Abstract
Purpose: :
To analyze and compare Humphrey visual field (HVF) 10-2 white and blue-yellow perimetry findings in patients who have taken hydroxychloroquine.
Methods: :
A prospective, cross-sectional, observational, case-control pilot study of patients who have taken hydroxychloroquine seen at Walter Reed National Military Medical Center was performed. A thorough medical history was taken on all patients. Each patient's chart was reviewed and screening performed to include best-corrected Snellen visual acuity, complete ophthalmologic examination, and white-on-white Humphrey visual field perimetry using the 10-2 SITA Standard program. Blue-on-yellow Humphrey visual field perimetry using the 10-2 FASTPAC program was also completed. SD-OCT and fundus autofluorescence (FAF) were performed at the discretion of the ophthalmologist.
Results: :
Twenty-four eyes of twelve patients who had taken hydroxychloroquine were enrolled. Sixteen eyes were considered low risk, six eyes were considered high risk, and two eyes had established toxicity. The average cumulative dose was 507, 1508, and 584 grams, respectively. Ten control eyes from five subjects who had never taken hydroxychloroquine were enrolled. In the ten control eyes, there were no suspicious changes on 10-2 white fields while one eye did have mild paracentral depression on the blue-yellow field. In the sixteen low risk eyes, there were three eyes with a suspicious paracentral defect on 10-2 white fields and no eyes with suspicious changes on 10-2 blue-yellow fields. SD-OCT and FAF were normal in all three eyes. In the six high risk eyes, four had paracentral defects on 10-2 white fields and mild diffuse depression on 10-2 blue-yellow fields. Two eyes had normal 10-2 white fields but did have mild paracental depression on 10-2 blue-yellow fields. SD-OCT was normal in all six eyes and FAF was normal in the two eyes for which the test was performed. In the two eyes with toxicity, the 10-2 white fields showed a generalized depression. The findings were similar on the 10-2 blue-yellow fields, but the depression was denser.
Conclusions: :
Hydroxychloroquine disrupts normal retinal metabolism by a complex process affecting photoreceptors and the trichromatic mosaic. The S-cones pathway is significantly different than the M and L-cones pathway. It reasons that these two systems are not uniformly affected and perimetry may reveal this. While changes on white-on-white testing usually start as localized defects, blue-on-yellow changes tend to be more diffuse in nature. This pilot study shows that perimetry is highly variable and that blue-on-yellow perimetry may be beneficial for some patients. A larger study will help clarify its role.
Keywords: drug toxicity/drug effects • perimetry • retina