GLOBAL AND REGIONAL DETECTION OF INDUCED OPTIC DISC CHANGE BY DIGITIZED IMAGE-ANALYSIS

Objective: To evaluate two new strategies for the detection of optic d isc change within individual eyes by digitized image analysis. Methods : Eleven normal optic discs of 11 monkeys were imaged with a digital i maging system (Topcon Imagenet, Topcon Instrument Corporation of Ameri ca, Paramus, NJ) at two intraocular pressures (10 and 45 mm Hg). To de tect global change in the disc, we compared conventional optic disc pa rameters with a new optic disc parameter: mean position of the disc. T o detect regional change, the 95% confidence interval for change was c alculated for each data point and mapped for each disc. Results: Poste rior deformation of the disc surface was detected in seven of 11 eyes using conventional parameters and in 10 of 11 eyes using mean position of the disc. Regions of posterior deformation were detected by 95% co nfidence interval for change mapping in all 11 discs as localized area s of confluent, posteriorly displaced points. Conclusions: Mean positi on of the disc outperformed conventional measurements in the detection of global optic disc change. Ninety-five percent confidence interval for change mapping may allow individual data point-based focal and reg ional analysis of the disc.