Understanding vascular diseases
THERE is a close association between vascular ( blood vessels) health and eye health. The retina ( nerve layer of the eye) is dependent on a consistent supply of oxygen and nutrients by thousands of blood vessels.
Certain systemic conditions that affect the health of blood vessels can have significant implications on the eye and consequently result in visual loss or blindness.
Retinal vascular diseases are linked to high blood pressure ( hypertension), diabetes and artherosclerosis ( thickening of the artery walls). The most common of these diseases are: Hypertensive retinopathy Diabetic retinopathy Retinal artery occlusion Retinal vein occlusion
Hypertension causes retinal blood vessels to narrow, harden and leak over time. Sometimes, it can also cause swelling of the optic nerve.
People with hypertensive retinopathy may experience visual loss or headaches.
It is important to have regular eye examinations as the eye is often the only place in the body that can show blood vessel damage from hypertension even at an early stage.
The main aim of treatment is to limit or prevent damage to the retina by optimising blood pressure with the use of medications or lifestyle changes.
In Malaysia, it is estimated that one in five individuals above the age of 30 may have diabetes.
High sugar levels in the blood cause damage to blood vessels and in the eye, resulting in diabetic retinopathy.
Visual loss from diabetic retinopathy can occur gradually ( as leakage of blood and fluid causes retinal swelling) or suddenly when a blood vessel bursts and blood fills the cavity of the eye ( vitreous haemorrhage).
Treatment of diabetic retinopathy starts with optimal management of all risk factors, including sugar levels, blood pressure and cholesterol levels.
Laser treatment is often required to prevent further bleeding. In the past decade, anti- VEGFs ( anti vascular endothelial growth factor) medications have been injected into the eye to reduce leakage and swelling.
Surgery is needed in advanced cases. Known as a vitrectomy, it is usually carried out by a subspecialist vitreoretinal surgeon.
Artery occlusions are caused by a clot or plaque ( embolus), which breaks free from the major artery in the neck ( carotid) or the valves or chambers in the heart.
Central retinal artery occlusion is a serious condition and can result in profound and permanent visual loss.
Emergency treatment is required to lower the eye pressure. Ocular massage and prompt treatment improve the chances of recovery.
It is important to manage all systemic risk factors ( such as hypertension and diabetes) and have regular eye examinations to pick up warning signs.
Vein occlusions are caused by a localised clot ( thrombus), which form as a result of the hardening of the artery adjacent to the vein.
The retinal arteries and veins cross over each other and it is at these crossings where vein occlusions can occur.
Visual loss may be partial if a branch vein is blocked or severe if the central vein is affected.
Treatment includes management of risk factors, anti- VEGF or steroid eye injections, or laser treatment in advanced cases.
Glaucoma can be a severe complication of retinal vascular diseases and prognosis for such eyes are usually poor.
When retinal vessels get blocked, the lack of oxygen supply triggers the release of hormones that stimulate the growth of abnormal blood vessels. This can cause an obstruction of the outflow, leading to neovascular ( or rubeotic) glaucoma.
Treatment involves extensive laser treatment and/ or anti- VEGF injections and in some cases, drainage surgery is required to control the glaucoma.
Retinal vascular diseases are potentially blinding conditions and often related to other vascular problems in the body.
It is vital that if you have hypertension, diabetes or heart disease, these conditions are optimally controlled.
For more information, contact Lee Eye Centre Sdn Bhd.
Going for regular eye checks will enable optometrists to identify early signs of optical vascular damage.