Scotoma analysis of 10-2 visual field testing with a white target in screening for hydroxychloroquine retinopathy

OBJECTIVE: To quantify the variability of scotomas detected by 10-2 visual field (VF) testing in patients taking hydroxychloroquine without and with retinopathy. DESIGN: Retrospective review of clinical charts and visual fields. SUBJECTS: Twenty-one patients taking hydroxychloroquine without retinopathy, and nine patients taking hydroxychloroquine and one patient taking chloroquine with retinopathy. METHODS: Retinopathy was defined by annular scotomas on 10-2 VF testing with corroborative spectral domain optical coherence tomographic outer retinal changes and multifocal electroretinographic changes leading to cessation of hydroxychloroquine or chloroquine. Location and depth of scotoma points on 10-2 VF testing were recorded and their fates followed in serial, reliable 10-2 VFs performed with a white target over time. MAIN OUTCOME MEASURES: Number of scotoma points and locations, percentage of persistent scotoma points, size of scotomas, location of scotomas, and percentage of scotomas deepening. RESULTS: A median of five, interquartile range (IQR) 3–8 scotoma points per VF occurred in patients without retinopathy. A median of 86%, IQR 63%–100% of these points resolve on the subsequent field. For patients with retinopathy, a median of 22%, IQR 10%–59% resolve. The median percentage of scotoma points in the zone 2–8 degrees from fixation in eyes with retinopathy was 79%, IQR 68%–85% compared to 60%, IQR 54%–75% in eyes without retinopathy (P=0.0094). Single-point scotomas were more common in eyes without than with retinopathy. Scotomas consisting of more than four contiguous scotoma points were generally indicative of retinopathy. CONCLUSION: Point scotomas are common and variable in 10-2 VF testing with a white target for hydroxychloroquine retinopathy in subjects without retinopathy. The annular zone 2 to 8 degrees from fixation was useful for distinguishing the significance of scotoma points. Scotomas with more contiguous scotoma points were more often associated with retinopathy.