Abstract
Purpose:
Reticular pseudodrusen (RPD) has been increasingly recognized as a risk factor for the development of advanced age-related macular degeneration (AMD). Although RPD are often present in eyes with features of the early stages of AMD, studies of the impact of RPD on retinal function to date have only been performed in eyes with RPD only. Thus, the purpose of this study was to investigate the influence of RPD on retinal function in eyes with intermediate AMD using microperimetry and multifocal electroretinography (mfERG).
Methods:
In this prospective cross-sectional study, mfERG, microperimetry, colour fundus photography, near-infrared reflectance (NIR) imaging and spectral-domain optical coherence tomography (SD-OCT) scans were performed in participants with bilateral intermediate AMD (drusen >125 μm). The presence of RPD was defined as groups of hyporeflective lesions against a mildly hyperreflective background on NIR, with corresponding hyperreflective signals above the RPE band on SD-OCT. The presence and extent of pigmentary changes and RPD within the central 3 mm diameter was examined using an Early Treatment of Diabetic Retinopathy Study (ETDRS) grid. Drusen volume within the central 3 mm diameter was also determined. The influence of these pathological features on microperimetry and mfERG within the same region were examined.
Results:
A total of 120 eyes of 60 participants (mean age was 70.5 ± 7.2 years, range 51 to 84) were included in this study. There were 39 eyes with RPD and 81 eyes without RPD. Microperimetric sensitivity was not significantly associated with the presence and extent of RPD (β Coefficient = -0.18, p = 0.068), but with drusen volume (β = -5.65, p < 0.001) and extent of pigmentary changes (β = -0.48, p < 0.001). The mfERG implicit time was independently and significantly associated with the presence and extent of RPD (β = 0.38, p = 0.001), drusen volume (β = 3.23, P = 0.023) and the extent of pigmentary changes (β = 0.55, p < 0.001). However, mfERG response amplitude was not significantly associated with the presence and extent of RPD (β = -0.75, p = 0.130).
Conclusions:
In eyes with intermediate AMD, the presence and extent of RPD had a significant impact on cone-mediated retinal function as measured by mfERG. Microperimetric sensitivity was influenced by AMD features but not by the presence or extent of RPD.