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.