Hydroxychloroquine, known by the brand name Plaquenil, is a medication used to manage autoimmune conditions like lupus and rheumatoid arthritis. While effective, its use can affect the retina in some individuals, making regular eye examinations a necessary part of the treatment plan to ensure patient safety.
Plaquenil and Vision Risk
The reason for specialized eye exams is the risk of developing hydroxychloroquine retinopathy. This condition involves damage to the retina, the light-sensitive tissue at the back of the eye, where toxic effects can accumulate and destroy photoreceptor cells. This damage can be irreversible and may progress even after stopping the medication.
This side effect is uncommon, affecting fewer than 2% of people within the first 10 years of treatment at recommended dosages. The risk is most influenced by the daily dose relative to body weight and the total duration of use. Therefore, the strategy for protecting vision is preventative screening to detect the earliest signs of change before a person notices symptoms.
Recommended Eye Screening Schedule
According to the American Academy of Ophthalmology, a baseline eye examination is recommended within the first year of starting Plaquenil. This initial assessment provides a reference point for future screenings. Annual screenings are advised to begin after five years of continuous use, as the risk is very low before this point.
Certain factors place an individual at higher risk and may require starting yearly screenings sooner. These include a daily dose higher than 5.0 mg per kilogram of body weight, use for more than five years, pre-existing kidney disease, or a prior retinal condition. The presence of these factors warrants a discussion with an ophthalmologist about a more frequent screening schedule.
Common Eye Tests for Plaquenil Users
Screening relies on advanced imaging and functional tests to detect subtle retinal changes. The two primary tests are Spectral-Domain Optical Coherence Tomography (SD-OCT) and an automated visual field test. The SD-OCT is a non-invasive scan that creates a detailed, cross-sectional image of the retina’s layers, allowing doctors to see microscopic signs of damage where toxicity first appears.
The automated visual field test, often a “10-2” test, assesses function by checking for blind spots in the central area of vision. It maps the retina’s sensitivity, and early Plaquenil toxicity can create a specific pattern of decreased sensitivity. This helps identify functional loss that may not yet be noticeable to the patient.
For at-home monitoring, some patients use an Amsler grid, which is a chart with a grid of straight lines. By looking at the grid one eye at a time, a person can spot wavy, blurry, or missing lines. While not a substitute for clinical exams, it helps detect central vision changes that should be reported to a doctor.
Interpreting Screening Results
The results of the SD-OCT and visual field tests are compared to baseline exams and previous screenings to identify any new or progressing changes. These tests can reveal signs of toxicity long before a person experiences symptoms like blurred vision or difficulty reading.
If tests show abnormalities consistent with hydroxychloroquine toxicity, the ophthalmologist communicates these findings to the prescribing doctor. The standard recommendation upon finding definite signs of toxicity is to stop taking Plaquenil. This action is taken to prevent further retinal damage and preserve existing vision.