Prevalence of Threshold Retinopathy of Prematurity in Infants Screened at a Tertiary Care University–Based Hospital

Abstract

Abstract: : Purpose: Prevalence rates of retinopathy of prematurity (ROP) vary widely in published reports. The purpose of this study is to determine the prevalence of threshold ROP requiring laser treatment over a 4 ½ year period at a Tertiary care University–based hospital. Methods: A retrospective chart review was performed on all premature infants who received ROP screening eye exams over a 54–month period from May 1998 to November 2002. All infants with a birthweight of less than 1500 grams or gestational age of 30 weeks or less were screened. Prevalence rates of threshold ROP requiring laser treatment were determined as a function of gestational age and birthweight. Results: Out of a total of 418 infants screened, 18 infants (4.31%) developed threshold ROP requiring laser photocoagulation. The average birthweight and gestational age of infants with threshold ROP was 776 grams and 25.9 weeks, respectively, compared with 955 grams and 27.1 weeks for non–threshold infants. For infants less than 750 grams, 9 out of 133 (6.77%) developed threshold ROP. For infants weighing 751–1000 grams, 5 out of 125 (4.00%) developed threshold ROP. For infants weighing 1001–1250 grams, 2 out of 93 (2.15%) developed threshold ROP. No infants greater than 1050 grams or over 28 weeks gestational age developed threshold ROP. Conclusions: A prevalence rate of 4.30% was found for threshold ROP in the screened infant population. Lower birth weight correlated with an increased prevalence of threshold ROP, consistent with previous reports. These results support the current recommendations for ROP screening eye exams to be performed in premature infants with a birthweight of less than 1500 grams or with a gestational age of 30 weeks or less. Lowering the birth weight screening limit to 1250 grams would have reduced the number of infants requiring screening by 10%, while also lowering the gestational age limit to 28 weeks would have reduced the number of infants requiring screening by 16%.

Keywords: retinopathy of prematurity • clinical (human) or epidemiologic studies: risk factor assessment • retina