Goniosynechialysis under a microscope alone and under direct gonioscopy for chronic angle-closure glaucoma patients coexisted with cataract

AIM: To compare the efficacy of goniosynechialysis (GSL) under a microscope alone (GM) and under direct gonioscopy (GG) for chronic angle-closure glaucoma (CACG) coexisted with cataract. METHODS: A prospective, single-center, and randomized controlled trial was conducted. Patients diagnosed as CACG and cataract were randomly allocated into either GM group or GG group. In GM group, the range of peripheral anterior synechiae (PAS) was confirmed through gonio-lens after phacoemulsification with intraocular lens implantation (PEI). PAS was separated only under a microscope. After separating the closed angle of 360° by this method, we used a surgical gonioscope to confirm the PAS range. If any remaining PAS was present, we would separate them with an iris repositor under the direct gonio-lens until angle of 360° was reopened. In GG group, PAS was separated under direct gonioscopy after PEI until angle of 360° was reopened. The range of residual PAS after GSLs was the primary outcome. Intraoperative complications (hyphema), intraocular pressure (IOP) and anti-glaucoma medication usage after operation were the secondary outcomes. RESULTS: Sixty eyes were included, each group comprising 30 eyes. The average age [GM group: 66.3±6.8y (12 males), GG group: 67.6±8.9y (7 males), P=0.550], the baseline IOP (GM group: 29.6±11.5 mm Hg, GG group: 32.4±12.2 mm Hg, P=0.366) and the average initial PAS extent (GM group: 8.9±2.6h, GG group: 9.4±2.5h, P=0.425) were similar in the two groups. In GM group, the PAS range reduced from 8.9±2.6h before operation to 7.2±2.9h after PEI and 3.3±2.2h after GSL. In GG group, the PAS range reduced from 9.4±2.5h before operation to 7.5±2.9h after PEI and 0.1±0.3h after GSL. The PAS after PEI was significantly reduced compared to the pre-operative PAS in both groups (all P<0.001). The extent of residual PAS after GSL in GM group was larger than that in GG group with significant statistical difference (P<0.001). Patients who underwent GSL without a gonioscope were more likely to develop hyphema than those who underwent GSL under direct gonioscopy. The difference of hyphema grade between the two groups was statistically significant (P=0.019). CONCLUSION: PEI alone can not open 360° of angle completely. PEI+GSL significantly reduced PAS range. But for patients with CACG, GSL under a microscope alone is more difficult to separate stable PAS completely and adequately than GSL under direct gonioscopy.