Inner-Retinal Thinning Observed in Eyes With Hydroxychloroquine Retinopathy

Eyes with severe hydroxychloroquine retinopathy exhibit macular ganglion cell complex (GCC) and peripapillary retinal nerve fiber layer (pRNFL) thinning, according to a study published in the American Journal of Ophthalmology. These changes correlated with worse perimetric function and warrant careful monitoring in these patients. 

Researchers enrolled 132 participants consisting of 66 patients with hydroxychloroquine retinopathy (mean age, 56.2±13.5 years; 95.5% women) and 66 age- and sex-matched controls (mean age, 56.8±14.0 years; 95.5% women) in a cross-sectional, case control study. Eyes with hydroxychloroquine retinopathy were stratified into early, moderate, and severe stages. Patients underwent comprehensive exams consisting of swept-source optical coherence tomography (SS-OCT), fundus autofluorescence (FAF), and standard automated perimetry. Inner-retinal thickness parameters were evaluated and compared between experimental and control groups. 

Overall, average macular GCC (99.6±21.8 vs 106.1±8.0 µm; P =.009) and pRNFL thickness (101.1±17.7 vs 104.5±11.6 µm; P =.021) were thinner in patients with retinopathy compared with control individuals. However, when divided into 12 clock-hour sectors, pRNFL thickness was thicker in the 3-, 8-, 9-, 10-, and 11-o’clock sectors in individuals with retinopathy compared with control group participants, reaching statistical significance in the 9- and 10-o’clock sectors (P <.001 and P =.024, respectively). Temporal pRNFL thickness was also thicker among individuals with retinopathy compared with the control group (89.6±15.1 vs 82.0±14.8; P <.001) despite thinner values than control individuals in the other 3 quadrants. All 6 macular GCC sectors revealed thinner values for patients with retinopathy compared with control group patients, but these values failed to reach statistical significance in the superior (P =.080) and superonasal (P =.171) sectors.  

Average and sectoral macular GCC measures differed according to disease severity, with the most pronounced differences noted between early and severe stages. Average macular GCC and peripapillary RNFL thickness were associated with mean deviation and visual field index.

“This study demonstrated that macular GCC and pRNFL thinning may be present in eyes with hydroxychloroquine retinopathy; further, it showed that such changes were prominent in severe retinopathy,” according to the researchers. “Our findings suggest that, in eyes with hydroxychloroquine retinopathy, degenerative changes can occur also in the inner-retinal layers as the disease advances, though retinal toxicity primarily occurs in the outer retinal layers.” 

Study limitations include the use of a cross-sectional design instead of a longitudinal study and ethnic homogeneity that failed to represent patients on a global level.