Chapter 3 Priorities and objectives - What do we want to achieve?
3.5.2 Refractive errors
Refractive errors can be divided into three major groups:
- people over 40 years of age with presbyopia (difficulty in near vision and reading)
- myopia
- uncorrected aphakia (eyes with lenses removed and not replaced by IOL or spectacles).
The global magnitude of refractive errors is not reliably known, as there is great variation in groupings according to age, definitions of blindness, and examination methods. Reports suggest that 5-25% of blindness in some countries is caused by refractive errors and as much as 4% of the population sees less than 6/18 (20/60, 0.33) because of this condition. Correction of significant refractive errors requires a well-trained refractionist and access to affordable and good-quality spectacles.
Presbyopia may be easiest to solve through bulk purchase of standard spheric reading spectacles. The costs of such spectacles are low and in most cases full refraction is not required.
Myopia usually develops at the age of 10-15 years. Intervention should focus on screening children in this age group using a simple test for refractive errors. Those who fail the test should be referred for refraction and provided with spectacles. Large-scale screening may increase awareness of refractive errors and motivate parents and grandparents to come forward for testing as well. Increasing demand for spectacles may also promote the development of more optical services.
Uncorrected aphakia is unfortunately still a frequent cause of blindness or low vision. Provision of aphakic glasses is an essential component of cataract intervention.
Training of refractionists and the development of affordable and good quality optical services should be an essential component in most VISION 2020 action plans.
Documents
Elimination
of avoidable visual disability due to refractive errors
How
to make spectacles at low cost
Low
vision care for the elderly - Report of a workshop
Consultation
on development of standards for characterization of visual loss and visual
functioning
Different
measurement systems for visual acuity
Articles
The
role of optometry in VISION 2020
Refractive
errors: magnitude of the need
Vision
testing for refractive errors in schools
Spherical
refraction for general eye workers
The
challenge of providing spectacles in the developing world
Case
finding for refractive errors: assessment of refractive error and visual
impairment in children
Case
finding in the clinic: refractive errors
Case
finding in the community: experience of Jatiya Andha Kallyan Somiti in
Comilla, Bangladesh