Abstract
Purpose :
Diabetic retinopathy contains both diabetic retinal microangiopathy and DRN. We investigated the structural changes in eyes diagnosed with treatment naïve high-risk PDR before and after panretinal photocoagulation (PRP). We hypothesize that clinical PDR may regress after treatment yet DRN may worsen.
Methods :
We retrospectively identified patients from a single institution who were recently diagnosed with high-risk PDR with or without macular edema and without previous treatment. Patients were included if SD-OCT images (Heidelberg Engineering, Heidelberg, Germany) were obtained before treatment and at least 3 months after starting treatment. Treatment included PRP and/or at least 3 intravitreal anti-vascular endothelial growth factor (VEGF) injections. Patients were excluded with a history of glaucoma, other retinal degenerations, and total central foveal thickness greater 350 µm. We obtained the mean of the parafoveal (1-3 mm) and perifoveal (3-6 mm) retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL) thickness using the Heidelberg software. Paired T-testing was performed to determine statistical significance.
Results :
We identified 10 patients (11 eyes) with a mean age of 53 years at baseline visit and mean follow-up visit of 11 ± 6 months. Seven eyes were treated with PRP, one eye with anti-VEGF injections, and 3 eyes with combination therapy. The mean central foveal thickness was 260 ± 30 microns at baseline and 289 ± 46 µmafter treatment. The perifoveal RNFL thickness before and after treatment was 34.3 ± 10.78 and 35.4 ± 11.11 µm, respectively (p = 0.30). The perifoveal GCL thickness before and after treatment was 31.5 ± 8.54 and 31.8 ± 9.22 µm, respectively (p = 0.61). Parafoveal region for RNFL and GCL thickness comparison also revealed no significance (p =0.84 and p = 0.72, respectively).
Conclusions :
Though this is the first study that has investigated retinal neurodegenerative changes before and after PRP in patients with PDR, this study did not find the significant correlation between the regression of PDR and the worsening of DRN. The possible reasons are due to a small sample size and a short follow-up period. The most important factor is that more sensitive and specific parameters for diagnosis and follow-up of DRN progression are required. Meanwhile, the current results support that the PRP is safe in PDR management.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.