Retinopathy of prematurity in infants < 32 weeks' gestation at birth in New South Wales in 1993 and 1994

Global Prevalence and Severity of Retinopathy of Prematurity over the Last Four Decades (1985-2021): A Systematic Review and Meta-Analysis

BACKGROUND

Retinopathy of prematurity (ROP) is a vasoproliferative disease of the retina that occurs in premature infants. The prevalence of ROP reported so far is inconsistent.

AIM

To conduct a systematic review to describe the trend of ROP prevalence between 1985 and 2021, and to determine the influence of countries' economic conditions on ROP prevalence.

METHODS

We searched PubMed, Embase, and Google Scholar for studies published between January 1985 and December 2021 using the following MeSH terms: "retinopathy of prematurity", "ROP", "incidence", and "prevalence". Two independent reviewers examined the articles to select studies that met the selection criteria and performed data extraction and study quality assessment. For the meta-analysis, the pooled prevalence was calculated using a random-effects model and R software.

RESULTS

Of 5,250 titles and abstracts, 139 original studies met the inclusion criteria; a total of 121,618 premature infants were included in these studies. The pooled prevalence of ROP was 31.9% (95% confidence interval [CI] 29.0-34.8) and that of severe ROP was 7.5% (6.5-8.7). In general, no significant differences in prevalence were found over the four decades; however, we found a higher prevalence in premature infants ≤28 weeks of gestational age. In addition, the highest ROP prevalence was found in lower-middle-income countries with high mortality rates. In contrast, the highest severe ROP prevalence was found in high-income countries.

CONCLUSION

ROP remains a common cause of morbidity in premature infants worldwide. Therefore, it seems necessary to maintain early identification strategies for patients at higher risk, particularly in low- and middle-income countries.

Survival rate dependent variations in retinopathy of prematurity treatment rates in very low birth weight infants

As increased oxidative stress causes increased mortality and morbidities like bronchopulmonary dysplasia (BPD) and retinopathy of prematurity (ROP) in very low birth weight infants (VLBWIs), the conundrum of improved survival but increased ROP observed with the high oxygen saturation target range of 91–95% is difficult to explain. To determine the survival rate-dependent variation in ROP treatment rate, 6292 surviving eligible VLBWIs registered in the Korean Neonatal Network were arbitrarily grouped according to the survival rate of infants at 23–24 weeks’ gestation as group I (> 70%, n = 1626), group II (40–70%, n = 2984) and group III (< 40%, n = 1682). Despite significantly higher survival and lower BPD rates in group I than in groups II and III, the ROP treatment rate was higher in group I than in groups II and III. However, the adjusted odds ratios for ROP treatment were not significantly different between the study groups, and the ROP treatment rate in the infants at 23–24 weeks’ gestation was 21-fold higher than the infants at ≥ 27 weeks’ gestation. The controversial association between improved survival and reduced BPD reflecting quality improvement of neonatal intensive care but increased ROP treatment rate might be primarily attributed to the improved survival of the most immature infants.

Sight-Threatening Retinopathy of Prematurity: Changing Trends in Treatment

PURPOSE

To study the incidence and treatment of severe retinopathy of prematurity (ROP) in infants younger than 30 weeks' gestational age (GA) in New South Wales and the Australian Capital Territory, Australia, from 2003 to 2008. These data were then compared to data from previously reported epochs (1986 to 1987, 1992 to 1997, and 1998 to 2002).

METHODS

Data were divided into two sub-epochs (2003 to 2005 and 2006 to 2008) to study trends and combined to compare over 22 years.

RESULTS

From 2003 to 2008, 2,550 of 3,004 (84.9%) infants survived, 200 (7.8%) were diagnosed as having severe ROP, and 119 (59.5%) required laser therapy. No significant difference in the incidence of severe ROP or treatment rate in infants younger than 27 and 30 weeks' GA from 2003 to 2005 and 2006 to 2008 occurred. Similarly, between 1986 and 2008 there was no difference in the incidence of severe ROP. However, the treatment rate significantly increased during this time.

CONCLUSIONS

The incidence of severe ROP has been stable since 1986. However, laser treatment significantly increased to include 8 infants with stage 2 ROP from 2003 to 2008.

Retinopathy of prematurity in extremely premature infants

INTRODUCTION

The incidence and severity of retinopathy of prematurity (ROP) in extremely premature infants have not been reported since publication of the Early Treatment of ROP study results. The survival rate of these infants continues to increase. We sought to determine the characteristics of ROP in a group of surviving infants <25 weeks estimated gestational age (EGA) at birth compared to a group 25 to 27 weeks EGA at birth.

METHODS

Retrospective review of infants born prior to 27 weeks EGA between January 2003 and July 2007 at a level-3 nursery at a regional academic medical center.

RESULTS

A total of 231 medical records were reviewed and found to have analyzable data. Of 79 infants <25 weeks EGA, 69 (87%) developed ROP, compared to 95 of 152 (62%) infants 25 to 27 weeks EGA. Type 1 ROP developed in 23% of infants in the <25 weeks EGA group, compared to 9% of infants in the 25 to 27 weeks EGA group. There was no difference in mean postmenstrual age when type 1 ROP was diagnosed. Lower birth weight predicted increased risk of type 1 ROP in the 25 to 27 weeks EGA group, but not in the <25 weeks EGA group.

CONCLUSIONS

Extremely premature infants are more likely to develop ROP and type 1 ROP, but the incidence may be lower than previously reported. Birth weight may not influence the incidence of type 1 ROP in this group of infants. Type 1 ROP does not develop at an earlier postmenstrual age in the extremely premature infant.

Immaturity, perinatal inflammation, and retinopathy of prematurity: a multi-hit hypothesis

OBJECTIVE

To explore the relationship among markers of infection/inflammation in their association with retinopathy of prematurity (ROP).

METHODS

We studied clinical characteristics and 4 single nucleotide polymorphisms in infection/inflammation-associated genes in a group of 73 children with a gestational age<32 weeks. Forty-four children (60%) had ROP, of whom 13 (30% of those with ROP) progressed to stage 3 ROP. No child had grade 4 or 5 ROP. We employed both descriptive and analytic statistical methods.

RESULTS

Clinical variables of infection/inflammation were consistently associated with an increased risk of ROP. Among infants with ROP, they were also associated with progression to ROP grade 3. Genetic markers were not associated with ROP occurrence, but with progression to high grade disease. In tri-variable analyses exploring the effects of gestational age <29 weeks, clinical chorioamnionitis (CAM) and neonatal systemic inflammatory response syndrome (SIRS) on ROP occurrence, low gestational age was the most important antecedent, while additional individual or joint exposure to SIRS and CAM add appreciably to this risk of progression to high grade disease.

CONCLUSION

Both antenatal and neonatal exposure to inflammation appear to contribute to the increased ROP risk in preterm infants.

Severe retinopathy of prematurity and visual outcomes in British Columbia: a 10-year analysis

OBJECTIVE

To describe the incidence trend and long-term visual outcomes of infants diagnosed with stages 3 to 4 retinopathy of prematurity (ROP) or laser-treated ROP born in British Columbia (Canada).

STUDY DESIGN

Data from all (n=1384) neonates with birth weight (BW) <1250 g, admitted to British Columbia Children's Hospital between period 1 (January 1992 to December 1996) and period 2 (January 1997 to December 2001) were analyzed. Ophthalmologic records of infants with stages 3 to 4 ROP or laser-treated ROP were abstracted. chi(2)- and t-test were used to compare neonatal characteristics between periods. Logistic regression was used to identify risk factors associated with visual impairment (defined as visual acuity <or=20/60 or visual field restriction of 20 degrees binocularly).

RESULT

Of 1159 surviving infants, 887 were examined for acute ROP (473 in period 1, 414 in period 2). Stages 3 to 4 ROP or laser-treated ROP were present in 35 infants in period 1 (7%) and 59 in period 2 (14%), P<or=0001. Infants born in period 2 had lower mean BW and gestational age. Among infants who developed severe ROP or laser-treated ROP, binocular visual impairment was present in eight children in period 1 and seven in period 2. Refractive errors, including myopia and astigmatism, were increased in period 2. Children who developed periventricular leucomalacia had the highest risk of visual impairment at 4 to 6 years of age.

CONCLUSION

During the 10-year study period, a significant increase in rates of stages 3 to 4 or laser-treated ROP was not associated with increases in visual impairment rates.

Treatment for retinopathy of prematurity in Denmark in a ten-year period (1996 2005): is the incidence increasing?

OBJECTIVE

The objective of this study was to analyze the population incidence of retinopathy of prematurity treatment in Denmark in the 10-year period from 1996 to 2005.

METHODS

Patient charts of infants treated for retinopathy of prematurity and the national birth registry provide information about neonatal parameters. These parameters, along with birth in the latter half of the period (2001-2005), were analyzed as risk factors for retinopathy of prematurity. The national registry for blind and visually impaired children was accessed to obtain information about visual impairment attributable to retinopathy of prematurity in both treated and untreated infants.

RESULTS

The study population consisted of 5467 Danish preterm infants born in 1996 to 2005, with a gestational age of < 32 weeks, who survived for > or = 5 postnatal weeks; 2616 were born in 1996 to 2000, and 2851 were born in 2001 to 2005. The incidence of treated retinopathy of prematurity cases increased significantly from 1.3% in 1996 to 2000 to 3.5% in 2001 to 2005. Significant risk factors for retinopathy of prematurity treatment were low gestational age, small for gestational age, male gender, and multiple birth. Other, yet unknown factors contributed to the increased incidence in the latter half of the period. Of the study population, 0.6% were registered as visually impaired because of retinopathy of prematurity within 2 years after birth (early-detected visual impairment). The incidences were not significantly different between 1996 to 2000 and 2001 to 2005. Of all of the early-detected, visually impaired children, 16% had not been treated for retinopathy of prematurity and were considered screening failures.

CONCLUSIONS

The incidence of retinopathy of prematurity treatment in Denmark has more than doubled during the past half-decade. This increase could not be fully explained by increased survival rates for the infants or by changes in the investigated neonatal risk factors.

Eye-hand co-ordination skills in very preterm infants <29 weeks gestation at 3 years: Effects of preterm birth and retinopathy of prematurity

INTRODUCTION

Preterm infants are known to have low gross motor and fine motor skills. We questioned whether poor eye-hand coordination skills are associated with moderate to severe stages of Retinopathy of Prematurity (ROP).

AIMS

The aim of this study was to examine development, with specific reference to eye-hand coordination skills, among preterm infants <29 weeks gestation with different stages of ROP at 3 years of age.

METHODS AND MATERIALS

Fifteen preterm infants (<29 weeks gestation) who developed Stage 3 ROP were matched for gestation, birthweight and gender with infants who developed Stage 2 and Stage 1/no ROP. Developmental (Griffiths Mental Development Scales and Peabody Developmental Motor Scales) and ophthalmic assessments in the 3 matched groups of 15 were performed at 3 years of age.

RESULTS

1) Whilst the eye-hand coordination scores and Peabody fine motor scores were lower in the Stage 3 ROP group, they were not significantly lower than the other ROP groups. 2) Locomotor, Peabody gross motor skills and hearing and speech were significantly lower in the infants with Stage 3 ROP. The other developmental domains were not significantly different to the severe ROP group. 3) All 3 groups (of preterm infants) had lower eye-hand coordination and Peabody fine motor scores compared to test norms. 4) There were 8 of 15 infants with Stage 3 ROP who developed moderate visual problems by 3 years of age.

CONCLUSION

In preterm infants, low eye-hand coordination/fine motor scores are likely to be due to their extreme prematurity.

Inflammation, brain damage and visual dysfunction in preterm infants

Antenatal intrauterine infection and the fetal inflammatory response appear to be important pathogenetic factors in preterm birth and subsequent neonatal disorders of the lung and brain. In this paper, we expand this concept to include visual dysfunction. Although present data tend to support our notion, we suggest that more experimental and epidemiological research is needed to elucidate mechanisms of infection/inflammation-induced damage to the eye and visual brain pathways of preterm infants.

Prenatal risk factors for severe retinopathy of prematurity among very preterm infants of the Australian and New Zealand Neonatal Network

OBJECTIVE

To identify prenatal and perinatal risk factors for clinically severe (stage 3 or 4) retinopathy of prematurity (ROP).

METHODS

Data were collected prospectively as part of the ongoing Australian and New Zealand Neonatal Network audit of high-risk infants (birth weight of <1500 g or gestational age [GA] of <32 weeks) admitted to a level III neonatal unit in Australia or New Zealand. Prenatal and perinatal factors to 1 minute of age were examined for the subset of infants with GA of <29 weeks who survived to 36 weeks' postmenstrual age and were examined for ROP (n = 2105). The factors significantly associated with stage 3 or 4 ROP were entered into a multivariate logistic regression model.

RESULTS

Two-hundred three infants (9.6%) had stage 3 or more ROP. Prematurity was the dominant risk factor, with infants with GA of <25 weeks having 20 times greater odds of severe ROP than infants with GA of 28 weeks. Birth weight for GA also had a "dose-response" effect; the more growth-restricted infants had greater risk, with infants below the 3rd percentile of weight for GA having 4 times greater odds of severe ROP than those between the 25th and 75th percentiles. Male gender was also a significant risk factor (odds ratio: 1.73; 95% confidence interval: 1.25-2.40).

CONCLUSIONS

These data, for a large, essentially population-based cohort, suggest that factors related to the degree of immaturity, intrauterine growth restriction, and male gender contribute to severe ROP.

Rétinopathie du prématuré : résultats de l’examen du fond d’œil chez 94 enfants à risque

PURPOSE

The purpose of this study was to evaluate the incidence and severity of retinopathy of prematurity (ROP) in infants of birth weight less than 1.500 g and/or under 32 weeks'gestation.

METHODS

Ninety-four preterm infants were examined following the Royal College of Ophthalmologists guidelines and retinopathy was graded using the International Classification of ROP. Screening limits were 1 500 g birth weight or 32 weeks'gestational age. Fundus examinations for ROP were performed at 5 weeks'chronological age from birth. Pupil dilation was obtained with instillation of 1% tropicamide three times at 15-minute intervals.

RESULTS

The 94 infants examined for ROP had a median gestational age of 292.3 weeks and a median birth weight of 1 110340 g. ROP was diagnosed in 21 of 94 subjects (22.3%) by fundus examination. ROP stage 3 developed in one preterm infant, ROP stage 2 developed in five preterm infants, and ROP stage 1 developed in 15 preterm infants. No premature babies developed stage 4 or stage 5 ROP. The disease regressed spontaneously in all cases and none of the infants required cryo/laser therapy. In the most premature infants, 23-26 weeks'gestation, 57% developed ROP and one developed severe ROP (stage 3). No disease more posterior to peripheral zone 2 was observed. The incidence of ROP was higher in infants exposed to greater than 21% oxygen (24.2%) than in infants who did not receive oxygen (17.8%). Oxygen, blood transfusion, and cardiopathy appear to be associated with an increased incidence of retinopathy of prematurity.

CONCLUSIONS

ROP continues to be a common problem associated with prematurity in France. This study found a similar incidence of prethreshold ROP when compared to recent studies. The data showed that blood transfusion and cardiopathy may play a role in the development of ROP in premature infants.

Retinopathy of prematurity in infants with birth weights greater than 1250 grams

PURPOSE

To determine whether severe retinopathy of prematurity (ROP) occurs in infants whose birth weights exceed 1250 g.

METHODS

We retrospectively reviewed the medical records of 1118 premature infants with birth weights > 1250 g, who were referred for screening examinations for ROP, to determine the severity of ROP observed. We then cross-tabulated these data with each infant's estimated gestational age and birth weight. Finally, we applied currently recommended screening guidelines retrospectively to determine whether they would have identified infants who had developed severe disease and who were subsequently treated.

RESULTS

Stage 3 ROP was detected in infants with estimated gestational ages up to and including 32 weeks and birth weights up to and including 1874 g. A total of 26 of the participants received laser treatment for threshold ROP. Seven of these infants would not have been referred for screening according to current guidelines.

CONCLUSIONS

Current screenings guidelines may fail to detect severe ROP in larger, more mature infants.

Screening for retinopathy of prematurity: evaluation and modification of guidelines

AIMS

To evaluate current screening guidelines for ROP (retinopathy of prematurity) and to determine whether they can be modified.

METHODS

In accordance with the authors' present criterion, infants born in Stockholm County, Sweden, from 1 August 1998 to 31 July 2000, with a gestational age of < or =32 weeks, were screened for ROP. The effectiveness of screening was studied.

RESULTS

The incidence of ROP was 25.5% in this study. A dropout group comprising almost 20% of the population studied (< or =32 weeks), was never referred, were lost to follow up, or died before screening was completed. No infant with a gestational age of >31 weeks at birth developed severe ROP (stages 3-5) and no infant with a gestational age of >29 weeks was treated for ROP.

CONCLUSION

80% of infants in this population with a gestational age at birth of < or =32 weeks, the current screening criterion, were effectively screened for ROP. The authors recommend that the screening criterion be lowered to Collapse

Key Words

• retinopathy of prematurity
• screening
• guidelines

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MESH Headings

• Birth Weight
• Female
• Gestational Age
• Humans
• Incidence
• Infant, Newborn
• Infant, Premature
• Logistic Models
• Male
• Practice Guidelines as Topic
• Predictive Value of Tests
• Prospective Studies
• Regression Analysis
• Retinopathy of Prematurity/diagnosis
• Retinopathy of Prematurity/epidemiology
• Sweden/epidemiology
• Vision Screening/methods

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Affiliation(s)

E Larsson Department of Ophthalmology, University Hospital, Uppsala, Sweden
G Holmström

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Incidence of ROP in two consecutive Swedish population based studies

AIMS

To prospectively analyse the present incidence of ROP (retinopathy of prematurity) in a well defined geographical area in Sweden, and to compare it with that from a decade earlier in exactly the same area.

METHODS

Infants born between 1 August 1998 and 31 July 2000 with a birth weight of 1500 g or less were studied. They were screened for ROP from 5 weeks of postnatal age until the retina was entirely vascularised. The incidence of ROP, with its various stages, was compared with that of a previous (1988-90) population based study in the same geographical area.

RESULTS

The incidence of ROP in the present study was 36.4% (mild (18.2%) and severe ROP (18.2%)), which was similar to that of the previous study. Gestational age at birth remained the most important risk factor for ROP. We found a change in the distribution of ROP. The probability of ROP, particularly severe ROP, was highest in the most immature infants while it was lower in the least immature ones.

CONCLUSIONS

The incidence of ROP remained the same in two consecutive population based studies. The more "mature" infants developed ROP, particularly severe ROP, less often, while the most immature infants had ROP more often, particularly severe ROP.