Abstract
Abstract: :
Purpose:To study the epidemiology of retinal anatomical outcomes of twins who underwent screening examinations for retinopathy of prematurity (ROP) at The University of Chicago Hospitals (UCH). Methods:We conducted a retrospective chart review of 120 eyes from 30 sets of twins screened and examined for ROP at the UCH, between July 2002 and October 2003. Information gathered for each patient included: gestational age at birth, birth weight, timing of first examination, Zone and Stage of disease at initial and worse examinations, and age at full vascularization. Results:We examined 120 eyes of 60 twins. The mean gestational age at birth was 31 weeks (range 25 – 37 weeks). The mean birth weight was 1518 grams (range 412 – 3035 grams). The average age at first examination was 34 weeks (range 29 – 40 weeks). At initial examination, most patients were noted to be in Zone II, Stage 0 (range Zone II – III, Stage 0 – 2). The average age when first fully vascularized was 42 weeks (range 37 – 54). The 60 patients were then divided into 2 groups: Group 1 – those who progressed to Stage 1 or worse, and Group 2 – those who remained at Stage zero throughout the examination period. Results for Group 1 which included 17/60 (28%) patients are as follows: average gestational age at birth was 28 weeks (range 25 – 35 weeks), average birth weight was 1089 grams (range 412 – 2425 grams). The average age when first fully vascularized was 46 weeks. Three patients required laser therapy for Stage 3 ROP. One went on to require vitrectomy for Stage 4 disease in one eye. Of the 17 patients, 10 are twin pairs. The remaining 7/17 (41%) had twin siblings who did not develop ROP. Group 2 results are as follows: total of 43/60 (72%) patients, average gestational age at birth was 32 weeks (range 26 – 37 weeks), average birth weight was 1688 grams (range 878 – 3035 grams). The average age when first fully vascularized was 41 weeks. Conclusions:There were 60 patients in the study, from 30 twin pairs. Of these, Group 1 was identified as progressing to develop Stage 1 or worse ROP, while Group 2 remained at Stage zero throughout the examination period. Group 1 is noted to have a lower gestational age at birth and lower birth weight when compared to Group 2. Furthermore, patients in Group 1 took longer, on average, reach complete vascularization. This study suggests that like patients born as single births, twins born at a lower gestational age and lower birth weight, have a higher likelihood of progression of ROP, and a longer interval prior to reaching complete vascularization.
Keywords: retinopathy of prematurity • clinical (human) or epidemiologic studies: natural history • clinical (human) or epidemiologic studies: outcomes/complications