Patient guide
Plaquenil (hydroxychloroquine) eye exams: why the screening matters
By Dr. Sam Khoury, Optometrist7 min read
Damage from hydroxychloroquine builds slowly and does not cause sudden symptoms. Sudden vision loss, a shadow or curtain across your vision, or new flashes of light are a different problem and need to be seen the same day. You can contact the office at (609) 246-0236. If the office is closed, or you cannot reach us, go to a hospital emergency room — most have an ophthalmologist on call.
Do not stop or change your hydroxychloroquine because of anything on this page. It is an important medicine for lupus, rheumatoid arthritis and other conditions, and any change is a decision for the doctor who prescribed it, made with your screening results.
Screening exists so that decision can be made early, before the medicine has affected your sight.
Why the screening exists
After years of use, hydroxychloroquine can damage the retina, the light-sensitive layer at the back of the eye. The risk is small at first and grows with the dose and with the number of years you have taken it.
In one large study of long-term users taking the recommended dose, fewer than 2 in 100 had retinal damage within the first ten years. After twenty years, the figure was close to 1 in 5. That is why the screening schedule gets closer together as the years go on, not further apart.
Early damage has no symptoms, and it does not reverse. Damage that has already started can keep progressing for a while even after the medicine is stopped. The aim of screening is to find changes on the tests well before you would notice anything yourself.
Where the damage starts
The very center of the retina, which you use to read, is usually spared at first. The damage tends to begin in a ring around it, which is why nobody notices it early and why the tests are aimed at that ring rather than at how well you read the chart.
- The center of vision, usually spared early on.
- The ring where damage usually starts.
- Farther out, where it often starts in people of Asian descent.
The retina seen from the front. Illustration, not to scale.
In many patients of Asian descent, the damage starts farther from the center. Tell us if that applies to you, because the field test is then set to cover a wider area.
What the screening involves
Two tests are done together, because neither one alone is reliable enough. Both are done in this office, at the same visit.
Automated visual field test
You look at a central target and press a button whenever you see a small light appear. It maps how sensitive each area of your vision is, including the ring where damage tends to start. It takes several minutes per eye and nothing touches the eye.
There is a learning curve. A first test that looks abnormal is often repeated before anything is concluded, so an odd result on the first try is not a reason to worry.
OCT scan
A scan that shows the layers of the retina in cross-section, a little like an ultrasound but using light. You look into the instrument for a few seconds; there is no contact, no air puff and no dye. It can show thinning in the ring around the center before the field test picks up a change.
A look at the retina itself
The retina is also examined directly, partly to make sure nothing else, such as macular degeneration or diabetic changes, could be confused with medication damage or would add to your risk.
Your pupils may be dilated for this. If they are, your eyes will be light-sensitive and close-up vision blurry for a few hours. Bring sunglasses, and if you would rather not drive afterward, bring a driver.
How often
Based on the American Academy of Ophthalmology recommendations:
- First year
- A baseline examination, ideally soon after starting. It records what your retina looks like before the medicine has had time to affect it, and checks for anything that would raise your risk.
- Years one to five
- No yearly screening is usually needed if the baseline was normal and you have none of the risk factors below. Your prescribing doctor may still ask for a check.
- After five years
- Every year, for as long as you take it.
- Higher risk
- If any risk factor below applies, yearly screening usually starts earlier.
What raises the risk
- A daily dose above 5 mg per kilogram of your actual body weight. In pounds: 400 mg a day is above that line if you weigh under 176 pounds, 300 mg a day if you weigh under 132 pounds. If that applies to you, mention it to your prescribing doctor rather than changing the dose yourself; they may have a reason for it. Tell them too if your weight has dropped a lot.
- More than five years of use.
- Kidney disease, which lets the medicine build up.
- Taking tamoxifen at the same time.
- Existing disease of the retina or macula.
What to bring
- Your current daily dose of hydroxychloroquine, and roughly when you started it.
- The name of the doctor who prescribes it, so the results can be sent to them.
- A list of your other medications.
- Any eye surgery you have had and any eye conditions you have been told about, such as glaucoma, cataract or macular degeneration. They can affect the same tests.
- Results of any earlier eye screening, if it was done somewhere else.
- Your glasses or contact lenses.
The results, including the field printouts and scans, are sent back to your prescribing doctor.
For prescribing doctors
Referrals for baseline and annual screening are welcome. Fax them to (609) 855-5028, with the daily dose, start date, current weight and, where relevant, kidney function or tamoxifen use. Questions: (609) 246-0236.
Common questions
My results were normal. Can I skip a year?
It is better not to. The risk rises with every year of use, so a normal result last year says less about this year than it seems to. Yearly screening after five years is what lets a change be caught early.
What happens if the screening finds something?
A possible change is usually confirmed first, often by repeating a test or adding another, and sometimes by referral to an ophthalmologist. The findings go to your prescribing doctor, who decides with you whether to change the dose or stop. Catching it early is what keeps that a choice rather than an emergency.
Do the tests hurt?
No. Nothing touches the eye for either test. The field test needs concentration more than anything else.
Does this go through my vision plan or my medical insurance?
Screening for a medication's effect on the eye is a medical visit and goes through your medical insurance, even though you are seeing an optometrist. Vision plans cover routine eye exams and eyewear.
Call with your plan details before you book and it can be sorted out beforehand rather than afterwards.
Book a screening
If you have started hydroxychloroquine in the last year, or have taken it for five years or more, it is time for an eye examination.
Khoury Eye Care, Hamilton Mall, 4403 Black Horse Pike, Mays Landing.