Background: Hydroxychloroquine retinal toxicity can occur in up to 7.5% of patients receiving treatment; however, possible genetic risk factors are poorly understood. The main objective of the study was to explore candidate genetic risk factors for retinal toxicity.Materials and Methods: Case-control study of patients with confirmed hydroxychloroquine retinal toxicity identified through ophthalmology departments of tertiary care hospitals and private ophthalmic practice in Australia. Participants were 26 Caucasian patients with hydroxychloroquine retinal toxicity who were matched with control subjects for age, gender, treatment duration and indication for hydroxychloroquine treatment. Participants underwent clinical examination, optical coherence tomographic scanning, automated field testing and whole exome sequencing of DNA extracted from saliva or blood. Outcome measures were grade of hydroxychloroquine toxicity and mutations in a panel of 40 candidate genes.Results: No susceptibility or protective factors were identified in either the cohort as a whole or any subset of patients.Conclusions and relevance: Further larger studies, with whole-exome analysis and consideration of additional modifying genes are needed.