Retinal Thickness Change Of Macular Fovea Measured By Optical Coherence Tomography After Viscocanlostomy And Trabeculectomy

Objective:To compare retinal thickness changes of the macular fovea in glaucoma patients undergoing viscocanlostomy or trabeculectomy at different times of follow-up and to investigate the relationship between thickness of macular fovea and the best corrected visual acuity(BCVA) after filtering surgery.Methods:In this follow-up study,38 qualified glaucoma patients,admitted in the First Affiliated Hospital of Nanjing Medical University during Jan 2007 to Oct 2007,were included.17 patients(24 eyes)underwent viscocanlostomy(VCO)and 21 patients(24 eyes)trabeculectomy.BCVA was obtained by optometer.Intraocular pressure(IOP)was measured using Non-contact tonometer and retinal thickness of the macular fovea was measured by Zeiss-Humphrey optical coherence tomography (OCT3000).All patients were followed up to 1 month after the operation and clinical examination and measurements were performed prior to surgery,at the 3rd day,1 week and 1 month after surgery.Results:In VCO group preoperative IOP under topical medication was 29.3±6.4 mm Hg.IOP was significantly decreased at all postoperative visits(P＜0.001):7.6±2.2 mm Hg at the 3rd day,9.6±3.3 mm Hg after 1 week and 12.4±3.4 mm Hg after 1 month.Foveal thickness at the 3rd day, and after 1 week was elevated compared with baseline(P＜0.05).Macular thickness changed from 150±13μm before surgery to 153±12μm after 3 days,154±13μm after 1 week,and 151±13μm after 1 month.BCVA was decreased at 3rd day and after 1 week when compared with preoperative level(P＜0.05).BCVA was 0.41±0.26 before operation,0.31±0.21 at the 3rd day,0.38±0.21 after 1 week and 0.41±0.26 after 1 month.In trabeculectomy group preoperative IOP under topical medication was 29.9±6.9mm Hg.IOP was significantly decreased at all postoperative visits(P＜0.001):7.9±2.1mm Hg at the 3rd day,9.6±2.4 mm Hg after 1 week and 12.9±2.8 mm Hg after 1 month.Foveal thickness at the 3rd day, 1 week and 1 month were elevated compared with baseline(P＜0.05).Macular thickness changed from 150±15μm before surgery to 153±14μm after 3 days,156±14μm after 1 week,and 158±14μm after 1 month.BCVA was decreased at all follow-up visits when compared with preoperative level(P＜0.05).BCVA was 0.42±0.28 before operation,0.30 ±0.20 at the 3rd day,0.33±0.25 after 1 week and 0.37±0.27 after 1 month.The trend of postoperative IOP changes was similar between two groups while trends of macular foveal thickness and BCVA changes were significantly different(P＜0.05).At all follow-up visits,the values of BCVA decrease were negatively correlated with that of macular foveal thickness increase,with the coefficients were -0.376,-0.395,-0.554 for each (P＜0.05).Conclusion:VCO and trabeculectomy both can control intraocular pressure effectively.Short term lowering of IOP after VCO had not lead to an irreversible change of macular foveal thickness.Thus VCO maybe a safe and effective method compared with trabeculectomy.