To investigate the use of a retinal thickness deviation map generated from swept-source optical coherence tomography (SS-OCT) images for hydroxychloroquine (HCQ) retinopathy screening.
Retrospective cohort study SUBJECTS: This study included 1,192 Korean patients with a history of HCQ treatment-881 (1,723 eyes) in the discovery set and 311 (591 eyes) in the validation set. Patients were screened for retinal toxicity using SS-OCT, fundus autofluorescence, and standard automated perimetry.
According to the 2016 American Academy of Ophthalmology guidelines, HCQ retinopathy was diagnosed by the presence of abnormalities on ≥1 objective structural tests alongside corresponding visual field defects. The 12 × 9 mm2 macular volume SS-OCT scan was performed and the retinal thickness deviation map was automatically generated using the built-in software. On this map, yellow pixels (retinal thickness <5% of the normative level) and red pixels (retinal thickness <1% of the normative level) were defined as abnormal. Abnormal findings were evaluated and diagnostic criteria were developed based on the discovery set data; criteria were validated using the validation set data.
(1) The rate and patterns of abnormalities on the retinal thickness deviation map, and (2) the sensitivity/specificity of the diagnostic criteria.
The retinal thickness deviation map showed the following abnormal patterns in eyes with HCQ retinopathy: pericentral (36.0%) or parafoveal (6.1%) ring, mixed-ring (34.2%), central island (13.2%), and whole macular thinning (10.5%). The criterion of ≥5 contiguous red pixels showing one of the five characteristic patterns in both eyes yielded the greatest diagnostic performance (sensitivity/specificity of 98.2%/89.1% and 100%/87.5% when applied to the discovery and validation set data, respectively). Moreover, the area of abnormal pixels on the retinal thickness deviation map was significantly correlated with the mean deviation (P <0.001) and pattern standard deviation (P <0.001) on the Humphrey 30-2 test in eyes with HCQ retinopathy.
The retinal thickness deviation map may facilitate the objective evaluation of HCQ retinopathy as it does not require subjective, morphologic evaluation of the outer retinal layers over macular areas. The map has the potential to enhance HCQ retinopathy screening when used in conjunction with conventional screening modalities.
Copyright © 2020. Published by Elsevier Inc.