Panretinal photocoagulation after or prior to intravitreal conbercept injection for diabetic macular edema: a retrospective study

BACKGROUND: Panretinal photocoagulation treatment (PRP) have been known as a standard treatment for proliferative diabetic retinopathy (PDR) or severe nonproliferative diabetic retinopathy (sNPDR). However, there is no consensus on when PRP should be administrated if anti-VEGF treatment is needed for the concurrent diabetic macular edema (DME). This study is to evaluate the difference between two groups of PRP prior to, or after intravitreal conbercept (IVC) for patients with PDR or sNPDR combined with DME. METHODS: This was a retrospective study. Fifty-eight eyes with DME secondary to PDR or sNPDR were divided into two groups; the PRP after (PRP-after group), or prior to (PRP-prior group), IVC. Changes in number of IVC injections, best corrected visual acuity (BCVA), and central subfield macular thickness (CSMT) were compared after 4 weeks, 12 weeks, 1 year, and 2 years from the first IVC injection. RESULTS: The mean number of injections in PRP-after group was 4.8 (1 year) and 6.4 (2 year), lower than 6.4 (1 year) and 8.5 (2 year) in PRP-prior group (both p = 0.002). There was no significant difference in change in BCVA and CSMT between two groups after each follow-up. CONCLUSION: PRP after IVC requires less injections but also yields similar visual and anatomic outcome comparing with PRP prior to IVC in patients with diabetic retinopathy combined with DME. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12886-021-01920-8.