Purpose
In eyes with large optic disc cupping and normal intraocular pressure (IOP), we investigated potential differences in clinical and epidemiological characteristics between those with and without glaucoma [large physiological optic disc cups (LPC)].
Methods
We consecutively enrolled individuals with LPC and glaucomatous patients (normal tension glaucoma). All eyes had suspicious appearance optic disc [vertical cup-to-disc ratio (VCDR)≥0.6) and untreated IOP<21 mmHg. For glaucomatous eyes, a reproducible glaucomatous visual field (VF) defect was required. Eyes with LPC required normal VF testing and at least 2 years of follow-up with no evidence of progressive glaucomatous neuropathy (based on stereophotographs). The following demographic and ocular characteristics were collected and compared between groups (glaucoma vs LPC): age, gender, race, central corneal thickness (CCT), refractive error (spherical equivalent), and optic disc characteristics (optic disc area and VCDR). Continuous variables with normal distribution were compared using independent samples t-test while those non-normally distributed were analyzed using Mann-Whitney test. Categorical data were analyzed using chi-square test and the alpha level (type I error) was set at 0.05.
Results
A total of 74 eyes with LPC (74 individuals) and 38 glaucomatous eyes (38 patients) were included. Glaucomatous patients were significantly older than those with LPC (57.1±13.9 vs 46.9±15.7 years; p<0.01). There were more women and Asian descendents in the glaucoma group (p≤0.02). Not only LPC eyes had smaller mean VCDR compared to glaucomatous eyes (0.64 vs 0.72; p<0.01), but also there was a trend for larger optic discs in these cases (median of 2.36 vs 2.16 mm2; p=0.13). In fact, 90% of the individuals with LPC presented with a maximum VCDR of 0.75. We found no significant differences in CCT and spherical equivalent between groups (p≥0.43).
Conclusions
In patients with large optic disc cupping and normal IOP, those older, women, Asian descends and with vertical cup-to-disc ratio>0,75 are more likely to have glaucoma, and therefore deserve a deeper investigation and closer monitoring.
Keywords: 464 clinical (human) or epidemiologic studies: risk factor assessment •
627 optic disc •
501 discrimination