The ocular hypertenion treatment tudy: reproducibility of cup/dik ratio meaurement over time at an optic dic reading center

PURPOE: To determine the reproducibility over time of viual etimate of the horizontal cup/dik ratio by trained technician from optic dik tereophotograph. METHOD: Baeline optic dik tereophotograph are graded at entry and regraded annually in a maked fahion. The 1,636 participant in the Ocular Hypertenion Treatment tudy (OHT) undergo tereocopic optic dik photography at tudy entry and annually thereafter. tereophotograph are graded independently by two technician at the Optic Dic Reading Center. If the reader’ etimate of horizontal cup/dik ratio differ by more than 0.2 dik diameter (DD), they attempt to reach a conenu; if they cannot, the horizontal cup/dik ratio i adjudicated by a glaucoma pecialit. REULT: The percent of regrading differing by 0.2 DD or more from the etimate of horizontal cup/dik ratio made at entry wa 4%, 6%, and 7%, repectively at year 1, 2, and 3. The percent differing by more than 0.2 DD wa 1% or le at all year. Intracla correlation coefficient were 0.93, 0.92, and 0.92, repectively. Etimate of horizontal cup/dik ratio from equential full-frame photograph and imultaneou plit-frame photograph appeared comparable and equally reproducible. Grading by technician were comparable to grading by glaucoma pecialit. CONCLUION: High reproducibility between repeated grading of baeline horizontal cup/dik ratio wa achieved by trained technician adhering to a rigorou protocol. Horizontal cup/dik ratio meaurement in OHT are ufficiently reproducible to provide information about the relationhip of cup/dik ratio to the prognoi of individual with ocular hypertenion.