Fluorophotometric measurements of aqueous-humor flow in post-YAG laser iridotomy for acute angle closure

Objective This study compared the rates of aqueous-humor flow and trabecular outflow in eyes that had undergone YAG laser iridotomy (LI) for primary-acute-angleclosure (PAC) attack and primary-angle-closure suspect (PACS). Methods Patients who had PAC attack in one eye and narrow occludable angles (PACS) in the other eye that had undergone YAG LI were recruited. All underwent complete ophthalmologic examination including gonioscopy, ultrasonic pachymetry, A scan, and fluorophotometry to determine the rate of aqueous-humor flow. The Goldmann equation was used to compute the outflow facility using the values of aqueous flow and intraocular pressure (IOP). Results Fifty eyes of 25 patients were included, 25 of which had PAC attack and 25 were PACS. The central corneal thickness (CCT), anterior-chamber depth, and anterior-chamber volume of the 2 groups were comparable. PAC-attack eyes had significantly higher IOP (18.4 mm Hg) than the PACS (14.12 mm Hg) (p = 0.001). The mean rate of aqueous flow was 2.50 ± 0.94 μL/min and 2.89 ± 1.17 μL/min in the PAC and PACS respectively (p = 0.20). The mean aqueous-outflow facility was 0.29 ± 0.18 μL/min and 0.59 ± 0.37 μL/min respectively (p = 0.0008). Conclusion A significantly lower aqueous-outflow facility was demonstrated by fluorophotometry among eyes with PAC. Despite the anatomically open angles, they continued to have higher IOPs.