Early retinal and retinal nerve fiber layer effects of hydroxychloroquine: a follow up study by sdOCT
Kocamis, Sucattin Ilker
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Context: The antimalarial drug hydroxychloroquine (HCQ), used in the treatment of rheumatologic disease, has been associated with the development of retinopathy. The long-term incidence of HCQ retinopathy has been estimated at 0.5% when recommended dosages (<= 6.5 mg/kg per day) are used. Objective: Evaluating the patients for whom HCQ treatment will be started before and after treatment prospectively with spectral domain (sd) optical coherence tomography (OCT) to observe possible early changes in the retinal and retinal nerve fiber layer thickness. Materials and methods: Thirty-six patients from rheumatology clinic who have been started HCQ therapy had clinical examination and sdOCT imaging before and 6 months after starting treatment. The baseline ophthalmological examinations and visual field analysis (on automated Humphrey visual field (HVF) 10-2 perimetry, Humphrey HFA II-i 750 i, Carl Zeiss Meditec AG, Jena, Germany) were completely normal. The sdOCT was performed with the Optovue technology according to the manufacturer's guidelines using EMM5, retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) scans. The retinal thickness values in central foveal, inferior and superior hemispheres, temporal, superior, nasal and inferior para-and perifoveal areas and the RNFL thickness of eyes were compared before and 6 months after starting treatment by the paired t test. Results: The retinal thickness values in central parafoveal (p = 0.02), and superior hemisphere (p = 0.01) in parafoveal area, parafoveal superior (p = 0.02), temporal (p = 0.03) and nasal (p = 0.04) quadrants were significantly thicker after 6 months of treatment. The thickness of the perifoveal area and the average RNFL thickness was not significantly different in any of the quadrants before and after starting HCQ treatment. The GCC thickness also did not change significantly different in superior and inferior hemisphere after starting treatment. Discussion and conclusion: We observe increased retinal thickness in parafoveal areas in patients on HCQ therapy at short term. Its clinical significance may be apparent in longer follow up studies.