Purpose: To prospectively investigate the development of quantitative autofluorescence (qAF) during progression from intermediate to late age-related macular degeneration (AMD).
Methods: Quantitative autofluorescence images from patients with intermediate AMD were acquired every three months with a Spectralis HRA + OCT (Heidelberg Engineering, Heidelberg, Germany) using a built-in autofluorescence reference. The association between changes in longitudinal qAF and progression toward late AMD was assessed using Cox regression models with time-dependent covariates.
Results: One hundred and twenty-one eyes of 71 patients were included, and 653 qAF images were acquired. Twenty-one eyes of 17 patients converted to late AMD (median follow-up: 21 months; 12 eyes: atrophic AMD; nine eyes: neovascular AMD). The converting patients' mean age was 74.6 ± 4.4 years. Eleven eyes in the converting group (52.4%) were pseudophakic. The presence of an intraocular lens did not affect the qAF regression slopes (P > 0.05). The median change for atrophic AMD was -2.34 qAF units/3 months and 0.78 qAF units/3 months for neovascular AMD. A stronger decline in qAF was significantly associated with an increased risk of developing atrophic AMD (hazard ratio = 1.022, P < 0.001). This association, however, was not present in the group progressing toward neovascular AMD (hazard ratio = 1.001, P = 0.875).
Conclusion: The qAF signal declines with progression to atrophy, contrary to developing neovascularization. Quantitative autofluorescence may allow identification of patients at risk of progressing to late AMD and benefits individualized patient care in intermediate AMD.