Visual conditions
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© CBM
A man carrying water in Luzhou, China. He is part of a CBM-supported CBR (Community Based Rehabilitation) programme for people with impaired vision.
Visual conditions such as cataract, glaucoma, retinal diseases, trachoma and Vitamin A deficiency occur frequently in the developing world, often affecting the poorest of the poor. Many conditions can be managed and supported with the right specialist eye care.
Blindness
What causes blindness?
The major causes of avoidable blindness in developing countries are cataract, refractive errors, glaucoma, trachoma, vitamin A deficiency, diabetic retinopathy and onchocerciasis. To provide cost-efficient treatment for these eye diseases and to improve available surgical facilities, CBM supports and sponsors
The major causes of avoidable blindness in developing countries are cataract, refractive errors, glaucoma, trachoma, vitamin A deficiency, diabetic retinopathy and onchocerciasis. To provide cost-efficient treatment for these eye diseases and to improve available surgical facilities, CBM supports and sponsors
- eye care services and hospitals
- training for eye specialists and ophthalmic nurses
- eye care programmes and programmes for blindness prevention
- the production and distribution of eye medicine
Cataract
A cataract is defined as a progressive opacity or clouding of the eye lens that eventually leads to blindness. Affected people feel like they are looking through a fog that becomes increasingly denser.
What Causes Cataract?
- The causes of cataract are not entirely understood.
- Most cataract cases occur at an older age and are caused by metabolic disorders and the ageing of body tissues.
- Cataracts can also be congenital or hereditary (e.g. due to rubella during pregnancy).
- Additional risk factors include: injuries, other eye diseases, ultraviolet radiation, smoking, and diabetes.
Childhood blindness
Childhood blindness is a general term used to embrace all occurrences of blindness in children.
The main cause is xerophthalmia, an eye disease caused by a vitamin A deficiency that leads to softening and opacity of the eye lens and eventually to irreversible blindness. Xerophthalmia can be cured by administering vitamin A capsules to balance the deficiency before blindness occurs.
Other causes include: measles, rubella, congenital cataract, congenital glaucoma, and retinopathy of prematurity (a potentially blinding eye disorder that primarily affects premature infants).
Therefore, the improvement of primary eye care for children to detect and treat causes of blindness is an important aspect of prevention.
River blindness (onchocerciasis)
River blindness (onchocerciasis) is a worm infection that may lead to irreversible blindness. Parasitic worms are transmitted to humans through the bite of the simulium fly (also called black fly) and migrate into the eye where they destroy the optic nerve.
As the simulium fly predominantly breeds in rivers in West and Central Africa, living near the contaminated rivers increases the risk of contracting the disease.
While the infection can be treated, the blindness, once occurred, is irrevocable. Ivermectin is used to kill the offspring of adult worms and to slow down the reproduction rate, thus resulting in fewer worms in the eyes.
Read more about the Neglected Tropical Diseases.
Age-related macular degeneration
This is an eye condition that progressively damages the macula - the area of the retina responsible for central and colour vision. While the condition rarely results in complete blindness and usually leaves peripheral vision intact, detailed central vision is affected, rendering the patient unable to read, drive a car, recognise faces or see objects in fine detail.
The condition is caused by the deterioration of the macula as one gets older. The cause is however unknown, although cigarette smoking is a significant risk factor. There is no treatment at present that cures this disease. Health care treatments which may halt or slow down progression are being evaluated. Low vision training and special devices can help patients to optimally utilise the remaining vision.
Diabetic retinopathy
This describes an eye condition that is related to diabetes, and damages the small blood vessels that nourish the retina. The retina transforms light entering the eye into signals which are interpreted by the brain as visual images. Damage to the retina may lead to poor vision and even blindness.
What causes Diabetic Retinopathy?
Approximately 20% of people with diabetes have some degree of diabetic retinopathy. Risk factors for developing retinopathy in diabetics include:
Approximately 20% of people with diabetes have some degree of diabetic retinopathy. Risk factors for developing retinopathy in diabetics include:
- long duration of diabetes
- more common in insulin-dependant diabetes
- poorly controlled blood sugar levels
- overweight
- high blood pressure
- high blood cholesterol
- pregnancy
How is Diabetic Retinopathy treated?
There is no absolute cure. Laser treatment is of proven value in preventing visual loss. Surgery on the retina may help restore some vision in severe cases.
To detect diabetic retinopathy at an early stage, patients with diabetes should:
There is no absolute cure. Laser treatment is of proven value in preventing visual loss. Surgery on the retina may help restore some vision in severe cases.
To detect diabetic retinopathy at an early stage, patients with diabetes should:
- have their eyes examined each year
- keep good control of their diabetes with treatment
- keep blood pressure down
- immediately report any changes in their vision to a doctor
Glaucoma
Glaucoma is a group of complex eye diseases, all of which involve progressive damage to the optic nerve. Affected people feel like they are looking through a tunnel that becomes increasingly narrower.
Glaucoma is often but not always accompanied by high interior pressure in the eye. Risk factors include: increasing age, family history of glaucoma, diabetes, and myopia.
As the condition progresses without obvious symptoms, glaucoma is often only detected after the optic nerve has been severely damaged. Treatment is aimed at stopping further loss of vision; it cannot restore vision already lost.
Treatment:
For the different types of glaucoma, different types of treatment are indicated:
- An eye operation or a laser procedure is often recommended
- In some patients, ongoing, life-long health care treatment is indicated
Trachoma
Trachoma is a bacterial infection of the eye. If untreated, the infection leads to conjunctival scarring and the inversion of the eyelashes. This causes scarring of the cornea and leads to incurable blindness.
What Causes Trachoma?
Trachoma is usually caused either by an infection, usually contracted during infancy, with the micro-organism Chlamydia Trachomatis, or by inadequate living conditions: lack of water, lack of sanitation, poor health care service, poverty and flies that transmit the disease.
While the infection can be treated, the blindness, once occurred, is irrevocable. Regular application of antibiotic eye ointments and regular face washes to treat the active infection help to treat the infection, but eyelid surgery for trichiasis (inturned eyelashes) at a more advanced stage of the disease may be necessary to help prevent blindness.
Read more about the Neglected Tropical Diseases.
Low Vision
In most developing countries there is a shortage of available and accessible ophthalmologic care, education and rehabilitation for persons with low vision. As a consequence persons with low vision are often socially and economically disadvantaged. CBM endeavours to enable these persons to make use of their skills, talents and opportunities in the most effective way.
CBM does this by making sure that basic eye care, education and vision rehabilitation services are available and accessible. In addition, CBM supports people with low vision with optical and non-optical assistive devices. For instance, every year thousands of magnifiers and other special devices sponsored by CBM are distributed to people who need them.
Objectives are:
- Create awareness about Low Vision among all parties involved.
- Promote early identification of Low Vision
- Develop training in Low Vision as part of exiting trainings and as postgraduate trainings.
- Organise availability of and access to low vision devices for programmes and individuals.
- Establish Low Vision services at primary, secondary and tertiary levels to provide comprehensive low vision care, using existing education, medical, rehabilitation and relevant community programmes
Focus on early intervention
CBM's efforts aim especially at children with low vision. Early intervention is encouraged in the form of
- training in effective use of vision such as eg vision stimulation
- training in the use of optical devices such as magnifiers and telescopes
- training to use vision and other senses to become independent, eg orientation and mobility
Rolf Müggenburg, Continental Director, Asia: “For CBM’s work, Low Vision is and will remain a cross cutting issue. We have developed so called Low Vision Implementation Plans for the different regions of Asia. These have the main aim to provide access to any client with Low Vision in the regions to the necessary clinical and functional assessments, to training, advice and devices to make optimal use of their vision in order to enable them to improve their quality of life and to promote independence and inclusion in the local community.”
