Refractive errors are a set of eye conditions that occur because of an irregular eye shape which affects the way light is focused in the eye- these conditions result in blurry or distorted vision.

There are three different types of refractive errors, namely myopia/near sightedness (close up sight is normal, but distant objects are blurry), hyperopia/ far sightedness (objects at close range are blurry, while distant objects are not) and astigmatism where your vision is blurred at all distances.

Statistics

According to the WHO website (Resnikoff et al: 2004), uncorrected refractive errors account for 18.2% of global blindness, making it the 2nd biggest cause of blindness worldwide.

Risk factors

• As refractive errors are hereditary, people with a family history of a refractive error are at risk of having the condition themselves.
• Eye injury as well as certain ocular disorders, like keratoconus, can put a person at risk of developing a refractive error.

Prevention and treatment

• Diagnosis and correction of a refractive error is quite quick and simple. Blindness as a result of this condition is avoidable if the condition is corrected, which is why it is important that every person have an eye examination at least once every two years.
• Refractive errors can be corrected through the use of glasses, contact lenses or refractive surgery.
• Corrective measures are relatively cheap and readily available.

People with diabetes are at risk of developing diabetic retinopathy, which is a disease of the blood vessels in the retina of the eye.

Statistics

According to the WHO website (Resnikoff et al: 2004), diabetic retinopathy accounts for 3.9% of global blindness, making it the 6th biggest cause of blindness worldwide.

Risk factors

People who are at risk of developing diabetic retinopathy are those with diabetes –type 1 and 2.

Prevention and treatment

• Everyone with diabetes should get a comprehensive dilated eye exam every year.
• Diabetics should have their blood sugar levels, blood pressure and cholesterol under control by maintaining a healthy diet and sticking to their treatment plan.
• Eliminating risks that are known to damage blood vessels, such as smoking, will help prevent the onset of diabetic retinopathy.
• Diabetic retinopathy is treated with laser surgery (scatter laser or focal laser treatment) or with a vitrectomy (surgical procedure). 

Age-related macular degeneration (AMD) is a degenerative retinal disease that affects the macula of the eye resulting in a progressive loss of central vision.

Statistics

According to the WHO website (Resnikoff et al: 2004), AMD accounts for 7.1% of global blindness, making it the 4th biggest cause of blindness worldwide.

Risk factors

There are certain factors that can increase your risk of developing AMD, which include:

• Unhealthy diet,
• Smoking and alcohol abuse,
• Prolonged exposure to sunlight,
• Cardiovascular disease and Hypertension,
• Genetics -  a family history of AMD will increase your chances of developing it and,
• Age - the older you get, the higher your chance of developing AMD.

Prevention and treatment

• A new treatment is available for “wet” AMD whereby an anti-angiogenic is injected into the eye to slow the formation of new rogue blood vessels which can cause sudden and dramatic vision loss.
• A regular eye examination, at least once every two years, will allow for early detection of AMD.
• A healthy diet with an increase in zinc and antioxidants will significantly reduce your risk of developing advanced AMD.