Quantification of Retinal Nerve Fiber Layer Thickness After Unilateral Acute Primary Angle Closure in Asian Indian Eyes

PURPOSE: To determine retinal nerve fiber layer thickness (RNFLT) using Spectral optical coherence tomography/scanning laser ophthalmoscope (Spectral OCT/SLO) in Asian Indian eyes after single, unilateral attack of acute primary angle closure (APAC). METHODS: Thirty-two patients with unilateral attack of APAC with normal optic disc and normal visual field, unaffected fellow eyes, and 35 age-matched normal control eyes were enrolled for the study. Six weeks after the remission of acute attack, peripapillary average, quadrant, and clock-hour RNFLT were compared between 3 groups using Spectral OCT/SLO. RESULTS: APAC patients had mean IOP of 51.3±13.3 mm Hg (range, 40-74) at the time of presentation with acute attack in the affected eye and 14.9±2.9 mm Hg at 6 weeks after resolution of APAC. Duration of symptoms of acute attack was 35.9±23.8 hours. Significant differences were found between RNFLT in APAC and fellow eyes for most the parameters except for 1, 4, 6, and 7-o'clock-hour sector. Most of the RNFLT parameters showed statistically significant difference between APAC and normal control eyes except for temporal quadrant, 6, 7-o'clock-hour sectors. Statistically significant differences were found between RNFLT in unaffected fellow and normal control eyes for most of the parameters except for 6, 7, 11 o'clock-hour sectors. CONCLUSIONS: RNFLT was found to be significantly thinner in APAC and unaffected fellow eyes when compared with normal age-matched controls. Hence, patients with APAC should be monitored carefully to determine its long-term effects on optic disc, RNFLT, and visual fields. Longitudinal studies can determine whether the RNFLT measurements remained stable or showed progression in these patients.