Evaluation of Retromode Imaging for Use in Hydroxychloroquine Retinopathy

To report on the application of retromode imaging using infrared lasers to eyes with hydroxychloroquine (HCQ) retinopathy, and to compare retromode images with those acquired via conventional objective screening imaging modalities-optical coherence tomography (OCT) and fundus autofluorescence (FAF).

Diagnostic validity assessment.

Setting: Institutional.

Sixty-two eyes of 31 patients with systemic lupus erythematosus or rheumatoid arthritis who were treated with HCQ and developed HCQ retinopathy (patient group), 270 eyes of 135 patients with the same diseases who were treated with HCQ but exhibit no retinopathy (HCQ-taking control group), and 162 eyes of 81 normal controls (normal control group).

Diagnosis of HCQ retinopathy was performed with screening tests recommended by the American Academy of Ophthalmology, including OCT, FAF, and visual field examination. Retromode imaging, using confocal scanning laser ophthalmoscopy, was performed for the patient group and both control groups. The findings on retromode imaging were correlated with outer retinal changes on OCT B-scan images, then compared with the FAF findings. The sensitivity and specificity of retromode imaging were calculated.

Findings of retromode imaging and sensitivity/specificity of the imaging.

All patients with HCQ retinopathy showed a parafoveal or pericentral ring-shaped or round area of decreased reflectance with prominent deep choroidal vessels, resulting in 100% sensitivity for the detection of retinopathy. Specificity of the imaging was 73.0% and 76.4% in the HCQ-taking control group and both control groups, respectively. Compared to FAF, retromode imaging enabled the detection of photoreceptor defects with greater sensitivity, particularly in eyes with early retinopathy. However, FAF provided additional information on the status of the retinal pigment epithelium, which could not be discriminated from photoreceptor defects in retromode imaging.

Retromode imaging may be useful for detecting HCQ retinopathy. However, its excellent sensitivity but limited specificity is suggestive of a supplementary role in screening HCQ retinopathy, particularly for early detection.