The effect of optic disc diameter on vertical cup to disc ratio percentiles in a population based cohort: the Blue Mountains Eye Study

Abstract

OBJECTIVE: The 97.5th percentile for vertical cup to disc ratio (VCDR) has been proposed as a useful tool to assist in the diagnosis of glaucoma in population studies. Previous reports of VCDR percentiles have either not been adjusted for disc size or have been calculated by regression analysis from small hospital based cohorts. The authors' aim was to generate VCDR percentiles in a large, population based sample. METHODS: Data were collected from 3654 individuals, aged 49 years or older, living in the Blue Mountains, west of Sydney. Vertical disc diameter and VCDR were determined by planimetry from stereo optic disc photographs. The distribution of VCDR and percentiles (95th, 97.5th, 99th) ..