More than three-quarters of Ghanaians over the age of 45 have an eye condition. The most common is uncorrected refractive error, such as near-sightedness (myopia), far-sightedness (hyperopia), astigmatism and presbyopia (inability to focus on near objects). Refractive error can, in most cases, easily be corrected by wearing prescription spectacles.
Many other eye conditions, however, may cause irreversible vision loss if not detected early. Having regular eye examinations will increase the chance of early detection of eye diseases that are mostly treatable. These eye diseases include:
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Cataract
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Corneal dystrophy
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Diabetic Retinopathy
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Dry Eye
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Glaucoma
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Inherited Retinal Dystrophy
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Macular Degeneration
Cataract
Age-related cataract is one of the most common causes of visual impairment in Australia and worldwide. Cataracts can also develop in individuals with metabolic disorders (for example, diabetes) and as a result of trauma to the eye.
Cataracts occur when the normally clear, crystalline lens in the eye becomes cloudy. The lens is the part of the eye that allows a focused image to be transmitted onto the retina.
The effects of cataracts on visual function include reduced detailed vision and reduced ability to detect low contrast information in visual scenes. Cataracts due to aging usually develop slowly and affect both eyes at different rates.
Surgical lens extraction and insertion of a replacement plastic lens is the standard procedure for restoring visual function once cataracts have developed. This is a highly successful procedure that is widely practised in Australia with few adverse effects.
Functional implications of a cataract include:
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Having difficulty seeing traffic when crossing the road
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Having difficulty driving
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Having difficulty reading
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Having difficulty judging depth
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Seeing a halo or double vision around lights at night
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Seeing images as if through a veil
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Being particularly sensitive to glare and light
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Having dulled colour vision.
Glaucoma
Glaucoma is a common eye disorder affecting visual function through damage to the optic nerve. It is commonly age-related, with incidence increasing after the age of 40 years. The condition affects one in 15 people over the age of 70. While rare in those under the age of 50, glaucoma can also occur in infancy and in the juvenile years.
Glaucoma is an eye disease that slowly damages the fine nerves connecting the eye to the brain. The damage generally occurs when pressure within the eye rises. If untreated, it causes a loss of peripheral vision, which can result in tunnel vision and even total blindness.
Early diagnosis of glaucoma is vital, particularly because people may have few or no symptoms in the early stages. In fact, one in two Australians with glaucoma may be undiagnosed. At present, raised intraocular pressure and family history of the disease are two important risk factors for developing glaucoma.
Once vision has been lost, it cannot be restored. Prevention of vision loss is therefore an important factor in reducing the impact of glaucoma. The mainstay of treatment is daily use of eye drops to reduce intraocular pressure and slow or halt death of neural tissue in the optic nerve.
Functional implications of glaucoma include:
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Having difficulty adjusting to lighting changes (e.g. between indoors and outdoors)
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Experiencing occasional blurred vision
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Seeing a halo around lights
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Being particularly sensitive to glare and light
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Having difficulty identifying the edge of steps
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Being unable to differentiate between the footpath and road
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Tripping over or bumping into objects.
Diabetic Retinopathy
Diabetes is a chronic condition that can have adverse effects on the eye and visual function. Diabetic Retinopathy (DR) is caused by complications of diabetes. It damages blood vessels that nourish the retina at the back of the eye. This progressively results in blurred vision. Severe vision loss may be preventable if the DR is detected and treated early and appropriately.
DR typically begins as small microaneurysms (ballooning of small blood vessels) in the retina. Intermediate signs are small dot haemorrhages in the retina, as well as small areas of blood vessel leakage (exudates) and small areas of reduced blood supply (cotton-wool spots). End-stage DR is characterised by internal eye (vitreous) haemorrhage, as well as retina scarring and detachment of the retina from the back of the eye (tractional retinal detachment).
DR is best minimised by maintaining good control of blood sugar levels and through early detection of disease progression. Early detection allows for intervention in the disease process, either through laser photocoagulation, or intravitreal injection of Anti-VEGF pharmaceutical agents or steroids to halt or delay progression of the ocular disease. Treatment may maintain vision, though it rarely restores it.
People with diabetes also have an increased risk of acquiring other vision conditions, such as glaucoma or cataracts. Regular eye examinations are essential to detect these vision conditions.
Functional implications of DR include:
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Having difficulty with fine details (e.g. when reading or watching television)
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Having difficulty with outdoor travel
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Experiencing visual fluctuations from hour to hour or day to day
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Seeing images as rippled (e.g. straight lines appear bent)
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Experiencing blurred, hazy or double vision
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Losing some field of vision
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Having difficulty seeing at night or in low light
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Being particularly sensitive to glare and light
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Having difficulty focusing
Dry Eye
Dry eye can be a chronic condition for many individuals. It requires frequent use of eye lubricants to obtain symptomatic relief and preserve corneal health.
The recent development of anterior chamber optical coherence tomography has enabled novel ways to quantitatively assess the eye’s tear film in dry-eye conditions. It is hoped that this new instrumentation will lead to a better understanding of the spectrum of dry-eye conditions and will subsequently lead to improved treatments.
PROGRAMS
Major Causes of Vision Loss
