Abstract
Purpose:
The effect of anti-VEGF treatment on recently-diagnosed nvAMD is typically monitored using visual acuity (VA) and central sub-foveal retinal thickness (CRT) measurements. Microperimetry has been used to map and measure central retinal sensitivity change following anti-VEGF therapy for nvAMD, typically using the mean dB change in the central 12 degrees on the retina. In this pilot study, as well as VA and CRT, microperimetry was used to assess retinal sensitivity in an area of interest defined as the choroidal neovascular membrane (CNVM) and its sequelae.
Methods:
Retinal sensitivity was acquired using the Nidek MP-1 microperimeter (Nidek Technologies, Padova, Italy) after commencing anti-VEGF treatment following diagnosis of nvAMD. VA (ETDRS letters) and CRT (µm) were also recorded at baseline and following each injection in the loading phase. Microperimetry data was available for the central 20˚, however analysis of changes in retinal sensitivity was limited to the area of interest, identified for each participant with the aid of both late frame Fluorescein Angiography and OCT images.
Results:
Data from 10 patients were analysed. From baseline, mean improvement in VA after 2 anti-VEGF treatments was 5.4 letters (±12.77) and CRT reduced by 48 µm (±112.67); retinal sensitivity improved by 2.52dB (±1.2). The mean number points analysed within the area of interest for each participant was 48 out of the total of 76 points tested. Following the first injection, 33% of these points (16 out of 48) showed an improvement of at least 2 dB in retinal sensitivity (range: 2 - 11 dB) and of these 9 points improved by at least 4 dB. Further gains in retinal sensitivity were recorded after 2 injections: 61% of points (28 out of 48) increased by a minimum of 2 dB from baseline (range: 2 - 16 dB) and at 17 points sensitivity was raised by a minimum of 4 dB (p=0.002). The increase in retinal sensitivity after 2 treatments was significantly greater than after 1 injection (p<0.001).
Conclusions:
Analysis of the area of interest using microperimetry demonstrates significant improvements in macular function in line with improvements in VA and CRT in the initial phase of nvAMD treatment with anti-VEGF agents.