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Query: UMLS:C0728731 (prematurity)
 7,134 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of oxygen in the immature or incompletely vascularized retina are conveniently divided into an initial vasoconstrictive and obliterative stage and a secondary vasoproliferative response that occurs after removal of the subject from an enriched oxygen environment. Vasoproliferation starts at the zone of perfused and nonperfused retina. The incompletely vascularized retina is uniquely responsive to these oxygen-induced changes. After vascularization is complete and the retinal vessels reach the ora, the susceptibility to hyperoxia disappears. The vessels in the temporal periphery of the retina have a peculiar susceptibility to the primary and secondary effects of hyperoxia on the immature retina. Ophthalmoscopic examination of the temporal periphery therefore should always be done carefully in the premature infant or in older individuals giving a history of prematurity. The indirect ophthalmoscope provides the most satisfactory instrument for examination. The incidence of retrolental fibroplasia has been greatly reduced following the incrimination of oxygen as its principal cause. Further studies are still required to determine precise blood oxygen levels that are safe for the premature retina and to discover other factors that may play a role in the pathogenesis or RLF.
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PMID:The role of oxygen in retrolental fibroplasia. 107 6

The effect of blood transfusion on the occurrence of RLF was evaluated in 58 infants who weighed less than 1001 g at birth (Group I) and 70 oxygen treated infants of various birth weights (Group II). Although there was no significant difference between Group I infants with or without exchange transfusion as to birth weight, gestational age, duration of oxygen therapy, peak Pa02's, or multiple births, there was a significantly increased incidence of pre-retrolental fibroplasia in transfused over non-transfused Group II infants. When Group II infants were stratified for prematurity and oxygen duration, this difference persisted in those not already at risk for RLF. This increased incidence of retinopathy in transfused infants suggests that blood transfusion may be a risk factor in the pathogenesis of RLF.
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PMID:Blood transfusion: a possible risk factor in retrolental fibroplasia. 689 73

Re-examination of corrected visual acuity was done in 137 18-year-old Danes, who were originally examined at the age of 10 years, as part of a study of sequels to low birth weight (LBW) (Fledelius 1976). Median values indicate that most adolescents are able visually to discriminate considerably above the customary 6/6 limit. As compared with low-birth-weighters (n=70), full-terms (n=67) show a significantly higher cumulated visual acuity score. Similarly, binocular median visual acuities are 1.2 (LBW) and 1.4 (in FT). The difference is neither explained by the ex-prematures' higher frequency of heterotropia, nor by their (minor) share of eyes with subnormal vision. The latter occurred especially in the subgroup of 'myopia of prematurity'. The exceptional cases with RLF-blindness were discarded from follow-up. Concerning visual acuity, the previously reported lagging behind of ex-prematures in childhood has proven to be not only a temporary delay, but a permanent (adult) feature.
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PMID:Ophthalmic changes from age of 10 to 18 years. A longitudinal study of sequels to low birth weight. II. Visual acuity. 721 Dec 84