The British Journal of Ophthalmology article, “Novel MYOC gene mutation in a Chinese family with primary open angle glaucoma” by Lei and coworkers describes a Tyr437His mutation in the myocilin gene. Contrary to descriptions in the title, abstract, and text of this article, the Tyr437His mutation is not novel. We and others have previously reported the same Tyr437His mutation in several publications dating back to 1997 [1-5].
1 Stone EM, Fingert JH, Alward WLM, et al. Identification of a Gene That Causes Primary Open Angle Glaucoma. Science 1997;275:668–70.
2 Alward WL, Fingert JH, Coote MA, et al. Clinical features associated with mutations in the chromosome 1 open-angle glaucoma gene (GLC1A). N Engl J Med 1998;338:1022–7.
3 Wiggs JL, Allingham RR, Vollrath D, et al. Prevalence of mutations in TIGR/Myocilin in patients with adult and juvenile primary open-angle glaucoma. Am J Hum Genet 1998;63:1549–52.
4 Fingert JH, Héon E, Liebmann JM, et al. Analysis of myocilin mutations in 1703 glaucoma patients from five different populations. Hum Mol Genet 1999;8:899–905.
5 Fingert JH, Stone EM, Sheffield VC, et al. Myocilin glaucoma. Survey of Ophthalmology 2002;47:547–61.
Dear Editors,
Thanks for your email and comments for John H Fingert et al.
In our work, we aim to characterize the genotype(s), phenotype(s) and age-related penetrance in a Chinese family with primary open-angle glaucoma (POAG). We recruited a four-generation Chinese family with 22 participants and identified a novel heterozygous MYOC gene mutation (exon3 c.1309T>C p.Y437H) only among seven POAG patients and one ocular hypertension (OHT) patient. Further, we summarized the exact phenotype characterization of MYOC Y437H mutation and calculated the age-related penetrance of this family. Hopefully, we can do a favor in establishing genotype–phenotype correlations, which play a significant role in predicting the range of phenotypic variation of a specific mutation, in managing the disease better and in genetic counselling.
To the best of our knowledge, this is the first report of Y437H mutation in Chinese.Thus, we titled our work as “A novel MYOC gene mutation in a Chinese family with primary open-angle glaucoma”, which we really mean is a novel mutation only in Chinese population. We are very sorry about the misunderstanding the inappropriate title of our article may cause. In “Molecular analysis” section, we have affirmed that the Y437H mutation has been reported and referred previous article titled” Identification of a gene that causes primary open angle glaucoma” and so on.
To avoid above misunderstanding ever happening, if it is possible we’d li...
Dear Editors,
Thanks for your email and comments for John H Fingert et al.
In our work, we aim to characterize the genotype(s), phenotype(s) and age-related penetrance in a Chinese family with primary open-angle glaucoma (POAG). We recruited a four-generation Chinese family with 22 participants and identified a novel heterozygous MYOC gene mutation (exon3 c.1309T>C p.Y437H) only among seven POAG patients and one ocular hypertension (OHT) patient. Further, we summarized the exact phenotype characterization of MYOC Y437H mutation and calculated the age-related penetrance of this family. Hopefully, we can do a favor in establishing genotype–phenotype correlations, which play a significant role in predicting the range of phenotypic variation of a specific mutation, in managing the disease better and in genetic counselling.
To the best of our knowledge, this is the first report of Y437H mutation in Chinese.Thus, we titled our work as “A novel MYOC gene mutation in a Chinese family with primary open-angle glaucoma”, which we really mean is a novel mutation only in Chinese population. We are very sorry about the misunderstanding the inappropriate title of our article may cause. In “Molecular analysis” section, we have affirmed that the Y437H mutation has been reported and referred previous article titled” Identification of a gene that causes primary open angle glaucoma” and so on.
To avoid above misunderstanding ever happening, if it is possible we’d like to change our title as “The clinical feature of myocilin Y437H mutation in a Chinese family with primary open-angle glaucoma”. If you have any queries, please don’t hesitate to contact us.
Yours sincerely,
Lei Lei
We appreciate the valuable comments from Dr. Sato regarding our recently published article.1 Dr. Sato’s comments raise important points about definition of collateral vessels in eyes with branch retinal vein occlusion (BRVO).
As previously reported,2 collateral vessels develop from the pre-existing retinal capillary network to drain a blood flow from an obstructed vein into an adjacent area in eyes with BRVO. Therefore, in the current study, we defined collateral vessels as dilated and tortuous capillaries occurring in pre-existing capillary beds and linking the obstructed vessel with the nearest patent vessel. Thus, the adjacent vessels also seemed to be dilated and tortuous, which had been similarly observed in our previous study.3 We speculate that the pressure gradient between an obstructed vein and neighbouring unobstructed vessels causes collateral vessels formation. The collaterals detection rate in the current study was higher than in the previous study.3 This is because wider optical coherence tomography angiography (OCTA) images, the size of which was 6 ✕ 6 mm in area, were used in the current study.
Regarding the other comment about the location of collateral vessels, Freund et al4 reported that collateral vessels were observed in only deep retinal capillary layer. However, we confirmed that the collateral vessels were present in both the superficial and the deep capillary layers on B scan images of OCTA. Additionally, fluoresc...
We appreciate the valuable comments from Dr. Sato regarding our recently published article.1 Dr. Sato’s comments raise important points about definition of collateral vessels in eyes with branch retinal vein occlusion (BRVO).
As previously reported,2 collateral vessels develop from the pre-existing retinal capillary network to drain a blood flow from an obstructed vein into an adjacent area in eyes with BRVO. Therefore, in the current study, we defined collateral vessels as dilated and tortuous capillaries occurring in pre-existing capillary beds and linking the obstructed vessel with the nearest patent vessel. Thus, the adjacent vessels also seemed to be dilated and tortuous, which had been similarly observed in our previous study.3 We speculate that the pressure gradient between an obstructed vein and neighbouring unobstructed vessels causes collateral vessels formation. The collaterals detection rate in the current study was higher than in the previous study.3 This is because wider optical coherence tomography angiography (OCTA) images, the size of which was 6 ✕ 6 mm in area, were used in the current study.
Regarding the other comment about the location of collateral vessels, Freund et al4 reported that collateral vessels were observed in only deep retinal capillary layer. However, we confirmed that the collateral vessels were present in both the superficial and the deep capillary layers on B scan images of OCTA. Additionally, fluorescein angiography images, which usually provides the information about retinal superficial capillaries and less about deep capillaries,5 also demonstrated the presence of collateral vessels, which may support the presence in the superficial capillaries.
The authors would again like to thank Dr. Sato for his interest in our work and the Editor for the opportunity to clarify the interesting and important issues that he has raised.
References:
1. Suzuki N, Hirano Y, Tomiyasu T, et al. Collateral vessels on optical coherence tomography angiography in eyes with branch retinal vein occlusion. Br J Ophthalmol. (in press).
2. Klein R, Klein B, Henkind P, et al. Retinal collateral vessel formation. Invest Ophthalmol. 1971;10:471-80.
3. Suzuki N, Hirano Y, Yoshida M, et al. Microvascular abnormalities on optical coherence tomography angiography in macular edema associated with branch retinal vein occlusion. Am J Ophthalmol. 2016;161:126-32.
4. Freund KB, Sarraf D, Leong BCS, et al. Association of optical coherence tomography angiography of collaterals in retinal vein occlusion with major venous outflow through the deep vascular complex. JAMA Ophthalmology. 2018;136:1262-70.
5. Mendis KR, Balaratnasingam C, Yu P, et al. Correlation of histologic and clinical images to determine the diagnostic value of fluorescein angiography for studying retinal capillary detail. Invest Ophthalmol Vis Sci. 2010;51:5864-9.
We would like to thank Dr. Tarannum Mansoori for the interest in our study, “Intraocular pressure change after injection of intravitreal dexamethasone (Ozurdex) implant in Korean patients” and highlighting important issues about the intraocular pressure (IOP) measurement methods and the correlation of IOP with age.1
We used KT-800 Non-Contact Tonometer (Kowa, Tokyo, Japan) to measure IOP initially and rechecked with GAT if necessary. Unless the patient was diagnosed with glaucoma, NCT was initially used to measure both pre- and post-injection IOP.
As Dr. Tarannum Mansoori has pointed out, we also agree that GAT is the gold standard for IOP measurement. If the IOP measured with NCT was found to be high, it was always rechecked with GAT. GAT was used in 2 situations in our study. First, when the patients had a previous history of glaucoma, and second, when the patients’ IOP as measured with NCT was high (greater than 20). Thus, in cases of high IOP, the measurement involved NCT and was also always double checked with GAT. Moreover, multiple IOP measurements were obtained with GAT in cases of high IOP, and the average value of the measurements was regarded as the final IOP.
The range of age of the patients for injection of intravitreal dexamethasone was broad, from 16 to 88 years. We know that very young age (less than six years) or an older age are risk factors for steroid-induced glaucoma.2 However, regrettably, we have not performed any further analysis...
We would like to thank Dr. Tarannum Mansoori for the interest in our study, “Intraocular pressure change after injection of intravitreal dexamethasone (Ozurdex) implant in Korean patients” and highlighting important issues about the intraocular pressure (IOP) measurement methods and the correlation of IOP with age.1
We used KT-800 Non-Contact Tonometer (Kowa, Tokyo, Japan) to measure IOP initially and rechecked with GAT if necessary. Unless the patient was diagnosed with glaucoma, NCT was initially used to measure both pre- and post-injection IOP.
As Dr. Tarannum Mansoori has pointed out, we also agree that GAT is the gold standard for IOP measurement. If the IOP measured with NCT was found to be high, it was always rechecked with GAT. GAT was used in 2 situations in our study. First, when the patients had a previous history of glaucoma, and second, when the patients’ IOP as measured with NCT was high (greater than 20). Thus, in cases of high IOP, the measurement involved NCT and was also always double checked with GAT. Moreover, multiple IOP measurements were obtained with GAT in cases of high IOP, and the average value of the measurements was regarded as the final IOP.
The range of age of the patients for injection of intravitreal dexamethasone was broad, from 16 to 88 years. We know that very young age (less than six years) or an older age are risk factors for steroid-induced glaucoma.2 However, regrettably, we have not performed any further analysis regarding the correlation with age in our study. We plan to perform further analysis and look forward to sharing our results in the near future.
References
1 Choi W, Park SE, Kang HG, et al. Intraocular pressure change after injection of intravitreal dexamethasone (Ozurdex) implant in Korean patients. Br J Ophthalmol 2018.
2 Lam DS, Fan DS, Ng JS, et al. Ocular hypertensive and anti-inflammatory responses to different dosages of topical dexamethasone in children: a randomized trial. Clin Exp Ophthalmol 2005;33:252-8.
We read the recent article in the journal by Monfermé and coauthors (1) on phenotypic associations of TYR R402Q compound heterozygosity with keen interest. Given our own and others previous findings (2-4) that the R402Q-S192Y haplotype seemed to have a stronger biological effect, we were surprised that a triallelic effect was not supported in the clinical discussion by Monfermé et al. When we examined these results more closely, we noted that their sample included 52 S192Y variant allele carriers out of the entire collection of 69 patients, of whom 31 (44.9%) carried the R402Q-S192Y double variant haplotype. In our own collections from the Australian general population (BNMS and BLTS, Duffy et al., in submission), only 6% of R402Q carriers also carried S192Y in cis. When we examined the European 1000 Genomes subsamples, there too only 7% of R402Q haplotypes had the 192Y rather than 192S wild type allele. So, even though Monfermé et al could not detect a statistically significant additive effect on OCA trait severity due to the S192Y polymorphism within their sample, it is clear that the S192 variant allele is markedly overrepresented compared to the general population, suggesting that it must have some relationship to albinism. This genetic association of the TYR R402Q-S192Y double variant haplotype with OCA1 is now clearly causative (2, 3), and explains some of the missing heritability that has previously been seen in OCA patients (4).
We read the recent article in the journal by Monfermé and coauthors (1) on phenotypic associations of TYR R402Q compound heterozygosity with keen interest. Given our own and others previous findings (2-4) that the R402Q-S192Y haplotype seemed to have a stronger biological effect, we were surprised that a triallelic effect was not supported in the clinical discussion by Monfermé et al. When we examined these results more closely, we noted that their sample included 52 S192Y variant allele carriers out of the entire collection of 69 patients, of whom 31 (44.9%) carried the R402Q-S192Y double variant haplotype. In our own collections from the Australian general population (BNMS and BLTS, Duffy et al., in submission), only 6% of R402Q carriers also carried S192Y in cis. When we examined the European 1000 Genomes subsamples, there too only 7% of R402Q haplotypes had the 192Y rather than 192S wild type allele. So, even though Monfermé et al could not detect a statistically significant additive effect on OCA trait severity due to the S192Y polymorphism within their sample, it is clear that the S192 variant allele is markedly overrepresented compared to the general population, suggesting that it must have some relationship to albinism. This genetic association of the TYR R402Q-S192Y double variant haplotype with OCA1 is now clearly causative (2, 3), and explains some of the missing heritability that has previously been seen in OCA patients (4).
1 Dermatology Research Centre, The University of Queensland, The University of Queensland Diamantina Institute, Brisbane, Qld, Australia; 2 QIMR Berghofer Medical Research Institute, Brisbane, Australia
References
1. Monferme S, Lasseaux E, Duncombe-Poulet C, et al. Mild form of oculocutaneous albinism type 1: phenotypic analysis of compound heterozygous patients with the R402Q variant of the TYR gene. Br J Ophthalmol 2018 doi: 10.1136/bjophthalmol-2018-312729
2. Jagirdar K, Smit DJ, Ainger SA, et al. Molecular analysis of common polymorphisms within the human Tyrosinase locus and genetic association with pigmentation traits. Pigment cell & melanoma research 2014;27(4):552-64. doi: 10.1111/pcmr.12253
3. Norman CS, O'Gorman L, Gibson J, et al. Identification of a functionally significant tri-allelic genotype in the Tyrosinase gene (TYR) causing hypomorphic oculocutaneous albinism (OCA1B). Sci Rep 2017;7(1):4415. doi: 10.1038/s41598-017-04401-5
4. Gronskov K, Jespersgaard C, Bruun GH, et al. A pathogenic haplotype, common in Europeans, causes autosomal recessive albinism and uncovers missing heritability in OCA1. Sci Rep 2019;9(1):645. doi: 10.1038/s41598-018-37272-5
We thank Dr. Montserrat for the letter regarding our article “Three-year outcomes of small incision lenticule extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) for myopia and myopic astigmatism.”1
Their first concern is that the predictability of the FS-LASIK group was 65% of eyes within ±0.5 diopter (D), which is also different from our experience. Of note, 95% of eyes were within ±1.25 D in the FS-LASIK group. This may be due to the long-term follow-up of 3 years leading to variability in the manifest refraction over time. In fact, our predictability results were similar to that of other long-term studies, as shown in Table 1.1-5 Moreover, it is likely a reflection of selection bias in our retrospective analysis i.e. patients with visual complaints were more willing to participate in the follow-up at 3 years – and we had acknowledged this as a limitation in our discussion. However, the probability of this bias may be the same for both surgical procedures and therefore did not significantly affect the final conclusion in our analysis.
Table1 Summary of Long-term Predictability Results for LASIK
Study Eyes （patients） Preoperative MRSE (D) Follow-up ± 0.50 of Emmetropia (%)
Han T 41(41) −7.15±1.92 3 years 65
Kobashi H 30(30) −3.81±1.40 2 years 73
Alio JL 97(70) −7.15±1.92 10 years 49
Zalentein WN 38(21) spere of -6.55±1.74 2 years 63
O'Doherty M 94(49) −4.85±2.35 5 years 60 ...
We thank Dr. Montserrat for the letter regarding our article “Three-year outcomes of small incision lenticule extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) for myopia and myopic astigmatism.”1
Their first concern is that the predictability of the FS-LASIK group was 65% of eyes within ±0.5 diopter (D), which is also different from our experience. Of note, 95% of eyes were within ±1.25 D in the FS-LASIK group. This may be due to the long-term follow-up of 3 years leading to variability in the manifest refraction over time. In fact, our predictability results were similar to that of other long-term studies, as shown in Table 1.1-5 Moreover, it is likely a reflection of selection bias in our retrospective analysis i.e. patients with visual complaints were more willing to participate in the follow-up at 3 years – and we had acknowledged this as a limitation in our discussion. However, the probability of this bias may be the same for both surgical procedures and therefore did not significantly affect the final conclusion in our analysis.
Table1 Summary of Long-term Predictability Results for LASIK
Study Eyes （patients） Preoperative MRSE (D) Follow-up ± 0.50 of Emmetropia (%)
Han T 41(41) −7.15±1.92 3 years 65
Kobashi H 30(30) −3.81±1.40 2 years 73
Alio JL 97(70) −7.15±1.92 10 years 49
Zalentein WN 38(21) spere of -6.55±1.74 2 years 63
O'Doherty M 94(49) −4.85±2.35 5 years 60
MSRE = manifest spherical refractive equivalent; D = diopters;
The conclusion of this study is that both SMILE and FS-LASIK were safe and equally effective for myopic and astigmatic correction. Short -term studies have reached similar conclusions, and no long-term studies show that FS-LASIK has better refractive outcomes than SMILE.2, 6
In this study, the Visumax system was used to make corneal flaps. While different machines may have different refractive outcomes, studies have reported that the Vismax and Intralase system have similar refractive results.7, 8 Moreover, a large number of basic and clinical studies comparing SMILE and FS-LASIK also used the same platforms (as in our study). 9-13 We also look forward to the comparison of SMILE and FS-LASIK with other platforms, but this does not affect the significance of our research.
We appreciate this opportunity to clarify these questions.
References
1. Han T., Xu Y., Han X., Zeng L., Shang J., Chen X. and Zhou X. Three-year outcomes of small incision lenticule extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) for myopia and myopic astigmatism. Br J Ophthalmol. 2019;103:565-568.
2. Kobashi H., Kamiya K., Igarashi A., Takahashi M. and Shimizu K. Two-years results of small-incision lenticule extraction and wavefront-guided laser in situ keratomileusis for Myopia. Acta Ophthalmol. 2018;96:e119-e126.
3. Alio J. L., Muftuoglu O., Ortiz D., Perez-Santonja J. J., Artola A., Ayala M. J., Garcia M. J. and de Luna G. C. Ten-year follow-up of laser in situ keratomileusis for myopia of up to -10 diopters. Am J Ophthalmol. 2008;145:46-54.
4. Zalentein W. N., Tervo T. M. and Holopainen J. M. Seven-year follow-up of LASIK for myopia. J Refract Surg. 2009;25:312-318.
5. O'Doherty M., O'Keeffe M. and Kelleher C. Five year follow up of laser in situ keratomileusis for all levels of myopia. Br J Ophthalmol. 2006;90:20-23.
6. Xia L. K., Ma J., Liu H. N., Shi C. and Huang Q. Three-year results of small incision lenticule extraction and wavefront-guided femtosecond laser-assisted laser in situ keratomileusis for correction of high myopia and myopic astigmatism. Int J Ophthalmol. 2018;11:470-477.
7. Rosman M., Hall R. C., Chan C., Ang A., Koh J., Htoon H. M., Tan D. T. and Mehta J. S. Comparison of efficacy and safety of laser in situ keratomileusis using 2 femtosecond laser platforms in contralateral eyes. J Cataract Refract Surg. 2013;39:1066-1073.
8. Ang M., Mehta J. S., Rosman M., Li L., Koh J. C., Htoon H. M., Tan D. and Chan C. Visual outcomes comparison of 2 femtosecond laser platforms for laser in situ keratomileusis. J Cataract Refract Surg. 2013;39:1647-1652.
9. Dong Z., Zhou X., Wu J., Zhang Z., Li T., Zhou Z., Zhang S. and Li G. Small incision lenticule extraction (SMILE) and femtosecond laser LASIK: comparison of corneal wound healing and inflammation. Br J Ophthalmol. 2014;98:263-269.
10. Riau A. K., Angunawela R. I., Chaurasia S. S., Lee W. S., Tan D. T. and Mehta J. S. Early corneal wound healing and inflammatory responses after refractive lenticule extraction (ReLEx). Invest Ophthalmol Vis Sci. 2011;52:6213-6221.
11. Ang M., Ho H., Fenwick E., Lamoureux E., Htoon H. M., Koh J., Tan D. and Mehta J. S. Vision-related quality of life and visual outcomes after small-incision lenticule extraction and laser in situ keratomileusis. J Cataract Refract Surg. 2015;41:2136-2144.
12. Liu M., Chen Y., Wang D., Zhou Y., Zhang X., He J., Zhang T., Sun Y. and Liu Q. Clinical Outcomes After SMILE and Femtosecond Laser-Assisted LASIK for Myopia and Myopic Astigmatism: A Prospective Randomized Comparative Study. Cornea. 2016;35:210-216.
13. Hou J., Wang Y., Lei Y. and Zheng X. Comparison of effective optical zone after small-incision lenticule extraction and femtosecond laser-assisted laser in situ keratomileusis for myopia. J Cataract Refract Surg. 2018;44:1179-1185.
We have read with interest the article by Han et al.,1 in which the authors compare the outcomes of myopia correction using small incision lenticule extraction (SMILE) versus laser in situ keratomileusis (LASIK) using the VisuMax® femtosecond laser (FS) to cut the corneal flap, and we have some concerns regarding this study we would like to share with the authors.
It is noteworthy that the authors found that only 65% of eyes were within ± 0.50 diopters of the attempted spherical equivalent correction after FS-LASIK, these results are clearly worse that those generally obtained with LASIK. It is accepted that the results obtained with excimer laser ablation, either using a surface ablation approach, or LASIK performed with mechanical microkeratome (MK) or using the Intralase® FS platform to correct myopia are quite similar.2,3 Indeed, our group has that 95% of unselected eyes with myopia of -3.9±1.5D3 and 80% of eyes with high myopia (-8.7±1.2D)4 were within ± 0.5D of emmetropia after LASIK. For this reason, we believe that the main conclusion of the article by Han et al.1 that “long-term outcomes of both SMILE and FS-LASIK are safe and equally effective for myopic and astigmatic correction” is clearly biased. In other words, the results of SMILE should have not been compared with a FS laser platform that does not seem to achieve the benchmark results clearly established for LASIK when correcting myopia.
It should be highlighted that different FS platforms appr...
We have read with interest the article by Han et al.,1 in which the authors compare the outcomes of myopia correction using small incision lenticule extraction (SMILE) versus laser in situ keratomileusis (LASIK) using the VisuMax® femtosecond laser (FS) to cut the corneal flap, and we have some concerns regarding this study we would like to share with the authors.
It is noteworthy that the authors found that only 65% of eyes were within ± 0.50 diopters of the attempted spherical equivalent correction after FS-LASIK, these results are clearly worse that those generally obtained with LASIK. It is accepted that the results obtained with excimer laser ablation, either using a surface ablation approach, or LASIK performed with mechanical microkeratome (MK) or using the Intralase® FS platform to correct myopia are quite similar.2,3 Indeed, our group has that 95% of unselected eyes with myopia of -3.9±1.5D3 and 80% of eyes with high myopia (-8.7±1.2D)4 were within ± 0.5D of emmetropia after LASIK. For this reason, we believe that the main conclusion of the article by Han et al.1 that “long-term outcomes of both SMILE and FS-LASIK are safe and equally effective for myopic and astigmatic correction” is clearly biased. In other words, the results of SMILE should have not been compared with a FS laser platform that does not seem to achieve the benchmark results clearly established for LASIK when correcting myopia.
It should be highlighted that different FS platforms approved for LASIK have been shown to obtain different refractive results, even using the same excimer laser.5 Thus, we do believe that the sound validation of new technology (SMILE) needs the comparison with the “benchmark” i.e. the results obtained with the “gold standard”, which is excimer ablation, in this case FS-LASIK performed with the Intralase.®
REFERENCES
1. Han T, Xu Y, Han X, et al. Three-year outcomes of small incision lenticule extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) for myopia and myopic astigmatism. Br J Ophthalmol 2019; 103:565-8.
2. Farjo AA, Sugar A, Schallhorn SC et al. Femtosecond lasers for LASIK flap creation. A report by the American academy of ophthalmology. Ophthalmology 2013; 120:e5-e20.
3. De Benito-Llopis L, Teus MA, Gil-Cazorla R, et al. Comparison between femtosecond laser assisted sub-bowman keratomileusis versus laser sub-epithelial keratectomy to correct myopia. Am J Ophthalmol 2009; 148:830-6.
4. De Benito-Llopis L, Teus MA, Sánchez-Pina JM. Comparison between LASEK with mitomycin C and LASIK for the correction of myopia of -7.00 to -13.75 D. J Refract Surg 2008; 24:516-23.
5. Garcia-Gonzalez M, Bouza-Miguens C, Parafita-Fernandez A, et al. Comparison of visual outcomes and flap morphology using 2 femtosecond-laser platforms. J Cataract Refract Surg 2018; 44:78-84.
We read the article published by Fieß, et al (1) with considerable interest and laud them on their study and the large cohort. Considerable work has been done earlier, which looks at factors associated with refractive errors, however few studies document association with birth weight. Keeping this in mind, we feel that there are a few points requiring further clarity in this article.
The authors mention their inability to control for factors such as paternal refractive error and family history. However, previous studies not only discuss the paternal refractive error and family history, but also expand the affecting factors to include the number of myopic parents. (2) In the study design described by Höhn et al. where comprehensive information on living conditions and birth weight was collected via computer-assisted telephone interviews, (3) information on number of myopic parents could also have been collected, and would have proven to be an important covariate in the analysis.
The authors also report that 8369 participants provided birth weight data, of which 45 were excluded due to unreliable self-reported data [<1000g (n=7) or >6000g (n=38)]. However, tables 2 and 3 report analysed results based on 8369 participants not 8324 (after exclusion of the 45). Even though 45 is an insignificant number, and does not affect the results as such, this aspect of the results needs further clarity.
We read the article published by Fieß, et al (1) with considerable interest and laud them on their study and the large cohort. Considerable work has been done earlier, which looks at factors associated with refractive errors, however few studies document association with birth weight. Keeping this in mind, we feel that there are a few points requiring further clarity in this article.
The authors mention their inability to control for factors such as paternal refractive error and family history. However, previous studies not only discuss the paternal refractive error and family history, but also expand the affecting factors to include the number of myopic parents. (2) In the study design described by Höhn et al. where comprehensive information on living conditions and birth weight was collected via computer-assisted telephone interviews, (3) information on number of myopic parents could also have been collected, and would have proven to be an important covariate in the analysis.
The authors also report that 8369 participants provided birth weight data, of which 45 were excluded due to unreliable self-reported data [<1000g (n=7) or >6000g (n=38)]. However, tables 2 and 3 report analysed results based on 8369 participants not 8324 (after exclusion of the 45). Even though 45 is an insignificant number, and does not affect the results as such, this aspect of the results needs further clarity.
Lastly, while the authors mention, further factors that affect BCVA and refractive errors such as amount of outdoor activity, near work in childhood and adolescence, prematurity (4,5) and gestational age, the non-inclusion of these possible confounders in their analysis makes it difficult to plan public health interventions based on these results. In the present form, the results of association of birth weight with myopic refractive error are significant but emphasise the need for further studies which control for gestational age, prematurity and other factors mentioned above, while studying the association, so that the effect can be isolated to birth weight. Public health interventions can then be planned accordingly.
We appreciate the opportunity to be able to discuss our views on the subject and the article in question.
References
1. Fieß A, Schuster AK, Nickels S, et al, Association of low birth weight with myopic refractive error and lower visual acuity in adulthood: results from the population-based Gutenberg Health Study (GHS), British Journal of Ophthalmology 2019;103:99-105.
2. Jones LA, Sinnott LT, Mutti DO, Mitchell GL, Moeschberger ML, Zadnik K. Parental history of myopia, sports and outdoor activities, and future myopia. Invest Ophthalmol Vis Sci. 2007;48(8):3524-32.
3. Höhn R, Kottler U, Peto T, et al. The ophthalmic branch of the Gutenberg Health Study: study design, cohort profile and self-reported diseases. PLoS One. 2015;10(3):e0120476. Published 2015 Mar 16. doi:10.1371/journal.pone.0120476
4. Cook A, White S, Batterbury M, et al. Ocular growth and refractive error development in premature infants without retinopathy of prematurity. Invest Ophthalmol Vis Sci. 2003;44:953–960.
5. Fieß A, Kölb-Keerl R, Knuf M, et al. Axial Length and Anterior Segment Alterations in Former Preterm Infants and Full-Term Neonates Analyzed With Scheimpflug Imaging. Cornea 2017;36:821–7.
We have read the paper written by Avila MY et al “Randomised prospective clinical trial of platelet-rich plasma injection in the management of severe dry eye” . Authors have evaluated the effectiveness of platelet-rich injection in lacrimal gland plus free-demand topical lubricants drops in Sjögren’s syndrome severe dry eye patients . Diagnosis was based on Schirmer I, break-up time(BUT), ocular surface staining (Oxford grid) and OSDI . Achieved results in interventional group showed a Schirmer I (6,7+/-0,9 vs 9,2+/-1 mm, p<0,002), BUT (6,4+/-0,4 vs 4,4+/-0,3 secs p=0,0005), staining (2,15+/-0,15 vs 1,2+/-0,18 p<0,001) and OSDI (59+/-0,4 VS 34+/-4, p<0,001). Surprisingly authors have not included the lacrimal osmolarity test, the most valuable diagnostic tool to rule in/out this disease (S and Sp >90%) . Unfortunately Schirmer I (without anesthesia) evaluates not just basal lacrimal tearing, it also measures reflex response giving confounding bias in measured result. Surface staining (a qualitative variable) was mistakenly analyzed with a t-paired student test. Regarding OSDI, PRP patients showed a test improvement (pre 59+/- 4,0 vs post 34+/-4,0) without change in disease severity. Finally, this trial enrolled a low number of patients (n=15) that according to authors assumptions we would expect a much greater sample size (Epidat 4.1 n=417 eyes). In conclusion, a novel and interesting new treatment for Sjögren’s dry eye patients that must be confirmed in the f...
We have read the paper written by Avila MY et al “Randomised prospective clinical trial of platelet-rich plasma injection in the management of severe dry eye” . Authors have evaluated the effectiveness of platelet-rich injection in lacrimal gland plus free-demand topical lubricants drops in Sjögren’s syndrome severe dry eye patients . Diagnosis was based on Schirmer I, break-up time(BUT), ocular surface staining (Oxford grid) and OSDI . Achieved results in interventional group showed a Schirmer I (6,7+/-0,9 vs 9,2+/-1 mm, p<0,002), BUT (6,4+/-0,4 vs 4,4+/-0,3 secs p=0,0005), staining (2,15+/-0,15 vs 1,2+/-0,18 p<0,001) and OSDI (59+/-0,4 VS 34+/-4, p<0,001). Surprisingly authors have not included the lacrimal osmolarity test, the most valuable diagnostic tool to rule in/out this disease (S and Sp >90%) . Unfortunately Schirmer I (without anesthesia) evaluates not just basal lacrimal tearing, it also measures reflex response giving confounding bias in measured result. Surface staining (a qualitative variable) was mistakenly analyzed with a t-paired student test. Regarding OSDI, PRP patients showed a test improvement (pre 59+/- 4,0 vs post 34+/-4,0) without change in disease severity. Finally, this trial enrolled a low number of patients (n=15) that according to authors assumptions we would expect a much greater sample size (Epidat 4.1 n=417 eyes). In conclusion, a novel and interesting new treatment for Sjögren’s dry eye patients that must be confirmed in the future with a more robust trial.
Reference:
1. Avila MY, et al. Br J Ophthalmol 2019;103(648653)
2. Aqrawi L, Chen X, Jensen J, Morthen M, Thiede B et al. Severity of clinical dry eye manifestations influences protein expression in tear fluid of patients with primary Sjögren’s syndrome. PlosOne. 2018; Oct:1-14
3. Karakus S, Akpek E, Agrawal D, Massof R. Validation of an objective measure of dry eye severity. Trans Vis Sci Tech. 2018;7(5):26
4. Wolffsohn J.S. TFOS DEWS II Diagnostic Methodology Report. The Ocular Surface 15 (2017);539-574
Dear Editor,
We have read with great interest the article by Singhal et al 1 on 'Clinical presentation and management of corneal fistula'. The authors have rightly highlighted the point that failure to perform simple test like Seidel test in cases of corneal ulcer, can lead to missing the diagnosis of corneal fistula, which in turn can lead to serious complications like endophthalmitis, panophthalmitis and phthisis bulbi.
One of the complications of persistent corneal fistula is the formation of anterior capsular cataract. It would have been more insightful if the authors had mentioned as to how many patients had developed anterior capsular cataract during follow up, as this can lead to a change in the future management of the eye.
Also, the authors have not mentioned the type of anaesthesia for doing the procedure. As creating the grooves around perforation to tuck in the tenons graft is difficult due to the friability of corneal tissue, the type of anaesthesia has a bearing on the intra operative surgical procedure. As doing the technique in topical anaesthesia will be technically challenging and administration of peribulbar block could lead to extrusion of the intraocular contents or extension of the perforation.
Although the study mentions the surgical technique for closing the fistula with a tenons patch graft, it does not mention the regimen of postoperative medical management.
In the discussion, the authors have mentioned that...
Dear Editor,
We have read with great interest the article by Singhal et al 1 on 'Clinical presentation and management of corneal fistula'. The authors have rightly highlighted the point that failure to perform simple test like Seidel test in cases of corneal ulcer, can lead to missing the diagnosis of corneal fistula, which in turn can lead to serious complications like endophthalmitis, panophthalmitis and phthisis bulbi.
One of the complications of persistent corneal fistula is the formation of anterior capsular cataract. It would have been more insightful if the authors had mentioned as to how many patients had developed anterior capsular cataract during follow up, as this can lead to a change in the future management of the eye.
Also, the authors have not mentioned the type of anaesthesia for doing the procedure. As creating the grooves around perforation to tuck in the tenons graft is difficult due to the friability of corneal tissue, the type of anaesthesia has a bearing on the intra operative surgical procedure. As doing the technique in topical anaesthesia will be technically challenging and administration of peribulbar block could lead to extrusion of the intraocular contents or extension of the perforation.
Although the study mentions the surgical technique for closing the fistula with a tenons patch graft, it does not mention the regimen of postoperative medical management.
In the discussion, the authors have mentioned that the cyanoacrylate glue application can lead to iritis. But all the cases included in the study had fistula size of not more than 3 mm. There is enough evidence to state that perforations and fistulas of sizes 2-3 mm can be closed safely with cyanoacrylate glue without any migration of the glue into the anterior chamber and obviate the need for other surgical treatment.2,3
References :
1. Singhal D, Sahay P, Maharana PK, et al. Clinical presentation and management of corneal fistula. Br J Ophthalmol. 2019 ;103:530-533.
2. Jhanji V, Young AL, Mehta JS, et al. Management of corneal perforation. Surv Ophthalmol. 2011 ;56:522-38.
3. Korah S, Selvin SS, Pradhan ZS, et al. Tenons Patch Graft in the Management of Large Corneal Perforations. Cornea 2016;35:696–9
Dear Editors,
The British Journal of Ophthalmology article, “Novel MYOC gene mutation in a Chinese family with primary open angle glaucoma” by Lei and coworkers describes a Tyr437His mutation in the myocilin gene. Contrary to descriptions in the title, abstract, and text of this article, the Tyr437His mutation is not novel. We and others have previously reported the same Tyr437His mutation in several publications dating back to 1997 [1-5].
1 Stone EM, Fingert JH, Alward WLM, et al. Identification of a Gene That Causes Primary Open Angle Glaucoma. Science 1997;275:668–70.
2 Alward WL, Fingert JH, Coote MA, et al. Clinical features associated with mutations in the chromosome 1 open-angle glaucoma gene (GLC1A). N Engl J Med 1998;338:1022–7.
3 Wiggs JL, Allingham RR, Vollrath D, et al. Prevalence of mutations in TIGR/Myocilin in patients with adult and juvenile primary open-angle glaucoma. Am J Hum Genet 1998;63:1549–52.
4 Fingert JH, Héon E, Liebmann JM, et al. Analysis of myocilin mutations in 1703 glaucoma patients from five different populations. Hum Mol Genet 1999;8:899–905.
5 Fingert JH, Stone EM, Sheffield VC, et al. Myocilin glaucoma. Survey of Ophthalmology 2002;47:547–61.
Dear Editors,
Show MoreThanks for your email and comments for John H Fingert et al.
In our work, we aim to characterize the genotype(s), phenotype(s) and age-related penetrance in a Chinese family with primary open-angle glaucoma (POAG). We recruited a four-generation Chinese family with 22 participants and identified a novel heterozygous MYOC gene mutation (exon3 c.1309T>C p.Y437H) only among seven POAG patients and one ocular hypertension (OHT) patient. Further, we summarized the exact phenotype characterization of MYOC Y437H mutation and calculated the age-related penetrance of this family. Hopefully, we can do a favor in establishing genotype–phenotype correlations, which play a significant role in predicting the range of phenotypic variation of a specific mutation, in managing the disease better and in genetic counselling.
To the best of our knowledge, this is the first report of Y437H mutation in Chinese.Thus, we titled our work as “A novel MYOC gene mutation in a Chinese family with primary open-angle glaucoma”, which we really mean is a novel mutation only in Chinese population. We are very sorry about the misunderstanding the inappropriate title of our article may cause. In “Molecular analysis” section, we have affirmed that the Y437H mutation has been reported and referred previous article titled” Identification of a gene that causes primary open angle glaucoma” and so on.
To avoid above misunderstanding ever happening, if it is possible we’d li...
Dear Editor,
We appreciate the valuable comments from Dr. Sato regarding our recently published article.1 Dr. Sato’s comments raise important points about definition of collateral vessels in eyes with branch retinal vein occlusion (BRVO).
Show MoreAs previously reported,2 collateral vessels develop from the pre-existing retinal capillary network to drain a blood flow from an obstructed vein into an adjacent area in eyes with BRVO. Therefore, in the current study, we defined collateral vessels as dilated and tortuous capillaries occurring in pre-existing capillary beds and linking the obstructed vessel with the nearest patent vessel. Thus, the adjacent vessels also seemed to be dilated and tortuous, which had been similarly observed in our previous study.3 We speculate that the pressure gradient between an obstructed vein and neighbouring unobstructed vessels causes collateral vessels formation. The collaterals detection rate in the current study was higher than in the previous study.3 This is because wider optical coherence tomography angiography (OCTA) images, the size of which was 6 ✕ 6 mm in area, were used in the current study.
Regarding the other comment about the location of collateral vessels, Freund et al4 reported that collateral vessels were observed in only deep retinal capillary layer. However, we confirmed that the collateral vessels were present in both the superficial and the deep capillary layers on B scan images of OCTA. Additionally, fluoresc...
We would like to thank Dr. Tarannum Mansoori for the interest in our study, “Intraocular pressure change after injection of intravitreal dexamethasone (Ozurdex) implant in Korean patients” and highlighting important issues about the intraocular pressure (IOP) measurement methods and the correlation of IOP with age.1
Show MoreWe used KT-800 Non-Contact Tonometer (Kowa, Tokyo, Japan) to measure IOP initially and rechecked with GAT if necessary. Unless the patient was diagnosed with glaucoma, NCT was initially used to measure both pre- and post-injection IOP.
As Dr. Tarannum Mansoori has pointed out, we also agree that GAT is the gold standard for IOP measurement. If the IOP measured with NCT was found to be high, it was always rechecked with GAT. GAT was used in 2 situations in our study. First, when the patients had a previous history of glaucoma, and second, when the patients’ IOP as measured with NCT was high (greater than 20). Thus, in cases of high IOP, the measurement involved NCT and was also always double checked with GAT. Moreover, multiple IOP measurements were obtained with GAT in cases of high IOP, and the average value of the measurements was regarded as the final IOP.
The range of age of the patients for injection of intravitreal dexamethasone was broad, from 16 to 88 years. We know that very young age (less than six years) or an older age are risk factors for steroid-induced glaucoma.2 However, regrettably, we have not performed any further analysis...
To the Editor:
We read the recent article in the journal by Monfermé and coauthors (1) on phenotypic associations of TYR R402Q compound heterozygosity with keen interest. Given our own and others previous findings (2-4) that the R402Q-S192Y haplotype seemed to have a stronger biological effect, we were surprised that a triallelic effect was not supported in the clinical discussion by Monfermé et al. When we examined these results more closely, we noted that their sample included 52 S192Y variant allele carriers out of the entire collection of 69 patients, of whom 31 (44.9%) carried the R402Q-S192Y double variant haplotype. In our own collections from the Australian general population (BNMS and BLTS, Duffy et al., in submission), only 6% of R402Q carriers also carried S192Y in cis. When we examined the European 1000 Genomes subsamples, there too only 7% of R402Q haplotypes had the 192Y rather than 192S wild type allele. So, even though Monfermé et al could not detect a statistically significant additive effect on OCA trait severity due to the S192Y polymorphism within their sample, it is clear that the S192 variant allele is markedly overrepresented compared to the general population, suggesting that it must have some relationship to albinism. This genetic association of the TYR R402Q-S192Y double variant haplotype with OCA1 is now clearly causative (2, 3), and explains some of the missing heritability that has previously been seen in OCA patients (4).
Yours,...
Show MoreWe thank Dr. Montserrat for the letter regarding our article “Three-year outcomes of small incision lenticule extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) for myopia and myopic astigmatism.”1
Their first concern is that the predictability of the FS-LASIK group was 65% of eyes within ±0.5 diopter (D), which is also different from our experience. Of note, 95% of eyes were within ±1.25 D in the FS-LASIK group. This may be due to the long-term follow-up of 3 years leading to variability in the manifest refraction over time. In fact, our predictability results were similar to that of other long-term studies, as shown in Table 1.1-5 Moreover, it is likely a reflection of selection bias in our retrospective analysis i.e. patients with visual complaints were more willing to participate in the follow-up at 3 years – and we had acknowledged this as a limitation in our discussion. However, the probability of this bias may be the same for both surgical procedures and therefore did not significantly affect the final conclusion in our analysis.
Table1 Summary of Long-term Predictability Results for LASIK
Show MoreStudy Eyes （patients） Preoperative MRSE (D) Follow-up ± 0.50 of Emmetropia (%)
Han T 41(41) −7.15±1.92 3 years 65
Kobashi H 30(30) −3.81±1.40 2 years 73
Alio JL 97(70) −7.15±1.92 10 years 49
Zalentein WN 38(21) spere of -6.55±1.74 2 years 63
O'Doherty M 94(49) −4.85±2.35 5 years 60
...
We have read with interest the article by Han et al.,1 in which the authors compare the outcomes of myopia correction using small incision lenticule extraction (SMILE) versus laser in situ keratomileusis (LASIK) using the VisuMax® femtosecond laser (FS) to cut the corneal flap, and we have some concerns regarding this study we would like to share with the authors.
Show MoreIt is noteworthy that the authors found that only 65% of eyes were within ± 0.50 diopters of the attempted spherical equivalent correction after FS-LASIK, these results are clearly worse that those generally obtained with LASIK. It is accepted that the results obtained with excimer laser ablation, either using a surface ablation approach, or LASIK performed with mechanical microkeratome (MK) or using the Intralase® FS platform to correct myopia are quite similar.2,3 Indeed, our group has that 95% of unselected eyes with myopia of -3.9±1.5D3 and 80% of eyes with high myopia (-8.7±1.2D)4 were within ± 0.5D of emmetropia after LASIK. For this reason, we believe that the main conclusion of the article by Han et al.1 that “long-term outcomes of both SMILE and FS-LASIK are safe and equally effective for myopic and astigmatic correction” is clearly biased. In other words, the results of SMILE should have not been compared with a FS laser platform that does not seem to achieve the benchmark results clearly established for LASIK when correcting myopia.
It should be highlighted that different FS platforms appr...
Dear Editor,
We read the article published by Fieß, et al (1) with considerable interest and laud them on their study and the large cohort. Considerable work has been done earlier, which looks at factors associated with refractive errors, however few studies document association with birth weight. Keeping this in mind, we feel that there are a few points requiring further clarity in this article.
The authors mention their inability to control for factors such as paternal refractive error and family history. However, previous studies not only discuss the paternal refractive error and family history, but also expand the affecting factors to include the number of myopic parents. (2) In the study design described by Höhn et al. where comprehensive information on living conditions and birth weight was collected via computer-assisted telephone interviews, (3) information on number of myopic parents could also have been collected, and would have proven to be an important covariate in the analysis.
The authors also report that 8369 participants provided birth weight data, of which 45 were excluded due to unreliable self-reported data [<1000g (n=7) or >6000g (n=38)]. However, tables 2 and 3 report analysed results based on 8369 participants not 8324 (after exclusion of the 45). Even though 45 is an insignificant number, and does not affect the results as such, this aspect of the results needs further clarity.
Lastly, while the authors mention, furt...
Show MoreWe have read the paper written by Avila MY et al “Randomised prospective clinical trial of platelet-rich plasma injection in the management of severe dry eye” . Authors have evaluated the effectiveness of platelet-rich injection in lacrimal gland plus free-demand topical lubricants drops in Sjögren’s syndrome severe dry eye patients . Diagnosis was based on Schirmer I, break-up time(BUT), ocular surface staining (Oxford grid) and OSDI . Achieved results in interventional group showed a Schirmer I (6,7+/-0,9 vs 9,2+/-1 mm, p<0,002), BUT (6,4+/-0,4 vs 4,4+/-0,3 secs p=0,0005), staining (2,15+/-0,15 vs 1,2+/-0,18 p<0,001) and OSDI (59+/-0,4 VS 34+/-4, p<0,001). Surprisingly authors have not included the lacrimal osmolarity test, the most valuable diagnostic tool to rule in/out this disease (S and Sp >90%) . Unfortunately Schirmer I (without anesthesia) evaluates not just basal lacrimal tearing, it also measures reflex response giving confounding bias in measured result. Surface staining (a qualitative variable) was mistakenly analyzed with a t-paired student test. Regarding OSDI, PRP patients showed a test improvement (pre 59+/- 4,0 vs post 34+/-4,0) without change in disease severity. Finally, this trial enrolled a low number of patients (n=15) that according to authors assumptions we would expect a much greater sample size (Epidat 4.1 n=417 eyes). In conclusion, a novel and interesting new treatment for Sjögren’s dry eye patients that must be confirmed in the f...
Show MoreDear Editor,
Show MoreWe have read with great interest the article by Singhal et al 1 on 'Clinical presentation and management of corneal fistula'. The authors have rightly highlighted the point that failure to perform simple test like Seidel test in cases of corneal ulcer, can lead to missing the diagnosis of corneal fistula, which in turn can lead to serious complications like endophthalmitis, panophthalmitis and phthisis bulbi.
One of the complications of persistent corneal fistula is the formation of anterior capsular cataract. It would have been more insightful if the authors had mentioned as to how many patients had developed anterior capsular cataract during follow up, as this can lead to a change in the future management of the eye.
Also, the authors have not mentioned the type of anaesthesia for doing the procedure. As creating the grooves around perforation to tuck in the tenons graft is difficult due to the friability of corneal tissue, the type of anaesthesia has a bearing on the intra operative surgical procedure. As doing the technique in topical anaesthesia will be technically challenging and administration of peribulbar block could lead to extrusion of the intraocular contents or extension of the perforation.
Although the study mentions the surgical technique for closing the fistula with a tenons patch graft, it does not mention the regimen of postoperative medical management.
In the discussion, the authors have mentioned that...
Pages