Impact of Uncorrected Refractive Error

Impact of Uncorrected Refractive Error

Visually disabling refractive error affects a significant proportion of the global population, occurring in both genders, in all ages and in all ethnic groups.

The most common cause of visual impairment, and the second leading cause of treatable blindness,1 uncorrected refractive error has severe social and economic effects on individuals and communities, restricting educational and employment opportunities of otherwise healthy people. The duration of the effect is also significant – refractive error can account for twice as many blind-person-years compared to cataract, due to the earlier age of onset.2

The need is very great for both children and adults. Studies have shown that refractive error in children causes up to 62.5% of blindness (≤ 6/60 in the better eye) in Chile,3 22% in Nepal,4 77% in urban India,5 and 75% in China.6 For visual impairment in children (≤ 6/12 in the better eye), refractive error is responsible for 55% in Chile, 86% in Nepal, 93% in China, 70% in rural India,7 and 83% in urban India.5 What is also disturbing is the amount of this refractive error that is uncorrected on presentation – 46% in Chile, 92% in Nepal, 58% in China, 86% in rural India. The burden even reaches to developed countries, with uncorrected refractive error causing 25% of all blindness (<6/60) in an Australian adult population and 56% of visual impairment (<6/12).8

The burden of refractive error is set to grow alarmingly due to an increase in myopia in both the developed and developing world, especially in urbanized East Asians, such as the Chinese populations in Hong Kong, Singapore and Taiwan.9-11

Refractive Error and Vision 2020

The impact and importance of uncorrected refractive error has now been recognized by Vision 2020. WHO established a Refractive Error Working Group (REWG), as part of global Vision 2020 activities, in recognition of this important facet of international eye care. The REWG is now developing international strategic plans and policies to eliminate uncorrected refractive error.

Optometry's Role in Correcting Refractive Error

The good news is that while refractive error is amongst the most common causes of blindness and visual impairment, it is also the easiest to 'cure'. Refractive error can be simply diagnosed, measured and corrected, and the provision of spectacles is an extremely costeffective intervention, providing immediate correction of the problem.

Throughout the world optometry has been the major provider of vision correction, but usually from a private practice setting. Public health optometry has not reached the communities that are in most need in any organized way. Despite this, on their own initiative, thousands of private optometrists worldwide have regularly visited communities in need to provide vision care and dispense spectacles. The opportunity now is for optometry to develop a concerted effort to create local capacity in these communities, in collaboration with its partners in Vision 2020, through service delivery, by creating human resources and by helping to develop the infrastructure needed, the three cornerstones of the Vision 2020 programmed.

Refractive Error Study In Children

A series of studies around the world have begun to fill in the gaps in our knowledge of the burden of blindness and impaired vision in children caused by refractive error. The studies address the variation of refractive error with age, gender, race and geographic region, the extent to which it is being corrected, and how the prevalence is changing over time. The Refractive Error Studies in Children (RESC) have so far been conducted in Nepal, China, Chile and India, using population-based, cross-sectional sampling, consistent definitions and a common methodology. ICEE is currently conducting the RESC study in KwaZulu Natal, South Africa in conjunction with the National Eye Institute and WHO, and sponsored by CBM International, Sight Savers International and ICEE. At the completion of the African study, data will have been collected on approximately 30,000 children worldwide. 

Conclusion

It should not be necessary for any child to struggle in school, to learn with an uncorrected refractive error. Nor should any older person be called upon to spend thirty or forty years without glasses, to see to read or sew or to manage a job. Optometry and the optical industry in its broadest sense should be able to find the financial resources to give this simplest gift of sight.

Preventable blindness is one of our most tragic and wasteful global problems. Optometry is an essential part of the team that will eliminate this tragedy, by understanding global eyecare needs and delivering effective and sustainable vision care to people in need, thereby ensuring their fundamental right to sight.

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Optom. Keyur Sharma
Assistant Professor