Topographic factors associated with anterior chamber angle narrowing in patients with keratoconus

To identify topographic determinants of the anterior chamber angle (ACA) in patients with keratoconus (KCN).

Four hundred and ten eyes of 294 patients with KCN were recruited for this study. First, complete ocular examinations were performed for all patients, including visual acuity measurement, refraction, and slit-lamp biomicroscopy. Then, all participants underwent corneal imaging by the Oculus Pentacam HR.

The mean age of the participants was 32.40± 8.52y (15-60y) and 69.5% of them were male. The mean ACA was 38.47°±5.75° (range: 14.40° to 56.50°) in the whole sample, 38.24°±6.00° in males, and 38.98°±5.11° in females (P=0.447). The mean ACA was significantly different among different groups of cone morphology, as patients with nipple cones showed the lowest mean ACA. Moreover, there were statistically significant differences in the mean ACA among different groups of cone locations, with patients having central cones exhibiting the lowest mean ACA (P<0.001). Anterior and posterior Q values were significantly, directly correlated with ACA (anterior Q: r=0.122, P=0.014, posterior Q: r=0.192, P<0.001).

This study provides critical insights into the risk factors for ACA narrowing in KCN patients, which is essential for planning intraocular surgeries. Patients with nipple and central cones exhibited the most significant ACA narrowing. Additionally, more negative Q-values are associated with increased ACA narrowing, highlighting the need for targeted diagnostic and therapeutic strategies.