Spectral-domain optical coherence tomography as a screening technique for chloroquine and hydroxychloroquine retinal toxicity.

Background And Objective: To determine the effectiveness of spectral-domain optical coherence tomography (SD-OCT) as a screening tool for the evaluation of chloroquine or hydroxychloroquine retinal toxicity.

Patients And Methods: This is a prospective, case-control study. Subject eyes were divided into four groups (group I = eyes with bull's eye maculopathy, group II = eyes with early changes of toxicity, group III = eyes with exposure but no signs of toxicity, and group IV = eyes of age-matched controls). Retinal thickness was measured via SD-OCT 0.5 and 1.0 mm from the foveal center.

Results: Mean retinal thickness 1.0 mm from the fovea in group I eyes was significantly thinner when compared to group IV. Eyes in group II also showed retinal thinning 1.0 mm from the foveal center when compared to both groups III and IV. Mean retinal thickness 0.5 mm from the foveal center did not differ significantly between any groups.

Conclusion: Significant retinal thinning occurred 1.0 mm, but not 0.5 mm, from the foveal center in patients with early and late chloroquine or hydroxychloroquine toxicity. Measuring retinal thickness 1.0 mm from the foveal center in patients receiving these medications may help screen for early toxicity.