GCC Thickness May Indicate Early Retinal Changes in Hydroxychloroquine Users

Researchers argue that using SD-OCT to monitor ganglion cell complex thickness in early courses of hydroxychloroquine treatment may help detect HCQ toxicity before fundus changes are seen. This OCT result from the study shows the both-eyes GCC analysis report of a 40-year-old woman diagnosed with RA taking oral hydroxychloroquine for seven years. The optic nerve head map shows normal cup-to-disc ratio, while the GCC analysis shows thinning. Photo: Acharya P, et al.BMC Ophthalmol. September 9, 2025. Click image to enlarge. One of the most common medications prescribed to patients with rheumatologic and dermatologic conditions, hydroxychloroquine is known to carry a significant risk of retinal toxicity and its use requires routine monitoring by eye doctors. The prevalence of hydroxychloroquine retinopathy is reported at 7.5%, with well-established associations related to dosage and duration of treatment. Early recognition of retinal toxicity in patients on this drug is vital to avert serious vision-threatening complications, such as bull’s eye maculopathy. In a recent cross-sectional, comparative study, researchers examined ganglion cell complex (GCC) thickness on OCT images of hydroxychloroquine users to see if the parameter may reveal retinal toxicity before ocular side effects or visual field loss occur. It found that GCC thickness was significantly reduced in patients on the drug, though there was no significant association between the measurement and treatment duration.Included were 87 participants, all of whom had used hydroxychloroquine for at least three months. The participants were divided into two groups: group 1 consisted of individuals who had been on hydroxychloroquine for less than five years, while group 2 included those treated for five years or longer. These patients were compared against a control group of age- and gender-matched healthy individuals. Each participant underwent visual acuity testing and advanced retinal imaging through RTVue spectral-domain OCT to measure GCC parameters, specifically focusing on average GCC thickness, superior and inferior thicknesses, global loss volume (GLV%) and focal loss volume (FLV%).The results revealed that participants in groups 1 and 2 had average GCC thickness values of 94.7μm and 92.7μm, respectively, whereas the control group had a thickness measurement of 99.8μm. The statistical analysis indicated a significant association between GCC thinning and hydroxychloroquine use.Furthermore, focal loss volume and global loss volume were also significantly elevated in the hydroxychloroquine-treated groups, suggesting that use of the drug may be potentially associated with retinal structural alterations. Specifically, group 1 displayed focal and global loss volume percentages of 1.76 ±2.5% and 4.07 ±3.27%, respectively, far exceeding the control values of 0.72 ±0.45% and 1.39 ±1.1%. The global loss volume observed in group 2 was also significantly greater than controls at 4.46 ±4.42%, though the difference in focal loss volume between that group and controls was insignificant.In their paper on the findings, the study authors explained that “various studies have reported that the first pathological changes occur in retinal ganglion cells,” due to the drug's accumulation in the cytoplasm of these cells, which leads to cell shrinkage and the formation of irregularly shaped cell bodies. They continued, “Since ganglion cells are affected in the early stages of the toxicity, assessment of GCC thickness [using SD-OCT] in early courses of treatment may be helpful in detection of hydroxychloroquine toxicity before any changes in the fundus are seen.” The study authors cited similar findings in prior investigations, which they argue “emphasizes the potential value of GCC measurements as a sensitive indicator of retinal changes linked to hydroxychloroquine use and emphasizes the significance of tracking GCC thickness in patients undergoing hydroxychloroquine therapy.”Click here for the journal source. Acharya P, Adhikari PG, Sitaula RK, et al. Ganglion cell complex thickness in patients taking oral hydroxychloroquine. BMC Ophthalmol. September 9, 2025. [Epub ahead of print]. This article was developed by the editorial staff in conjunction with experts in the field. In the process, AI may have been among the editorial tools used to meet the goals of human editors, who approved all content.