A study on laser photocoagulation in diabetic macular edema: Assessment with optical coherence tomography

Abstract

Introduction: Diabetic macular edema (DME) is the most common cause of visual loss among diabetic patients. Macular photocoagulation is the established mode of treatment for clinically significant macular edema (CSME). Objective: This study was conducted to know the response of focal and diffuse diabetic edema separately to frequency doubled Nd:YAG. Materials and Methods: A prospective study with total of 30 consecutive eyes with Clinically Significant Macular Edema (CSME) over 8 months in our institution and divided into two groups with 15 each as focal and diffuse on the basis of fundus bio-microscopy and fluorescein angiography. Baseline measurements were done by OCT. Patients with diffuse diabetic macular edema underwent modified grid laser photocoagulation with Frequency Doubled Nd: YAG. Patients of focal diabetic macular edema underwent focal photocoagulation with Frequency Doubled Nd: YAG. Patients were followed up at 4 weeks and 12 weeks with repeat measurements by OCT with Humphrey Zeiss Stratus 3.0. Data entered in excel sheet and analyzed using SPSS software. The demographical data was analyzed with descriptive and the correlations by Pearson correlation. Results: Among 15 eyes with focal macular edema mean age of patients was 59.80 ± 5.13 years whereas among diffuse macular edema, it was 67.80 ± 3.76 years. In the focal group, the mean BCVA letter score did not reveal a significant change at 4 and 12 weeks compared with the baseline (p=0.52 and p=0.74, respectively). In the diffuse group, the mean BCVA letter score showed a gradual decrease at 4 weeks and increased at 12 weeks compared with the baseline however this was not statistically significant. When central foveal thickness, perifoveal thickness, maximum retinal thickness and total macular volume were compared at baseline, 4 weeks and 12 weeks after surgery, it was found that visual outcome was better after laser photocoagulation in CSME when assessed using OCT. Conclusion: Laser photocoagulation