Sickle cell eyes is an informal name for the ways sickle cell disease damages the eye. The most important is sickle cell retinopathy, where sickled red cells block the small blood vessels at the edge of the retina. Early on it often causes no symptoms. Left unchecked, it can lead to bleeding inside the eye or retinal detachment. Regular dilated eye exams catch most problems while they can still be treated.
This guide covers why the eye is vulnerable, how the changes progress, what doctors look for, and how vision is protected.
Why Sickle Cell Disease Affects the Eyes
In sickle cell disease, hemoglobin S makes erythrocytes (red blood cells) stiff and sticky when oxygen levels fall. The retina uses a lot of oxygen. Its outer edge, the peripheral retina, is supplied by very narrow end-arterioles, and those are easily blocked.
A block cuts off oxygen to the tissue beyond it, a state called ischemia. The oxygen-starved retina releases growth signals, especially vascular endothelial growth factor (VEGF). VEGF tells the eye to grow new vessels. These new vessels are fragile and grow in the wrong places, which is where the danger to vision comes from. The underlying protein chemistry is covered in our article on sickle hemoglobin.
Which Genotypes Are Most at Risk?
You might expect the most severe genotype to cause the most eye disease, but that isn’t the case. Proliferative retinopathy is more common in HbSC disease than in HbSS. One explanation is that HbSC blood is thicker because of its higher hemoglobin level, which favors blockage in small vessels. In HbSS, the more severe anemia may partly protect the retina. Eye damage is also possible in HbS/beta-thalassemia, and it is rare in sickle cell trait.
Non-Proliferative Changes
Many eye findings in sickle cell disease don’t threaten sight on their own. They do show that small blood vessels are being blocked. An eye doctor may describe:
- Salmon patches: Pink-orange bleeds within the retina that fade over time.
- Iridescent spots: Small, shiny deposits left behind after a salmon patch clears.
- Black sunburst lesions: Flat, dark scars of pigment from older bleeds.
- Comma-shaped conjunctival vessels: Short, broken vessel segments on the white of the eye.
- Angioid streaks: Cracks in a layer under the retina, seen in some patients.
Blocked vessels near the center of vision can also cause macular thinning. Scans often pick this up even when the person notices nothing.
Proliferative Sickle Retinopathy: The Five Stages
The Goldberg classification describes how proliferative disease progresses. It is still used in clinics to decide who needs treatment.
| Stage | What happens | Typical symptoms |
|---|---|---|
| I | Peripheral arterioles become blocked | None |
| II | Arteriovenous connections form at the edge of the blocked area | None |
| III | New vessels grow into a “sea fan” pattern | Usually none |
| IV | Sea fans bleed into the vitreous gel | Floaters, sudden blurring |
| V | Scar tissue pulls the retina loose (retinal detachment) | Shadow or curtain over vision, vision loss |
Sight is usually normal through the first three stages. That’s why screening matters so much: by the time someone notices symptoms, the disease may already be at stage IV or V. Some sea fans close off on their own (autoinfarction), but we can’t predict which ones will.
Other Eye Emergencies in Sickle Cell Disease
A sudden, painless loss of vision in one eye can mean the central retinal artery is blocked, and that needs same-day care. Hyphema is blood in the front chamber of the eye, usually after an injury. People with sickle cell disease or trait need it handled with extra care, because sickled cells can clog the eye’s drainage channels and raise the pressure quickly. Some glaucoma drugs that are routine in other patients are avoided in this situation.
How Sickle Cell Eyes Are Diagnosed
Diagnosis rests on a dilated fundus examination by an eye specialist. The eye drops open the pupil so the far edge of the retina can be seen, and that edge is exactly where sickle changes begin.
- Fluorescein angiography: A dye is injected into a vein and photographed as it passes through the retina. It shows blocked areas and leaking new vessels.
- Widefield retinal imaging: Captures much more of the peripheral retina in one picture.
- Optical coherence tomography (OCT): Scans the retinal layers to show macular thinning or swelling.
- OCT angiography: Maps blood flow without dye and is increasingly used for follow-up.
Widely followed guidance recommends a first dilated retinal exam at around age 10 for children with sickle cell disease. If that exam is normal, it is repeated every one to two years. People with HbSC or known retinopathy may be seen more often.
Treatment and Management
Treatment depends on the stage. Non-proliferative changes are usually just watched. Treatment is considered for proliferative disease, especially when sea fans are growing, when they appear in both eyes, or when there has already been bleeding.
- Laser photocoagulation: Scatter laser to the oxygen-starved retina lowers VEGF and encourages sea fans to shrink. It is the most established option.
- Anti-VEGF injections: Medicines injected into the eye to make new vessels regress. They’re used in selected cases, sometimes alongside laser or before surgery.
- Vitrectomy: Surgery to clear a vitreous bleed that won’t settle or to repair a retinal detachment. Surgeons plan it carefully because the eye’s circulation is already fragile.
Good overall control of the disease helps the eyes too. Hydroxyurea, transfusion programs, and treatment of high blood pressure all support long-term health. For how eye complications fit into the bigger picture, see our article on the life span of sickle cell patients and our sickle cell guide. There is more detail on staging and laser in our dedicated article on sickle cell retinopathy.
When to See a Doctor
Get urgent eye care the same day if you have sickle cell disease and notice any of these:
- A sudden shower of new floaters or flashes of light
- A dark curtain or shadow over part of your vision
- Sudden blurring or loss of vision in one eye
- Any injury to the eye, especially if you can see blood in the front of it
Without symptoms, stick to your scheduled screening exams. Most sight-threatening changes start silently.
Frequently Asked Questions
Can sickle cell disease cause blindness?
It can, mainly through vitreous hemorrhage or retinal detachment from untreated proliferative retinopathy. With regular screening and timely laser or surgery, most people keep useful vision.
Why is HbSC more likely to affect the eyes than HbSS?
People with HbSC tend to have higher hemoglobin and thicker blood, which favors blockage in small retinal vessels. That’s why HbSC patients are often screened closely, even when their overall disease seems mild.
How often should someone with sickle cell have an eye exam?
A common approach is a dilated exam from about age 10, then every one to two years if it’s normal. If retinopathy is found, your eye doctor will set a shorter interval.
Does sickle cell trait affect the eyes?
Retinopathy is rare in sickle cell trait. The main concern is hyphema after an eye injury, which needs careful handling because pressure inside the eye can rise quickly.
