Hydroxychloroquine retinopathy screening

Hydroxychloroquine retinopathy

It is known that some people who take HCQ for more than five years and/or in high doses are at increased risk of damage to their retina, the light sensitive layer of cells at the back of the eye. This is known as retinal toxicity or retinopathy.

Severe retinopathy, especially in the central area called the macula, causes significant, irreversible sight loss.

For this reason, patients taking HCQ who qualify for regular eye health checks on the NHS will be offered them. Some patients may have to pay for this service privately.

Monitoring for HCQ retinopathy

The aim of monitoring is not to prevent retinopathy but to detect the earliest definitive signs of the condition, before a patient notices any symptoms.

The risk of getting HCQ retinopathy is negligible unless you have been taking the drug for at least five years. You will only be invited into the annual screening programme after this time, unless there are exceptional circumstances.

All appointments, assessments and/or screenings will take place in your local eye hospital or opticians.

The monitoring tests

Annual monitoring assessment

Once you have been taking HCQ for five years you may be invited for annual monitoring tests on the NHS. However, some patients may not be entitled to this on the NHS.

You might be invited before five years of treatment if you are taking a high dose, your kidneys are not working properly, or you are also taking tamoxifen. If you are taking chloroquine rather than HCQ, you will be invited to enter the annual monitoring programme after one year of treatment, because the risk of retinopathy is much higher with chloroquine.

During the annual monitoring assessment you will have two types of retinal photographs or scans.

One scan provides a cross-sectional image of the various layers of your retina. This is called an optical coherence tomography (OCT) scan. The second type of scan is called a fundus autofluorescence scan, which produces an image of the retina that can detect abnormal levels of a substance called lipofuscin in the retina; this may be an early sign of disease. This scan uses a brighter light that may be slightly uncomfortable for you.

During these tests you will be seated in front of a large, camera-like machine with a chin rest. You may have several photographs and scans taken to ensure that good images are obtained of your retina.

Before the tests you may be given eye drops that temporarily widen (dilate) your pupils. This is to allow more light into the eye to give a better view of your retina. The drops will make your vision blurry for a few hours or longer in some people. You may also be more sensitive to light.

Most individuals will not need any further tests. Typically, the retinal scans are inspected after you have left the clinic. A letter will be sent to you, and the GP or prescriber of HCQ/chloroquine to let you know the outcome of the monitoring assessment. 

Rarely, some individuals may be asked to perform a test called a visual field test. 

In this test, one eye is tested at a time while the other is temporarily covered with a patch. You will be seated in front of a machine called a perimeter and asked to look through a viewfinder at a fixed spot inside the machine.

A computer randomly flashes points of light and when you see a light, you press a button. It is important to keep looking straight ahead – don’t move your eyes to look for the light, wait until it appears in your side vision. It is normal for some of the lights to be difficult to see and a delay in seeing a light does not necessarily mean your field of vision is damaged. If you need to rest during the test, just tell the operator and they will pause until you are ready to carry on.

Very rarely, it may be necessary to undergo a test called multifocal electroretinography. This is a test which measures the responses of the macula area to an array of flashing hexagonal lights using electrodes placed around the eye.

This test may be used in very specific circumstances to help to determine if an individual has definite retinopathy when at least one other test is suggestive of retinopathy but two others appear normal.

Test results

No signs of retinopathy

If the tests do not show signs of retinopathy, you will be invited back for re-screening in one year. The results of your tests will be kept for comparison with future results.

Possible retinopathy

If there is an abnormality found on one of the retinal scans, you may be invited back for a visual field test and possibly to have some of the retinal scans repeated.

Even if one test result is consistently abnormal, you may be advised that treatment can be continued as a definite diagnosis of retinopathy will not have been made. 

You should be reassured that the monitoring of your eyes for HCQ retinopathy is designed to pick up the very earliest evidence of retinopathy, before it has a significant impact on your vision.

Definite retinopathy

If two of the tests are found to show abnormalities, and both are consistent with hydroxychloroquine toxicity, this means there are definite signs of retinopathy. The degree of retinopathy will be described as ‘mild’, ‘moderate’ or ‘severe’. 

If the degree of retinopathy is mild and you are having a good response to the HCQ, you and your doctor may decide to continue with it, perhaps at a lower dose.

If there is a suitable alternative, you and your doctor may decide to switch medications. If you are diagnosed with retinopathy, you will no longer be monitored in this way. However, your GP and/or the hospital doctor prescribing HCQ will continue to monitor your condition.

It is very important that you attend all your monitoring appointments. If you cannot attend on a given day, contact the eye screening department or opticians to make an alternative appointment as soon as possible.

The information on this webpage has been produced in association with the Royal College of Ophthalmologists (RCOphth). You can read more on Hydroxychloroquine retinopathy monitoring by referring to the guidelines and recommendations on the RCOphth website.