Selective Scatter Photocoagulation (SSP) in Patients with Proliferative Diabetic Retinopathy without High Risk Characteristics

Abstract

In the proliferative stage of diabetic retinopathy neovascularization is seen to occur on and adjacent to the disc (NVD) and also elsewhere in the retina (NVE). The bleeding from these vessels results in preretinal and vitreous hemorrhage causing severe visual loss. The Diabetic Retinopathy Study (DRS) identified certain high-risk characteristics, the presence of which predisposes these eyes to the risk of Severe Visual Loss (SVL).The High-Risk Characteristics (HRC) are disc neovascularization (NVD) that is atleast 1/4-1/3 disc area in extent, any disc neovascularization (NVD) with pre-retinal or vitreous hemorrhage or neovascularization elsewhere (NVE) that is atleast 1/2 disc areas in extent and associated with pre-retinal or vitreous hemorrhage. Patients who have NVE but no signs of preretinal or vitreous hemorrhage are categorized as Proliferative Diabetic Retinopathy without High Risk Characteristics (PDR-non-HRC). The Diabetic Retinopathy Study (DRS) recommended prompt Pan Retinal Photocoagulation (PRP) in all patients meeting the High-Risk Criteria (HRC). PRP was found to reduce the risk of severe visual loss by more than 50%. The progression to severe visual loss at 5 years was 50% in those not lasered and only 20% in those treated by PRP [4,5]. DRS also recommended PRP to be considered prior to development of HRC in patients without high risk characteristics and also in cases of very severe or severe non-proliferative diabetic retinopathy in special situations such as patients who cannot maintain a regular follow-up. However Pan retinal photocoagulation can cause significant side effects like decreased visual field, reduced dark adaptation and worsening or inducement of macular edema [6,7]. To minimize the side effects of Pan retinal photocoagulation, the author has been treating patients who have proliferative diabetic retinopathy without high risk characteristics using Selective Scatter Photocoagulation (SSP). The observations of this approach are reported herein. No prior literature exists on the use of this approach in the management of patients with proliferative diabetic retinopathy.