Correlation between microperimetry and imaging in extensive macular atrophy with pseudodrusen-like appearance

Purpose: To determine the correlation between microperimetry and imaging findings in extensive macular atrophy with pseudodrusen-like appearance (EMAP). Methods: This cross-sectional, observational study included 44 consecutive patients with EMAP (88 eyes) and 30 healthy subjects (60 eyes). Both groups underwent visual acuity assessment, mesopic and scotopic microperimetry, fundus photography, autofluorescence, optical coherence tomography, and optical coherence tomography angiography. Retinal sensitivity was also subdivided in macular (04 degrees) and paramacular areas (810 degrees). 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 three stages described by Romano et al: 19 eyes in Stage 1, 31 in Stage 2, and 38 in Stage 3. Results: Mesopic and scotopic retinal sensitivity were significantly reduced in patients with EMAP compared with controls, particularly in the macular area (all P < 0.001). Mesopic retinal sensitivity 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 retinal sensitivity (all P > 0.05). Conclusion: The findings highlight that patients with EMAP 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 a clinical end point and suggests defective transportation across the RPEBruch membrane complex in its pathogenesis.