Comparative Evaluation of Functional Aqueous Humor Outflow in Primary Open Angle Glaucoma Versus Primary Angle...

Aqueous humor outflow (AHO) is significantly lower in primary angle closure glaucoma (PACG) compared with primary open angle glaucoma (POAG).

To quantitatively compare circumferential, perilimbal aqueous humor outflow (AHO) pathways in patients of primary open angle glaucoma (POAG) and primary angle closure glaucoma (PACG) using aqueous angiography (AA).

Thirty-two eyes of 32 patients were included, with 16 patients with POAG and 16 age-matched patients with PACG presenting with age-related cataract and planned phacoemulsification surgery. IOP and the number of antiglaucoma medications (AGMs) were noted. All patients underwent AA with 0.1% indocyanine green dye injected into the anterior chamber before the capsulorrhexis step, followed by capture of images up to 60 seconds. Images at 60 seconds were exported for image analysis, in which the mean gray value was assessed to calculate angiographic signal intensity (ASI) along the limbus into 8 sectors (45 degrees each), 4 quadrants (90 degrees each), and overall flow (360 degrees) for POAG and PACG. Statistical tests for the relationship of age and severity of disease with overall flow were performed.

The mean age (years) was 58.8±5.8 (POAG) and 59.8±8.6 (PACG) [ P =0.704]. The mean preoperative IOP [POAG (16.5±2.48 mm Hg) and PACG (18.44±4.03 mm Hg)] and median number of AGMs {POAG [3 (1.75-3.25)] and PACG [3 (2.75-4)]} between the 2 groups were comparable ( P >0.05). There was no significant difference in the severity of baseline disease between POAG (MD=-16.79±8.73) and PACG (MD=-16.39±9.57), P =0.904. The overall flow was lower in PACG [123.72 (105.18-205.68)] compared with POAG [188.32 (163.58-234.40)], P =0.029. In multivariate linear regression analysis, higher overall flow in POAG compared with PACG (β=56.705, P =0.010) was noted. The correlation with age [POAG ( r =-0.267, P =0.316); PACG ( r =-0.301, P =0.256)] and MD [POAG ( r =0.106, P =0.697); PACG ( r =0.515, P =0.044)] was documented.

Both POAG and PACG had segmental AHO. PACG eyes had lower functional AHO compared with POAG in phakic, dilated patients. With increasing disease severity, a decrease in overall flow was noted in PACG.