Impacts of intravitreal anti-VEGF therapy on retinal anatomy and neurophysiology in diabetic macular edema

Abstract

Purpose To evaluate anatomical and neuroretinal functional aspects in patients with diabetic macular edema (DME) after intravitreal anti-vascular endothelial growth factor (VEGF) therapy, in particular aflibercept. Materials and methods This prospective single-centered interventional study was performed at Afyonkarahisar Health Science University Faculty of Medicine, Department of Ophthalmology, where 32 eyes of 32 patients with DME were investigated. All patients received five intravitreal aflibercept injections on a monthly basis and were followed up for >= 6 months. After a comprehensive ophthalmological examination, including the measurements of visual acuity and intraocular pressure, and an antero-posterior segment slit-lamp biomicroscopy before and after full pupil dilation, fundus fluorescein angiography and optical coherence tomography were performed at baseline and during the third and sixth months post-therapy. Microperimetry and multifocal electroretinography were also performed at baseline and during the sixth months. Results Mean visual acuity increased from 0.73 to 0.57 and 0.33 logarithm of the minimum angle of resolution (logMAR) during the third and sixth months, respectively (p < 0.001). Changes in intraocular pressure were not statistically significant (p = 0.472). There was statistically significantly decreased mean central macular thickness from 390.2 mu m to 242.6 and 289.7 mu m during the third and sixth months, respectively (p < 0.001). Significantly improved fixation patterns during the sixth month, along with significantly increased macular sensitivity from 8.2 to 14.2 dB (p < 0.001) and significantly decreased local deficit from - 10.3 to 5.5 dB (p < 0.001) were observed. Further, there was a significantly increased N1 amplitude in the first ring and significantly increased P1 amplitude in all rings (p for each parameter < 0.05). There was also significantly decreased N1 wave implicit time in all rings and significantly decreased P1 wave in the second, third, fourth and fifth rings (p for each parameter < 0.05). Conclusions Patients with DME showed profound improvement in the retinal neurophysiological function, which was also accompanied by anatomical and ultrastructural integrity recovery after intravitreal aflibercept therapy. In the pathogenesis of DME, the influence of neurodegeneration has been increasingly gaining significant attention. Consequently, the need to assess neurophysiological effects of anti-VEGF therapy using a variety of diagnostic measures like electrophysiological studies and multimodal imaging technologies is undeniably growing.