[Analysis of retinopathy of prematurity with birth weight higher than 2 kg in Xi'an area].

OBJECTIVE: To survey popularity and clinical characteristics of retinopathy of prematurity (ROP) in Xi'an area in infants with birth weight over 2 000 g.

METHODS: Retrospective case-series study. ROP screening data of 1 866 infants was collected and reviewed from Department of Ophthalmology, Xijing Hospital from January 2008 to December 2012.One thousand eight hundreds and sixty-six cases (3 732 eyes) with 1 166 males and 700 females were examined. Their gestation age was (34 ± 4) weeks (24-46 weeks), and birth weight was (2 106 ± 743) g (730-4 900 g) . All the related information about infants accepted examinations was screened, inquired and recorded carefully, such as gestation age, birth weight, continuous inhalation of oxygen and respirator applied records.Whether they had asphyxia, hypoxic-ischemic encephalopathy, acute respiratory distress syndrome, pneumonia, jaundice, anemia, congenital heart disease was also recorded. Moreover the physical situations of maternity including gestational hypertension, premature rupture of amniotic fluid, placenta abruption and placenta previa were also assessed. Percentiles (P90 and P95) of birth weight in ROP infants were calculated. Birth weight over 2 000 g in ROP patients was identified as high birth weight, whereas birth weight less than 2 000 g was confirmed as low birth weight. Clinical characteristics were compared in the two groups. T-test, Chi-square test, and Fisher's exact test were used for this study.

RESULTS: In all the infants examined, 243 cases were screened out as ROP patients with different stages. The positive rate was 13.0%. Among them, 96 cases needed to be treated which was 39.5%. They were severer than pre-threshold Type I. P90 and P95 of birth weight percentiles of these ROP infants were 2 060 g and 2 240 g.If birth weight less than 2 000 g was confirmed as screen guideline, 9.9% patients might be excluded. There were 24 ROP infants whose birth weight were over 2 000 g with gestation age of (33 ± 3) weeks (28-40 weeks) , and with birth weight of (2 411 ± 354) g (2 100-3 300 g) .Six of them needed to be treated, which was 6.3%. Compared with ROP infants with low birth weight, they had almost same stages and risk factors.

CONCLUSIONS: High birth weight ROP infants occupies some proportions in Xi'an area. They has no special characteristics or severity compared with low birth weight ones.