薄角膜正常眼压性青光眼OCT检测与分析

Analysis of normal tension glaucoma with thin cornea-using optical coherence tomography

目的探讨薄角膜正常眼压性青光眼（NTG）患者视盘周围视网膜神经纤维层（RNFL）厚度及视盘结构的OCT特征。方法采用OCT对21例（42只眼）中央角膜厚度（CCT）低于正常人群范围（〈500μm）的正常眼压性青光眼患者进行RNFL及视盘扫描，并根据其CCT值分为：组1（480μm≤CCT〈500μm）和组2（460μm≤CCT〈480μm），比较分析两组RNFL厚度、视盘参数及30。中心视野指数。结果两组患者的OCT检测参数包括Avg．Thick、Savg、Iavg、Navg、Tavg差异无统计学意义（P〉O．05），Max—Min值差异有统计学意义（P〈0．05）；视盘参数（垂直盘沿容积值等）、视野参数（MD、MS值）差异无统计学意义（P〉O．05）。两组患者的RNFL平均厚度与视野平均缺损值MD呈强且负的直线关系（r=-0．602，P=0．000）。结论OCT能对NTG患者视盘及视网膜神经纤维层做出定量测量和分析，且与视野检测指标有良好的相关性，在NTG的早期诊断中有重要意义；薄角膜NTG患者的角膜厚度水平与视网膜神经纤维层缺损程度无明显相关。

Objective To investigate the thickness changes of peripapillary retinal nerve fiber layer （RNFL） in normal tension glaucoma （NTG） with thin cornea measured by optical coherence tomography （OCT）. Methods Twenty-one NTG patients （42 eyes） with thin cornea were divided into two groups accord- ing to their central corneal thickness （CCT）： group 1 （480μm≤CCT〈500μm）and group 2 （460μm≤CCT〈480μm）, and analysis the different results of OCT scan and visual outcome in two groups. Results There were no significant differences in OCT parameters of Avg., Thick, Savg, Iavg, Navg and Tavg among the two groups （P 〉0.05）, while Max-Min was lower in group 2 （P 〈0.05）; There were also no significant differences in the optic nerve head analysis results, visual field mean defect （MD） and mean sensitivity （MS） among two groups （P 〉0.05）. The average RNFL thickness and MD showed a strong and negative linear relationship（r =-0.602, P =0.000）. Conclusions OCT can make quantitative measurement and analysis of optic disc and RNFL for NTG patients, and has a good correlation with vision field. It has important significance in the early diagnosis of NTG. For NTG patients with thin corneas, there is no significant correlation between the level of CCT and extent of retinal nerve fiber layer defect.