Evaluation of the corneal endothelium in systemic lupus erythematosus patients under long-term hydroxychloroquine treatment using specular microscopy

Background The antimalarial medication called hydroxychloroquine (HCQ) is often used in the treatment of systemic lupus erythematosus (SLE). While it reduces the disease flares and mortality, the prolonged use may cause ocular toxicity, including corneal endothelial changes. Objective The aim of this study was to evaluate the effects of the long-term HCQ use (3 years or more) on the corneal endothelium in SLE patients using specular microscopy. Patients and methods This is a retrospective cohort cross-sectional study, which included 60 eyes of 30 participants who were split into two groups: 30 eyes of 15 SLE patients who had received HCQ treatment for at least 3 years and 30 eyes of 15 healthy volunteers as a control group. Every participant received a thorough ophthalmologic evaluation, and specular microscopy to measure the endothelial cell density, hexagonality, coefficient of variation (CV), and the SD of the mean cell area as a supportive measurement. Results The mean age of the SLE patients was 37.07±6.96 years compared to 33.67±6.88 years in the control group ( P =0.062). All participants were females (100%). There were no statistically significant differences in the best-corrected visual acuity, color vision, intraocular pressure, and fundus findings between the two groups ( P >0.05). In addition, the specular microscopy showed no significant differences in the endothelial cell number, endothelial cell density, hexagonality, and corneal thickness between the two groups ( P >0.05). However, the patients on HCQ had significantly higher CV than the controls ( P =0.01). Conclusion The long-term HCQ therapy in SLE patients may be associated with subtle corneal endothelial morphologic changes, particularly an increase in the CV.