Blindness is defined as inability to count fingers at a distance of 3 metres,or a visual acuity of less than 3/60 in the better eye with the best possible correction.
In addition,when the visual field is less than 10 degrees, the eye is considered to be blind even if visual acuity is not impaired. A person is considered to have severe visual loss if the best corrected visual acuity ‘is less than 6/60 or there is inability to count lingers at 6 metres.
Blindness is a major health problem worldwide. It is estimated that 38 million persons are blind in the world and that 110 million have low visions. The overwhelming majority of the world’s blind live in the developing countries; 7 million are in Africa; the blindness rates are 10 to 40 times greater than in thedeveloped countries.
In Tanzania and Gambia 0.7 % of the population are blind, and in Chad and Malawi, 3.1 % and 1.3 % respectively.
A major portion of the blindness in developing countries can be either cured or prevented by reasonable deployment of skills and resources, and this is termed avoidable blindness.
The major causes of blindness are:
l. Cataract – treatable.
2 Trachoma – treatable and preventable.
3. Onchocerciasis – controllable and treatable.
4. Xerophthalmia – preventable and treatable .
5. Glaucoma – treatable.
6. Trauma – to some extent preventable and treatable.
The general lack of eye care services in underserved communities in developing countries is responsible for much blindness. Early treatment of infections and nutritional eye
disease is essential to prevent visual loss, and such treatment can be delivered effectively by auxiliary health personnel.
PREVENTION OF BLINDNESS PROGRAMME
The objectives of the WHO Prevention of Blindness Programme are to make essential eye care available to all populations and to eliminate avoidable blindness.
The aim is to reduce national blindness rates to less than 0.5%, with no more than 1% in any individual community.
This is now embodied in “VISION 2020”- The “Right to Sight” initiative. The initiative aims to eliminate avoidable blindness, the global number of blind individuals would increase from 44 million in the year 2000 to 76 million in 2020.
It has been predicted that a successful VISION 2020 initiative would result in only 24 million blind in 2020 and lead to 429 million blind person-years avoided. A conservative estimate
of the economic gain is $102 billion. Therefore VISION 2020 initiative has the potential to increase global economic productivity. In most African countries, there is generally a serious shortage of sound data on blindness and its causes. It is desirable to try and obtain population-based sample data on blindness whenever possible, but this may not be feasible in all African countries in the near future.
It is necessary that national prevention of blindness progranunes be formulated within the context of primary health care. There should be specific governmental budgetary allocation for blindness prevention if the implementation of
the programme is to succeed.
The development of manpower for blindness prevention is of critical importance. There is a serious shortage of higher levels of personnel, especially ophthalmologists. This has led to the development of alternative categories of health personnel to perfonn some of these higher functions.
In programme implementation, monitoring and evaluation are vital for success. To achieve satisfactory implementation, prevention of blindness and delivery of eye care should be an integral part of the general health services at all levels. The practice now is to develop these facilities as a three-tiered structure comprising primary, secondary and tertiary eye care.
PRIMARY EYE CARE
Primary eye care provides simple, preventive and curative services which can be carried out by primary health workers or other trained or interested persons. Their field of attention is primarily in the areas of inflamed (“red”) eyes including eye injuries, loss of vision and pain in the eye.
They may provide definitive treatment, or may initiate treatment and refer, or may refer alone to a secondary or tertiary centre. Supervision of th is level by secondary or tertiary centres is mandatory to success.
SECONDARY EYE CARE
The eye care facilities available at the secondary level should provide for the definitive management of common blinding conditions such as cataract, trichiasis and entropion, eye injuries, closed-angle glaucoma and corneal and intraocular infections.
This level of eye care is usually carried out in dispensaries or district and regional hospitals by staff such as ophthalmic medical assistants, ophthalmic nurses, general medical practitioners trained in eye care, or by qualified ophthalmologists depending upon the level of manpower available.
When circumstances so demand, it is advisable
some ophthalmic medical assistants and interested general medical practitioners are trained to perform cataract extractions. Referrals from the secondary level go to the
tertiary centres which should also assist in the training and supervision of personnel of the secondary level.
TERTIARY EYE CARE
This level is the top of the referral tree and should be equipped and manned accordingly. These are the Teaching Hospitals. Apart from their other functions, staff of these institution should be involved in the training of the various categories of health care personnel in eye care and support of the work at the primary and secondary levels.
They should provide technical leadership and show initiative in the promotion of public health ophthalmology and research.
PROBLEMS OF BLINDNESS PREVENTION IN AFRICA
The principal problems which afflict prevention of blindness in Africa and most developing parts of the world are:
I. Lack of relevant data on blindness and its distribution.
2 Lack of suitably -trained manpower:
(i) ophthalmologists
(ii) ophthalmic medical assistants/clinical officers
(iii) ophthalmic nurses
(iv) ophthalmic opticians/optometrists
3. Inadequate or poor basic equipment for eye care
4. Inadequate or irregular supply of eye care drugs and supplies.
5. Lack of transport and other facilities for outreach work.
6. Poor remuneration of medical, paramedical and allied personnel.
Rehabilitation of the Blind and Low Vision
It is necessary that the large number of incurably blind and low vision persons be rehabilitated in a special way so that they can fend for themselves and cam their livelihood and, in general, live as useful citizens without being an undue burden on others.
In the case of blind children, special educational facilities need to be p rovided and training in braille given to enable them lead a more normal life.
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Voluntary national associations for the blind, trans-national, non-governmental agencies and social welfare departments and other governmental institutions have undertaken
these onerous tasks in various countries. Training may be not only academic but also oriented towards crafts, industry related skills, farming and co-operatives of various sorts.
Post-training employment facilities need to beplanned and executed as well as continued monitoring of their welfare.
The expense of rehabilitating the blind gives a good justification for Governments and agencies investing in blindness prevention programmes. Such investments have a very high cost/benefit ratio.
This article was adapted from Principles and Practice of Surgery by Badoe and Achampong.
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