Humphrey visual field findings in hydroxychloroquine toxicity

To analyze Humphrey visual field (HVF) findings in hydroxychloroquine (HCQ) retinal toxicity.

HVF tests were interpreted retrospectively in this observational case series of 15 patients with HCQ toxicity. Patients seen at Lahey Clinic were identified by diagnosis coding search. Patients with age-related macular degeneration or glaucoma with visual field loss were excluded. HVFs done before the diagnosis were analyzed to see if earlier diagnosis could have been possible.

A total of 66 HVFs were reviewed and categorized. Some abnormalities were subtle. Paracentral defects were seen on 10-2 tests whereas 24-2 tests, due to their compressed scale, showed central changes. The abnormalities were often more obvious on pattern deviation rather than the gray scale. Of those patients with prior HVFs available for review, 50% showed HVF abnormalities typical of HCQ toxicity present several months or years before diagnosis. HVF changes preceded fundus changes in nine patients.

HVF abnormalities indicating HCQ toxicity vary depending on the specific HVF test performed. Clinicians need to be aware of the subtle nature of HVF changes in early toxicity.