Risk analysis of prethreshold retinopathy of prematurity

Pathophysiology of Retinopathy of Prematurity

Retinopathy of prematurity (ROP) is a complex disease involving development of the neural retina, ocular circulations, and other organ systems of the premature infant. The external stresses of the ex utero environment also influence the pathophysiology of ROP through interactions among retinal neural, vascular, and glial cells. There is variability among individual infants and presentations of the disease throughout the world, making ROP challenging to study. The methods used include representative animal models, cell culture, and clinical studies. This article describes the impact of maternal-fetal interactions; stresses that the preterm infant experiences; and biologic pathways of interest, including growth factor effects and cell-cell interactions, on the complex pathophysiology of ROP phenotypes in developed and emerging countries.

Retinopathy of Prematurity: Advances in the Screening and Treatment of Retinopathy of Prematurity Using a Single Center Approach

PURPOSE

To focus on the longitudinal evaluation of high-risk infants for the development of retinopathy of prematurity (ROP) at a single tertiary neonatal intensive care unit (NICU), and to evaluate evolving demographics of ROP and the transition of treatment-warranted disease.

DESIGN

Retrospective cohort study.

METHODS

A consecutive retrospective review was performed of all infants screened for ROP between 1990 and 2019 at the Jackson Memorial Hospital neonatal intensive care unit. All inborn infants meeting a birth criteria of <32 weeks' gestational age (GA) or a birthweight (BW) of 1500 g were included. Longitudinal demographic, diagnostic, and treatment data were reported.

RESULTS

Between January 1, 1990, and June 20, 2019, a total of 25,567 examinations were performed and 7436 patients were included. Longitudinal trends over 3 decades demonstrated a decreasing incidence of ROP (P < .05). Although the mean BW and GA increased over 3 decades, patients with ROP demonstrated lower BW and GA over time (P < .05). The prevalence of micro-premature infants (as defined by BW <750 g) continues to rise over time. Micro-preemies demonstrated increasing severity of zone and stage grading, plus disease, and propensity to require treatment (P < .05). The rate of progression of ROP to stage 4 and 5 disease has decreased over time, and there has been an associated increased adoption of intravitreal bevacizumab as primary and salvage therapy.

CONCLUSIONS

Understanding the evolution of ROP infants and treatment over time is critical in identifying high-risk infants and in reducing the incidence of severe-stage ROP. Micro-prematurity is one of the significant risk factors for treatment-warranted ROP that continues to increase as neonatal care improves. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Aflibercept for Retinopathy of Prematurity: A Systematic Review and Meta-Analysis

BACKGROUND AND OBJECTIVE

To determine the effectiveness of aflibercept in retinopathy of prematurity (ROP).

PATIENTS AND METHODS

We performed a systematic review and meta-analysis of proportions from the literature in PubMed and Cochrane Library using search terms related to the use of aflibercept in ROP. Studies in non-preterm infants or that did not use aflibercept as the initial treatment were excluded. Risk of bias was assessed by the ROBINS-I (Risk Of Bias in Non-randomized Studies of Interventions) tool.

RESULTS

We identified six case series. Collectively, 218 eyes were treated with aflibercept for ROP. We found an average 97% (95% confidence interval [CI], 93% to 99%) regression rate with aflibercept and an average 16% (95% CI, 5% to 41%) recurrence rate. With the exception of one outlier study, these numbers are similar to previous reports using anti-vascular endothelial growth factor (VEGF) agents in ROP.

CONCLUSIONS

Aflibercept holds promise for use in ROP and has been demonstrated to be efficacious in six case series. Randomized, controlled clinical trials appear warranted to compare aflibercept with other anti-VEGF agents. [Ophthalmic Surg Lasers Imaging. 2021;52:673-681.].

Neurodevelopmental outcomes following bevacizumab treatment for retinopathy of prematurity: a systematic review and meta-analysis

OBJECTIVE

To systematically review the studies exploring the association between bevacizumab and neurodevelopmental outcomes.

METHODS

Embase, Medline, CINAHL, and Cochrane Library databases were searched for studies examining neurodevelopmental outcomes of preterm infants treated with bevacizumab compared to laser ablation or cryotherapy for severe retinopathy of prematurity (ROP).

RESULTS

Thirteen studies (clinical trial = 1; cohort studies = 12) were included. Random-effects model meta-analysis showed significant increased odds of cognitive impairment associated with bevacizumab treatment on both unadjusted (unadjusted odds ratio (OR) 1.61; 95% confidence interval (CI) 1.12, 2.30) and adjusted analyses (adjusted OR 1.90; 95% CI 1.22, 2.97). Infants treated with bevacizumab for severe ROP had significantly lower Bayley-III cognitive (mean difference (MD) -1.66; 95% CI -3.21, -0.12), and language composite scores (MD -5.50; 95% CI -8.24, -2.76) compared to infants treated with laser ablation or cryotherapy.

CONCLUSION

Bevacizumab treatment for severe ROP is associated with increased risk of cognitive impairment and lower cognitive and language scores in preterm infants.

Tutorial on Biostatistics: Receiver-Operating Characteristic (ROC) Analysis for Correlated Eye Data

Purpose: To demonstrate methods for receiver-operating characteristic (ROC) analysis of correlated eye data.Methods: We applied the Obuchowski's nonparametric approach and cluster bootstrap for estimating and comparing the area under ROC curve (AUC) between different sets of predictors to three datasets with varying inter-eye correlation.Results: In an optic neuritis (ON) study of 152 eyes (80 patients), the AUC of optical coherence tomography retinal nerve fiber layer thickness for diagnosing ON (inter-eye kappa = 0.13) was 0.71 [95% confidence interval (95% CI): 0.622, 0.792] from the naïve approach without accounting for inter-eye correlation was narrower than from nonparametric (95% CI: 0.613, 0.801) or cluster bootstrap (95% CI: 0.614, 0.797) approaches. In an analysis of 198 eyes (135 patients), the baseline Age-related Eye disease Study scale predicted 5-year incidence of advanced age-related macular degeneration (inter-eye kappa = 0.23) with AUC of 0.72. The 95% CI from the naïve approach was slightly narrower (0.645, 0.794) than from the nonparametric (0.641, 0.797) or cluster bootstrap (0.641, 0.793) approaches. In an analysis of 1542 eyes (771 infants), birthweight and gestational age predicted treatment-requiring retinopathy of prematurity (inter-eye kappa = 0.98) with AUC of 0.80. Furthermore, the 95% CI from the naïve approach was narrower (0.769, 0.835) than from the nonparametric (0.755, 0.848) or cluster bootstrap (0.755, 0.845) approaches. 95% CIs for AUC differences between different models were narrower in the naïve approach than the nonparametric or cluster bootstrap approaches.Conclusion: In ROC analysis of correlated eye data, ignoring inter-eye correlation leads to narrower 95% CI with underestimation dependent on magnitude of inter-eye correlation. Nonparametric and cluster bootstrap approaches properly account for inter-eye correlation.

A Good Way to Reduce Screening for Retinopathy of Prematurity: Development of the ROP Model in a China Preterm Population

Importance: Retinopathy of prematurity (ROP) is a preventable cause of blindness in children. Without treatment, more than 45% of eyes may suffer permanent vision loss. Current ROP screening guidelines, which include a range of birth weights (BWs) and gestational ages (GAs), may require screening many low-risk preemies who might develop severe ROP. Method: All high-risk infants in the neonatal intensive care unit (NICU) of the First Affiliated Hospital of Zhengzhou University from 2017 to 2021 were included in this retrospective cohort study. Each of the 27 candidate risk factors was evaluated in univariate analysis and adjusted for known risk factors (i.e., GA and BW). The significant results were analyzed in a backward selection multivariate logistic regression model. Receiver operating characteristic (ROC) curves and a nomogram were drawn. Results: The study included 2,040 infants who underwent ROP screening. The weight gain rate [OR, 2.65; 95% confidence interval (CI), 1.49-1.21 ≤ 12 g/d vs. > 18 g/d; P = 0.001], blood transfusion (OR, 2.03; 95% CI, 1.14-3.64; P = 0.017), invasive mechanical ventilation (OR, 1.74; 95% CI, 1.15-2.66; P = 0.009) and N-terminal segment of pro-B-type natriuretic peptide (NT-proBNP) ≥ 25,000 ng/L (OR, 1.51; 95% CI, 1.00-2.28; P = 0.048) were four new statistically independent risk factors in addition to GA and BW. The area under the curve (AUC) of the final multivariate model was 0.90 (95% CI, 0.88-0.92; P < 0.001). Conclusions and Relevance: These findings add to our understanding of ROP screening because they include all eligible infants rather than only high-risk infants, as in previous studies. Under the control of BW and GA, low weight gain rate, increased number of blood transfusion, invasive mechanical ventilation and NT-proBNP ≥ 25,000 ng/L were "new" statistically independent risk factors for ROP. The ROP risk can be calculated manually or represented by a nomogram for clinical use.

Perinatal Risk Factors for the Retinopathy of Prematurity in Postnatal Growth and Rop Study

Objective: To evaluate perinatal risk factors for retinopathy of prematurity (ROP), in a large, broad-risk cohort of premature infants. Study design: Secondary analysis of data from the Postnatal Growth and ROP (G-ROP) Study, a retrospective cohort study of infants undergoing ROP examinations at 29 North American hospitals in 2006-2012. Results: Among 7483 infants, 3224 (43.1%) had any ROP and 931 (12.4%) had severe ROP (Type 1 or 2 ROP). In multivariable logistic regression analysis, significant risk factors for any ROP were lower birth weight (BW, odds ratio (OR) = 5.2, <501 g vs. >1250 g), younger gestational age (GA, OR = 32, <25 vs. >29 weeks), 1-min Apgar score <4 (OR = 1.2), race (OR = 1.6, White vs. Black), outborn (OR = 1.5), and delivery room intubation (OR = 1.3); and for severe ROP were lower BW (OR = 20, <501 g vs. >1250 g), younger GA (OR = 30, <25 vs. >29 weeks), male (OR = 1.5), Hispanic ethnicity (OR = 1.8), race (OR = 1.6, White vs. Black), outborn (OR = 1.6), and delivery room intubation (OR = 1.6). Together, these factors predicted well for any ROP (area under ROC curve (AUC) = 0.87) and severe ROP (AUC = 0.89), but BW and GA were the dominant factors for ROP (AUC = 0.86) and severe ROP (AUC = 0.88). Conclusions: Based on the largest report to date with detailed ROP data from infants meeting current screening guidelines, ROP risk is predominantly determined by the degree of prematurity at birth, with other perinatal factors contributing minimally.

Vessel Tortuosity Cutoff Values Using the Modified ROPtool May Predict Need for Treatment in Retinopathy of Prematurity

BACKGROUND AND OBJECTIVE

To quantify vessel tortuosity among infants with retinopathy of prematurity (ROP).

PATIENTS AND METHODS

This was a retrospective study including 61 RetCam images from 33 infants. The laser treatment (LT) group included 17 infants who underwent laser for ROP. The no-treatment (NT) group included 16 infants. The modified ROPtool was used to calculate mean vessel tortuosity (MVT) and highest vessel tortuosity (HVT) for the participants and for the standard plus disease photograph from the Early Treatment for Retinopathy of Prematurity (ETROP) study.

RESULTS

The median MVT was 1.226 versus 1.056 for the LT and NT groups, respectively (P < .001). The median HVT was 1.346 versus 1.088 (P < .001). An MVT of 1.124 was 96.7% sensitive and 100% specific for identifying infants with treatment-requiring ROP. Both MVT and HVT cutoff values correctly captured plus disease in the standard ETROP trial photograph.

CONCLUSION

The modified ROPtool can be used to identify infants who have treatment-requiring ROP with a high level of sensitivity and specificity. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:215-220.].

Heated and Humidified High Flow Nasal Canal Oxygen Supplementation as an Effective Treatment for High-Risk Prethreshold Retinopathy of Prematurity

PURPOSE

We evaluated the effect of heated and humidified high flow nasal cannula (HFNC) oxygen supplementation to promote regression of high-risk prethreshold retinopathy of prematurity (Hrp-ROP) in premature infants.

METHODS

A prospective study was designed for Hrp-ROP premature infants undergoing HFNC oxygen supplementation to evaluate its capacity for promoting ROP regression. Statistical analysis with independent samples t-tests and Fisher's exact tests was performed, and forest plots were created to illuminate the odds ratio of factors associated with ROP regression as well as HFNC complication.

RESULTS

With HFNC, 16 of 20 infants with Hrp-ROP experienced regression, which is higher than the natural regression rate, comparing to the data in other clinical trials (52% in the STOP-ROP study). Among four progressed ROP infants, three were treated with laser photocoagulation and one received anti-vascular endothelial growth factor (VEGF) therapy. The anti-VEGF treated patient encountered ROP recurrence one month after injection and was treated successfully by additional HFNC. No significant differences between regression and progression cases were found for gestational age, birth weight, plus disease, age for HFNC, and SO2 level. The blood saturation of oxygen was significantly increased after HFNC (92 ± 1.3% vs. 96.6 ± 0.8%, P < 0.001), while the heartbeat rate (HR) and respiratory rate (RR) had no significant differences (139.4 ± 5.4 vs. 140.6 ± 4.5, P = 0.409; 37.7 ± 2.3 vs. 37 ± 1.9, P = 0.330, respectively). The main complication of HNFC was nasal erosion associated with airflow and HFNC duration (RR = 1.8, P = 0.026; RR = 1.8, P = 0.026, respectively).

CONCLUSIONS

The progression of Hrp-ROP was significantly decreased after HFNC oxygen supplementation with slightly tolerable complication.

TRANSLATIONAL RELEVANCE

Our study suggests that HNFC can be an alternative treatment for Hrp-ROP, potentially avoiding the problems caused by other invasive treatment.

The severity and associated comorbidities of retinopathy of prematurity among micro-premature infants with birth weights less than 750 grams

OBJECTIVES

To evaluate the characteristics and comorbidities associated with ROP in micro-premature infants and their results.

METHODS

This is a retrospective chart review involving multiple intensive care units in Central Texas from 2011 to 2016. Infants were included if birth weight (BW) was≤750 g with confirmed ROP by the International Classification of Retinopathy of Prematurity (ICROP). Neonates were examined and treated with laser ablation or intravitreal ranibizumab (IVR) with subsequent laser treatment, guided by fluorescein angiography, if met treatment criteria defined as type 1 ROP by the Early Treatment of Retinopathy of Prematurity standards. Time to regression was defined clinically. Results were analyzed using chi-squared test.

RESULTS

100 neonates were included in the study. Mean BW was 599 grams and mean gestational age was 24.2 weeks. Forty neonates were classified as type 1 ROP and therefore required intervention; of them 21 received laser alone and 19 required IVR with subsequent laser. Only 2 patients received more than one IVR injection. None of the patients progressed to stage 4 or 5 ROP.

CONCLUSIONS

Despite such low birth weights, none of these neonates progressed to stage 4 or 5 ROP likely because of prompt examination and treatment with laser or with IVR and subsequent laser. IVR might serve as a bridge to laser in type 1 ROP allowing some retinal vessel development prior to definitive laser treatment.

Discordant retinopathy of prematurity in twin anemia-polycythemia sequence

We report the case of severe retinopathy of prematurity (ROP) in the donor twin with twin anemia-polycythemia sequence managed with the novel treatment of intrauterine blood transfusions. The fellow polycythemic twin was managed with intrauterine venesection and developed only mild ROP. Thus, despite intrauterine improvement of the twins' hemodynamic conditions, the risk of developing severe ROP remained in the donor twin.

PERIPHERAL AVASCULAR RETINA WITH DISK ANOMALY AND HIGH MYOPIA: A Novel Association in a Hereditary Isolated Ocular Disorder

PURPOSE

To describe a family pedigree with a previously undescribed association of autosomal dominantly inherited ocular abnormalities.

METHODS

Case series study performed on 15 family members. Examination included history taking, visual acuity, intraocular pressure, slit-lamp, gonioscopy, indirect ophthalmoscopy (10 members), fluorescein angiography (5 members), general examination and renal ultrasound (4 members), and hemoglobin electrophoresis for the proband and another member.

RESULTS

Family pedigree revealed autosomal-dominant inheritance. Visual acuity ranged from 6/36 to no light perception. Examination revealed rubeosis in 7 eyes and atrophia bulbi in 11 eyes. Indirect ophthalmoscopy for 11 eyes revealed evidence of an ocular triad of peripheral avascular retina, disk anomaly (cavitary optic disk anomaly or disk dysplasia), and tessellated fundus of high myopia. The authors also observed new vessels elsewhere with or without extensive subretinal exudations in 6 eyes. All patients with any residual vision (up to perception of light) had nystagmus. Four affected members underwent general examination, renal ultrasound, and serum creatinine level (to exclude papillorenal syndrome), and all were normal. Hemoglobin electrophoresis (to exclude sickle cell retinopathy) revealed within normal values.

CONCLUSION

To the authors' knowledge, the aforementioned ocular triad has not been previously described, in association, with an autosomal-dominant pattern of inheritance.

Current understanding and management of aggressive posterior retinopathy of prematurity

Aggressive posterior retinopathy of prematurity (ROP), previously referred to as “Rush disease”, is a rapidly progressive form of ROP. This form of ROP typically presents in very low birth weight babies of early gestational age. Historically, anatomical and functional outcomes have been poor with standard treatment. This review is designed to discuss current knowledge and treatment regarding this aggressive form of ROP. Recommendations regarding management of these difficult cases are detailed.

Predictors for the development of referral-warranted retinopathy of prematurity in the telemedicine approaches to evaluating acute-phase retinopathy of prematurity (e-ROP) study

IMPORTANCE

Detection of treatment-requiring retinopathy of prematurity (ROP) involves serial eye examinations. An ROP prediction model using predictive factors could identify high-risk infants and reduce required eye examinations.

OBJECTIVE

To determine predictive factors for the development of referral-warranted (RW) ROP.

DESIGN, SETTING, AND PARTICIPANTS

This multicenter observational cohort study included secondary analysis of data from the Telemedicine Approaches to Evaluating Acute-Phase Retinopathy of Prematurity Study. Infants included in the study had a birth weight (BW) of less than 1251 g.

EXPOSURES

Serial ROP examinations of premature infants who had 2 or more ROP examinations.

MAIN OUTCOMES AND MEASURES

Incidence of RW-ROP (defined as the presence of plus disease, zone I ROP, or ROP stage 3 or greater in either eye) and associations with predictive factors.

RESULTS

Among 979 infants without RW-ROP at first study-related eye examination (median postmenstrual age, 33 weeks; range, 29-40 weeks) who underwent at least 2 eye examinations, 149 (15.2%) developed RW-ROP. In a multivariate model, significant predictors for RW-ROP were male sex (odds ratio [OR], 1.80; 95% CI, 1.13-2.86 vs female), nonblack race (OR, 2.76; 95% CI, 1.50-5.08 for white vs black race and OR, 4.81; 95% CI, 2.19-10.6 for other vs black race), low BW (OR, 5.16; 95% CI, 1.12-7.20 for ≤500 g vs >1100 g), younger gestational age (OR, 9.79; 95% CI, 3.49-27.5 for ≤24 weeks vs ≥28 weeks), number of quadrants with preplus disease (OR, 7.12; 95% CI, 2.53-20.1 for 1-2 quadrants and OR, 18.4; 95% CI, 4.28-79.4 for 3-4 quadrants vs no preplus disease), stage 2 ROP (OR, 4.13; 95% CI, 2.13-8.00 vs no ROP), the presence of retinal hemorrhage (OR, 4.36; 95% CI, 1.57-12.1 vs absence), the need for respiratory support (OR, 4.99; 95% CI, 1.89-13.2 for the need for controlled mechanical ventilator; OR, 11.0; 95% CI, 2.26-53.8 for the need for high-frequency oscillatory ventilation vs no respiratory support), and slow weight gain (OR, 2.44; 95% CI, 1.22-4.89 for weight gain ≤12 g/d vs >18 g/d). These characteristics predicted the development of RW-ROP significantly better than BW and gestational age (area under receiver operating characteristic curve, 0.88 vs 0.78; P < .001).

CONCLUSIONS AND RELEVANCE

When controlling for very low BW and prematurity, the presence of preplus disease, stage 2 ROP, retinal hemorrhage, and the need for ventilation at time of first study-related eye examination were strong independent predictors for RW-ROP. These predictors may help identify infants in need of timely eye examinations.

Retinopathy of prematurity risk prediction for infants with birth weight less than 1251 grams

OBJECTIVE

To predict retinopathy of prematurity (ROP) exam findings among infants with birth weight <1251 g from 32-40 weeks postmenstrual age (PMA).

STUDY DESIGN

Secondary analysis of 3714 eye exams from 1239 infants.

RESULTS

The likelihood of developing type 1 ROP by 40 weeks PMA varied by gestational age (GA) (P < .001), from 33% for ≤25 weeks, 10% for 26 or 27 weeks, 4% for 28 or 29 weeks, and none for ≥30 weeks. By 40 weeks PMA, 51% with GA ≤27 weeks still needed subsequent exams. Previous exam findings, GA, and PMA were predictive of the development of type 1 ROP (area under the curve, 0.78) or mature retina (area under the curve, 0.85).

CONCLUSIONS

This analysis provides the opportunity for development of an ROP approach to estimate resource needs in the neonatal intensive care unit and to facilitate communication with families when planning discharge or transfer.

Risk factors for retinopathy of prematurity: insights from outlier infants

PURPOSE

To investigate the characteristics of outlier infants for insights into ROP risk.

METHODS

Chart data were collected from 1,354 infants screened for ROP at Weill Cornell Medical Center and Columbia University Medical Center. ROP exam results and clinical risk factors were recorded. The cohort was stratified by weight, highest ROP stage, and need for ROP treatment. Descriptive and correlational statistics were performed.

RESULTS

For the overall cohort, regression analysis found that birth weight (OR: 0.741 per 100 g; 95 % CI: 0.606, 0.905), gestational age at birth (OR: 0.563 per week; 95 % CI: 0.454, 0.697), multiple gestation (OR 2.02, 95 % CI: 1.15, 3.56), bronchopulmonary dysplasia (OR: 4.68, 95 % CI: 1.93, 11.35), and necrotizing enterocolitis (OR 2.80, 95 % CI: 1.40, 5.16) were independent risk factors for treatment-requiring ROP. Black race was found to be a protective factor for treatment-requiring ROP (OR 0.244, 95 % CI: 0.095, 0.626). Among 15 infants with BW <500 g, there were no significant differences in any clinical risk factors between the 12 (80 %) with ROP vs the three (20 %) without ROP. Similarly, among infants with BW >1500 g, the 17 (9 %) with ROP only differed from the 166 (91 %) without ROP with respect to a higher incidence of necrotizing enterocolitis among those with ROP (11.8 % vs 0 %).

CONCLUSIONS

Although known clinical risk factors were predictive of ROP stage and need for laser treatment in this cohort, they were not significantly associated with ROP at extremes of birth weight. This suggests that other clinical, maternal, or genetic factors may protect from or predispose to ROP.

Weight at first detection of retinopathy of prematurity predicts disease severity

OBJECTIVE

To investigate whether postnatal weight at first detection of retinopathy of prematurity (ROP) can predict preterm infants who will develop severe ROP warranting treatment.

DESIGN

This modern, population-based cohort included 147 infants born at gestational age (GA) <32 weeks in the Gothenburg region during 2011-2012 and screened for ROP at Sahlgrenska University hospital. GA, birth weight (BW), and weekly postnatal weight from birth until postmenstrual age (PMA) 40 weeks data were retrospectively retrieved. Birth weight SD scores (BWSDS) were calculated. ROP data, including first detected ROP stage, maximal ROP stage, ROP treatment, and PMA at first detected sign of ROP were also retrieved. Weight SDS (WSDS) at first ROP detection was calculated.

RESULTS

Stepwise multivariate logistic regression analysis revealed that the best fit-model of risk factors for developing severe ROP warranting treatment included; GA (OR=0.28, CI 95% 0.12 to 0.66, p<0.01) and WSDS at first ROP detection (OR=0.22, CI 95% 0.05 to 0.89, p<0.05).

CONCLUSIONS

Low weight and low WSDS at first ROP detection can be useful predictors for ROP warranting treatment.

A hybrid method in combining treatment effects from matched and unmatched studies

The most common data structures in the biomedical studies have been matched or unmatched designs. Data structures resulting from a hybrid of the two may create challenges for statistical inferences. The question may arise whether to use parametric or nonparametric methods on the hybrid data structure. The Early Treatment for Retinopathy of Prematurity study was a multicenter clinical trial sponsored by the National Eye Institute. The design produced data requiring a statistical method of a hybrid nature. An infant in this multicenter randomized clinical trial had high-risk prethreshold retinopathy of prematurity that was eligible for treatment in one or both eyes at entry into the trial. During follow-up, recognition visual acuity was accessed for both eyes. Data from both eyes (matched) and from only one eye (unmatched) were eligible to be used in the trial. The new hybrid nonparametric method is a meta-analysis based on combining the Hodges-Lehmann estimates of treatment effects from the Wilcoxon signed rank and rank sum tests. To compare the new method, we used the classic meta-analysis with the t-test method to combine estimates of treatment effects from the paired and two sample t-tests. We used simulations to calculate the empirical size and power of the test statistics, as well as the bias, mean square and confidence interval width of the corresponding estimators. The proposed method provides an effective tool to evaluate data from clinical trials and similar comparative studies.

Retinopathy of prematurity

The immature retinas of preterm neonates are susceptible to insults that disrupt neurovascular growth, leading to retinopathy of prematurity. Suppression of growth factors due to hyperoxia and loss of the maternal-fetal interaction result in an arrest of retinal vascularisation (phase 1). Subsequently, the increasingly metabolically active, yet poorly vascularised, retina becomes hypoxic, stimulating growth factor-induced vasoproliferation (phase 2), which can cause retinal detachment. In very premature infants, controlled oxygen administration reduces but does not eliminate retinopathy of prematurity. Identification and control of factors that contribute to development of retinopathy of prematurity is essential to prevent progression to severe sight-threatening disease and to limit comorbidities with which the disease shares modifiable risk factors. Strategies to prevent retinopathy of prematurity will depend on optimisation of oxygen saturation, nutrition, and normalisation of concentrations of essential factors such as insulin-like growth factor 1 and ω-3 polyunsaturated fatty acids, as well as curbing of the effects of infection and inflammation to promote normal growth and limit suppression of neurovascular development.

Development of refractive error in individual children with regressed retinopathy of prematurity

PURPOSE

We investigated longitudinally the refraction development in children with regressed retinopathy of prematurity (ROP), including those with and those without a history of peripheral retinal laser photocoagulation.

METHODS

Longitudinal (0-7 years) cycloplegic refraction data were collected prospectively for two groups of preterm children: severe ROP group included those with regressed ROP following bilateral panretinal laser photocoagulation (n = 37; median gestational age [GA] = 25.2; range, 22.7-27.9 weeks) and mild/no ROP group included those with spontaneously regressed ROP or no ROP (n = 27; median GA = 27.1; range, 23.1-32.0 weeks). Analyses were based on spherical equivalent (SEQ), anisometropia, astigmatism, and age (corrected for gestation).

RESULTS

The prevalence, magnitude, and rate of myopic progression all were significantly higher in the severe ROP group than in the mild/no ROP group. Longitudinal SEQ in the severe ROP group were best fit with a bilinear model. Before 1.3 years old, the rate of myopic shift was -4.7 diopters (D)/y; after 1.3 years, the rate slowed to -0.15 D/y. Longitudinal SEQ in the mild/no ROP group was best fit with a linear model, with a rate of -0.004 D/y. Anisometropia in the severe ROP group increased approximately three times faster than in the mild/no ROP group. In the severe ROP group, with-the-rule astigmatism increased significantly with age.

CONCLUSIONS

The severe ROP group progressed rapidly toward myopia, particularly during the first 1.3 years; anisometropia and astigmatism also increased with age. The mild/no ROP group showed little change in refraction. Infants treated with laser photocoagulation for severe ROP should be monitored with periodic cycloplegic refractions and provided with early optical correction.

Progression of myopia and high myopia in the Early Treatment for Retinopathy of Prematurity study: findings at 4 to 6 years of age

PURPOSE

To report the prevalence of myopia and high myopia in children <6 years of age born preterm with birth weights <1251 g who developed high-risk prethreshold retinopathy of prematurity and who participated in the Early Treatment for Retinopathy of Prematurity trial.

METHODS

Surviving children from the cohort of 401 participants who had developed high-risk prethreshold ROP in one or both eyes underwent cycloplegic retinoscopy at 6 and 9 months corrected age and yearly between 2 and 6 years postnatal age. Eyes were randomized to receive treatment at high-risk prethreshold ROP or conventional management with treatment only if threshold ROP developed. Myopia (spherical equivalent ≥0.25 D) or high myopia (≥5.00 D) in eyes at 4-, 5-, and 6-year examinations was reported.

RESULTS

At ages 4, 5, and 6 years, there was no difference in the percentage of eyes with myopia (range, 64.8%-69.9%) and eyes with high myopia (range, 35.3%-39.4%) between earlier treated and conventionally managed eyes.

CONCLUSIONS

Approximately two-thirds of eyes with high-risk prethreshold ROP during the neonatal period are likely to be myopic into the preschool and early school years. In addition, the increase in the proportion of eyes with high myopia that had been observed in both earlier-treated and conventionally managed eyes between ages 6 months and 3 years does not continue between ages 3 and 6 years.

Pregnancy disorders appear to modify the risk for retinopathy of prematurity associated with neonatal hyperoxemia and bacteremia

OBJECTIVE

To explore (1) whether extremely low gestational age newborns exposed to inflammation-associated pregnancy disorders differ in retinopathy of prematurity (ROP) risk from infants exposed to placenta dysfunction-associated disorders, and (2) whether ROP risk associated with postnatal hyperoxemia and bacteremia differs among infants exposed to these disorders.

METHODS

Pregnancy disorders resulting in preterm birth include inflammation-associated: preterm labor, prelabor premature rupture of membranes (pPROM), cervical insufficiency, and abruption and placenta dysfunction-associated: preeclampsia and fetal indication. The risk of severe ROP associated with pregnancy disorders was evaluated by multivariable analyses in strata defined by potential effect modifiers, postnatal hyperoxemia and bacteremia.

RESULTS

Compared to preterm labor, infants delivered after pPROM were at reduced risk of plus disease (Odds ratio = 0.4, 95% confidence interval: 0.2-0.8) and prethreshold/threshold ROP (0.5, 0.3-0.8). Infants delivered after abruption had reduced risk of zone I ROP (0.2, 0.1-0.8) and prethreshold/threshold ROP (0.3, 0.1-0.7). In stratified analyses, infants born after placenta dysfunction had higher risks of severe ROP associated with subsequent postnatal hyperoxemia and bacteremia than infants born after inflammation-associated pregnancy disorders.

CONCLUSION

Infants exposed to placenta dysfunction have an increased risk of severe ROP following postnatal hyperoxemia and bacteremia compared to infants exposed to inflammation-associated pregnancy disorders.

Incidence of cataract development by 6 months' corrected age in the Early Treatment for Retinopathy of Prematurity study

PURPOSE

To report the incidence of cataract development by 6 months' corrected age in preterm children who participated in the Early Treatment for Retinopathy of Prematurity study.

METHODS

Infants who developed prethreshold retinopathy of prematurity (ROP) in one or both eyes and were determined by the RM-ROP2 model to have a high risk of poor structural outcome without treatment were randomized to receive early treatment (ET), defined as laser photocoagulation at high-risk prethreshold ROP, or to be conventionally managed (CM), receiving treatment only if threshold ROP developed. Data on eyes developing a cataract by 6 months' corrected age were analyzed.

RESULTS

Of 401 randomized infants, 366 survived patients were followed, and 8 eyes of 7 patients (1.9%) developed cataracts by 6 months' corrected age. Among these patients, mean birth weight was 754 g, and mean gestational age was 25.7 weeks. Mean gestational age at treatment was 36.3 weeks for ET patients and 39.5 weeks for CM patients. Three ET eyes and 5 CM eyes developed a cataract. Of the CM eyes, 3 with and 2 without laser treatment developed a cataract. All 6 treated eyes had plus disease when treated. Three eyes had ROP in zone 1, whereas the other 3 had ROP in zone 2. All eyes were treated using a diode laser.

CONCLUSIONS

By 6 months' corrected age, a small number of both ET and CM eyes developed cataracts following diode laser treatment for retinopathy of prematurity. Absence of obvious intraoperative complications does not preclude subsequent cataract development, which can occur without laser treatment.

Incidence of retinopathy of prematurity and risk factors in the South-Western region of iran

AIMS

The aim of this study was to report the incidence of retinopathy of prematurity (ROP) and the contribution of various risk factors to ROP in the south-western region of Iran.

MATERIAL AND METHODS

This cross-sectional case-control series reviewed all low birth weight (LBW, ≤2000 g) neonates and/or neonates less than 32 weeks gestational age who had been hospitalized in the Neonatal Intensive Care Unit from 2006 to 2010. The cohort was divided into infants without ROP (nonROP group) and infants with ROP (ROP group). Infants were first examined by a group of pediatric ophthalmologists 6 weeks after delivery, and then were followed every 1-2 weeks until death, discharge or complete retinal avascularization. If an infant developed ROP, further examinations were performed based on the Early Treatment for Retinopathy of Prematurity Study protocol. Demographic data, medical treatment, and ophthalmic disorders were all statistically analyzed.

RESULTS

A total of 576 infants met the criteria for evaluation. Of 576 total patients, 183 infants (32%) (88 males, 95 females) had ROP. There were significant differences between groups in gestational age, body weight, and duration of oxygen administration, and sepsis (P<0.05). Male/female ratio, single and multiple births, and jaundice, phototherapy, and blood transfusion were not significant. The majority of ROP was stage I or II (137, 74.8%). Stage III or greater developed in 46 infants (25.1%) [Note: The ocular history and ocular outcomes are not risk factors.]

CONCLUSIONS

The incidence of ROP in this study is higher than that in other parts of the world. Awareness and knowledge of ROP and its relative risks need to be reinforced in ophthalmologists and other health practitioners.

Effect of the oxygen saturation target on clinical characteristics of early- versus late-onset retinopathy of prematurity

PURPOSE

To investigate the relationship between postmenstrual age of onset of retinopathy of prematurity (ROP) and the need for treatment, while examining the effects of two different neonatal oxygen saturation protocols on this relationship.

METHODS

A retrospective chart review was conducted for eligible inborn infants born before and after the institution of a new oxygen protocol adjusting target oxygen saturation from 90%-99% to 85%-93%. Early versus late-onset ROP was defined as first presence of any stage disease on examination at <36 versus ≥ 36 weeks' postmenstrual age, respectively.

RESULTS

The median birth weight/postmentrual age of infants was 840 g per 26.1 weeks (early-onset ROP) versus 952.5 g per 28 weeks (late-onset ROP; P < 0.01 vs P < 0.01). ROP developed in 119 of 369 (32.2%) of high oxygen target infants, and 100 of 373 (26.8%) infants in the low-target group (P = 0.11). Cumulatively, 35 of 144 (24.3%) of early-onset and 8 of 69 (11.6%) of late-onset patients required treatment (P = 0.03). Maximal severity of disease after treatment, including retinal detachment frequency, was similar in early- and late-onset patients, independent of the oxygen protocol (P = 1.00).

CONCLUSIONS

The clinical behavior of type 1 ROP is similar in early-and late-onset disease, regardless of oxygen saturation targets. Type 1 ROP disease occurred in 11.6% of patients with late-onset ROP.

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.

Outcome of eyes developing retinal detachment during the Early Treatment for Retinopathy of Prematurity study

OBJECTIVE

To describe the structural and visual outcomes at age 6 years of retinal detachment (RD) from retinopathy of prematurity (ROP) in the Early Treatment for Retinopathy of Prematurity (ETROP) study.

METHODS

Prospective multicenter nonrandomized series of infants with high-risk prethreshold ROP who developed an RD by 6 months corrected age treated with observation or vitreoretinal surgery.

RESULTS

Of 401 patients, 63 (89 eyes) experienced RD. Follow-up at age 6 years was available for 70 eyes (79%) of 49 surviving patients. The RDs were stage 4A in 28 eyes (40%), stage 4B in 14 (20%), stage 5 in 13 (19%), and not classified in 15 (21%). The macula was attached in 17 of 50 eyes (34%) after vitrectomy with or without scleral buckle, in 6 of 9 (67%) after scleral buckle only, and in 2 of 11 eyes (18%) observed. An attached macula at age 6 years after vitreoretinal surgery was present in 5 of 16 eyes (31%) with stage 4A, 6 of 10 (60%) with stage 4B, and 0 of 10 with stage 5. Favorable visual acuity (>20/200) was found in 6 of 70 eyes (9%); 5 had stage 4A, and 1 was not classified.

CONCLUSIONS

Macular attachment was achieved in approximately one-third of eyes with RD and favorable visual acuity in some eyes with stage 4A.

Grating visual acuity results in the early treatment for retinopathy of prematurity study

OBJECTIVE

To compare grating (resolution) visual acuity at 6 years of age in eyes that received early treatment (ET) for high-risk prethreshold retinopathy of prematurity (ROP) with that in eyes that underwent conventional management (CM).

METHODS

In a randomized clinical trial, infants with bilateral, high-risk prethreshold ROP (n = 317) had one eye undergo ET and the other eye undergo CM, with treatment only if ROP progressed to threshold severity. For asymmetric cases (n = 84), the high-risk prethreshold eye was randomized to ET or CM.

MAIN OUTCOME MEASURE

Grating visual acuity measured at 6 years of age by masked testers using Teller acuity cards.

RESULTS

Monocular grating acuity results were obtained from 317 of 370 surviving children (85.6%). Analysis of grating acuity results for all study participants with high-risk prethreshold ROP showed no statistically significant overall benefit of ET (18.1% vs 22.8% unfavorable outcomes; P = .08). When the 6-year grating acuity results were analyzed according to a clinical algorithm (high-risk types 1 and 2 prethreshold ROP), a benefit was seen in type 1 eyes (16.4% vs 25.2%; P = .004) undergoing ET, but not in type 2 eyes (21.3% vs 15.9%; P = .29).

CONCLUSION

Early treatment of eyes with type 1 ROP improves grating acuity outcomes, but ET for eyes with type 2 ROP does not. APPLICATION TO CLINICAL MEDICINE: Type 1 eyes should be treated early; however, based on acuity results at 6 years of age, type 2 eyes should be cautiously monitored for progression to type 1 ROP. Trial Registration clinicaltrials.gov Identifier: NCT00027222.

Astigmatism progression in the early treatment for retinopathy of prematurity study to 6 years of age

PURPOSE

To examine the prevalence of astigmatism (≥ 1.00 diopter [D]) and high astigmatism (≥ 2.00 D) from 6 months after term due date to 6 years of age in preterm children with birth weight of less than 1251 g in whom high-risk prethreshold retinopathy of prematurity (ROP) developed and who participated in the Early Treatment for ROP study.

DESIGN

Observational cohort study.

PARTICIPANTS

Four hundred one infants in whom high-risk prethreshold ROP developed in 1 or both eyes and were randomized to early treatment (ET) versus conventional management (CM). Refractive error was measured by cycloplegic retinoscopy. Eyes were excluded if they underwent additional retinal, glaucoma, or cataract surgery.

INTERVENTION

Eyes were randomized to receive laser photocoagulation at high-risk prethreshold ROP or to receive treatment only if threshold ROP developed.

MAIN OUTCOME MEASURES

Astigmatism and high astigmatism at each study visit.

RESULTS

For both ET and CM eyes, there was a consistent increase in prevalence of astigmatism over time, increasing from 42% at 4 years to 52% by 6 years for the group of ET eyes and from 47% to 54%, respectively, in the CM eyes. There was no statistically significant difference between the slopes (rate of change per month) of the ET and CM eyes for both astigmatism and high astigmatism (P = 0.75).

CONCLUSIONS

By 6 years of age, astigmatism of 1.00 D or more developed in more than 50% of eyes with high-risk prethreshold ROP, and nearly 25% of such eyes had high astigmatism (≥ 2.00 D). Presence of astigmatism was not influenced by timing of treatment, zone of acute-phase ROP, or presence of plus disease. However, there was a trend toward higher prevalence of astigmatism and high astigmatism in eyes with ROP residua. Most astigmatism was with-the-rule (75°-105°). More eyes with type 2 than type 1 ROP had astigmatism by 6 years. These findings reinforce the need for follow-up eye examinations through early grade school years in infants with high-risk prethreshold ROP.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

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.

Final visual acuity results in the early treatment for retinopathy of prematurity study

OBJECTIVE

To compare visual acuity at 6 years of age in eyes that received early treatment for high-risk prethreshold retinopathy of prematurity (ROP) with conventionally managed eyes.

METHODS

Infants with symmetrical, high-risk prethreshold ROP (n = 317) had one eye randomized to earlier treatment at high-risk prethreshold disease and the other eye managed conventionally, treated if ROP progressed to threshold severity. For asymmetric cases (n = 84), the high-risk prethreshold eye was randomized to either early treatment or conventional management. The main outcome measure was ETDRS visual acuity measured at 6 years of age by masked testers. Retinal structure was assessed as a secondary outcome.

RESULTS

Analysis of all subjects with high-risk prethreshold ROP showed no statistically significant benefit for early treatment (24.3% vs 28.6% [corrected] unfavorable outcome; P = .15). Analysis of 6-year visual acuity results according to the Type 1 and 2 clinical algorithm showed a benefit for Type 1 eyes (25.1% vs 32.8%; P = .02) treated early but not Type 2 eyes (23.6% vs 19.4%; P = .37). Early-treated eyes showed a significantly better structural outcome compared with conventionally managed eyes (8.9% vs 15.2% unfavorable outcome; P < .001), with no greater risk of ocular complications.

CONCLUSIONS

Early treatment for Type 1 high-risk prethreshold eyes improved visual acuity outcomes at 6 years of age. Early treatment for Type 2 high-risk prethreshold eyes did not. Application to Clinical Practice Type 1 eyes, not Type 2 eyes, should be treated early. These results are particularly important considering that 52% of Type 2 high-risk prethreshold eyes underwent regression of ROP without requiring treatment. Trial Registration clinicaltrials.gov Identifier: NCT00027222.

Digital image analysis of plus disease in retinopathy of prematurity

An accurate assessment of retinopathy of prematurity (ROP) is essential in ensuring correct and timely treatment of this potentially blinding condition. Current modes of assessment are based upon clinical grading by expert examination of retinal changes. However, this may be subjective, unreliable and difficult and there has been significant interest in alternative means of measurement. These have been made possible through technological advancements in image capture and analysis as well as progress in clinical research, highlighting the specific importance of plus disease in ROP. Progress in these two fields has highlighted the potential for digital image analysis of plus disease to be used as an objective, reliable and valid measurement of ROP. The potential for clinical and scientific advancement through this method is argued and demonstrated in this article. Along with the potential benefits, there are significant challenges such as in image capture, segmentation, measurement of vessel width and tortuosity; these are also addressed. After discussing and explaining the challenges involved, the research articles addressing digital image analysis of ROP are critically reviewed. Benefits and limitations of the currently published techniques for digital ROP assessment are discussed with particular reference to the validity and reliability of outcome measures. Finally, the general limitations of current methods of analysis are discussed and more diverse potential areas of development are discussed.

Early weight gain predicts retinopathy in preterm infants: new, simple, efficient approach to screening

BACKGROUND

The risk for sight-threatening retinopathy of prematurity is predicted by using gestational age and/or weight at birth. All infants below a threshold undergo serial ophthalmologic examinations for identification of those who would benefit from treatment (approximately 10%). We hypothesized that factoring in postnatal weight gain could identify children at risk for sight-threatening retinopathy of prematurity more specifically and earlier.

METHODS

Weekly weights from birth to postmenstrual week 36 were retrospectively entered into a surveillance system that gave an alarm when the rate of weight gain decreased to a certain level. For all children (N = 354) screened and/or treated for retinopathy of prematurity at Sahlgrenska University Hospital in 2004-2007, weekly weights were recorded. One child was excluded because of known nonphysiologic weight gain (hydrocephalus).

RESULTS

For 127 (36%) of 353 children, no alarm was given; for 40%, alarm at low risk was given after postmenstrual week 32. None of those children developed retinopathy of prematurity requiring treatment. Of the remaining 24% of children who received alarm at high or low risk before 32 postmenstrual weeks, 41% developed proliferative retinopathy of prematurity and 29% were treated because of sight-threatening disease. The median time from alarm to treatment was 9 weeks.

CONCLUSIONS

The weight, insulin-like growth factor, neonatal retinopathy of prematurity algorithm detected early 100% of infants who developed retinopathy of prematurity requiring treatment and correctly predicted the majority who did not require treatment. With this simple postnatal evaluation, costly stressful eye examinations can be markedly reduced (approximately 75% of infants). In addition, early identification of children at risk may lead to the initiation of interventions and possibly prevent sight-threatening retinopathy of prematurity.

Evaluation of a computerized system for mechanical ventilation of infants

OBJECTIVE

To evaluate a computerized system for mechanical ventilation of infants.

METHODS

FLEX is a computerized system that includes the features of a patented mode known as adaptive-support ventilation (ASV). In addition, it has many other features including adjustment of positive end-expiratory pressure (PEEP), fraction of inspired oxygen (F(IO2)), minute ventilation, and control of weaning. It is used as an open-loop decision support system or as a closed-loop technique. Blood gas and ventilation data were collected from 12 infants in the neonatal intensive care at baseline and at the next round of evaluation. This data were input to open-loop version of FLEX. The system recommendations were compared to clinical determinations.

RESULTS

FLEX recommended values for ventilation were on the average within 25% and 16.5% of the measured values at baseline and at the next round of evaluation, respectively. For F(IO2) and PEEP, FLEX recommended values were in general agreement with the clinical settings. FLEX recommendations for weaning were the same as the clinical determinations 50% of the time at baseline and 55% of the time at the next round of evaluation. FLEX did not recommend weaning for infants with weak spontaneous breathing effort or those who showed signs of dyspnea.

CONCLUSIONS

A computerized system for mechanical ventilation is evaluated for treatment of infants. The results of the study show that the system has good potential for use in neonatal ventilatory care. Further refinements can be made in the system for very low-birth-weight infants.

Astigmatism in the Early Treatment for Retinopathy Of Prematurity Study: findings to 3 years of age

PURPOSE

To examine the prevalence of astigmatism (> or =1.00 diopter [D]) and high astigmatism (> or =2.00 D) at 6 and 9 months corrected age and 2 and 3 years postnatal age, in preterm children with birth weight of less than 1251 g in whom high-risk prethreshold retinopathy of prematurity (ROP) developed and who participated in the Early Treatment for Retinopathy of Prematurity (ETROP) Study.

DESIGN

Randomized, controlled clinical trial.

PARTICIPANTS

Four hundred one infants in whom prethreshold ROP developed in one or both eyes and who were randomized after they were determined to have a high risk (> or =15%) of poor structural outcome without treatment using the Risk Management of Retinopathy of Prematurity (RM-ROP2) program. Refractive error was measured by cycloplegic retinoscopy. Eyes with additional retinal, glaucoma, or cataract surgery were excluded.

INTERVENTION

Eyes were randomized to receive laser photocoagulation at high-risk prethreshold ROP (early treated [ET]) or to be conventionally managed (CM), receiving treatment only if threshold ROP developed.

MAIN OUTCOME MEASURES

Astigmatism and high astigmatism at each visit. Astigmatism was classified as with-the-rule (WTR; 75 degrees -105 degrees ), against-the-rule (ATR; 0 degrees -15 degrees and 165 degrees -180 degrees ), or oblique (OBL; 16 degrees -74 degrees and 106 degrees -164 degrees ).

RESULTS

The prevalence of astigmatism in ET and CM eyes was similar at each test age. For both groups, there was an increase in prevalence of astigmatism from approximately 32% at 6 months to approximately 42% by 3 years, mostly occurring between 6 and 9 months. Among eyes that could be refracted, astigmatism was not influenced by zone of acute-phase ROP, presence of plus disease, or retinal residua of ROP. Eyes with astigmatism and high astigmatism most often had WTR astigmatism.

CONCLUSIONS

By age 3 years, nearly 43% of eyes treated at high-risk prethreshold ROP developed astigmatism of > or =1.00 D and nearly 20% had astigmatism of > or =2.00 D. Presence of astigmatism was not influenced by timing of treatment of acute-phase ROP or by characteristics of acute-phase or cicatricial ROP. These findings reinforce the need for follow-up eye examinations in infants with high-risk prethreshold ROP.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Outcome of retinopathy of prematurity patients following adoption of revised indications for treatment

Background

The Early Treatment for Retinopathy of Prematurity study (ETROP), published in 2003, established new guidelines for treatment of retinopathy of prematurity (ROP) and demonstrated improved outcomes compared to previous guidelines. We examined outcomes before and after implementing the ETROP recommendations.

Methods

A retrospective chart review was performed using records of infants who had laser ablations for ROP performed from January, 2000 through December, 2005. Data collected included date of birth; birth weight; estimated gestational age (EGA); grading of ROP; date of laser ablation; and outcome of laser surgery. Univariate association with threshold or prethreshold treatment (Pre-ETROP and Post-ETROP, respectively) were assessed using t-tests or Wilcoxon tests. Additional comparison between groups was performed using Fisher's exact tests.

Results

581 patients were examined before and 464 after December 2003. Of these, 29/581 (5% – Pre-ETROP Group) and 53/464 (11% – Post-ETROP Group) patients advanced to criteria requiring laser treatment respectively (P = 0.0001). The average estimated gestational age (EGA) at birth was 26.3 and 25.2 weeks, with an average birth weight of 888 and 707 grams for Pre and Post-ETROP Groups, respectively. Stage 5 retinal detachment (RD) developed in 10.3% of eyes in the Pre-ETROP Group and 1.9% of eyes in the Post-ETROP Group (P = 0.02).

Conclusion

After the ETROP guidelines were implemented, there was a decrease from 10.3% to 1.9% of eyes developing Stage 5 retinal detachment, despite this group having a lower average EGA and lower average birth weight. These results underscore the importance of adoption of the Revised Indications.

Progression and timing of treatment of zone I retinopathy of prematurity

PURPOSE

To clarify the progression of zone I retinopathy of prematurity (ROP) and elucidate the most suitable time and method of treatment.

DESIGN

Interventional case series.

METHODS

Forty-six eyes of 23 zone I ROP infants were studied at a single institution. Birth weight ranged from 448 to 954 g, and gestational age ranged from 22 to 26 weeks. Fundus examination was started at 29 or 30 weeks postmenstrual age and was performed once or more per week. The first treatment was performed using laser photocoagulation or cryotherapy when zone I ROP progressed to the following criteria. Treatment criteria A included 35 eyes of 18 cases of zone I any stage ROP with plus disease (Early Treatment for Retinopathy of Prematurity [ETROP] type 1), criteria B included five eyes of three cases of zone I stage 3 ROP with or without plus disease (ETROP type 1), criteria C included six eyes of four cases of stage 1 or stage 2 ROP without plus disease; the demarcation lines belonged, in large part, within the zone I area.

RESULTS

Hazy media such as corneal opacity, miotic pupil, tunica vasculosa lentis, and hazy vitreous persisted until approximately 32 weeks postmenstrual age. The mean period between stage 1 and stage 3 mild was one week, that between stage 1 and stage 3 moderate was 1.7 weeks, and that between stage 1 and stage 3 severe was 1.3 weeks. The period between stage 1 and the first treatment was zero to 20 days, and 60.9% of all the cases were treated within 10 days after stage 1. Six of 46 eyes had unfavorable outcomes. Surgical results of our treatment were comparable or better than those of other reports.

CONCLUSIONS

Immediate treatment was required when zone I ROP was diagnosed behind persistent hazy media.

Progression of myopia and high myopia in the early treatment for retinopathy of prematurity study: findings to 3 years of age

PURPOSE

Examine the prevalence of myopia and high myopia, at 6 and 9 months postterm and 2 and 3 years postnatal in preterm children with birth weights < 1251 g who developed high-risk prethreshold retinopathy of prematurity (ROP) in the neonatal period and participated in the Early Treatment for ROP Study.

DESIGN

Randomized controlled clinical trial.

PARTICIPANTS

Four hundred one infants who developed prethreshold ROP and were determined to have a significant risk (>/=15%) of poor structural outcomes without treatment. Children underwent cycloplegic retinoscopy at examinations between 6 months postterm and 3 years' postnatal age.

INTERVENTION

Eyes were randomized to receive treatment at high-risk prethreshold ROP (early treated [ET]) or conventional management (CM), with treatment only if threshold ROP developed.

MAIN OUTCOME MEASURES

Myopia (spherical equivalent >/= 0.25 diopters [D]) or high myopia (>/=5.00 D) at each visit.

RESULTS

Prevalences of myopia were similar in treated eyes in the ET and CM groups, increasing from approximately 58% to 68% between 6 and 9 months, with little change thereafter. Both ET and CM eyes showed an increasing prevalence of high myopia, approximately 19% at 6 months and increasing 4% to 8% at successive examinations. Zone of ROP and presence or absence of plus disease had little effect on prevalence of myopia or high myopia between ages 6 months and 3 years. However, eyes with ROP residua (straightened temporal vessels or macular heterotopia) showed a higher prevalence of myopia and high myopia than eyes without residua.

CONCLUSIONS

Approximately 70% of high-risk prethreshold ROP eyes were myopic in early childhood, and the proportion with high myopia increased steadily between ages 6 months and 3 years. Timing of treatment of high-risk prethreshold ROP did not influence refractive error development. There was little difference in prevalence of myopia or high myopia between eyes with zone I and eyes with zone II ROP, nor between eyes with plus disease and eyes with no plus disease. However, prevalence of myopia and high myopia was higher in eyes with retinal residua of ROP than in eyes with normal-appearing posterior poles, highlighting the importance of follow-up eye examinations of infants who had prethreshold ROP.

Telemedicine screening for retinopathy of prematurity in developing countries using digital retinal images: a feasibility project

PURPOSE

To determine the feasibility in a middle-level human development country of onsite training, image collection, Internet transfer, and remote grading of digital retinal images from babies screened for retinopathy of prematurity (ROP).

METHODS

Two experienced nurses in a neonatal nursery in Lima, Peru, were trained to take posterior pole (30 degrees ) digital retinal images. Nurses obtained posterior pole retinal images from babies undergoing routine ROP screening and selected images for uploading via Internet for remote evaluation by five masked ROP experts. Results of gradings were compared with same-day clinical diagnostic examinations by an experienced ophthalmologist. Success rates for image acquisition and transfer for grading by expert readers were calculated.

RESULTS

Serial image sets from 26 of the 28 babies enrolled in this study were obtained; two babies were too unstable for imaging. Fifty-six of 58 (96.6%) imaging sessions were successful in obtaining retinal images. Three hundred thirty of 336 (98.2%) images obtained were successfully uploaded to an interactive database. Remote graders judged 93.6% to 97.3% of image sets suitable for ROP grading. Preliminary results indicate sensitivities for detection of serious ROP from 45.5% to 95.2% among individual readers, with specificities of 61.7% to 96.2% when images were gradable.

CONCLUSIONS

A telemedicine approach for ROP screening using digital retinal images obtained by nonophthalmologists is feasible in rapidly developing countries that lack ROP-trained ophthalmologists. If remote grading of digital images is validated as an effective method for identifying referral-warranted ROP (RW-ROP), images obtained by nonphysicians may provide a means of identifying babies who require a diagnostic examination by an ophthalmologist.

Human recombinant erythropoietin and the incidence of retinopathy of prematurity: a multiple regression model

BACKGROUND

Recombinant human erythropoietin (rhEPO) is used for the treatment of anemia of prematurity. However, it has also been found to have properties similar to vascular endothelial growth factor (VEGF), the major angiogenic factor implicated in the pathogenesis of retinopathy of prematurity (ROP). We sought to determine whether rhEPO is an independent risk factor for the development of ROP.

METHODS

Data were analyzed from 264 infants admitted to the Loma Linda University Children's Hospital neonatal intensive care unit in 1994 and 2002. The data included demographic characteristics, incidence of major morbidities, rhEPO treatment, number of red blood cell transfusions received, and incidence and severity of ROP. A multiple logistic regression model was used to determine the relation of the studied risk factors to the incidence (any stage) and severity (threshold ROP requiring cryotherapy or laser photocoagulation) of ROP.

RESULTS

The risk of developing ROP increased among infants who received >20 doses of rhEPO was higher compared with those who received < or =20 doses (OR, 3.53; 95% CI, 1.59, 7.85). These infants were also more likely to require laser photocoagulation (OR, 4.31; 95% CI, 1.99, 9.33). The age at which rhEPO was started was also a significant risk factor, with those starting rhEPO after 20 days of age having almost fourfold the risk of ROP compared with those starting it on or before 20 days of age (OR, 3.57; 95% CI, 1.59, 8.03).

CONCLUSIONS

rhEPO was found to be a significant independent risk factor for the development of ROP.