Abstract
Purpose: :
White 10-2 automated fields are a standard test in screening for hydroxychloroquine (HCQ) retinopathy. Older literature had suggested that red targets may be more sensitive than white targets, although there is a paucity of data. We compare these two modalities in selected cases of HCQ usage, both with and without toxicity.
Methods: :
Our patients were using HCQ for lupus and related diseases. Humphrey 10-2 automated fields were performed using standard protocols and either white III or red III target sizes. Patients were also tested with objective modalities such as SD-OCT and mfERG to verify or rule out toxicity.
Results: :
Some patients with only minimal or borderline parafoveal sensitivity losses on white testing showed strikingly complete bull’s eye patterns of loss with red fields. On the other hand, other patients with toxicity showed similar patterns of loss in their white pattern deviation plots and red fields. Some patients without toxicity, or normal subjects, showed non-specific losses or depression on red testing that were not present with white and were sometimes located in parafoveal regions.
Conclusions: :
Our cases support the historical suggestion that red visual field testing is more sensitive but less specific than white. Some cases of HCQ toxicity with only subtle white field losses can be recognized or confirmed more definitively with red fields. However, for others there is little difference, and red testing produces more false areas of loss in non-toxic patients. We conclude that either red or white fields are acceptable screening tools as long as examiners understand test variability, and have a low threshold for early signs of abnormality. The addition of objective tests for screening, and certainly for confirmation of toxicity, is recommended.
Keywords: drug toxicity/drug effects • macula/fovea • visual fields