mfERG allows early detection of macular changes with hydroxychloroquine treatment
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In patients treated with hydroxychloroquine, multifocal electroretinography could detect abnormalities in macular function early, before overt maculopathy was present, according to a study.
Chloroquine and hydroxychloroquine (HCQ) are used in rheumatic autoimmune diseases such as rheumatoid arthritis and systemic lupus erythematosus. As both these drugs have a high affinity for melanin, they tend to accumulate in the retina, specifically in the retinal pigment epithelium, as well as in the iris and ciliary body, Gaurav Kiri, MS, said at the virtual Association for Research in Vision and Ophthalmology meeting.
“Because they can stay in these tissues for months, prolonged use can result in toxic maculopathy and consequent loss in VA. Therefore, these patients require regular monitoring,” he said.
In a study, multifocal electroretinography (mfERG) was used to examine the clinical and vision function characteristics of patients sent for HCQ maculopathy screening at the USF Eye Institute in Tampa, Florida, from December 2014 to October 2019. Recording of mfERG was performed binocularly, focusing on ring ratios R1/R2, R5/R3 and R5/R4.
Seventy-eight eyes of 39 patients were included, with age ranging from 30 to 84 years and duration of HCQ treatment from less than 1 year to 22 years.
“In 44% of the patients, at least one mfERG ring ratio was abnormal. In 20.5%, more than one was abnormal, and in 2.5%, all three mfERG ratios were abnormal. However, there was no significant difference in VA between participants with normal and abnormal ring ratios,” Kiri said. “These findings demonstrate that VA is a poor indicator of early HCQ-induced changes, and abnormality in mfERG might appear before changes in VA.”
For 11 patients, at least one mfERG follow-up testing was available at an average period of 1.2 years. For this group, R1/R2 ring ratios increased in eight eyes and decreased in 14 eyes, although none of the eyes in which the ratio increased were considered to have maculopathy.
“Due to the low number of patients, our results should be interpreted with caution,” Kiri said. “A long period of observation with more follow-up data is need for definitive conclusions.”
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Kiri G, et al. Characteristics and findings of patient population sent for hydroxychloroquine (HCQ) maculopathy screening. Presented at: Association for Research in Vision and Ophthalmology annual meeting; June 12, 2020 (virtual meeting).
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