Comparative Study between the Efficacy and Safety of Subthreshold Laser and Conventional Grid Laser for Diabetic Macular Edema

Background: One of the most prevalent and potentially devastating eye consequences of diabetes mellitus is diabetic retinopathy (DR). Damage to the retina's microvascular system causes diabetic macular edema (DME). Retinal laser photocoagulation has been the gold standard for treating numerous retinal diseases, including DME. Objective: To compare the efficacy and safety of conventional grid laser photocoagulation and Subthreshold laser treatment (STLT) in cases of DME. Patients and methods: A Total of 40 eyes of patients diagnosed with DME were divided into two groups, each group containing 20 eyes. Group (A) received subthreshold laser treatment sessions, and group(B) received conventional grid laser photocoagulation treatment. Before treatment, all patients in both groups underwent best corrected visual acuity (BCVA) measurement, ophthalmological Examination including slit lamp biomicroscopy examination, fundus color photos and optical coherent tomography (OCT) imaging. All cases were selected from the outpatient clinic of the Ophthalmology Department at Al-Azhar University Hospitals (AL-Hussein and Sayed Galal) from November 2022 to January 2024. Results: The mean of BCVA After Three months for patients of STLT group was 0.80±0.16 and it was 0.57±0.16 for patients of conventional laser photocoagulation (CLP) group. The mean of central macular thickness (CMT) After Three months for patients of SLT group was 277.90μm±27.28μm and it was 332.10μm±43.63μm for patients of CLP group, and these was highly statistically significant. Conclusion: Subthreshold laser treatment is a more effective and safer treatment option for diabetic macular edema than conventional laser photocoagulation in the form of grid laser treatment.