A retrospective evaluation of the effect of hydroxyquinine on RPE thickness

Background: To investigate a possible structural difference in the retina of hydroxychloroquine (Plaquenil)-treated patients as an explanation for the protective effect of this medication against age-related macular degeneration (AMD). Methods: In this retrospective study, we compared the mean thickness of the retinal outer band (consisting of the Bruch's membrane and retinal pigment epithelium layer), as measured by optical coherence tomography (OCT), of 54 eyes of 27 hydroxychloroquine-treated rheumatoid arthritis patients (study group), 40 eyes of 20 healthy similar aged individuals (control group I), and 22 eyes of 11 non-hydroxychloroquine-treated rheumatoid arthritis patients (control group II). Results: The mean thicknesses of the outer band of the retinal pigment epithelium layer was 60.4 ± 7.4, 43.3 ± 2.7, and 39.7 ± 3.6 μm for the study group, control group I, and control group II, respectively. P values for differences in mean thicknesses were < 0.0001 between the study group and each of the control groups, and 0.086 between the two control groups. Conclusion: Treatment with hydroxychloroquine was associated with increased thickness of the outer band of the retinal pigment epithelium layer. This finding may explain the protective effect of hydroxychloroquine against age-related macular degeneration (AMD).