Changes in Caucasian eyes after laser peripheral iridotomy: an anterior segment optical coherence tomography study

To evaluate by anterior segment optical coherence tomography (AS-OCT) the changes in the anterior chamber structures in Caucasian eyes after laser peripheral iridotomy (PI).

Retrospective study of consecutive Caucasian primary angle closure suspect (PACS), primary angle closure (PAC) or primary angle closure glaucoma (PACG) patients who underwent laser PI over a 25-month period at a specialist glaucoma practice. The AS-OCT images of the temporal and nasal angles (in light and dark) before and after laser PI were analysed. The parameters studied were trabecular-iris angle (TIA), angle opening distance (AOD), trabecular-iris space area (TISA), trabecular-iris contact length (TICL), iris thickness (IT) and maximum iris bow height (MIBH).

Images of 71 eyes of 71 patients were assessed. The mean age at laser PI was 60.3 ± 10.0 years. Forty (56.3%) were women, and 14 (19.7%) had PACG. The mean time from laser PI to the follow-up AS-OCT scan was 5.92 ± 3.22 weeks. The IT did not alter significantly after laser PI, but there were significant increases in the TIA, AOD and TISA, as well as a significant decrease in MIBH, in both light and dark. There was no difference in the magnitude of change seen between the temporal and nasal angles, or between PACS/PAC and PACG eyes.

In Caucasian eyes, laser PI resulted in significant angle widening (increased TIA, AOD and TISA) and iris profile flattening (decreased MIBH) at the temporal and nasal angles based on AS-OCT imaging in both light and dark.