Measurements of Diameter and Area of Optic Disc with the Scale of the Volk Lens

ABSTRACT

The measurement of the area of the optic disc is important to classification of congenital anomaly of optic disc and diagnosis and following up of glaucoma. This study was performed to measure easily the diameter and area of the optic disc using the retinal scale of the Volk lens although recently the study was reported to measure the optic disc with computerized optic disc analysis system. We evaluated the measurement of the diameter and area of the optic disc of 31 patients(56 eyes) using the retinal scale of Volk lens and then corrected the magnification of central fundus photographs using Litmann's method. The mean refractive power and the mean axial length was -0.24 diopter(range -4.5 to 4.25 diopter), and 22.91 mm (range 20.5 to 26.1mm), respectively. The mean horizontal diameter, the mean verticaI diameter, and the mean area of optic disc was 1.75 +/- 0.18mm, 1.90 +/- 0.19mm, and 2.62 +/- 0.50mm2, respectively. We think that the measurement of the optic disc area with Volk lens is useful method in following up of cup-disc ratio in outpatient basis.