Dear Editor

We read with great interest the article by Kello et al.[1] on the causes of severe visual impairment and blindness in children in schools for the blind in Ethiopia. The authors have to be congratulated for the hardhitting and well written article. A current concern for people involved in pediatric eye care is the emergence of what is probably the third epidemic of retinopathy of prematurity (ROP) in developing countries.[2,3] It is therefore significant that no case of ROP was found in the population screened in this study. Several factors could account for this:
1. The very low or nil prevalence of ROP in countries such as Ethiopia, where the study was carried out, is most probably due to lack of intensive care facilities for premature infants and their low survival rates.
2. The variation in the incidence of ROP between ethnic groups could also account for this, with the available evidence suggesting that African-American infants are less prone to severe outcome ROP than white infants.[4,5]
3. However, it is also important to note that the article mentions that children with mental retardation were not examined owing to the admission criteria of the blind schools that precludes their admission. This too could have accounted for the gross underestimation of the prevalence of ROP as suggested by Jacobson et al.[6] In addition, these children with mental handicap could be suffering from cerebral palsy and would have been at high risk for ROP due to the higher incidence of retinal vascular anomalies associated with both cerebral ischaemia and prematurity.[7]
4. A large number of infants had phthisis bulbi (51 cases). In children with bilateral phthisis bulbi, there is a possibility that an unknown proportion developed the condition secondary to endstage ROP.

In conclusion, if improvement in perinatal care occurs in Ethiopia, the overall numbers of children with ROP would increase as is seen in other developing countries like India with infant mortality rates (IMRs) between 10-60 per 1000 live births3. Lack of ophthalmologists experienced in the management of ROP could be effectively circumvented by introduction of a digital retina camera technology to improve access to subspecialty care[8] for cases requiring treatment. As a lower cost option, screening infants under 1200 g alone might be more cost effective [9] and could be the first step, with modification of the screening guidelines made later, consequent to research undertaken within the country itself.

References

(1) A B Kello and C Gilbert. Causes of severe visual impairment and blindness in children in schools for the blind in Ethiopia. Br J Ophthalmol 2003;87:526-530.

(2) Wheatley CM, Dickinson JL, Mackey DA, Craig JE, and Sale MM. Retinopathy of prematurity: recent advances in our understanding. Arch Dis Child Fetal Neonatal Ed 2002;87: F78-82.

(3) Gilbert C, Rahi J, Eckstein M, et al. Retinopathy of prematurity in middle-income countries. Lancet 1997;350: 12-4.

(4) Schaffer DB, Palmer EA, Plotsky DF, et al. Prognostic factors in the natural course of retinopathy of prematurity. Ophthalmology 1993; 100: 230-7.

(5) Saunders RA, Donahue ML, Christmann LM, et al. Racial variation in retinopathy of prematurity. Arch Ophthalmol 1997;115: 604-8.

(6) Jacobson L, Fernell E, Broberger U, et al. Children with blindness due to retinopathy of prematurity: a population-based study. Perinatal data, neurological and ophthalmological outcome. Dev Med Child Neurol 1998; 40: 155-9.

(7) Pennefather PM, and Tin W. Ocular abnormalities associated with cerebral palsy after preterm birth. Eye 2000;14: 78-81.

(8) Schwartz DS, Harrison SA, Ferrone PJ, Trese MT. Telemedical evaluation and management of retinopathy of prematurity using a fiberoptic digital fundus camera. Ophthalmology 2000;107: 25-8.

(9) Lee SK, Normand C, McMillan D, et al. Evidence for changing guidelines for routine screening for retinopathy of prematurity. Arch Pediatr Adolesc Med 2001;155: 387-95.