Prevalence and course of strabismus through age 6 years in participants of the Early Treatment for Retinopathy of Prematurity randomized trial.

PURPOSE: To present strabismus data for children who participated in the Early Treatment for Retinopathy of Prematurity (ETROP) randomized trial. METHODS: The prevalence of strabismus, categorized as present or absent, was tabulated for all children with history of high-risk prethreshold retinopathy of prematurity (ROP) who participated in the ETROP randomized trial and were examined at 9 months to 6 years of age. Relationships among strabismus and demographic measures, eye characteristics, and neurodevelopmental factors were analyzed. RESULTS: Among the 342 children evaluated at 6 years, the prevalence of strabismus was 42.2%. Even with favorable acuity scores in both eyes, the prevalence of strabismus was 25.4%, and with favorable structural outcomes in both eyes the prevalence of strabismus was 34.2%. Of children categorized as visually impaired as the result of either ocular or cerebral causes, 80% were strabismic at the 6-year examination. Of 103 study participants who were strabismic at 9 months, 77 (74.8%) remained so at 6 years. Most strabismus was constant at both the 9-month (62.7%) and the 6-year examination (72.3%). After multiple logistic regression analysis, risk factors for strabismus were abnormal fixation behavior in one or both eyes (P < 0.001), history of amblyopia (P < 0.003), unfavorable structural outcome in one or both eyes (P = 0.025), and history of anisometropia (P = 0.04). Strabismus surgery was performed for 53 children. By 6 years, the cumulative prevalence of strabismus was 59.4%. CONCLUSIONS: Most children with a history of high-risk prethreshold ROP develop strabismus at some time during the first 6 years of life.

Retinopathy of prematurity in infants weighing less than 500 grams at birth enrolled in the early treatment for retinopathy of prematurity study.

PURPOSE: To describe patient characteristics, classification, and onset of prethreshold retinopathy of prematurity (ROP), and ocular findings at 6 months corrected age in infants with birth weights <500 g who were enrolled in the Early Treatment for Retinopathy of Prematurity (ETROP) Study. DESIGN: Multicenter randomized clinical trial. PARTICIPANTS: Sixty-three infants with birth weights <500 g who developed ROP and were enrolled in the ETROP Study. METHODS: Infants <1251 g at birth were logged at 26 study centers from October 1, 2000, to September 30, 2002, and underwent examinations for ROP. Infants who developed ROP and whose parents/legal guardians consented were enrolled in the ETROP Study. Infants who developed high-risk prethreshold ROP were randomized; 1 eye was treated early with peripheral retinal ablation and the other eye was managed conventionally, or, in asymmetric cases, the high-risk eye was randomized to early peripheral retinal ablation or conventional management. All eyes reaching prethreshold ROP were examined when infants reached 6 months corrected age. MAIN OUTCOME MEASURES: Retinopathy of prematurity incidence, characteristics, and ocular findings among participants. RESULTS: Thirty-four infants reached prethreshold or worse severity in 1 or both eyes. Retinopathy of prematurity was located in zone I in 43.3% of all prethreshold eyes, and plus disease was present in 46.7%. Median postmenstrual age for diagnosis of all prethreshold ROP was 36.1 weeks, but earlier (35.1 weeks) for eyes that developed high-risk prethreshold ROP. In the 27 surviving infants with prethreshold ROP, ophthalmic examination at 6 months corrected age showed a normal posterior pole in 22 (81.5%), a favorable structural outcome with posterior pole abnormalities in 4 (14.8%), and an unfavorable structural outcome (stage 4B) in 1 (3.7%). One infant developed amblyopia, 4 infants developed nystagmus, 4 infants developed strabismus, and 8 infants developed myopia >-5.00 diopters. CONCLUSIONS: This is the first report on characteristics of prethreshold ROP in infants with birth weights <500 g. These infants are at high risk for developing prethreshold ROP, although many initially achieve a favorable structural outcome. They are at risk of developing strabismus, nystagmus, high myopia, and abnormal retinal structure and should therefore receive continued long-term follow-up. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Severe visual impairment in children with mild or moderate retinal residua following regressed threshold retinopathy of prematurity.

PURPOSE: To describe clinical features of patients from the Cryotherapy for Retinopathy of Prematurity (CRYO-ROP) trial who, after developing severe ROP in infancy, had minimal or moderate retinal residua in at least one eye but a visual acuity of worse than 20/200 in both eyes at the 10 year examination. METHODS: Data from the 10 year CRYO-ROP Trial follow-up exams were evaluated to identify all patients with retinal outcomes of no retinopathy of prematurity (ROP) residua, straightened temporal vessels, or macular heterotopia in at least one eye, but visual acuity less than 20/200 in both eyes. Presence of optic atrophy, nystagmus, and optic disk cupping and developmental survey results were examined. RESULTS: Of 247 patients examined at 10 years, 16 met our inclusion criteria. At the last age at which the following data were recorded, seven had optic atrophy at the 10 year examination, one had optic disk cupping >0.5 at the 5(1/2) year examination, and eight had nystagmus under binocular conditions at the 24 month examination. Nine patients had a below-normal developmental test score on the Functional Independence Measure for Children (WeeFIM). After clinical data interpretation, we concluded that the predominant cause of visual impairment was postgeniculate disease in five patients, ROP in six patients, and combined anterior and posterior visual pathway disease in two patients; in three patients data were insufficient to make a determination. CONCLUSIONS: Poor visual function with mild to moderate retinal residua of severe ROP in at least one eye is relatively rare. In such patients, anterior, posterior, or combined visual pathway disease can occur.

15-year outcomes following threshold retinopathy of prematurity: final results from the multicenter trial of cryotherapy for retinopathy of prematurity.

OBJECTIVE: To report the ocular structure and visual acuity outcomes at age 15 years, and the incidence of retinal detachment between 10 and 15 years of age, for patients in the Multicenter Trial of Cryotherapy for Retinopathy of Prematurity (CRYO-ROP). METHODS: Subjects were 254 survivors from 291 preterm children with birth weights less than 1251 g and severe (threshold) retinopathy of prematurity (ROP) in one or both eyes, who participated in the CRYO-ROP trial. At age 15 years, unfavorable ocular structure was posterior retinal fold or worse judged by study-certified ophthalmologists. Unfavorable distance visual acuity was 20/200 or worse measured by study-certified testers using Early Treatment of Diabetic Retinopathy Study recognition acuity charts. RESULTS: Thirty percent of treated eyes and 51.9% of control eyes (P<.001) had unfavorable structural outcomes. Between 10 and 15 years of age, new retinal folds, detachments, or obscuring of the view of the posterior pole occurred in 4.5% of treated and 7.7% of control eyes. Unfavorable visual acuity outcomes were found in 44.7% of treated and 64.3% of control eyes (P<.001). CONCLUSION: The benefit of cryotherapy for treatment of threshold ROP, for both structure and visual function, was maintained across 15 years of follow-up. New retinal detachments, even in eyes with relatively good structural findings at age 10 years, suggest value in long-term, regular follow-up of eyes that experience threshold ROP.

Risk analysis of prethreshold retinopathy of prematurity.

OBJECTIVE: To present a new multifactorial algorithm to integrate important risk factors for unfavorable retinal outcome in eyes that reached prethreshold retinopathy of prematurity (ROP) in the Cryotherapy for Retinopathy of Prematurity (CRYO-ROP) study. A computerized risk model (RM-ROP2) was developed from this algorithm to identify high-risk prethreshold eyes for enrollment in the Early Treatment for Retinopathy of Prematurity randomized trial. METHODS: Data were analyzed from 613 eyes (1 eye per infant) in the natural history cohort of the Multicenter Trial for Cryotherapy for Retinopathy of Prematurity. These eyes were selected from infants in whom 1 or both eyes progressed to prethreshold ROP. Eyes that progressed to threshold ROP and were randomized to cryotherapy were excluded from this study, but control eyes that reached threshold ROP were included. The course of ROP for 1 prethreshold eye for each infant was tracked until the evaluation of its structural outcome at 3 months' postterm. Tables present structural outcome by selected risk characteristics. A multiple logistic risk model is used to summarize the combined effect of all of these known prognostic risk factors as they relate to structural outcome. RESULTS: Eyes were classified by predicted outcome into 10 risk categories, lowest to highest. Both the observed and predicted outcomes in each category showed an increasingly unfavorable outcome when viewed from lowest to highest risk. Prethreshold ROP eyes were then divided into 2 groups, high-risk, eyes (risk, 0.15-1.0) and low-risk eyes (risk, <0.15). High-risk eyes had an unfavorable outcome of 36% at 3 months' postterm; whereas, only 5% of the low-risk eyes had an unfavorable outcome. CONCLUSION: The model effectively identifies prethreshold ROP eyes that have a relatively high risk and eyes that have a lower risk of an unfavorable structural outcome at 3 months.

Evidence-based screening criteria for retinopathy of prematurity: natural history data from the CRYO-ROP and LIGHT-ROP studies.

BACKGROUND: The Multicenter Trial of Cryotherapy for Retinopathy of Prematurity (CRYO-ROP) demonstrated the efficacy of treatment for threshold ROP and indicated the need for worldwide ROP screening. Previous guidelines for ROP screening have been largely based on clinical impression; we can now develop evidence-based screening recommendations. OBJECTIVE: To define the appropriate ages and retinal ophthalmoscopic signs that determine when to commence and conclude acute phase ROP screening. DESIGN: Analysis of data from 2 prospective randomized controlled trials: CRYO-ROP (January 1, 1986, to November 30, 1987) and Light Reduction in ROP (LIGHT-ROP) (July 1, 1995, to March 31, 1997). SETTING: Neonatal intensive care units in 23 study centers in the United States for CRYO-ROP and 3 centers for LIGHT-ROP. PATIENTS: Eyes were examined sequentially in 4099 infants with birth weight less than 1251 g (CRYO-ROP study) and in 361 infants with birth weight less than 1251 g and gestational age less than 31 weeks (LIGHT-ROP study). RESULTS: In 99% of infants, retinal conditions indicating a risk of poor outcome were not observed before 31 weeks' postmenstrual age or 4 weeks' chronologic age. Signs indicating that the risk of visual loss from ROP was minimal or had passed were the infant's attainment of 45 weeks' postmenstrual age without the development of prethreshold ROP or worse, progression of retinal vascularization into zone III without previous zone II ROP, and full vascularization. CONCLUSIONS: The initial eye examination should be conducted by 31 weeks' postmenstrual age or 4 weeks' chronologic age, whichever is later. Acute phase ROP screening can be discontinued when any of the 3 signs is present, indicating that the risk of visual loss from ROP is minimal or passed.