Sickle cell retinopathy

This page contains a summary of our information on sickle cell retinpathy. To read our full information, download our factsheet.

Sickle cell retinopathy can affect the retina in different ways. The type that is most likely to affect sight is known as proliferative sickle cell retinopathy (PSR).

If there is a reduced blood supply to the retina, the ischaemic retina produces an increase in a protein called vascular endothelial growth factor (VEGF). This protein stimulates growth of new blood vessels in the outer edges of your retina (peripheral retina). The new blood vessels are weak and leaky and can cause further damage to your retina and vision. When new blood vessels grow, it is known as proliferative sickle cell retinopathy (PSR). The new blood vessels form fan-shaped networks (known as sea-fan) along the surface of the retina and back of the vitreous gel inside the eye. Movement between the two surfaces can cause the new blood vessels to leak, resulting in a bleed into the vitreous gel, known as vitreous haemorrhage.

The development of these networks can vary from very small sea-fans that resolve on their own, to large fast developing sea-fans that join up with other sea-fans and expand.

In about four out of 10 people with PSR, the new blood vessels block up and the sea-fan resolves on its own. In other cases, the sea-fans do not grow much bigger and do not bleed either.

Many people with PSR have no symptoms in the early stages. However, some people with PSR can have temporary or irreversible sight loss. This affects roughly 10-12 out of every 100 people with sickle cell disease over their lifetime.

PSR is more common in people with HbSC type of sickle cell disease than those with HbSS.

Some large studies have estimated it affects almost five in 10 people with HbSC and about two in 10 people with HbSS.

PSR usually starts between the ages of 15 and 24 in males and 20 and 39 in females. However, it can start as early as 8 years old in those with HbSC and 13 years old in HbSS.

The following factors can increase the risk of PSR causing sight loss:

• Age – increasing age can increase the risk of sight loss due to PSR.
• Male gender – males are more likely to experience sight loss due to PSR than females.
• HbSC – people with HbSC type of sickle cell disease are more likely to experience sight loss from PSR than people who have other types.

People with PSR can have sight loss from the following complications:

• Vitreous haemorrhage
  A vitreous haemorrhage is where blood from new blood vessels leak into the vitreous gel. The vitreous gel is normally clear to let light pass through to the retina. If there is blood in the vitreous gel, this can block the light and cause vision to become cloudy.
• Retinal detachment
  A retinal detachment is where the retina separates from the inside of the eye. This can occur due to the new blood vessels pulling on the retina (tractional retinal detachment) and/or due to a small tear occurring in the retina. A retinal detachment can cause sight loss in the affected area and needs to be treated very quickly.

Some of the other ways that sickle cell disease can affect the retina and cause reduced vision include:

• Sickle cell maculopathy
  Sickle cell maculopathy happens when there is a loss of blood supply to the macular area (central area of the retina). It can cause the macula area to become thin which affects how well it works to give you detailed vision. Rarely, the very centre of the macula, known as the fovea may be affected and cause reduction in vision.
• Retinal artery occlusion
  A retinal artery occlusion is where the blood vessels delivering blood and oxygen to the retina becomes blocked, causing a sudden loss of sight. The amount of sight lost depends on where the blockage has occurred.
• Epiretinal membrane (ERM)
  ERM is a condition where a sheet of naturally occurring cells develops on or above the surface of the macula. ERM can affect vision if this sheet of cells starts to shrink, causing the retina to wrinkle up under it. This wrinkling of the retina can then cause distortion and blurring of your vision, as well as a possible reduction in your level of sight.
• Macular hole
  A macular hole describes a small gap which develops in the centre of the macula. A macular hole affects your central vision. It can make your vision distorted and blurred and affect how well you can see detail. You may also have a blank patch in the centre of your vision.

Early detection during regular checks by your ophthalmologist

Early detection of PSR at the back of the eye can prevent sight loss. It is important for anyone with sickle cell disease to have regular eye examinations.

The current NICE guidelines recommend that everyone with sickle cell disease should be seen every two to three years by an ophthalmologist (eye doctor) if they have no sickle cell retinopathy and every year if there is sickle cell retinopathy present.

In an eye examination the ophthalmologist will be able to examine the health of the retina. They can detect the early stages of sickle cell retinopathy before and if PSR (new blood vessel growth) develops as well as any other associated complications.

Being aware of the symptoms

Sometimes, PSR is diagnosed because you suddenly notice signs that your eyesight has changed.

These signs may include:

• Floaters: this is where you can see small dark dots, squiggly lines or cobwebs, or a ‘dark shadow’ or a curtain moving across your vision.
• Blurred vision
• Flashing lights: sudden flashes of light

It is important that you ask for an urgent appointment with your optometrist (optician) or your eye clinic (if you are already looked after by an ophthalmologist), if you notice any of these.

Sea-fans resolve on their own in around four out of 10 people. Therefore, your ophthalmologist may want to monitor them for some time before considering any treatment. There is ongoing research to understand better which sea-fans are likely to bleed and which ones can be monitored.

The aim of treatment is to reduce the risk of any sea-fan causing vitreous haemorrhage and reduce the traction between the vitreous and the retina.

Laser treatment

Laser treatment may be used when sea-fan is present and thought to be at risk of causing a vitreous haemorrhage or retinal detachment. Applying laser to the areas around the sea-fan helps to reduce the production of proteins such as VEGF. The result is that the sea-fan may be more likely to shrink and less likely to bleed or pull on the retina.

Anti-VEGF treatment

Anti-VEGF medications are used commonly to reduce new blood vessel growth in several different conditions. They work by blocking the action of VEGF. VEGF is a protein produced by the retina when there is not enough oxygen or blood flow to an area. VEGF stimulates the growth of new blood vessels. Anti-VEGF medications work by helping to reduce new blood vessel growth.

In many countries, anti-VEGF treatments are used alone or in addition to localised laser to reduce the risk of bleeding or to help promote clearing of vitreous haemorrhage. Sometimes these injections will be used for people who have previously had laser treatment or before they have a treatment called vitrectomy. These injections are not currently licensed for PSR and are rarely used in the UK. Large studies are still required to understand when these treatments are most beneficial in the treatment of PSR.

Vitrectomy

The middle part of your eye ball is filled with a clear gel (called the vitreous gel). If you have a bleed from your retina into the vitreous gel, your vision will become cloudy. Often, this blood is reabsorbed by your body and your vision gets better on its own over a few months.

However, if your vision doesn’t improve, you may need to have vitrectomy surgery. In this surgery, the cloudy vitreous gel is removed and replaced with a clear liquid, which usually helps to improve your vision.

Your ophthalmologist may advise you to wait for up to six months before carrying out a vitrectomy, and this might be frustrating. However, over this time, your ophthalmologist will monitor how the bleeding changes, to see if there are any new bleeds, and whether your bleeding has begun to be reabsorbed.

If your retina detaches, then vitrectomy is needed to reattach your retina and restore vision.

It’s completely natural to be upset when you’ve been diagnosed with sickle cell retinopathy and it’s normal to find yourself worrying about the future of your sight.

We can support you at every step, putting you in touch with the advisors you need from any of our supportive teams – just get in touch with our Sight Loss Advice Service.

You can find out tips for making the most of your sight by downloading our booklet:

Download our Making the most of your sight booklet (PDF).

Download our Making the most of your sight booklet (Word).

Sickle Cell Society: https://www.sicklecellsociety.org/