Abstract
Purpose:
To assess physical parameters of optic disc morphology in primary open angle glaucoma with a stereo fundus camera.
Methods:
The Glaucoma Stereo Analysis Study (GSAS), a cross sectional multicenter collaborative study, enrolled 187 criteria-eligible eyes with primary open angle glaucoma from 187 subjects (male: female = 100: 87, age = 62 ± 9, range: 30-80). The diagnosis of glaucoma was based on glaucomatous fundus appearances and the corresponding visual field defects. The data included best-corrected visual acuity, refractive error, intraocular pressure, mean deviation (MD) as measured with the Humphrey field analyzer (HFA, SITA standard 30-2), and MD slope, as determined by more than six reliable HFA results were collected retrospectively. Exclusion criteria included 1) a history of intraocular surgery other than for cataracts or glaucoma, 2) any history of intraocular surgery in the previous three years, 3) most recent MD < −12 dB. If both eyes met the inclusion criteria, the eye with more advanced glaucoma was selected. The optic disc imaged with a commercially available stereo fundus camera (nonmydWX, Kowa Company, Ltd., Japan) was three-dimensionally analyzed using newly developed software to calculate the various optic disc parameters. Mean rim decentering was defined as (superotemporal rim area − inferotemporal rim area)/(superotemporal rim area + inferotemporal rim area). The Spearman rank correlation coefficient was used to assess correlations in the data.
Results:
The quantitative disc parameters in this study were as follows: vertical disc width, 1.86 ± 0.23 mm; horizontal disc width, 1.66 ± 0.28 mm; vertical cup-to-disc ratio (C/D), 0.82 ± 0.08; horizontal C/D, 0.74 ± 0.09; superior rim-to-disc ratio (R/D), 0.08 ± 0.06; inferior R/D, 0.04 ± 0.05; mean cup depth, 0.20 ± 0.09mm; maximum cup depth, 0.52 ± 0.19 mm; and disc tilt angle, 10.5 ± 12.5 degrees. Mean rim decentering was 0.30 ± 0.42 and the absolute value of rim decentering was 0.45 ± 0.27. There were negative correlations between disc tilt angle and age (r= −0.30, p<0.0001) or refractive error (r= −0.36, p<0.0001).
Conclusions:
We were able to obtain basic data set of GSAS. The nonmydWX system made it possible to perform quantitative analyses of the optic disc in glaucoma.
Keywords: 627 optic disc •
550 imaging/image analysis: clinical •
465 clinical (human) or epidemiologic studies: systems/equipment/techniques