Difference in Ocular Perfusion Drop After Intravitreal Aflibercept in Patients with Neovascular AMD and Diabetic Macular Edema.

PURPOSE: Vascular endothelial growth factor (VEGF) is a factor in the pathogenesis of Age-Related Macular Degeneration (AMD) and Diabetic Macular Edema (DME), yet they differ in pathogenesis. It has been shown that only patients with diabetic retinopathy have elevated VEGF levels in the aqueous humor. Intravitreal injections of anti-VEGF substances have been the gold standard in treating diseases for several years, but an impact on ocular perfusion has been assumed. This study aimed to investigate the effects of intravitreal aflibercept injection (IVI) on ocular perfusion in patients with AMD and DME.

METHODS

This prospective study included 36 eyes of 36 patients, with 18 patients having nAMD (n = 18) and 18 patients having DME (n = 18), all treated with IVI. Ocular perfusion was measured using Laser Speckle Flowgraphy (LSFG). The parameter Mean Blur Rate (MBR) reflects erythrocyte flow velocity and serves as an indirect marker of perfusion. MBR was measured at the optic nerve head (ONH). The device's software can analyze MBR in areas of major retinal vessels (MV) and in microperfusion areas of the tissue (MT). Measurements were conducted at three time points (before scheduled IVI, as well as 1 week and 4 weeks after).

RESULTS

In patients with AMD, significant decrease in MV was observed, while no significant change was noted for MV in patients with DME (Analysis of Variance, ANOVA, p = 0.04 vs. p = 0.2). However, both groups showed a significant decrease in MT (ANOVA, p < 0.001 for both groups).

CONCLUSION

The results indicate that retinal perfusion as measured with LSFG is less impaired in patients with DME following IVI treatment. This could be related to endothelial dysfunction, which appears to be restricted to retinal endothelial cells, as MT as a surrogate marker of choroidal perfusion showed a significant reduction in the DME group. Responses highlight physiological differences between retinal and choroidal capillaries.