Retinal Disease

Retinal disease is a group of conditions affecting your retina, the light-sensitive layer at the back of your eye that turns light into signals your brain can read as pictures. Some of these conditions are inherited and some develop over time, and many can cause sight loss if they aren't treated.

What are the symptoms of retinal disease?

Most retinal conditions show up as a change in your vision rather than pain. You often won't feel anything at all, which is why any change in how you see is worth taking seriously.

Symptoms include:

• floaters, which look like specks or threads drifting across your vision, and flashes of light
• blurred vision, or vision that just seems altered
• blind spots, either in the middle of your vision or off to the sides
• distortion, where straight lines look bent or wavy
• sudden loss of vision
• trouble seeing at night, or difficulty adjusting when the light level changes

What causes retinal disease and who is at risk?

There isn't a single cause. Damage to your retina can come from your genes, from another illness, from an injury or from an infection.

• Inherited conditions are passed down through families and are caused by a change in one or more of the genes that keep your retinal cells working properly. More than 270 genes are known to cause inherited retinal disease.
• Other illnesses can damage the retina indirectly. Diabetes and high blood pressure both harm small blood vessels, and that damage reaches the retina. Inflammatory conditions can also cause harm.
• Injuries to the eye can damage the retina and the macula. One condition, macular pucker, sometimes appears after eye surgery.
• Infections can leave retinal damage behind, though the retinal condition itself isn't catching.

Things that raise your risk include:

• getting older
• smoking
• carrying excess weight
• having diabetes or high blood pressure
• having had a retinal tear or detachment before, or a previous eye injury or eye operation
• a family history of retinal disease
• severe short-sightedness
• certain medicines, including hydroxychloroquine and pentosan polysulfate

Your sex or ethnicity can also matter, depending on which retinal condition is involved.

Are there different types of retinal disease?

Yes, and they're usually grouped by what part of the retina is affected and what's gone wrong.

Conditions affecting the retina generally

• diabetes-related retinopathy
• retinal detachment, where the retina pulls away from the back of your eye
• retinal tears or holes
• retinal vein occlusion, where a vein draining the retina becomes blocked, either the main vein or one of its branches
• infectious retinitis
• central serous retinopathy
• birdshot chorioretinopathy and other inflammatory conditions.

Conditions affecting the macula

The macula is the small central part of your retina that lets you see fine detail. Conditions affecting it include macular pucker, also called an epiretinal membrane, macular hole, age-related macular degeneration and macular oedema, which is swelling caused by fluid building up.

Inherited retinal conditions

These include retinitis pigmentosa, Usher syndrome, Stargardt disease and retinoschisis. Retinoschisis can either be something you're born with or something that develops later.

Inherited conditions vary a lot. Some stay much the same throughout your life, while others cause vision to worsen gradually. Which one you have, and how severe your particular gene change is, shapes what you can expect.

How is retinal disease diagnosed?

Your eye care professional checks your retina as part of a routine eye examination, which is one reason it's worth going as often as you're advised to.

You'll be given eye drops that widen your pupils, so that the back of your eye can be seen properly. These blur your vision for a few hours afterwards. If anything looks wrong, you may be sent for further tests or referred to a retinal specialist.

Further tests can include:

• optical coherence tomography (OCT), a scan that builds a detailed cross-section of your retina
• fluorescein angiography, where a fluorescent dye is injected so the blood flow in your retina can be photographed
• fundus autofluorescence, an imaging test that doesn't involve any injection
• electroretinography, which measures how well your retina is actually working
• genetic testing, to confirm an inherited condition.

If genetic testing is suggested, you'll usually meet a genetic counsellor first to work out which test makes sense for you. The test itself normally means giving a blood or saliva sample, which is sent to a laboratory.

Genetic testing can identify most, but not all, of the gene changes that cause inherited retinal disease. Knowing which gene is involved confirms the diagnosis, tells you how your vision is likely to be affected over time, and can open the door to research trials.

How is retinal disease treated?

Treatment depends entirely on which condition you have. In some cases it stops the disease. In others, it slows down how quickly it gets worse.

Injections

Medicine can be injected into the jelly-like fluid inside your eye. This is used for wet age-related macular degeneration, advanced diabetic retinopathy, macular oedema, eye infections and inflammatory eye conditions.

There's no real recovery period afterwards. You may be told to rest your eyes, use artificial tears and avoid rubbing them.

Laser treatment

Lasers are used to seal retinal tears, to deal with blood vessels growing where they shouldn't, and to treat macular oedema and central serous retinopathy.

Surgery

Vitrectomy is an operation used for retinal detachment, macular pucker, macular hole, eye injuries including foreign objects in the eye, and eye infections.

For a detached retina specifically, other options are:

1. Scleral buckle surgery, where a piece of silicone is stitched to the outside of your eye to press the wall of the eye gently inwards.
2. Cryopexy, which uses intense cold to create scarring that seals a tear or detachment.
3. Pneumatic retinopexy, where a gas bubble is injected into your eye to hold the retina in place. This is always combined with either cold treatment or laser.

Surgery carries risks, including infection, scarring, dry eyes, blurred or reduced vision, bleeding, and eye pressure that is either too high or too low.

Medicines and gene therapy

Severe eye infections are treated with antibacterial, antifungal or antiviral medicines depending on the cause.

For inherited conditions, gene therapy works by putting a working copy of the faulty gene into the retina, where retinal cells take it up and start making the protein that was missing. The retina is a good target for this kind of treatment because it's small and reachable.

Gene therapy tends to work better when started early because once too many retinal cells have been lost there is less left to rescue.

When should I see a doctor?

Have your eyes tested as often as your optometrist recommends, particularly if you have diabetes, high blood pressure or a family history of retinal disease.

Contact an eye care professional if you notice any change in your vision, however minor it seems.

Go to your nearest emergency department, or call 999, if you have:

• sudden loss of vision, whether complete or partial
• severe pain in your eye
• a serious eye injury

Getting seen quickly matters with retinal conditions. Early diagnosis and treatment give the best chance of holding on to your sight.