Sickle Cell Disease is a genetic blood disorder that affects millions worldwide, primarily individuals of African, Mediterranean, Middle Eastern, and Indian ancestry.
The condition is characterised by the production of abnormal haemoglobin, which causes red blood cells to assume a sickle or crescent shape. These misshapen cells are less flexible and can obstruct blood flow, leading to numerous complications.
While much attention is given to the painful crises, anaemia, and organ damage caused by SCD, its impact on vision is equally significant and often overlooked.
The eyes are highly vascularised organs, relying on a steady blood supply to maintain function and health.
In SCD, the abnormal red blood cells can block blood flow in the small vessels of the eye, leading to complications such as:
Sickle Cell Retinopathy:
SCR is one of the most common eye complications in SCD. It occurs when sickled cells block the retinal blood vessels, leading to ischaemia (lack of oxygen) and abnormal blood vessel growth (neovascularisation).
These fragile new vessels can rupture, causing bleeding, scarring, and retinal detachment, potentially resulting in vision loss.
Hyphaema:
Hyphaema or hyphema refers to bleeding in the anterior chamber of the eye, often caused by trauma. People with SCD are at a higher risk of hyphaema due to the fragility of their blood vessels.
This condition can increase intraocular pressure, leading to secondary glaucoma if not promptly treated.
Central Retinal Artery Occlusion:
CRAO is a rare but severe complication where the main artery supplying the retina becomes blocked, potentially resulting in sudden, painless vision loss in the affected eye.
Iris Atrophy and Neovascularisation:
Chronic ischaemia in the eye can cause atrophy of the iris and the development of abnormal blood vessels, further increasing the risk of complications like glaucoma.
Glaucoma:
Elevated intraocular pressure, either due to hyphaema or abnormal vessel growth, can damage the optic nerve, leading to glaucoma and potential vision loss.
Vaso-Occlusion in Retinal Vessels:
Sickled cells can obstruct the tiny blood vessels in the retina, the light-sensitive tissue at the back of the eye. This blockage reduces oxygen supply (ischaemia) and can result in retinal damage or the death of retinal tissue.
Proliferative Sickle Cell Retinopathy:
Chronic oxygen deprivation can trigger abnormal blood vessel growth (neovascularisation), which is prone to rupture and can further compromise blood flow.
Ischaemia in Choroidal Circulation:
Sickled cells can impair circulation in the choroid, a layer of blood vessels that nourishes the outer retina, leading to ischaemia and vision problems.
Orbital Bone Infarction:
SCD can cause infarction (tissue death) in the orbital bones surrounding the eye, which may indirectly affect blood flow or pressure in the eye’s vascular system.
Sickle Cell Maculopathy:
Poor blood flow to the macula, the central part of the retina responsible for detailed vision, can lead to scarring, swelling, or atrophy, impairing central vision.
The early detection of vision problems in Sickle Cell Disease is crucial, and patients and caregivers should be vigilant for symptoms such as blurred or distorted vision, sudden loss of vision, eye pain or redness, sensitivity to light, and floating spots or flashes of light within the eye.
The following factors exacerbate poor blood flow:
Dehydration: Increases the likelihood of red blood cells sickling and clumping.
Low Oxygen Levels: Hypoxia can trigger more extensive sickling.
Infections or Stress: Can precipitate a sickling crisis, leading to widespread vaso-occlusion.
High Altitude or Low Pressure: May worsen oxygen deprivation and sickling.
While not all vision problems associated with SCD can be prevented, early intervention can minimise their impact. Here are some strategies:
Regular eye exams: Patients with SCD should have comprehensive dilated eye exams annually or as recommended by an ophthalmologist. Early detection of retinopathy or other complications can prevent progression to vision loss.
Control of SCD: Managing the underlying disease is essential. Treatments such as hydroxyurea, regular blood transfusions, and bone marrow transplants can reduce the frequency of sickling events and improve overall blood flow.
Laser therapy: In cases of proliferative sickle cell retinopathy, laser photocoagulation can seal off abnormal blood vessels and prevent further complications like bleeding or retinal detachment.
Surgical interventions: Procedures such as vitrectomy may be necessary for severe cases involving retinal detachment or persistent bleeding.
Education and awareness: Patients should be educated about the potential for eye complications and encouraged to report any changes in vision promptly.
Foods and key nutrients to support eye health
Nutrition plays a vital role in maintaining good eyesight, especially for individuals at risk of vision problems. If you’re looking to improve or maintain your eyesight, focus on these proven nutrients and include the following foods in your diet to support eye health:
Leaf greens: Spinach, kale, and collards are rich in lutein and zeaxanthin, antioxidants that protect the retina.
Fatty fish: Salmon, mackerel, tuna, flaxseeds, and walnuts provide omega-3 fatty acids, which support retinal health and reduce inflammation. Omega-3 fatty acids also help prevent dry eyes and reduce the risk of macular degeneration.
Vitamin C and E: Help prevent cataracts and macular degeneration. Citrus fruits such as oranges, lemons, grapefruits, nuts, and seeds are high in vitamin C, which can help prevent eye damage caused by oxidative stress.
Vitamin A: Essential for night vision and overall eye health. Found in carrots, sweet potatoes, and leafy greens. These are rich in beta-carotene, a precursor to vitamin A, which is vital for good vision.
Nuts and seeds: Almonds, walnuts, and sunflower seeds provide vitamin E, which protects cells in the eyes from damage.
Eggs: Eggs contain lutein, zeaxanthin, and zinc, all of which are important for maintaining healthy vision.
Berries: Blueberries and other dark berries contain antioxidants that improve circulation to the eyes and reduce the risk of retinal damage.
Staying hydrated and maintaining a balanced diet rich in these nutrients can help protect eye health and potentially reduce complications related to SCD.
In conclusion, vision problems in Sickle Cell Disease are serious but often manageable with proper care and early detection. Awareness of these potential complications is essential for patients, caregivers, and healthcare providers. By prioritising regular eye exams, effective management of SCD, and a nutrient-rich diet, individuals can reduce their risk of vision loss and maintain a better quality of life.
Until next time.
Credit: Tola Dehinde