Abstract
Purpose:
To obtain quantitative fundus autofluorescence (qAF) measurements in patients with Bull’s-Eye maculopathy (BEM) and determine whether qAF can differentiate between ABCA4- and non-ABCA4-related disease in this phenotype that is common to some retinal dystrophies.
Methods:
40 BEM patients (mean age of 32.0 years; range: 8-67 years) were studied. All patients exhibited a well-delineated macular lesion and qualitatively normal appearing surrounding retina without flecks. AF images (30°, 488 nm excitation) were acquired with a confocal scanning laser ophthalmoscope equipped with an internal fluorescent reference to account for variable laser power and detector sensitivity. The gray levels (GLs) of each image were calibrated to the reference, zero GL, magnification, and normative optical media density, to yield qAF. All patients were screened for mutations in the ABCA4 gene with the ABCR700 microarray and/or by next generation sequencing.
Results:
At least one ABCA4 mutation was identified in 23 patients, who tended to be younger (mean age: 23.9 years) than ABCA4-negative patients (mean age: 42.9 years). Only 3 ABCA4-positive patients, 2 of which were homozygous for G1916E, did not have qAF levels above the 95% confidence interval of normal controls. Conversely, 15/17 ABCA4-negative patients had qAF levels within the normal range.
Conclusions:
The qAF method permits a determination of genotype-phenotype correlations and can help to identify BEM patients that should be considered for ABCA4 screening.
Keywords: 696 retinal degenerations: hereditary •
582 ipofuscin •
550 imaging/image analysis: clinical