Optic Disc Measurements with Topographic Scanning System

ABSTRACT

Quantitative analysis of the optic nerve head topography is important in diagnosis, differential diagnosis and follow-up of optic nerve diseases, especially in glaucoma. This study was undertaken to analyze the optic nerve head with confocal scanning laser ophthalmoscope(TopSSTM Software Version 2.2, LDT.Inc) and further to determine gender, age, refractive error and axial length-based on differences in the size and topography of the optic disc. One hundred normal human optic nerve heads of 100 subjects (42 men, 58 women, mean age 43.3+/-14.5 years) were evaluated. The men value of the parameters in TopSSTM were as follows horizontal disc diameter 1.62+/-0.17mm, vertical disc diameter 1.77+/-0.24mm average disc diameter 1.71+/-0.15mm, disc area 2.31+/-0.43 mm2, cup area 1.01+/-0.50 mm2, horizontal cup to disc ratio 0.52+/-0.17, vertical cup to disc ratio 0.47+/-0.20, average cup to disc ratio 0.45+/-0.18, rim area 1.30+/-0.35 mm2. There were no significant correlations between these morphometric optic disc parameters and age, refractive error or axial length(p>0.05). However, male subjects had about 10% larger optic discs compared with female subjects. The optic disc size was well correlated with cup area and rim area (p<0.05).