Optic Disc Progression in Ocular Hypertension, Early Glaucoma
Results
Subjects
The study consisted of both eyes of 96 women (57%) and 72 men (43%) with a self-described racial composition of 162 (96%) white, 1 African American, 2 Asian, 2 Hispanic, and 1 native American. The age range at study entry was 34 to 87 years (mean±SD: 58.1±11.1). The mean number of years between baseline and most recent follow-up photo was 5.5±1.7(SD) years (range, 2.0–7.9 y) with a median of 6.1 years. The graders determined that 58% (195) of the 336 study eyes were glaucomatous at baseline based on optic disc appearance.
Progressive Glaucomatous Optic Neuropathy
Ninety-two of 336 (27.4%) eyes in 67 patients were found to have progressive disc changes; 44 were right eyes and 48 were left eyes. This corresponds to 40.0% (67/168) of patients having progressive disc changes in 1 or both eyes (bilaterally in 25 study subjects and unilaterally in 42 subjects). Table 1 shows that increased excavation was more common than any other feature of progressive disc changes (P < 0.001). Increased rim thinning occurred second most commonly. Fifty-two of the 92 eyes (56%) with progression were noted to have more than 1 feature of progressive disc changes, such as increased excavation and increased rim thinning in the same eye. Sixteen eyes (17%) had 3 or more signs of progressive disc changes.
Increased Excavation
As noted above, increased excavation was the most commonly described feature of optic nerve progression; noted in 89% of eyes with progressive disc changes (n=82/92). Increased excavation most frequently occurred in the inferotemporal quadrant (76%), followed by the superotemporal quadrant (54%). The superonasal (17%) and inferonasal (8.5%) quadrants were less commonly affected (Table 2). These percentages add to more than 100% because 38% of eyes (n=31) had increased excavation in more than 1 quadrant. Twenty-seven of these 31 eyes (87%) had increased excavation in at least one of the temporal quadrants (superotemporal and inferotemporal quadrants). Five of the 82 eyes with increased excavation (6%) exhibited increased excavation in all 4 quadrants.
Increased Rim Thinning
Increased rim thinning was the second most commonly feature of optic nerve progression; occurring in 50 of the 92 eyes (54%) with progressive disc changes; 46 eyes exhibiting 1 to 3 quadrants of rim thinning and 4 eyes with generalized rim thinning. The locations of increased rim thinning were similar to the excavation findings, with the inferotemporal quadrant most commonly affected (76% of eyes with rim thinning). The superotemporal (52%), superonasal (22%), and inferonasal (10%) quadrants were affected less frequently (Table 2). Eighteen of the 50 eyes (36%) had rim thinning in more than 1 quadrant. Ten of those 18 eyes (56%) exhibited rim thinning affecting the temporal quadrants only.
Other Features of Progression
New or increased notching was noted in 15 eyes (16%); in 14 of the 15 (93%) eyes, the notch was located in the superior or inferior 3 clock hours (11 to 1 o'clock and 5 to 7 o'clock). New or increased retinal NFL defects were noted in 2 eyes and both were located in the inferotemporal region (5 o'clock meridian for left eye and 7 o'clock for the right eye).
Other Changes (Not Required for Progression)
We noted new disc hemorrhages in 8 eyes (9%); 6 of these were located in the inferior or inferotemporal quadrant whereas the other 2 were located either superonasally or superotemporally. We noted one new acquired pit of the optic nerve and it was located at the 12 o'clock meridian. We found increased beta parapapillary atrophy in 5 eyes (5%).
Sensitivity, Specificity, and Reproducibility of Grading Stereo Disc Photography
Initial agreement between the graders was 71% (Cohen κ 0.4). They were able to reach consensus on 95% of eyes after reexamining the photographs together. Adjudication by a third grader was required for 16 of the 336 eyes (5.3%). Twenty eyes were classified as having "false progression" (ie, the baseline image was judged to be worse than the follow-up image). The sensitivity, specificity, and reproducibility of determining progressive disc changes were each 80% (8/10) (95% confidence interval 54% to 100%).