KL Mayer, R Duerksen.
Neonates at Risk of Retinopathy of Prematurity in Paraguay.
Med Channel Jan ;4(1):19-21.

Retinopathy of prematurity (ROP) is a vasoproliferative retinopathy which can occur in premature babies as a result of interruption of the normal process of retinal vascularisation. The earliest signs usually occur 5-7 weeks after birth, and are characterised by a demarcation line at the junction of the vascularised and avascular peripheral retina (Stage 1). Subsequently a distinct ridge forms (Stage 2), followed by extraretinal fibrovascular proliferatiori (Stage 3). `Plus` disease exists when there is arterial tortuosity and venous dilatation in the posterior segment, and breakdown of the blood ocular barriers. Sub-total and total retinal detachment (Stage 4 and Stage 5) may develop. The extent of retinopathy is described in terms of clock hours, each clock hour representing a 30 segment of a 360 circle. Although spontaneous regression is common in Stages 1,2 and early Stage 3 disease, careful observation is required to detect babies who progress to stages of ROP that need treatment, i.e., the presence of `threshold disease`, defined as Stage 3 `plus` disease with 8 or more total clock hours of involvement, or 5 or more continuous clock hours of involvement. Treatment should be by laser or cryotherapy to the avascular peripheral retina, which prevents progression to Stages 4 and 5 in approximately 50% of cases. Childhood visual loss due to ROP was very rare prior to 1944. This changed dramatically with the administration of supplemental oxygen to preterm infants in the late 1040s. By 1950, ROP was the commonest cause of blindness in children in western countries. With the implication of hyperoxia in the pathogenesis of ROP, oxygen restriction decreased the incidence of blindness from ROP in the mid 19506 to mid 19606. Advances in neonatal intensive care since the 1960s have increased the survival of low birth weight (LBW,- less than 1.500 gms) and extra low birth weight babies (ELBW.- less that 1,000 gms), and in the west ROP now occurs mainly in ELBW babies. Low birth weight and preterm birth are considered the most important factors to determine infants at risk of ROP Other factors that are associated with ROP include apnoea and respiratory distress. Data from blind school studies carried out in Chile` and Paraguay` in 1992 show that ROP was responsible for 18% of childhood visual loss in both countries. In 1994 the proportion of blindness in children in schools for the blind in Paraguay had increased to 33% 3 Before planning a nation-wide screening programme for the detection and treatment of ROP there is a need to determine how many babies are at risk of ROP For Latin. America, the degree of risk based oil birth weight is probably as follows: ` This retrospective study was undertaken to determine the number of babies at risk of ROP born in Paraguay during a one year period.

PakMediNet -Pakistan's largest Database of Pakistani Medical Journals - http://www.pakmedinet.com