To compare retinal layer volumes using spectral-domain optical coherence tomography between eyes with hydroxychloroquine (HCQ) toxicity and control eyes.Methods:
Using a previously validated algorithm, volumetric analysis from the macular cube scan of the ganglion cell layer, inner plexiform layer, inner nuclear layer, and outer retina (outer plexiform layer to retinal pigment epithelium) layers were compared in three sets of patients: patients with a clinical diagnosis of HCQ toxicity, age-matched patients taking HCQ but not manifesting overt toxicity, and age-matched control patients.Results:
There were 14 patients in each group. The ganglion cell layer (P = 0.01), inner plexiform layer (P = 0.004), inner nuclear layer (P < 0.001), and outer plexiform layer to retinal pigment epithelium (P < 0.001) volumes were significantly reduced in HCQ toxicity eyes relative to the HCQ exposure eyes. There were no significant inner and outer retinal volume differences between the HCQ exposure group and group with no HCQ use (P > 0.05 for all layers). Increasing disease severity correlated with increasing volume loss in the inner retina (2.27 mm3 in early disease vs. 1.78 mm3 in advanced retinopathy, P = 0.02).Conclusion:
Hydroxychloroquine toxicity seems to result in both outer and inner retinal volumetric thinning compared with age-matched control patients and patients taking HCQ but not manifesting toxicity.