Changes in the lamina and prelamina after intraocular pressure reduction in patients with primary open-angle glaucoma and acute primary angle-closure.

PURPOSE: To compare changes in the prelamina and lamina of patients with POAG and acute primary angle-closure (APAC) after IOP reduction.

METHODS

We analyzed 20 patients with POAG who were scheduled to undergo glaucoma surgery and 17 patients with APAC scheduled for laser peripheral iridoplasty. Horizontal B-scans of the optic nerve head were obtained using Heidelberg Spectralis optical coherence tomography. The prelaminar position (PLP), laminar position (LP), and prelaminar thickness (PLT) were measured. Scans were obtained before and at 1 month after the intervention. Regression analysis was used to evaluate factors related to the changes in PLP, LP, and PLT.

RESULTS

Mean IOP reduction after the intervention was 21.69 ± 4.26 mm Hg in the POAG group and 23.06 ± 4.54 mm Hg in the APAC group (P = 0.746). After IOP reduction, the mean changes in the PLP were 21.92 ± 13.16 μm in the POAG group and 47.84 ± 28.05 μm in the APAC group (comparison between two groups, P < 0.001). After IOP reduction, the mean changes in the LP were 19.17 ± 7.25 μm in the POAG group and 32.70 ± 23.23 μm in the APAC group (comparison between two groups, P < 0.001). After IOP reduction, the APAC group exhibited a significantly greater increase in PLT than the POAG group (comparison between two groups, P < 0.001). Cumulative IOP insult, IOP percent reduction, duration of IOP elevation, and diagnosis of APAC were significantly related to the changes in the prelamina and lamina in regression analysis.

CONCLUSIONS

IOP reduction leads to different responses of the prelamina and lamina between POAG and APAC patients. Anterior movement of the prelamina and lamina and thickening of the prelamina were more pronounced in the optic nerve head of APAC patients.