Eikelboom R H, Cooper R L, Barry C J
Department of Ophthalmology, University of Western Australia, Nedlands.
Invest Ophthalmol Vis Sci. 1990 Nov;31(11):2373-83.
The main object of this research was to develop a reliable method of screening glaucoma suspects and patients for early loss of or changes in the retinal nerve fiber layer (RNFL). This study quantifies the variances due to photography, digitizing, and analysis of red-free photographs of the RNFL. The influence of pupil size, optic disc position and eye movements, film processing, digitizing, and intra- and interphotographic-session and intra- and interoperator variances were established. It was found that pupils needed to be dilated to at least 6 mm, that the optic disc had to be positioned in a standardized area in the negative, that the head of the subject had to remain still during photography, and that film processing and digitizing of the negative needed to be strictly controlled to minimize the variance in collection of densitometry data from RNFL red-free photographs. It was established that focusing of the negatives during digitization was not crucial. Criteria were defined for acceptable negatives. Interphotographic-session and intraoperator variances were not significant in most cases when negatives were digitized to these criteria. Analysis of interphotographic-session variance showed that there were still some factors in photography, film processing, and/or image digitizing that were not sufficiently controlled for long-term follow-up without normalization of the data. Densitometry data gathered using the established protocol, from negatives of 71 subjects were analyzed; best sensitivity and specificity rates of 80% and 100%, respectively, were achieved for the diagnosis of glaucoma.
本研究的主要目的是开发一种可靠的方法，用于筛查青光眼疑似患者和患者视网膜神经纤维层（RNFL）的早期损失或变化。本研究量化了由于摄影、数字化以及对RNFL无赤光照片的分析所导致的差异。确定了瞳孔大小、视盘位置和眼球运动、胶片冲洗、数字化以及摄影会话内和会话间以及操作员内和操作员间差异的影响。结果发现，瞳孔需要扩张至至少6毫米，视盘必须位于底片的标准化区域内，受试者头部在摄影过程中必须保持静止，并且底片的胶片冲洗和数字化需要严格控制，以尽量减少从RNFL无赤光照片收集光密度测量数据时的差异。确定数字化过程中底片的聚焦并不关键。定义了可接受底片的标准。当底片根据这些标准进行数字化时，在大多数情况下，摄影会话间和操作员内差异并不显著。摄影会话间差异分析表明，在摄影、胶片冲洗和/或图像数字化过程中，仍存在一些因素未得到充分控制，无法在不进行数据归一化的情况下进行长期随访。对使用既定方案从71名受试者的底片收集的光密度测量数据进行了分析；青光眼诊断的最佳灵敏度和特异度分别达到80%和100%。
