Comment on “The diurnal variation pattern of choroidal thickness in macular region of young healthy female individuals using spectral domain optical coherence tomography”

Dear Editor,We have read and reviewed the article entitled＂The diurnal variation pattern of choroidal thickness in macular region of young healthy female individuals using spectral domain optical coherence tomography＂by Zhao et al^（[1]）with great interest.

Macular thickness as a predictor of loss of visual sensitivity in ethambutol-induced optic neuropathy

Ethambutol is a common cause of drug-related optic neuropathy.Prediction of the onset of ethambutol-induced optic neuropathy and consequent drug withdrawal may be an effective method to stop visual loss.Previous studies have shown that structural injury to the optic nerve occurred earlier than the damage to visual function.Therefore,we decided to detect structural biomarkers marking visual field loss in early stage ethambutol-induced optic neuropathy.The thickness of peripapillary retinal nerve fiber layer,macular thickness and visual sensitivity loss would be observed in 11 ethambutol-induced optic neuropathy patients（22 eyes） using optical coherence tomography.Twenty-four healthy age-and sex-matched participants（48 eyes） were used as controls.Results demonstrated that the temporal peripapillary retinal nerve fiber layer thickness and average macular thickness were thinner in patients with ethambutol-induced optic neuropathy compared with healthy controls.The average macular thickness was strongly positively correlated with central visual sensitivity loss（r2=0.878,P=0.000）.These findings suggest that optical coherence tomography can be used to efficiently screen patients.Macular thickness loss could be a potential factor for predicting the onset of ethambutol-induced optic neuropathy.

Real-life experience of ranibizumab therapy for neovascular age-related macular degeneration from Turkey

AIM： To report the real-life experience and clinical results of intravitreal ranibizumab injections to neovascular agerelated macular degeneration（nAMD） in a single institution in Turkey.METHODS： A total of 101 eyes of 89 patients with nAMD treated with intravitreal ranibizumab injection, followed up for at least 24 mo between 2009 and June 2014, which were evaluated retrospectively. A pro re nata（PRN） treatment protocol was performed after the patients had received three, monthly loading injections. Best corrected visual acuity（BCVA） and central macular thickness measurements were evaluated at baseline and 3, 6, 12, 18, and 24 mo. Number of injections and visits were also recorded.RESULTS： Of the 89 patients, 34（38.2%） were male and 55（61.8%） were female and the mean age was 74.0±9.5（52-91）y. The mean follow-up period was 24.82±4.4（24-29）mo. Mean number of visits was 8.4±1.12（7-12） in the first year and 6.6±1.33（4-12） in the second year. The mean number of injections was 5.8±1.6（3-10） and 4.2±2.2（0-9） in the first and second year, respectively. The mean BCVA was 59±15.8 letters at baseline by the Early Treatment Diabetic Retinopathy Study（ETDRS） chart. The mean BCVA at 3, 12, and 24 mo was 70.3±15.9, 67.9±14.3 and 67.3±16.9 letters, respectively. Improvement in visual acuity for each of the visits from baseline was found to be statistically significant（P〈0.01）. Visual acuity in 9 eyes at month 3, 7 eyes at month 12, and 13 eyes at month 24 did not change. The mean central macular thickness（CMT） was 437.99±164.78 μm at baseline. The mean CMT was 348.05±138.47 μm, 349.27±139.79 μm, and 344.13±146.30 μm at months 3, 12, and 24, respectively. The decrease in CMT for each of the visits from baseline was found to be statistically significant（P〈0.01）.CONCLUSION： Anatomical and functional achievement are obtained in our study, but the mean number of injections and visits are found to be lower than the findings reported in randomized controlled clinical trials in the literature. However, the mean number of injections and visits in our study are compatible with the findings reported in real-life experience studies in the literature.