Optic Disc Measurements with Stereophotograph in Normal Eyes

ABSTRACT

Optic disc can be analyzed with computerized optic nerve head analyzer or confocal scanning laser ophthalmoscope because optic disc has 3-dimensional structure. But the great cost of these instruments makes their utility for the average ophthalmologist unlikely. We measured optic discs with personal computer and stereophotograph and report as follows. Seventy-six optic discs of 76 normal subjects[61 men, 15 women; mean age 25.5 years] were evaluated by stereoscopic optic disc photography. The area and length were measured by a computer graphic program and converted to absolute unit with Littmann's formula. The mean vertical disc diameter[1.94+/-0.24 mm], the mean horizontal disc diameter[1.67+/-0.23 mm], the mean vertical cup diameter[1.03+/-0.20 mm], the mean horizontal cup diameter[0.96+/-0.19 mm], the mean disc area[2.64+/-0.62 mm2], the mean disc circumference length[5.84+/-0.67 mm], the mean cup area[0.82+/-0.30 mm2], the mean cup base area[0.22+/-0.17 mm2], the mean cup slope area[0.60+/-0.21 mm2] and the mean rim area[1.82+/-0.41 mm2] were evaluated. The new technique to measure optic disc with stereophotograph and personal computer is thought to be a useful method to understand threedimensional structure of optic disc with relatively simple instruments.