INTEROBSERVER VARIATION IN THE MEASUREMENTS OF PERIPAPILLARY ATROPHY IN GLAUCOMA

Purpose: The purpose of this retrospective study is to compare the mea surements of intrapapillary and peripapillary parameters between two o bservers and test the usefulness of measuring different types of cresc ents. Methods: Optic disc photographs of 23 eyes of 23 patients with g laucoma and 23 age-matched normal eyes were measured in Oulu and in Er langen using manual planimetric techniques. The authors measured the f ollowing magnification corrected intrapapillary and peripapillary area s: optic disc, neuroretinal rim, cup:disc area ratio, scleral ring, ce ntral (zone beta), and peripheral peripapillary atrophy (zone alpha). Twenty-one patients with glaucoma had a follow-up of 3.2 years (range, 1.1-4.7 years), and followup for 19 control eyes was 3.7 years (range , 2.5-5.9 years). The measurements were performed in a masked fashion for the diagnosis and temporal sequence of the photographs. Results: C entral peripapillary atrophy (zone beta) was statistically significant ly largest in primary open-angle glaucoma in both centers (Oulu, P = 0 .003; Erlangen, P = 0.004), whereas normal and exfoliative eyes did no t differ significantly from each other. The results for peripheral per ipapillary atrophy (zone alpha) and scleral ring were less consistent. Despite statistically significant interobserver correlations ranging from r = 0.30 (scleral ring area; P = 0.0472) to r = 0.97 (optic disc area; P = 0.0001), the means of all parameters, except for zone alpha and beta, differed statistically significantly between the two observe rs. Conclusions: The central peripapillary atrophy, or zone beta, is t he most reproducible parameter when measuring peripapillary atrophy in glaucoma. Nonetheless, its measurement is of limited usefulness in th e recognition of glaucoma or progression of glaucomatous nerve damage.