Global and regional detection of induced optic disc change by digitized image analysis
C. F. Burgoyne, R. Varma, H. A. Quigley, S. Vitale, M. E. Pease and P. L. Lenane
Dana Center for Preventive Ophthalmology, Johns Hopkins School of Medicine, Baltimore, Md.
OBJECTIVE: To evaluate two new strategies for the detection of optic disc
change within individual eyes by digitized image analysis. METHODS: Eleven
normal optic discs of 11 monkeys were imaged with a digital imaging system
(Topcon Imagenet, Topcon Instrument Corporation of America, Paramus, NJ) at
two intraocular pressures (10 and 45 mm Hg). To detect global change in the
disc, we compared conventional optic disc parameters with a new optic disc
parameter: mean position of the disc. To detect regional change, the 95%
confidence interval for change was calculated for each data point and
mapped for each disc. RESULTS: Posterior 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% confidence interval for change mapping in all 11 discs
as localized areas of confluent, posteriorly displaced points. CONCLUSIONS:
Mean position 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
regional analysis of the disc.
