Hamilton Glaucoma Center and Department of Ophthalmology, University of California-San Diego, La Jolla, CA 92093-0946, USA.
Invest Ophthalmol Vis Sci. 2013 May 7;54(5):3205-14. doi: 10.1167/iovs.12-11467.
To investigate the relationship between cup-to-disc ratio (CDR) and estimates of retinal ganglion cell (RGC) number.
This cross-sectional study included 156 healthy eyes, 53 glaucoma suspects, and 127 eyes with glaucoma. All eyes had standard automated perimetry (SAP), Cirrus SD-OCT, and stereoscopic optic disc photography within 6 months. CDR was determined from stereoscopic photographs by two or more masked graders. The number of RGCs in each eye was estimated using a published model that combines estimates of RGC number from SAP sensitivity thresholds and SD-OCT retinal nerve fiber layer measurements.
The mean estimated RGC count was 1,063,809 in healthy eyes; 828,522 in eyes with suspected glaucoma; and 774,200 in early, 468,568 in moderate, and 218,471 in advanced glaucoma. Healthy eyes had a mean vertical CDR of 0.45 ± 0.15 vs. 0.80 ± 0.16 in glaucomatous eyes. There was good correlation between stereophotographic vertical CDR and SD-OCT vertical CDR (R(2) = 0.825; P < 0.001). The relationship between estimated RGCs and vertical CDR was best represented using a third degree polynomial regression model, including age and optic disc area, which accounted for 83.3% of the variation in estimated RGC counts. The nonlinear relationship between RGC estimates and CDRs indicated that eyes with a large CDR would require loss of large RGC numbers for a small increase in CDR.
The relationship between estimated RGC counts and CDR suggests that assessment of change in CDR is an insensitive method for evaluation of progressive neural losses in glaucoma. Even relatively small changes in CDR may be associated with large losses of RGCs, especially in eyes with large CDRs. (ClinicalTrials.gov numbers, NCT00221923, NCT00221897.).
探讨杯盘比（CDR）与视网膜神经节细胞（RGC）数量估计值之间的关系。
本横断面研究纳入了 156 只健康眼、53 只青光眼疑似眼和 127 只青光眼眼。所有眼均在 6 个月内接受了标准自动视野计（SAP）、Cirrus SD-OCT 和立体视盘照相检查。CDR 由两名或更多的盲法阅片者从立体照片中确定。使用结合 SAP 敏感性阈值和 SD-OCT 视网膜神经纤维层测量值来估计 RGC 数量的已有模型来估计每只眼的 RGC 数量。
健康眼中平均估计的 RGC 计数为 1,063,809；疑似青光眼眼中为 828,522；早期青光眼眼中为 774,200，中度青光眼眼中为 468,568，晚期青光眼眼中为 218,471。健康眼的垂直 CDR 平均值为 0.45 ± 0.15，而青光眼眼中为 0.80 ± 0.16。立体照相垂直 CDR 与 SD-OCT 垂直 CDR 之间有良好的相关性（R(2) = 0.825；P < 0.001）。包括年龄和视盘面积在内的三阶多项式回归模型最能代表 RGC 估计值与垂直 CDR 之间的关系，该模型解释了估计 RGC 计数变异的 83.3%。RGC 估计值与 CDR 之间的非线性关系表明，CDR 较大的眼需要大量 RGC 数量损失才能使 CDR 略有增加。
RGC 估计值与 CDR 之间的关系表明，评估 CDR 的变化是评估青光眼进行性神经损失的一种不敏感方法。即使 CDR 相对较小的变化也可能与 RGC 的大量损失相关，尤其是在 CDR 较大的眼中。（临床试验编号：NCT00221923，NCT00221897。）
