Eye Health

Updated 20 May 2015

What is eye disease?

There are so many different conditions that can affect the eye. Some are not cause for concern but conditions such as glaucoma can lead to serious visual impairment and even blindness.


There are many different conditions that can affect the eye. Some are minor and resolve by themselves quickly, such as viral conjunctivitis, but others could be serious and lead to serious visual impairment, such as glaucoma.

Vision loss or impairment can be sudden or gradual. Some serious eye problems can lead to total loss of vision. A decrease in vision is usually one of the first presenting symptoms and should always be investigated.

Blindness can be the result of serious untreated eye problems, but according to the South African National Council for the Blind, eighty percent of blindness is avoidable, which is why early diagnosis and treatment are so essential in the case of eye diseases.

Problems affecting the eye can range from infections of the eye or the eyelid, genetically inherited eye problems, eye injuries or objects in the eye, and eye disorders which are the result of conditions that affect many organs, such as diabetes or hypertension.

Many eye diseases have no early symptoms and changes in vision only occur when the disease is advanced, making treatment more difficult.

Many people experience a degree of age-related deterioration in their visual abilities. Blurred vision, some loss of peripheral vision and a decrease in visual acuity can be some of the symptoms experienced later in life.

One of the most common symptoms experienced by large numbers of people is redness of the eyeball, which is due to swollen or dilated blood vessels. This makes the eye look bloodshot, according to the National Institutes of Health this can be caused by allergies (allergic conjunctivitis) or eye fatigue to name but two possibilities. A painful red eye is a concerning matter and should be investigated at all times.

Genetic inheritance can increase your risk for certain eye problems, such as glaucoma and colour blindness. Eye problems can also sometime be the result of other chronic conditions, such as uncontrolled diabetes and hypertension.

Optometrists can examine your eyes to find out whether you might need glasses or medical treatment. An ophthalmologist is a specialist in medical and surgical eye problems.

4 types of eye problems

Eye infections

These can be caused by bacteria, fungi or viruses. Infections can occur in different parts of the eye and can affect just one eye or both. In the case of a condition such as infectious conjunctivitis, the infection can spread easily from one eye to the other or from one person to another, according to the Merck Manuals.

Signs of an eye infection include eye pain and a discharge, a feeling that there is a foreign body in the eye, redness of the eye or eyelids and in some cases, decreased vision. These are of the most common eye infections:

- Conjunctivitis, better known as pink eye, is an infection of the mucous membrane covering (the conjunctiva) the front of the eye and which lines the inside of the eyelids. These can be caused by both bacteria and viruses.

- Eyelid inflammation, also known as blepharitis, is an inflammation of the follicles of the eyelashes.

- A stye is a red painful bump on the eyelid caused by a bacterial infection of the sebaceous glands.

Read: Eye infections: when to consult your doctor

Genetically inherited eye problems

Some eye problems are genetically inherited. Five out of every 10 000 children are born with eye malformations, according to the Children’s National Health System, so it is relatively rare. Examples include: anopthalmia (where an eye or both eyes are absent) and underdeveloped optic nerves.

Other genetically inherited eye problems can include glaucoma, age-related macular degeneration and cataracts. These three conditions usually develop in older patients, but a family history of the disease does increase a person’s risk for these eye problems. Sometimes children can also be affected by these eye diseases.

Glaucoma can damage the eye’s optic nerve and can lead to vision loss and blindness. Increased pressure within the eye contributes to the development of glaucoma in some cases, says the National Eye Institute.

A cataract is a clouding of the lens of the eye that can cause a loss of vision. This is the leading cause of blindness around the world, according to the Merck Manuals. Cataracts can be usually be removed and replaced with an artificial lens. Although this is not a very complicated operation, many people around the world do not have access to the type of medical services that can provide this procedure.

A squint (strabismus) is a condition in which the eyes point in different directions. Squints can affect as many as one in 20 children, according to the Children’s National Health System. These can easily be corrected by surgery.

So-called ‘refractive errors’, which include near-sightedness, far-sightedness and astigmatism can develop with age, but sometimes children are born with these eye problems.

Eye injuries and foreign objects in the eye

The eyes, though well protected, can suffer injuries ranging from mild, such as a minor corneal scratch to severe, such as retinal detachment.

In the case of injury to the eye in an accident, immediate medical treatment is required to prevent permanent eye damage and vision loss.

Eye injuries can be the result of direct trauma, or the penetration of an object into the eye. These can cause corneal scratches, or far more serious injuries like severe damage or even loss of the globe. Substances, such as acids, oven cleaners and chalk dust can cause serious damage if they get into your eyes. Others, such as shampoo, can cause burning and stinging and short-term discomfort, but may not cause serious long-term injury.

A black eye can be the result of being struck in the eye or in the area around the eye, causing bruising around the eye socket. Fractures or cracks in the facial bones surrounding the eye also warrant immediate treatment. Black eyes should therefore always be examined by a doctor.

Trauma to the eye can cause retinal detachment, which is a serious condition that needs immediate medical treatment.

Read: Symptoms of eye injuries

Eye problems related to other conditions

Some conditions can affect many of the organs in the body, of which the eye could be one.

An example of this would be diabetic retinopathy, which could be complication of both diabetes type 1 and diabetes type 2. The blood vessels in the retina of the eye are damaged, and this can eventually lead to blindness. According to the South African National Council for the Blind, diabetic retinopathy is the sixth biggest cause of blindness worldwide.

High blood pressure could also cause hypertensive retinopathy, and multiple sclerosis could cause the eyelid muscles to droop.

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Megan Goodman qualified as an optometrist from the University of Johannesburg and is currently practising at Tygerberg Academic Hospital in Cape Town. She has recently completed a Masters degree in Clinical Epidemiology at Stellenbosch University. She has a keen interest in ocular pathology and evidence based medicine as well as contact lenses.

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