Comparison of yellow micro pulse photocoagulation and traditional laser grid photocoagulation for diabetic macular edema

Abstract

Objective To compare the clinical results of yellow micro-pulse laser and traditional laser grid (MLG) photocoagulation for diabetic macular edema (DME).Methods Seventy-eight patients (106 eyes) with DME diagnosed by fundus fluorescein angiography (FFA) and optical coherence tomography (OCT) were enrolled in this study.The patients were divided into micro-pulse group (39 patients,51 eyes)and MLG group (39 patients,55 eyes).The patients of micro-pulse group underwent 577 nm yellow micropulse laser therapy,while the patients of MLG group underwent continuous wavelength laser photocoagulation with a 561 nm yellow green laser.All the patients were examined documenting corrected visual acuity,macular retinal thickness (CMT) and mean sensitivity within macular 10 ° examination before and after treatment.Six months after treatment was considered as the judgment time for the therapeutic effects.The mean corrected visual acuity,CMT and MS were comparatively analyzed.Results Six months after treatment,the mean corrected visual acuity of micro-pulse group and MLG group were 0.45±0.20 and 0.42±0.20,which increased significantly compared to those before treatment (t=3.404,2.316; P＜0.05).The difference of mean corrected visual acuity between before and after treatment of micro-pulse group and MLG group were 0.08 ± 0.02 and 0.06 ± 0.03,the difference was statistically significant between two groups (t=0.532,P＞0.05).The mean CMT of micro-pulse group and MLG group were (323.94 ± 68.30) and (355.85±115.88) μm,which decreased significantly compared to those before treatment (t=4.028,2.039; P＜0.05).The difference of mean CMT between before and after treatment of micro-pulse group and MLG group were (55.12±13.68) and (22.25±10.92) μm.The difference was not statistically significant between two groups (t=1.891,P＞0.05).The mean MS of micro-pulse group and MLG group were (6.63 ± 2.65) and (4.53 ± 1.81) dB.The mean MS of micro-pulse group increased significantly compared to that before treatment (t =3.335,P ＜ 0.05).The mean MS of MLG group decreased significantly compared to that before treatment (t=3.589,P＜0.05).The difference of mean MS between before and after treatment of micro-pulse group and MLG group were (1.10 ± 0.33) and (-0.91 ±0.25) dB.The difference was statistically significant between groups (t =4.872,P＜0.05).Conclusions In the treatment of DME,yellow micro-pulse laser therapy and MLG can improve visual acuity,and reduce CMT.In addition,yellow micro-pulse laser therapy can improve the MS,but MLG reduces MS. Key words: Diabetic retinopathy/therapy; Macular edema/therapy; Laser coagulation; Treatment outcome