Wide-field optical coherence tomography in ABCA4-associated inherited retinal dystrophies

Aim: With a need to expand the monitoring options in therapeutic clinical trials, we evaluated the additional information provided by wide-field optical coherence tomography (W-OCT) compared to conventional macular volume scan OCT (M-OCT) in ABCA4 gene-associated inherited retinal dystrophies (ABCA4-IRD).Methods: A consecutive series of 52 ABCA4-IRD patients (mean age at last examination: 35.9 years, range 8.8-68.7 years) was examined between 2015 and 2021. Ophthalmologic examination included clinical examination, M-OCT [20 × 20 degree field (6.2 mm × 6.2 mm)], W-OCT [55 × 25 degree field (16.1 mm × 7.3 mm)], multicolor reflectance photography, fundus (FAF), and near-infrared autofluorescence (NIA) in macular and wide-field mode. Molecular genetic testing to confirm the clinical phenotype was performed in all patients.Results: In 37/52 (71.2%) of patients W-OCT revealed alterations of the outer retinal layers beyond the area covered by M-OCT at their last examination. In 15 patients, lesions were located within the area covered by M-OCT. Lesions beyond M-OCT consisted of subretinal material (31/37), as well as patches (18/37) or large continuous areas (3/37) of photoreceptor and retinal pigment epithelial dystrophy. In one patient, W-OCT identified peripheral lesions that were not detectable in wide-field FAF and NIA. In 48/52 patients, two causative mutations in the ABCA4 gene were identified, while the remaining four patients carried one pathogenic ABCA4 variant.Conclusion: W-OCT as well as wide-field FAF and NIA document lesions in the retinal mid- and far periphery in the majority of ABCA4-IRD patients and provide means for detailed analysis of progression and future treatment planning and monitoring