视网膜神经纤维层厚度与11778位点Leber视神经病变患者视功能预后的关系

Correlation between retinal nerve fiber layer thickness and visual prognosis in patients of Leber Hereditary optic neuropathy with 11778 mutation

目的:研究视网膜神经纤维层(RNFL)厚度变化与11778位点突变的Leber遗传性视神经病变(LHON)患者远期视功能的相关性,以及早期RNFL厚度对远期视功能的预测价值。方法:回顾性分析经mtDNA检查确诊为11778 G>A/ND4位点突变的LHON患者23例44眼,以病程30mo远视力0.5(LogMAR)为标准将患者分为两组,先得到两组患者各预定时间点(病程)的RNFL厚度均值并对比获得备选的RNFL预测界值,再以备选界值为标准,将不同RNFL厚度的患眼分为两组进行统计分析,判断该界值能否用于预测远期视力和视野,最终选定能同时评估远期视力和视野的最早界值为目标界值。结果:根据RNFL厚度均值的分布获得备选界值为:病程2mo 130μm,病程4mo 100μm,病程8mo 80μm,病程12mo 65μm,分析发现病程8mo时RNFL厚度是否超过80μm对远期视力的区分更佳,且对远期视野平均缺损(MD)及平均敏感度(MS)值均有很好的区分(P<0.05)。病程8mo时RNFL≤80μm的患眼远期(病程30mo)视力均低于LogMAR 0.5(WHO低视力标准),100%患眼远期为低视力;而病程8mo时RNFL>80μm的患眼中,31%患眼远期视力优于LogMAR 0.1(相当于小数视力0.8),仅34%患眼为远期低视力,且RNFL>80μm的患眼视力和视野均显著优于RNFL≤80μm。结论:病程8mo时RNFL厚度是否超过80μm可作为判断远期视力和视野的最佳预测界值,该界值对11778位点突变的LHON患者的远期视力、视野均有良好的预判性。

AIM:To study the correlation between retinal nerve fiber layer(RNFL)thickness changes and long-term visual function in Leber hereditary optic neuropathy(LHON)patients with 11778 mutations,and evaluate the role of early RNFL thickness in predicting long-term visual function.METHODS:A retrospective analysis with 44 eyes from 23 LHON patients who were diagnosed with 11778 G>A/ND4 mutations by mt-DNA sequencing were included.The patients were divided into two groups based on whether BCVA is above LogMAR 0.5(equivalent to 0.3 decimal,WHO Low Vision standard)or not at 30mo follow up.Then,when the RNFL data of the two groups of patients at each predetermined time point(course of disease)were obtained,the candidate cutoffs of RNFL thickness were obtained by comparing the mean RNFL thicknesses of the two groups.Based on the obtained candidate cutoff values,the eyes with different RNFL values were divided into two groups for statistical analysis to determine whether the cutoff values can be used to predict prognosis of BCVA and visual field.Finally,the earliest cutoff value of RNFL thickness that can predict both BCVA and visual field is the target value.RESULTS:According to the distribution of mean RNFL values in the eyes of patients with different BCVA groups,the candidate cut-off values of RNFL were determined as:130μm after 2mo,100μm after 4mo,80μm after 8mo,and 65μm after 12mo from onset.Further analysis revealed that the RNFL value exceeds 80μm of 8mo after onset can be a better cutoff value to distinguishes the long-term vision,and which can predict both MD and MS of visual field with good distinction(all P<0.05).It was found that the long-term BCVA of 100%of the eyes with RNFL values less than 80μm after 8 months from onset was lower than LogMAR 0.5(equivalent to 0.3 decimal);while for eyes with RNFL thickness higher than 80μm after 8mo from onset,31%of patients had vision greater than LogMAR 0.1(equivalent to 0.8 decimal),and only 34%of patients had long-term prognosis of low vision.In addition,the BCVA,MD and MS of visual field of the eyes with RNFL value exceeded 80μm were significantly better than those with eyes with RNFL less than 80μm.CONCLUSION:In this study,whether the RNFL value exceeded 80μm after 8mo from onset can be used as the best predictive cut-off value for judging long-term BCVA and visual field.