Prevalence of cataract blindness along with Cataract Surgical Coverage can give important information about the impact of a cataract intervention programme. The surgical coverage for persons indicates to which extent people, disabled by bilateral operable cataract, had surgery in one or both eyes. It relates directly to the prevalence of bilateral cataract blindness.
Cataract surgical coverage for eyes also includes people with operable cataract in one eye and a normal other eye. It relates more to the total surgical workload for the ophthalmologists.
Both indicators only provide quantitative data. Visual outcome is not taken into account and can be calculated separately from the same data.
Indicators obtained through population based surveys are influenced by events over a previous period of several years. The effects of recent changes in strategy are likely to be diluted by effects from the period before the change in strategy. Prevalence and coverage data should be collected at regular intervals, say every 3-5 years, to reveal trends. Rapid assessments, conducted by local staff, using simple, standardised survey methodology and software for data analysis, can be undertaken.
As can be seen from Karnataka, usually a lower prevalence of cataract blindness is linked with a higher coverage. The factors that determine this relation are the proportion of first eyes being operated on and the proportion of operations on eyes not yet blind.
It is not always possible to assess in retrospect whether a person with one or two aphakic eyes was actually blind (VA<3/60), severely visually impaired (VA<6/60) or visually impaired (VA<6/18) at the time of surgery. The proportion of operations on non-cataract blind patients is difficult to assess. In Karnataka state, the results show that only 5% of all surgeries were with intraocular lens implantation.5 Most cataract surgeries were done on patients or eyes with a VA<3/60 and hence, the cataract surgical coverage for this level will be fairly correct.
In Ahmedabad district, however, many more people with a VA better than 3/60 were also operated upon. In such situations, it will be more accurate to use the cataract surgical coverage at level <6/60 or even <6/18.
It is possible to assess the visual acuity of all (pseudo) aphakic eyes in the sample to assess outcome, and look at the reasons for failure. If patient records are available, the proportion of first eyes and second eyes can be calculated and this can give an impression of utilisation of resources.
By comparing pre-operative vision with post-operative vision the Success Rate and the Sight Restoration Rate can be calculated. This indicates the proportion of all cataract operations which change a blind person into a sighted person.7 Such outcome indicators reveal the quality of cataract surgery and visual rehabilitation.
Cataract blindness is a dynamic entity, determined by demographic changes in the population, incidence of cataract blindness, and quality and quantity of the surgical services provided. These dynamics are difficult to capture in time bound static indicators. One should not look at coverage data in isolation but use them in combination with other parameters.
What is really needed is a mathematical simulation model that can capture these dynamics and can predict future trends in cataract blindness.8 The indicators described above can assist in developing such a model.
Central Ophthalmic Cell, Ministry of Health & Family Welfare, Government of India: Annual Results Cataract Performance.
The Epidemiology of Blindness in Nepal - Report of the 1981 Nepal Blindness Survey, The Seva Foundation, 1988.
Foster A. A simple method for evaluating surgical cataract services in prevention of blindness programmes. J Comm Eye Health 1992; 10: 2-5.
Limburg H, Kumar R, Indrayan A, Sundaram KR. Rapid Assessment of Prevalence of Cataract Blindness at District Level. Int J Epidemiol 1997; 26: 1049-54.
Limburg H, Kumar R. Follow-up study of blindness attributed to cataract in Karnataka state of India - results from district level rapid assessments (submitted for publication).
Limburg H, Vasavada A, Muzumdar G, Khan MY, Vaidyanathan K. Rapid assessment of cataract blindness in an urban setting - results from a survey in Ahmedabad District, Gujarat (submitted for publication).
Limburg H, Kumar R, Bachani D. Monitoring and evaluating cataract intervention in India. Br J Ophthalmol 1996; 80: 951-5.
Limburg H, Kumar R, Bachani D. Forecasting cataract blindness - and planning to combat it. World Health Forum 1996; 17: 15-20.
Patient Counsellors: The Role of Patient Counsellors in Increasing the Uptake of Cataract Surgeries and IOLs
Asim Kumar Sil DO DNB
Gobardanga Station Road
PO Khantura, Dist 24 Parganas (North)
West Bengal - 743273
India This article gives the experience of the eye hospital of the Vivekananda Mission Ashram, where we have found that patient counsellors make a major contribution to increasing the uptake of cataract services, particularly intraocular lens (IOL) surgery.
Patient counselling is an important part of medical or surgical management of a disease. Every patient should know about the nature of the disease and the benefits of the treatment suggested by the doctor. In industrialised countries this part of treatment is adequately managed but in developing countries patient counselling is very much neglected. The reason may be the larger volume of patients per doctor who finds it difficult to explain everything to the patient to take away anxieties and apprehensions. Patient counsellors are very useful in providing this service.
We have found it useful to select for counsellor training people who have been observed at work for at least six months. This gives the employer a chance to assess the worker’s attitude towards patients and his or her interest in learning basic aspects of ophthalmology. Keeping these aspects in mind, ophthalmic nurses and field workers are good choices for the post of counsellors because they already have a basic knowledge of common eye problems and are exposed to the community to some extent. A less experienced person may also be found suitable for the job and can be trained in the hospital and at outreach camps.