Abstract
Purpose: :
The Early Treatment Diabetic Retinopathy Study has shown that PRP reduces the risk of severe visual loss in all stages of non-proliferative diabetic retinopathy (NPDR). The absolute risk reduction in this group of all-comer NPDR and the risk of deferring treatment, however, is small. Therefore, PRP treatment is usually deferred until patients develop PDR. Our study’s aim was to examine whether PRP reduces the risk of adverse events in a subgroup of patients known as high-risk NPDR, as defined by capillary dropout on fluorescein angiography (FA). Specifically, we investigated whether PRP treatment at this high-risk stage leads to improved outcomes measured as the lack of progression to PDR and vitreous hemorrhage (VH).
Methods: :
A retrospective chart review was performed at the University of Florida ophthalmology clinic. Included patients had a prior diagnosis of high risk NPDR confirmed with an FA identifying capillary-dropout, had no observation of neovascularization, had no prior history of having a PRP treatment, and went on to have PRP treatment at our clinic. The patient’s fundus was examined for the development of VH or PDR. Data was analyzed using the Kaplan-Meier estimator. Incidence of conversion to PDR or VH was also calculated. Change in visual acuity was measured using a paired t-test and LogMAR conversion of visual acuity on a Snellen chart.
Results: :
A search of the University of Florida database for eyes treated for the first time with PRP for high-risk NPDR resulted in a total of 38 eyes in 23 patients. Incidence of VH following PRP treatment was 10.4% at one year post-treatment. Kaplan-Meier estimator resulted in 94.12% of patients without VH at six months and 90.35% at one year and two years. Incidence of conversion to PDR following PRP treatment was 38.9% at one year post-treatment. Kaplan-Meier estimator resulted in 82.35% of patients without PDR at six months, 67.65% at one year, and 30.07% at two years. Paired t-test used for visual acuity changes showed no significant difference in visual acuity at six months post-PRP treatment (p=0.206).
Conclusions: :
Despite treatment with PRP at the high-risk stage of NPDR, there was a significant amount of individuals who developed PDR within the year. However, our incidence of VH at one year is substantially less than prior reports (8.28% vs. 37%, respectively). Earlier treatment at this threshold of disease is more effective in mitigating VH than the convention of treating once retinopathy has become proliferative. Furthermore, there was no significant adverse effect on vision. Further investigation is warranted in this high-risk non-proliferative group to determine whether PRP is beneficial in reducing adverse outcomes prior to conversion to PDR.
Keywords: diabetic retinopathy • retinal neovascularization • clinical (human) or epidemiologic studies: prevalence/incidence