contrary to the results in the present study where the infants with PCG fared better than the neonates (48.9% >6/60), the previous study found that 76.3% newborns with PCG had a vision better than 6/60. Additionally, the previous study, found visual acuity to be better than 6/60 in a greater proportion of patients (76.1%) at the last follow-up, as compared to the proportion in the study by Chaudhary et al (55.3%). Applying the WHO recommendation of measuring vision in the better eye, (4) the results improved to 89.3% in the study by Sood et al. (3)
A possible reason for these disparities between the studies could be the difference in presentation times of the patients and the study inclusion criteria. While the present study reports late presentation, over half of the patients (53%) in the earlier pub...
Show MoreDear Editor,
We read with interest the post-hoc study by Waldstein and colleagues concerning the impact of posterior vitreous detachment (PVD) on the efficacy of anti-VEGF treatment in neovascular age-related macular degeneration (AMD). However, the reliability of spectral-domain optical coherence tomography (SD-OCT) in confirming PVD status, upon which the findings of this study are dependent, is questionable.[1, 2] In particular, OCT is poor at distinguishing between fully attached vitreous and complete PVD.
Hwang et al recently reported limited sensitivity of SD-OCT in detecting complete PVD when compared to clinical findings at the time of vitrectomy.[1] It was found that among patients awaiting vitrectomy, OCT diagnosis of complete PVD (based on the absence of visible posterior vitreous cortex or a premacular bursa on SD-OCT) had a positive predictive value of just 53% when compared to intra-operative findings.
PVD remains a clinical diagnosis that is based on the identification of the posterior hyaloid membrane (PHM), a diaphanous, wrinkled film observable during biomicroscopic examination. The Weiss ring which it incorporates is a more variable and less reliable confirmatory sign of PHM detachment from the optic nerve head. The visible PHM is a consistent clinical finding in patients with PVD and correlates histopathologically with a type IV collagen basement membrane which begins life attached to the retina as the internal limiting membrane.[3...
Show MoreTabandeh and colleagues[1] presented a contrarian viewpoint on the redundancy of scleral-depressed vitreous base shaving: a procedure we have come to take for granted during vitrectomy for retinal detachment (RD). Their excellent outcomes are great news for trainee surgeons, as lens touch is likely during meticulous base dissection in phakic eyes. Sutureless micro-incision vitreous surgery is indeed more secure with residual peripheral vitreous, which plugs the sclerotomy leaks. The authors’ attribution of their high success rate to circumferential laser photocoagulation is validated by a randomized clinical trial.[2] The cases with residual silicone oil (13/89; 15%) should however not be included in the anatomical success; a significant percentage of them re-detach after oil removal.[3]
Show MoreThe optional use of scleral buckle in this study is confusing. The authors have not specified the choice of buckle (most probably an encircling belt-buckle). Vitreous base-shaving is critical to anatomical success when no encirclage is used.[3] The authors reported no additional benefit from buckling, though it was preferentially performed for complex detachments. We therefore do not have clarity about the one moot issue this study could settle: whether vitrectomy sans base-shaving is good enough for simple RD at least. A recent study suggested that anterior dissection is essential in the presence of posteriorly inserted vitreous base.[4] Did the authors observe this vitreous config...
Dr. Portabella reviewed the stability of 345 consecutive cases of scleral-sutured posterior chamber IOLs retrospectively.1 In discussing sutured scleral-fixated IOLs several main points must be considered: 1) type of suture utilized; 2) length of follow-up; 3) multiple surgeons or single surgeon; 4) type of knot utilized; and 5) reoperation rate.
This paper by Portabella et al.1 involved use of Prolene (polypropylene) or Mersilene sutures, follow-up with a maximum of 10 years, multiple surgeons, a knot with a single loop through the sclera and around the haptic, and a reoperation rate of 7.2%. The Vote et al study2 reviewed 61 eyes with Prolene sutures, follow-up with a maximum of 10.6 years, multiple surgeons, variable knots, and an extremely high rate of redislocation of 26.2%, which they postulated was due to suture breakage. This high rate of redislocation has not been confirmed in any other study.3,4
A recent study by Kokame et al3 involved 118 eyes utilizing 10-0 Prolene sutures, a single surgeon, follow-up of up to 24.75 years, a knot with two sutures - one secured to the haptic by a cow-hitch and the other to the sclera with both sutures tied together in a single knot under a scleral flap, and a broken suture rate of 0.5% (1/214 fixation sutures). The maximum follow-up of 24.75 years with stable fixation strongly supports the stability of 10-0 Prolene. Higher rates of redislocations of sutured scleral-fixated IOLs can be due to multiple surgeo...
Show MoreDear Editor,
Show MoreWe have read the clinical case report entitled “Ocular manifestations of a patient hospitalized with a new coronavirus disease confirmed in 2019” by Chen L, et al.1 We congratulate the authors for this important work and wish to share our comment concerning the retinal findings. The authors indicated that Spectral-domain optical coherence tomography (SD-OCT) imaging was normal in both eyes. However, we would like to highlight the presence of hyper-reflective focal points at the level of the internal plexiform layer (IPL) and the ganglion cell layer (GCL). The report later published by Marinho PM, et al. in Lancet on May 12, 2020 "Retinal findings in patients with COVID-19" described the presence of focal hyperreflective dots at the IPL and GCL levels in all patients (24 eyes of 12 patients), which was the first report of SD-OCT retinal abnormalities in patients with COVID 19.2 We compared the two SD-OCT images published by Chen L, et al. to those published by Marinho PM, et al. All images were reviewed by two different retina specialists (NM, RTJH), and our analysis was strongly consistent. We have implemented the algorithm using the Python script3 to adjust the size and resolution of the images, and flipped the C by Marinho PM, et al. using fovea as the reference to obtain comparable images. We overlaid the images published by Chen L, et al. with those published by Marinho PM, et al. We were able to demonstrate that the hyperreflective lesions...
At the outset, we would like to congratulate the authors for determining the presence of the viral RNA over time in conjunctival specimens of a patient with COVID-19, which was much needed.
Show MoreThe clinical course of viral conjunctivitis is self-limiting. Usually only supportive treatments like cold compress, artificial tears and topical steroids are given. The time duration taken for symptoms to subside without treatment ranges from 4-6 days to 2-3 weeks, depending upon the type of disease.[1] Clinical studies regarding the usage of antivirals for conjunctivitis reveal that they were effective only for DNA viruses and was not free of toxicity.[2]
In the case report regarding ocular manifestation of patient with 2019 novel corona virus disease,[3] the ocular symptoms of patient resolved after 5 days of its onset and the author claims it to be possibly due to treatment with ribavirin eye drops. As Corona virus is a RNA virus, we believe that antiviral therapy would have been limited use. Adequate corneal tissue levels of antiviral agents are achieved by both topical and systemic administration.[4] If antiviral therapy was the reason for improvement of ocular symptoms, the patient was on three oral antiviral drugs (Umifenovir, lopinavir and ritonavir) in addition to topical ribavirin. Therefore, attributing only topical ribavirin for curing ocular symptoms may not be appropriate with the limited evidence.
The authors also had mentioned that sterile synthetic f...
Synopsis:
Applying Pearson r to assesses the repeatability of a test is a methodologic mistake which leads to misinterpretation.
Repeatability of automated leakage quantification and microaneurysm identification utilising an analysis platform for ultra-widefield fluorescein angiography. Avoid misinterpretation
Show MoreDear editor, We were interested to read the paper by Jiang A et al. published in Apr 2020 edition of the Br J Ophthalmol.1 Ultra-wide field fluorescein angiography (UWFA) provides unique opportunities for panretinal assessment of retinal diseases. The objective quantification of UWFA features is a labour-intensive manual process, limiting its utility. The authors aimed to assesses the consistency/repeatability of an automated assessment platform for the characterization of retinal vascular features, quantification of microaneurysms (MA) and leakage foci in UWFA images. For each eye, two arteriovenous-phase images and two late-phase images were selected. Automated assessment was performed for retinal vascular features, MA identification and leakage segmentation. Panretinal and zonal assessment of metrics was performed. The authors mentioned a significant correlation between paired time points for retinal vessel area and vessel length on early images (Pearson r=0.92, p<0.0001; Pearson r=0.94, p<0.0001) and late images (Pearson r=0.92, p<0.0001; Pearson r=0.92, p<0.0001, respectively). Panretinal and zonal MA counts demonst...
Optic disc drusen pose a diagnostic challenge when trying to differentiate between papilloedema and pseudopapilloedema.1 Dahlman-Noor et al highlight the importance of a structured history when evaluating children with optic nerve head (ONH) swelling. The authors recommend a future study to explore the diagnostic accuracy of an algorithm published by the Royal College of Paediatrics and Child Health (RCPCH) which details key features of the history (e.g. headache, vomiting, visual symptoms) that should trigger neuroimaging.2
As part of a prospective study of children referred to our regional paediatric ophthalmology service for assessment for ONH swelling, we implemented this algorithm. 122 children under 16 years of age were assessed from 1st January to 31st December 2018. 93% (113/122) had optic disc drusen, 4% (5/122) had normal optic discs, and 3% (4/122) had papilloedema. Two cases of papilloedema were caused by idiopathic intracranial hypertension (IIH) and two by venous sinus thrombosis.
Of the 118 patients with drusen or normal discs, only one fulfilled the RCPCH criteria for neuroimaging: a 14-year-old girl with persistent headaches and vomiting. Neuroimaging and lumbar puncture were unremarkable, and her symptoms were ultimately attributed to migraine.
For the four patients with papilloedema, the algorithm-derived questions would have triggered neuroimaging in three cases. This yields a specificity of 99% but a sensitivity of only...
Show MoreWe thank S N Gillan et al for their original study investigating the influence of medical student career aims on ophthalmic surgical simulator performance. The authors reported no association between medical student interest in pursuing an ophthalmic career and microsurgical task performance.
The authors recruited subjects from the medical student division of the ‘Moorfields Academy’ and deemed these subjects as students with career interests in ophthalmology. However, we suggest that a more accurate measure in determining ophthalmic career interest would be whether these students had undertaken the ‘Duke Elder exam’, an annual national undergraduate prize examination in ophthalmology, and the only specialty-specific prize examination in the UK. We believe that undertaking the ‘Duke Elder exam’ and the preparation that this involves demonstrates commitment to the ophthalmic specialty more than being a member of the ‘Moorfields Academy’. Almost 30% of candidates ranked in the top 20 in this exam eventually pursue an ophthalmic career [1].
Moreover, as the ‘Duke Elder exam’ can be taken multiple times during the course of a medical degree, it would have been particularly interesting to examine the correlation between the frequency that this exam had been taken with microsurgical task performance. However, we would also like to state that a proportion of the subjects in this study have likely undertaken the ‘Duke Elder exam’. Finally, using the ‘Duke Elder exam’...
Show MoreTo,
The editor
We would like to congratulate and highly appreciate Ha et al. for this simple and innovative study on ‘Changes in intraocular pressure during reading or writing on smartphones in patients with normal tension glaucoma’. However, we have few queries and seek your kind attention.
First, out of 38 trabeculectomised eyes, 12 were not using any anti-glaucoma medications whereas remaining was on some antiglaucoma medications. An overall analysis was done including all trabeculectomised eyes. However, we think, it would have been better analyzed if the authors had compared eyes with or without antiglaucoma medications separately. We are interested to know the pattern of intraocular pressure (IOP) fluctuation in eyes with trabeculectomy not using any antiglaucoma medications.
Second, in this present study, no control group was included.
Third, it was established that there is circadian pattern of IOP change in normal tension glaucoma patients. Therefore, we are interested to know whether IOP was measured in all patients at the same time of day or was it measured at different times of the day.
References
Show More1. Ha A, Kim Y K, Kim J et al. Changes in intraocular pressure during reading or writing on smartphones in patients with normal-tension glaucoma. Br J Ophthalmol. 2019; Sep314467doi.org/10.1136/bjophthalmol-2019-314467
2. Lee Y R, Kook M S, Joe S G et al. Circadian (24- hour) pattern of intraocular pressure and visual...
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