Screening for toxic retinopathy due to antimalarial drugs in Tunisia

Toxic retinopathy due to antimalarial drugs is characterized by structural anomalies associated with severe, irreversible visual loss. The advantage of ophthalmologic monitoring is to detect these anomalies at an asymptomatic, preclinical stage, so that the recommended dose can be adjusted before the ophthalmologic manifestations appear.

Cross-sectional study carried out in the ophthalmology department of Habib Bourguiba University Hospital, Sfax, between August 2016 and February 2018. All patients treated in the internal medicine department of Hedi Chaker University Hospital with synthetic antimalarial drugs for at least 1 year were included. A complete ophthalmologic examination and specialized retinal testing (fundus autofluorescence, 10-2 automated visual field and swept source OCT) were performed for all patients.

Fifty-six patients treated with antimalarial drugs were analyzed. The main indication was systemic lupus erythematosus (80.3%). Fifty-three patients (94.64%) were treated with hydroxychloroquine, and 3 patients (5.4%) with chloroquine. Thirteen patients (23.2%) exhibited signs of retinal toxicity, with fundus autofluorescence alterations in 8% of cases, fundus anomalies in 12.5% of cases, 10-2 automated visual field defects in 16% of cases, and SS-OCT alterations in 23.2% of cases. We did not find a statistically significant association between retinal toxicity, weight, age, sex and renal insufficiency (p values of 0.8, 0.6, 0.66 and 0.7 respectively). Furthermore, the association between the cumulative dose and retinal toxicity was statistically significant (p=0.02). The prevalence of toxic retinopathy was identified as 5% at 5 years, 25% at 10 years and 70% at 20 years.

A better understanding of the risk factors for retinal toxicity is necessary when prescribing synthetic antimalarial drugs. Screening should be systematic. It should be based on a combination of functional and anatomic tests. The frequency of screening depends on the associated risk factors.