A Comparative Study of the Effect of Different Laser Techniques on the Choroidal Thickness

Abstract

Background Retinopathy is a common and specific microvascular complication of diabetes. Clinical and experimental findings suggested that choroidal vasculopathy in diabetes may play a role in the pathogenesis of diabetic retinopathy. Spectral-domain optical coherence tomography (SD-OCT) can analyze choroidal structure and histopathological changes in diabetes. Purpose To compare choroidal thickness (CT) before and after panretinal photocoagulation (PRP), modified grid laser (MGP) and combined (panretinal photocoagulation & modified gird laser) using SD-OCT. Design Comparative prospective non-randomized case study, included 30 eyes of 30 patients from both sexes aging from 15 to 60 years. All patients were from Ain-Shams University Hospitals outpatient clinics. Patients were divided into 3 equal groups: Group A Patients with PDR underwent PRP, Group B: Patients with macular edema (ME) underwent MGP, Group C: Patients with PDR&ME underwent combined (PRP & MGP). All cases underwent SD-OCT with CT measurement before and at 1 & 3 Mns after laser therapy with assessment of best corrected visual acuity (BCVA). Results Mean age of participant was 50.83 ± 5.34 (SD). The mean CT in group A at baseline was 329.00 ± 36.08 μm (SD). This was increased to 336.40 ± 35.64 μm at 1 month then was decreased to 309.10 ± 38.87 μm at 3 Mns after laser therapy. This was showed highly statistically significant difference (P-value = 0.000). In group B the CT at baseline was 328.90 ± 19.69 μm. This was decreased to 313.90 ± 17.83 μm & 288.90 ± 23.10 μm after 1 & 3 months respectively with highly statistically significant difference (P-value = 0.000). While in group C the mean CT at baseline 329.80 ± 21.06 μm. This was decreased to 318.10 ± 19.25 μm, 300.40 ± 17.98 μm at 1 & 3 months after combined laser respectively. This was showed highly statistically significant difference (P-value = 0.000). There was no statistically significant difference between the studied groups regarding preoperative and postoperative (after 1&3 Mns) CT. There was no statistically significant difference observed between the studied groups regarding preoperative BCVA (P-value = 0.437). While P-value showing highly statistically significant difference between the studied groups regarding postoperative BCVA (P-value = 0.000). Conclusion The Choroidal thickness decreased in all 3 studied groups; suggesting that all laser techniques may reduce choroidal vascular permeability or cause atrophy of choroidal vessels over a 12-week period.