Plaquenil Toxicity and Retinal Health

Plaquenil (hydroxychloroquine) is highly effective for treating inflammatory and autoimmune disorders, yet its potential to cause retinal toxicity remains a concern among healthcare providers and patients alike. Studies estimate that about 7.5% of patients on long-term therapy develop retinal changes, with risk spiking to nearly 20% after 20 years of use. Even when detected, the vision loss that accompanies this condition cannot be reversed, making early detection and regular screening crucial.

The underlying mechanism is complex and still not fully understood. The decision to continue or discontinue the drug always involves weighing the benefits against the risks, and this is why communication between prescribing physicians, patients, and our retina specialists is so important.

The retina is the light-sensitive layer at the back of the eye, essential for transforming light into the signals sent to the brain. When Plaquenil accumulates in the retina, it may interfere with the metabolism of retinal cells, disrupt retinol recycling, and impact lysosomal function. Although the exact mechanism is not fully defined, the consequence is damage to both the retinal pigment epithelium and photoreceptors. This damage may initially be subtle and undetectable without modern imaging techniques, only becoming apparent when more advanced retinal changes have already occurred.

In earlier times, clinicians recognized Plaquenil toxicity by a characteristic “bull’s-eye” pattern of maculopathy, where the central fovea is surrounded by a ring of depigmentation and hyperpigmentation. Unfortunately, by the time this pattern can be seen with standard examination techniques, the damage is already well advanced. That’s why new screening methods are now crucial; they can detect early changes long before any visible signs appear during a routine retinal exam.

Research into hydroxychloroquine toxicity has provided us with useful statistics for guiding both treatment and patient counseling. A pivotal study from 2014 found that the overall prevalence of retinal toxicity in patients using hydroxychloroquine for at least five years was around 7.5%. However, the risk can climb dramatically with prolonged therapy, reaching nearly 20% after 20 years of daily use. This data underscores the importance of careful dosing and regular ocular monitoring over the long term.

It’s worth noting that many patients can and do use Plaquenil safely for extended periods when proper guidelines are followed. For those with normal baseline examinations and adherence to recommended doses (not exceeding 5.0 mg/kg/day based on real body weight), the risk of developing toxicity within the first five years is very low. Even in later years, should a patient have no abnormalities, the chance of experiencing sudden changes in the coming year remains low. Nonetheless, these statistics reinforce the need for vigilance and regular eye examinations, especially as treatment duration lengthens.