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Updated: Sep 2, 2026
Quantitative Fundus Autofluorescence for the Evaluation of Retinal Diseases
Published on: March 11, 2016
Validation of Ultra-Widefield Autofluorescence Imaging as an Endpoint for Disease Progression in Choroideremia: A
Mechteld C S van Olden1, Jeroen A A H Pas1,2, Suzanne Yzer1
1Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands.
Objective:
Promising gene therapy studies in patients with choroideremia (CHM) have failed to meet the primary endpoint of best-corrected visual acuity, but other therapeutic effects in the peripheral fundus may not have been discovered. Ultra-widefield fundus autofluorescence (UWF-FAF) is able to capture peripheral retinal changes as potential structural endpoint. We compared UWF-FAF with conventional FAF in patients with CHM to evaluate its potential as additional imaging modality for future clinical trials.
Design:
Retrospective cohort study.Subjects: Participants with genetically confirmed CHM and both central 30° and 55° FAF and UWF-FAF imaging available.
Methods:
Conventional FAF (30° or 55°) and UWF-FAF images obtained on the same day were retrospectively aligned for direct comparison and then analyzed. Two independent graders outlined atrophic areas and preserved retinal pigment epithelium (RPE) islands. Between-modality differences with standard errors, 95% confidence intervals (CIs), and 2-sided P values (α = 0.05) were calculated. Intergrader agreement was assessed using intraclass correlation coefficients (ICCs).
Main Outcome Measures:
Between-modality differences in area measurements of FAF and UWF-FAF with standard errors, 95% CIs and ICCs.
Results:
Ninety-six FAF images from 15 patients were included (35 FAF 30°, 20 FAF 55°, and 41 UWF-FAF). Intergrader ICCs ranged from 0.625 to 0.998, indicating good-to-excellent agreement. Within the 30° field, no significant difference was found for the total cohort (0.01; 95% CI, -0.02 to 0.04; P = 0.438) or for atrophy (-0.06; 95% CI, -0.14 to 0.01; P = 0.089), whereas preserved RPE islands differed significantly (0.04; 95% CI, 0.01-0.06; P = .005). Within the 55° field, differences did not reach statistical significance for the total cohort (0.08; 95% CI, -0.01 to 0.18; P = 0.077), atrophy (0.10; 95% CI, -0.09 to 0.28; P = 0.260), or islands (0.07; 95% CI, -0.001 to 0.15; P = 0.054).
Conclusion:
In our current study UWF-FAF provided comprehensive atrophy measurements quantitatively comparable to conventional FAF in CHM, supporting its usefulness as a structural clinical trial endpoint for disease progression. Due to significant differences in preserved RPE island measurements the modalities should not be used interchangeably.
Financial Disclosures:
The authors have no proprietary or commercial interest in any materials discussed in this article.
