Protecting Your Eyes from Medication Side Effects
Understanding Drug-Induced Retinal Toxicity
Drug-induced retinal toxicity occurs when a medication taken for another health condition causes damage to the retina. The retina converts light into signals your brain uses to create images. When certain drugs build up in the eye over time, they can harm the retinal cells needed for clear central vision.
This type of toxicity is different from side effects that affect the front of the eye, like dry eye or blurred vision from eye drops. Retinal toxicity targets the deeper structures of the eye and can sometimes cause permanent vision changes if not caught early.
Drugs taken by mouth or through an IV travel through the bloodstream and can reach the eye through the retinal or uveal circulation (the blood supply of the eye). The eye has natural barriers, including the blood-retinal barrier, that normally prevent harmful substances from entering. However, inflammation or disease can weaken these barriers and allow drugs or their byproducts to accumulate inside the eye.
Once inside the eye, certain medications have a strong attraction to melanin, the pigment found in the retinal pigment epithelium (RPE). The RPE is a layer of cells that supports the light-sensing photoreceptor cells. Drugs that bind to melanin can remain in the eye long after a patient stops taking the medication, which may explain why damage sometimes continues even after the drug is discontinued.
Several categories of systemic medications carry a risk of retinal toxicity. The most well-studied include the following:
- Hydroxychloroquine (Plaquenil) and chloroquine, used for lupus, rheumatoid arthritis, and malaria
- Pentosan polysulfate sodium (Elmiron), used for interstitial cystitis (a chronic bladder condition)
- Phenothiazines such as chlorpromazine (Thorazine) and thioridazine, used for psychiatric conditions
- Corticosteroids, used for inflammation, autoimmune disorders, and other conditions
- Interferon, used for hepatitis C and certain cancers
- Niacin (vitamin B3) at high doses, used for cholesterol management
Who Is Affected and Risk Factors
Hydroxychloroquine is one of the most commonly prescribed medications linked to retinal toxicity. A study of 2,361 long-term users found a 7.5% overall rate of retinal toxicity among patients who took the drug for more than five years (AAO, 2014). That rate climbs to approximately 20% after 20 years of use.
The key risk factors for hydroxychloroquine retinopathy include cumulative dosage over time, which may be more important than the daily dose. A daily dose above 5.0 mg per kilogram of body weight also raises risk. A 2024 study further identified specific risk factors for different subtypes of hydroxychloroquine retinopathy, reinforcing the importance of individualized screening.
Pentosan polysulfate sodium (PPS), sold under the brand name Elmiron, is the only FDA-approved oral medication for interstitial cystitis. Research has found that roughly one in four people (25%) taking Elmiron for five years or longer developed significant retina damage (Ophthalmology journal, as reported by Drugwatch). The risk rises sharply with higher cumulative exposure. Studies found that 12 to 13% of patients with 500 to 999 grams of cumulative PPS exposure developed retinopathy, while 42 to 50% of patients with more than 1,500 grams of exposure developed the condition.
Interferon-associated retinopathy occurs in approximately 12% of otherwise healthy patients (ScienceDirect, 2014). In patients who also have systemic vascular disease such as diabetes or high blood pressure, the rate jumps to 65%. This significant difference highlights the importance of vascular health in determining who is most vulnerable.
Corticosteroids, whether taken by mouth, inhaled, or applied to the skin, can trigger central serous chorioretinopathy (CSC). CSC causes fluid to build up under the retina, leading to vision distortion. Patients on long-term or high-dose corticosteroids face a higher risk.
Certain factors make retinal toxicity more likely regardless of which medication is involved. These include the following:
- Longer duration of treatment
- Higher cumulative or daily dosage
- Pre-existing kidney disease, which slows drug clearance from the body
- Pre-existing retinal disease or macular degeneration
- Coexisting diabetes or high blood pressure
Signs and Symptoms
In its early stages, hydroxychloroquine toxicity may cause no noticeable symptoms at all. As damage progresses, patients may notice trouble reading due to paracentral scotomas (blind spots near the center of vision). Diminished color vision is another common sign. Unfortunately, most patients do not notice symptoms until the scotomas become large enough to interfere with daily activities, which is why screening is so important.
PPS maculopathy often causes difficulty adjusting to darkness, known as prolonged dark adaptation. Patients may also experience nyctalopia (night blindness) and blurred vision. These symptoms may develop gradually, making them easy to dismiss at first.
Central serous chorioretinopathy from corticosteroid use most commonly presents as blurry central vision in one eye. Straight lines may appear wavy or distorted. Niacin toxicity presents with blurred vision, decreased visual sharpness, and metamorphopsia (distortion of images). Approximately 15% of patients taking systemic medications experience dry eye syndrome and other ocular complications, though these are distinct from retinal toxicity.
Diagnosis and Testing
The American Academy of Ophthalmology (AAO) has published screening guidelines for patients taking hydroxychloroquine. These recommend a baseline eye exam within the first year of starting the drug, followed by annual screening after five years of use. Patients with additional risk factors may need screening sooner.
In June 2020, the FDA updated the label for pentosan polysulfate sodium to warn about retinal pigmentary changes. The updated label recommends vision tests within six months of starting treatment and periodic tests afterward.
A retina specialist may use several advanced tests to detect drug-induced retinal toxicity before symptoms appear. These include the following:
- Optical coherence tomography (OCT), which creates detailed cross-section images of the retina to reveal thinning or structural changes
- Fundus autofluorescence (FAF), which uses a special camera to detect changes in the RPE
- Visual field testing, which maps areas of reduced or lost vision
- Multifocal electroretinography (mfERG), which measures the electrical response of different areas of the retina to light
In hydroxychloroquine toxicity, OCT may show thinning of the outer retinal layers in a ring pattern around the central macula. Fundus autofluorescence can reveal a characteristic pattern of damage to the RPE before symptoms develop. In PPS maculopathy, testing may show dense clusters of pigment changes in the macula along with RPE atrophy. These findings help a retina specialist determine whether medication-related damage is occurring and how severe it may be.
Treatment Options
There is currently no treatment that can reverse hydroxychloroquine-induced retinal damage. The most effective strategy is early detection through regular screening. If toxicity is identified, the prescribing doctor will evaluate whether the medication should be stopped. Keeping the daily dose below 5.0 mg per kilogram of body weight is recommended to reduce risk. Because hydroxychloroquine binds to melanin in the RPE, damage may continue to progress for a period even after the drug is discontinued.
For PPS-associated retinopathy, the primary approach involves taking the lowest effective dose and undergoing regular eye exams with a retina specialist. If retinopathy is detected, discontinuation of the medication may be considered in consultation with the prescribing doctor. It is important to know that PPS retinopathy can continue to progress even after the medication is stopped, making ongoing monitoring essential.
For central serous chorioretinopathy linked to corticosteroid use, the first step is to work with the prescribing physician to discontinue or taper the corticosteroid when medically possible. Patients should not suddenly stop high-dose corticosteroids on their own, as this can cause serious medical problems including adrenal crisis. Once the corticosteroid is safely reduced, the fluid under the retina often resolves on its own over weeks to months.
Across all forms of drug-induced retinal toxicity, the guiding principle is the same: detect early, minimize exposure, and monitor closely. A retina specialist can help coordinate care with the prescribing physician to balance the benefits of the systemic medication against the risk to vision. In some cases, alternative medications may be available that carry a lower risk of retinal damage.
What to Expect
When drug-induced retinal toxicity is caught at an early stage, stopping or adjusting the medication can often prevent further significant vision loss. Mild changes detected on screening tests may not affect daily vision. However, the prognosis depends heavily on the specific drug, the duration of exposure, and the degree of damage already present at the time of detection.
If retinal toxicity is not detected until symptoms become obvious, the damage is often more extensive and may be irreversible. In advanced hydroxychloroquine toxicity, patients can develop a characteristic bull's eye pattern of damage in the macula that leads to permanent central vision loss. Advanced PPS maculopathy can cause progressive vision decline that continues even after the drug is stopped. This is why adherence to screening schedules is critical.
Even after a medication is discontinued, patients with drug-induced retinal toxicity will need ongoing monitoring with a retina specialist. Some forms of toxicity, particularly from hydroxychloroquine and PPS, can progress after the drug is no longer in the body. Regular follow-up exams allow for tracking any changes and adjusting care as needed.
Living with Drug-Induced Retinal Toxicity
Managing drug-induced retinal toxicity requires coordination between a retina specialist and the doctor who prescribed the systemic medication. Patients should make sure all of their doctors are aware of any retinal findings. Decisions about continuing, changing, or stopping a medication should be made jointly, weighing the benefits of the drug against the risk to vision.
Patients diagnosed with retinal changes from medications can take several practical steps to protect their remaining vision and adapt to any visual changes:
- Use adequate lighting when reading or performing detail work
- Ask a retina specialist about low-vision aids if central vision is affected
- Keep all scheduled screening and follow-up appointments
- Report any new visual symptoms to a retina specialist promptly
- Maintain a list of all current medications to share with every doctor
Learning that a medication you need for one health condition has affected your vision can be stressful. Support from family, friends, and patient advocacy organizations can be valuable. A retina specialist can also provide referrals to low-vision rehabilitation services if needed. Taking an active role in your screening schedule and communicating openly with your doctors can help you feel more in control of your care.
When to See a Retina Specialist
If you have been prescribed hydroxychloroquine, pentosan polysulfate sodium, or another medication known to carry retinal risk, ask about a baseline eye exam with a retina specialist before or shortly after starting the drug. This baseline exam creates a reference point for future comparison.
Contact a retina specialist or seek emergency care right away if you experience any of the following while taking a systemic medication:
- Sudden vision loss in one or both eyes
- A shadow or curtain across part of your vision
- Sudden increase in floaters or flashes of light
- Rapid worsening of central vision or new blind spots
While drug-induced retinal toxicity typically develops gradually, sudden visual changes can indicate a serious problem that requires immediate evaluation.
For hydroxychloroquine, the AAO recommends annual screening beginning after five years of use, or sooner if additional risk factors are present. For pentosan polysulfate sodium, the FDA recommends a vision exam within six months of starting the drug and periodic exams thereafter. Patients taking interferon, high-dose niacin, long-term corticosteroids, or phenothiazines should discuss an appropriate screening schedule with a retina specialist.
Questions and Answers
In most cases, retinal damage from systemic medications cannot be reversed once it has occurred. This is particularly true for hydroxychloroquine and pentosan polysulfate sodium toxicity. The goal of screening is to detect changes at the earliest possible stage so the medication can be adjusted before significant, irreversible damage develops. Some conditions, like corticosteroid-induced central serous chorioretinopathy, may improve after the drug is discontinued.
The American Academy of Ophthalmology recommends a baseline eye exam within the first year of starting hydroxychloroquine. After that, annual screening with a retina specialist should begin after five years of use. Patients with kidney disease, higher daily doses, or other risk factors may need to start annual screening sooner. The exam should include OCT and visual field testing at a minimum.
This decision should be made jointly by the retina specialist and the prescribing physician. In some cases, the systemic medication may be essential for managing a serious health condition, and the decision may involve lowering the dose, increasing monitoring frequency, or switching to an alternative drug. Patients should not stop prescribed medications on their own without medical guidance, as some drugs require careful tapering.
Yes. Risk factors include longer duration of drug use, higher cumulative doses, pre-existing kidney disease, and pre-existing retinal conditions. For interferon therapy, patients with diabetes or high blood pressure face a substantially higher risk of retinal complications, with rates as high as 65% in those with coexisting vascular disease compared to 12% in healthy patients (ScienceDirect, 2014). Discussing your full medical history with a retina specialist helps determine your individual risk level.
Share the results of every retinal screening with all of your prescribing physicians. If a retina specialist detects any changes, provide the specific findings and recommendations to the doctor who prescribed the medication. This allows your medical team to make informed decisions about your treatment plan. Keeping an updated medication list and sharing it at every appointment helps all of your doctors coordinate your care effectively.