Comparative Study between Targeted Retinal Photo coagulation With and Without Single Intravitreal Bevacizumab Injection Versus Conventional Panretinal Photocoagulation for Proliferative Diabetic Retinopathy Treatment

Document Type : Original Article


The Department of Ophthalmology, Faculty of Medicine, Cairo University


Abstract Background: Proliferative diabetic retinopathy (PDR) has traditionally been addressed with conventional panretinal argon laser photocoagulation (PRP). However, it may cause anatomical and functional adverse events arousing the need to explore alternative treatment modalities. Aim of Study: The study's objective was to examine and compare the effectiveness of targeted retinal photocoagulation (TRP) alone or in combination with a single intravitreal bevacizumab injection and regular conventional PRP alone in the management of individuals with naive mild to moderate PDR without macular edema. Patients and Methods: A prospective interventional ran-domized study that enrolled cases with naïve mild to moderate PDR but no high-risk characteristics (HRC) or macular edema. Forty eyes have completed the study. 20 eyes received PRP and the other 20 eyes had targeted retinal photocoagulation (TRP), 9 eyes of which were injected with single intravitreal bevacizumab injection one week after the laser treatment). Baseline and three months postoperative data were registered, including Best Corrected Visual acuity (BCVA), detailed fundus examination, fundus fluorescein angiography (FA) with photomontaging of seven 30 degrees standard images to assess the neovascular process and SD-OCT Macula; to assess the Central Sub Field Foveal Thickness (CSFT) using the ETDRS Map. Results: 20 eyes were treated with conventional PRP with mean age of 45.85±10.93. The mean duration of diabetes was 21.25±7.73 with mean HBA1c of 8.62±1.19. Mean baseline (BCVA) was 0.27±0.16 log MAR which increased to 0.26 ± 0.16 logMAR (p-value=0.671). Mean baseline CSFT was 228.40±31.04µm which increased to 270.25±57.85µm (p-value=0.004) after 3 months. Regression of proliferative state was achieved in 75% (15 eyes) at the end of third month following PRP. While regarding the TRP group, the average age was 46.2 ±9.29 with average diabetes duration of 17.4±8.03 with mean HBA1c of 8.96±1.63. Baseline mean LogMar BCVA was 0.49 ±0.31 which increased to 0.48±0.3 log (p-value=0.868). Baseline mean CSFT was 248.50±39.05µm which increased to 262.15±35.34µm (p-value=0.018) at 3 Months. The mean percentage of change in CSFT was 19.14% following PRP and 6.52% following TRP. Post treatment CSFT was different among both groups (p-value=0.007). Regression of the pro-liferative state was achieved in 90% (18 eyes) of the TRP group after 3 months (p-value=0.407). Conclusion: TRP is not inferior to conventional PRP in control of the neovascular process and achieving regression of the proliferative state either used alone or in combination of single intravitreal injection of bevacizumab. Vision was almost not affected by neither PRP nor TRP, however the percentage of induced change in the CSFT caused by TRP was definitely less than that was caused by PRP.