Topographic Analysis of Two-Wavelength Autofluorescence Supports Higher Macular Xanthophyll Pigment in AMD Than Aging: ALSTAR2 Baseline.

Abstract

Purpose: To advance metabolic imaging of the high-risk macula lutea by quantifying the topography of macular pigment optical density (MPOD), measured with two-wavelength autofluorescence (2WAF), and quantitative (short-wavelength) autofluorescence (qAF) intensity, which share the same signal source and cross-retinal light path, in aging, early (e), and intermediate (i) age-related macular degeneration (AMD).

Methods: 2WAF and qAF images of 384 pseudophakic eyes of 230 persons (mean age, 74.2 ± 5.7 years; 145 female) from ALSTAR2 (AREDS 9-step classification: 170, normal; 118, eAMD; 96 iAMD) were shown as maps (intensity, z-score) and meridian plots. Correlations were determined in Early Treatment Diabetic Retinopathy Study (ETDRS) subfields.

Results: MPOD was higher in the central subfield (P < 0.01) in iAMD compared to eAMD and normal eyes, and qAF was lower in the central subfield and inner ring (both P < 0.01) in AMD compared to normal eyes. MPOD differed along horizontal versus vertical meridians, depending on disease stage. Pixel-level z-score maps and meridian plots showed distinct annuli of alternating levels of MPOD anchored on the foveal center, unrelated to qAF. Across the central subfield, high 2WAF was associated with low qAF in all disease stages (r = -0.47, r = -0.47, r = -0.42; all P < 0.001). In the inner ring, correlations were significant for normal and eAMD only (r = -0.31, P = 0.004 and r = -0.22, P ≤ 0.001, respectively).

Conclusions: New analytics support previously reported higher MPOD in AMD compared to normal eyes, especially central subfield and inner ring. MPOD and qAF differ by disease-stage-related topography and correlations, supporting independent use in metabolic imaging of the macula lutea.