The anterior chamber angles in Nigerians.

The anatomic configuration of the anterior chamber angles in 240 newly diagnosed cases of primary glaucoma in Nigerian adults 30 years and above have been studied. The gonioscopic features in eyes of glaucoma patients 30 years and over have been compared to 250 subjects without glaucoma. Closed angles (Scheie grade 0 or 1) was found in 15.0% of cases compared to 1.6% of controls. There was a statistical significant difference in the distribution of angle width between the 2 groups (X2 = 71.47, P < 0.0001). Grade angle 0 was not found in the control group, subjects with closed angles in the controls had at least grade 1 angle width. Anterior iris insertion characterized the anterior chamber angles in eyes of subjects in the glaucoma group occurring in 14.2% compared to 3.2% of eyes in the control group. This difference was statistically significant (X2 = 18.79, P < 0.0001). 38.8% of eyes with glaucoma were considered to have occludable angles compared to 10.4% of control eyes, a difference also statistically significant (X2 = 53.52, P < 0.0001). Trabecular meshwork pigmentation and peripheral iris curvature did not occur differently in the two groups. Mean central anterior chamber depth (CACD) was shallower in cases than in controls. This difference was statistically significant P = 0.002. The mean depth was shallower in female cases than male cases. It decreased with age in subjects with glaucoma and those without. The mean CACD increases with increasing angle width. Just over half of subjects with closed angles have mean CACD less than 2.5 mm. The other subjects with angle closure glaucoma with higher CACD may have plateau iris. Closed angles, anterior iris insertion and shallower central anterior chamber depth are statistically significantly associated with eyes glaucoma. Increased pigmentation and peripherally convex iris curvature were not significantly associated with eyes glaucoma.