Longitudinal impact of drusen volume on quantitative fundus autofluorescence in patients with early and intermediate age-related macular degeneration

Abstract

Purpose : The aim of this prospective and observational study was to find a correlation between drusen volume and quantitative autofluorescence (qAF), as both may represent an indicator of progression for age-related macular degeneration (AMD).

Methods : 88 eyes of 52 patients (40 female) with early and intermediate AMD were enrolled in this study and had a mean follow-up of 9.2 ± 5.6 months with a total of 312 examinations. Patients with changes other than early and intermediate AMD were excluded. History of cataract surgery was no exclusion criteria. Drusen volume was manually extracted from 6x6mm OCT scans (Spectralis, Heidelberg Engineering, Heidelberg, Germany) for the ETDRS pattern sections six to nine as well as for the total pattern. qAF was measured using a rotated Delori pattern. The inner and middle eight-section-rings were averaged for total qAF as well as grouped according to the ETDRS pattern section six to nine. A linear mixed model with a dependent variable qAF and independent parameters drusen volume, age, sex and lens status, considering patient and eye specific random effects was calculated.

Results : Patient mean age at baseline was 75.58 ± 4.96 years. 42 eyes (48%) were pseudophakic and 46 eyes (52%) phakic. Applying the linear mixed model, we found no significant correlation between drusen volume and qAF, neither for the total values within the ETDRS pattern (p=0.914) nor the ETDRS sections six to nine (p=0.792, p=0.452, p=0.141 and p=0.706, respectively). Sex and lens status did not show significant correlation with qAF (p=0.431 and p=0.21, respectively). However, we found a significant correlation between age and qAF (p=0.025) with an estimated slope coefficient of -2.7.

Conclusions : Our study shows that qAF and drusen volume do not correlate. This finding may be due to nonconformity between lipofuscin content of retinal pigment epithelium and drusen size during course of disease.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.