Correlation between Microperimetry and Imaging in Extensive Macular Atrophy with Pseudodrusen-like appearance (EMAP)

Purpose: To determine the correlation between microperimetry and imaging findings in extensive macular atrophy with pseudodrusen-like appearance (EMAP). Mthods: This cross-sectional, observational study included 44 consecutive EMAP patients (88 eyes) and 30 healthy subjects (60 eyes). Both groups underwent visual acuity assessment, mesopic and scotopic microperimetry, fundus photography, autofluorescence, optical coherence tomography (OCT) and OCT angiography. Retinal sensitivity (RS) was also subdivided in macular (0-4°) and para-macular areas (8-10°). Scotopic sensitivity loss was defined as the difference between scotopic and mesopic sensitivities for each tested point. Eyes with EMAP were further classified into the 3 stages described by Romano et al: 19 eyes in stage 1, 31 in stage 2, 38 in stage 3. Results: Mesopic and scotopic RS were significantly reduced in EMAP patients compared with controls, particularly in the macular area (all p<0.001). Mesopic RS progressively declined in more advanced EMAP stages (all p<0.01), but no scotopic differences were observed between stages 2 and 3 (p=0.08). Remarkably, scotopic sensitivity loss was significantly higher in stage 1 (p<0.05).On multivariate analysis, mesopic dysfunction was associated with larger atrophic areas (p<0.01), foveal involvement (p=0.03) and fibrosis (p=0.02). Conversely, no independent variable was associated with a reduced scotopic RS (all p>0.05). Conclusions: Our findings highlight that EMAP patients suffer from a severe cone- and rod-mediated dysfunction on microperimetry. The predominant rod impairment in the early cases (stage 1) emphasizes the importance of dark-adapted scotopic microperimetry as clinical endpoint and suggests a defective transportation across the RPE-Bruch's membrane complex in its pathogenesis.