Abstract
Abstract: :
Purpose: To study the natural history data from the Loma Linda University (LLU) NICU to determine if initial birth weight (BW) and gestational age (GA) may be used to predict the appropriate timing of initial eye exams in infants at risk for retinopathy of prematurity (ROP). Current screening criteria at LLU involves an initial examination of all infants with BW < 1000gms at six wks and infants 1000–1500gms at 4 wks post natal age (PNA). Recently published natural history data form the CRYO–ROP and LIGHT–ROP studies recommend initial screening eye exams at 31 wks post–menstrual age or 4 wks PNA, whichever is later. Methods: We performed a retrospective chart review of all infants examined at the LLU NICU in the year 2002 for possible ROP. A total of 145 infants were examined. Variables evaluated in this abstract include BW, GA, post conceptional age (PCA) at exam, ROP stage and zone, and the presence of plus disease. Attention was focused on initial onset of any ROP and development of pre–threshold ROP. Pre–threshold ROP was defined as any ROP in Zone I, Zone II Stage II with plus disease, and Zone II Stage III with or without plus disease which did not necessitate laser treatment. Results: Of the 145 infants examined, 86 developed ROP (59.3%). Infants with ROP were segregated into groups via initial BW. The incidence of any ROP developing was 32/37 (86.5%) for BW < 750gms, 34/41 (83%) for BW 750–1000gms, and 20/67 (29.9%) for BW> 1000gms. Further analysis was done to determine the average GA and PCA at initial diagnosis of ROP. Infants with BW < 750gms had a mean GA of 24.75 wks and a mean PCA of 34.63 wks, BW 750–1000gms had a mean GA of 26.42 wks and a PCA of 35.27 wks, BW > 1000gms mean GA was 27.85 wks and mean PCA was 35.9 wks. Only six infants had a diagnosis of Zone I ROP at initial diagnosis, two with BW > 1000 and the rest < 750 gms. Pre–threshold ROP was diagnosed at a mean PNA of 9.9 wks for infants BW < 750gms, 9.3 wks for infants BW 750–1000gms, and 8.1 wks for infants BW > 1000gms. Only five infants met our pre–threshold ROP criteria at six weeks PNA, one necessitating laser treatment. Conclusion: In our patient population, we conclude that the initial screening exam can be safely delayed until 6 wks PNA. Although this deviates from our present criteria, delay of the initial screening exam to 6 weeks still allows for the appropriate detection and treatment of clinically relevant ROP while decreasing unnecessary exams and stress to the infant.
Keywords: retinopathy of prematurity • retinal neovascularization • clinical (human) or epidemiologic studies: prevalence/incidence