Refractive Error in Children in Cambodia and Childhood Blindness/Severe Visual Impairment in Sri Lanka

This study has two main components with a common theme of paediatric ophthalmology in Asia. The first component aimed to assess the prevalence of refractive error in 12-14 year old children in urban Phnom Penh and rural Kandal Provinces of Cambodia. The prevalence of refractive error in Cambodia has not been previously studied and is important for the planning and implementation of refraction services. Uncorrected refractive error is a leading cause of visual impairment worldwide and can have a dramatic impact on a child’s learning capability. The chief aim of the second component was to determine the major causes of childhood blindness and severe visual impairment in Sri Lanka, in particular those that are avoidable and what public health strategies need to be implemented to address them. A randomised cluster sample cross-sectional survey of ten schools from Phnom Penh Province and 26 schools from Kandal province was undertaken in October 2010. Random selection of children at each school was used to identify the study sample. Children were examined by teams of Australian and Cambodian optometrists, ophthalmic nurses and ophthalmologists who performed visual acuity (VA) testing and cycloplegic refraction. 5527 children were included in the study. The prevalences of uncorrected, presenting and best-corrected VA ≤ 6/12 in the better eye were 2.48%, 1.90%, and 0.36% respectively. In Phnom Penh Province, the prevalences of uncorrected, presenting and best-corrected VA ≤ 6/12 in the better eye were 5.91%, 4.36% and 0.75% respectively. In Kandal Province, the prevalences of uncorrected, presenting and best-corrected VA ≤ 6/12 in the better eye were 0.51%, 0.51% and 0.14% respectively. Only 43 children presented with glasses whilst a total of 315 glasses were dispensed. The total prevalence of refractive error was 6.57% but Refractive Error in Children in Cambodia and Childhood Blindness/Severe Visual Impairment in Sri Lanka iii there was a significant difference between urban (13.7%) and rural (2.5%) schools (p value < 0.0001). Refractive error accounted for 82.3% of the visual impaired eyes, cataract for 1.7%, and other causes in 7.1%. Myopia (spherical equivalent of ≤ -0.50D in either eye) affected 5.5% of 12 year old children increasing to 6.0% of 14 year olds. Myopia was associated with increased age, female gender and schooling in urban centres. Thirteen schools for the blind were visited in Sri Lanka between October 2008 and October 2009 by a team of ophthalmologists and optometrists. Each child’s examination findings were recorded in a standardized World Health Organisation Prevention of Blindness Eye Examination Record for Childhood Blindness Form. Of the 206 children surveyed, 83.5% were blind (BL=Visual acuity [VA] <3/60), and 9.2% had severe visual impairment (SVI=VA <6/60 to 3/60 in the better eye) on presentation. The major anatomical site of BL/SVI was the retina in 35.9% of cases, followed by the whole globe in 22.4% of cases. The major underlying aetiologies of BL/SVI were unknown in 43.75% of cases and hereditary in 37.5%. Avoidable causes of BL/SVI accounted for 34.9% of cases; retinopathy of prematurity made up the largest proportion of this subgroup. The data support the need to develop specialised paediatric ophthalmic services, particularly in the face of advancing neonatal life support in Sri Lanka. One third of the children could have had improved vision with the prescription of an optical device highlighting the need for increased optician services. Refractive Error in Children in Cambodia and Childhood Blindness/Severe Visual Impairment in Sri Lanka iv