Retinopathy of prematurity in infants less than 29 weeks' gestation: 3 1/2 years pre- and postsurfactant

Change in the incidence and severity of Retinopathy of Prematurity (ROP) in a Neonatal Intensive Care Unit in Northern India after 20 years: Comparison of two similar prospective cohort studies

PURPOSE

To report the change in incidence and severity of retinopathy of prematurity (ROP) in the neonatal unit of a tertiary hospital after a 20-year period.

METHODS

A prospective cohort study of one-year duration was conducted between July 2013 and June 2014 in the neonatal intensive care unit (NICU) of a tertiary hospital. Inborn babies with birth weight ≤1700 g and gestational age ≤37 weeks were included. Change in incidence and severity of ROP were compared to a similar study in the same NICU between January and December 1993.

RESULTS

The 2013 study included higher numbers of newborn infants than the 1993 study (293 vs. 157). The mean (SD) birth weight and gestational age of the infants in the 2013 study were significantly lower than the 1993 study [1288.6 (229.8) vs. 1378.1 (232.6) g); p = 0.0001 and 31.7 (2.1) vs. 32.2 (2.31) weeks; p = 0.04]. Nevertheless, the overall incidence of ROP decreased from 49% to 26.6% (p < 0.001) after the 20-year interval. The incidence of stage 3 ROP decreased non-significantly from 24.7% to 12.8% (p = 0.058). Multivariate logistic regression analysis showed that birth weight ≤1250 g and belonging to the 1993 cohort were independently associated with an increased risk of ROP after adjusting for covariates (p = 0.013).

CONCLUSION

The incidence of ROP improved significantly over a 20-year period in association with improved NICU management strategies despite an increase in the number of eligible neonates with lower birth weights and gestational ages.

Ocular Findings in Low Birthweight and Premature Babies in the First Year: Do We Need to Screen?

Purpose

There is no standardized approach for the ophthalmic care follow-up of children screened for retinopathy of prematurity (ROP). The authors report the ocular findings at 12 months in preterm and low birthweight babies screened for ROP over a 5-year period (1998–2003).

Methods

The case notes of 211 babies were retrospectively reviewed for birth details, maternal details, presence of ROP, and findings at follow-up screening which included visual acuity, refraction at 12 months, presence of squint, and any other ocular problems.

Results

At 1 year follow-up, 16.6% of ROP positive children failed a screening visit because of squint (6.66%), refractive error (6.66%), and optic nerve abnormalities (3.33%). At 1 year follow-up, 10% of ROP negative children had failed a screening visit because of squint (3.75 %), refractive error (3.75%), and other pathology (2.5%).

Conclusions

The authors recommend screening all babies with ROP at 12 months to identify amblyogenic factors such as squint and refractive error. Parents of infants who do not develop ROP should be advised of the increased risk of visual problems in their children and to have their child examined in the preschool period.

Increased use of heated humidified high flow nasal cannula is associated with longer oxygen requirements

AIM

There has been an increased use of heated humidified high flow nasal canula (HFNC) in premature babies (PBs) admitted to our neonatal unit. The aim of this study is to identify clinical characteristics in PBs < 29 weeks gestational age (GA) that distinguish between those who did not or did receive HFNC.

METHODS

This study compared prospectively collected data from 2010 to 2012. Comparisons were undertaken between PBs<29 weeks GA who received continuous positive airway pressure (CPAP: 44/72 (61.1%)) to those who received both CPAP and HFNC (28/72 (38.9%)). Data were analysed using general linear models.

RESULTS

There were no significant differences in baseline characteristics between the groups (GA: 27.6 ± 1.1 vs. 27.5 ± 1.1 (weeks), birth weight: 1066 ± 209 vs. 1057 ± 304 (grams) respectively). When analysing outcome measures with multivariate analysis, we found the corrected GA to cease CPAP and oxygen were significantly longer in the HFNC group (31.2 ± 2.1 vs. 32.7 ± 2.0 weeks, P = 0.01 and 32.8 ± 3.5 vs. 36.5 ± 2.8 weeks, P < 0.0001 respectively).

CONCLUSIONS

Increased use of HFNC has been associated with increased oxygen requirements. These findings highlight the need to review the use of HFNC in small PBs.

Incidence and risk factors for retinopathy of prematurity in extreme low birth weight Chinese infants

The objective of this study is to determine the incidence and risk factors of retinopathy of prematurity (ROP) in extremely low birth weight (ELBW) Chinese infants. A retrospective medical record review of all ELBW (≤1,000 g) neonates screened for ROP from 2007 to 2012 was performed in Hong Kong. ROP screening was conducted at 2 neonatal intensive care units by 3 pediatric ophthalmologists using the Royal College of Ophthalmologists ROP guideline and the International Classification of ROP. Maternal and neonatal covariates were analyzed using univariate and multivariate regression analyses for both ROP and Type 1 ROP. In 131 ELBW Chinese infants, the mean gestational age (GA) and birth weight (BW) were 27.3 ± 3.3 weeks and 806.9 ± 133.7 g, respectively. The incidence of ROP and Type 1 ROP was 53.4 and 14.5 %, respectively. For ROP, a lighter BW, smaller GA, vaginal delivery, postnatal hypotension, inotrope use, bronchopulmonary dysplasia, surfactant use, invasive mechanical ventilation, and supplementary oxygen were independent risk factors for ROP, while PET was protective (P ≤ 0.02). On multivariate analysis, a smaller GA was a risk factor, while PET and congenital heart disease were protective for ROP development (P ≤ 0.01). For Type 1 ROP, a lighter BW, smaller GA, surfactant use, and invasive mechanical ventilation were independent risk factors for ROP, while PET was protective (P ≤ 0.02). There were no significant covariates on multivariate analysis for Type 1 ROP. In ELBW, preterm Chinese infants, a smaller GA was a risk factor for ROP, while PET and congenital heart disease were protective for ROP development in multivariate analysis.

An epidemiological analysis of retinopathy of prematurity over 10 years

PURPOSE

To analyze the incidence of retinopathy of prematurity (ROP) in a single neonatal intensive care unit over 10 years to clarify its ROP profile and how it was modified by advances in neonatal care.

METHODS

Epidemiological data related to incidence and severity of ROP were collected over 10 years. Premature infants with a birth weight of less than 1,500 g underwent a screening fundus examination and ROP was defined according to the International Classification of Retinopathy of Prematurity. The survival rates and incidence of ROP were calculated and compared for two consecutive time periods (1995-1999 vs 2000-2004), dividing the study population into subgroups according to their birth weights and gestational age.

RESULTS

Data of 607 preterm infants were collected. Survival rate significantly improved in the later time period (from 76.6% to 88.6%). The incidence of total, severe, and surgical ROP did not differ overall in the two time periods despite changes in survival rate, although some changes occurred in the most immature infants over time.

CONCLUSION

Increased survival of immature infants seemed to correlate with an increased risk for severe ROP and need for retinal ablation therapy, even if the incidence did not reach statistical significance.

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.

Trends in the incidence of severe retinopathy of prematurity in a geographically defined population over a 10-year period

OBJECTIVE

To examine trends in the incidence of severe (> or =grade 3) retinopathy of prematurity (ROP) in infants with birth weight of < or =1250 g in a geographically defined population over a 10-year period.

METHODS

An observational study was conducted of all infants who had a birth weight < or =1250 g and were born to mothers who were resident in the county of Leicestershire, United Kingdom, during the period January 1, 1990, to December 30, 1999. Cases were identified by the Trent Neonatal Survey. The incidence of severe ROP (> or =grade 3) was compared in 2 successive 5-year periods: 1990-1994 and 1995-1999.

RESULTS

Comparing the first 5-year period (1990-1994) with the second (1995-1999), the total number of live births fell (60 789 vs 56 564). However, there was a significant increase in the number of births with birth weight < or =1250 g (including live and dead; 615 vs 734; live births only: 455 vs 556). Survival to 42 weeks of infants who were born at < or =1250 g was significantly better in the latter time period (203 vs 302; odds ratio [OR] for death: 0.54; 95% confidence interval [CI]: 0.39-0.75). The number of cases of severe ROP was 4 times higher during the second time period compared with the first (9 vs 36). A significantly increased risk for the development of severe ROP was seen during the second time period (OR: 2.92; 95% CI: 1.37-6.20). Even after allowing for the change in gestation induced by the improved survival during the second time period, the increased risk remained (OR: 2.81; 95% CI: 1.27-6.21).

CONCLUSIONS

There is strong evidence that the incidence of severe ROP among infants with birth weight < or =1250 g increased in the latter half of the last decade. The increased risk seems to be independent of the increase in survival.

Is retinopathy of prematurity increasing among infants less than 1250 g birth weight?

OBJECTIVE

Retinopathy of prematurity (ROP) is a complication seen in many very low birth weight infants. Severe ROP has been called a "marker" for severe disability. The purpose of this study was to evaluate the occurrence and severity of ROP among infants < or =1250 g birth weight treated in the Special Care Nursery at Women & Infants' Hospital over a period of 7 years from 1994 to 2000.

STUDY DESIGN

This was a retrospective review of ROP data combined with neonatal follow-up data. Of the 1002 infants born with birth weights <1250 g, ophthalmologic data were available for 739 of 839 survivors. Analysis of variance and chi2 along with logistic regression were used to analyze outcomes.

RESULTS

An increase in the overall occurrence of ROP was identified (40% to 54% linear trend, p=0.007). The occurrence of threshold ROP ranged from 2% to 5% (NS). Infants at greatest risk of ROP were those micropremies with birth weights <750 g (p<0.001).

CONCLUSION

Severe ROP continues to be a significant morbidity among infants <750 g.

The management of retinopathy of prematurity

Retinopathy of prematurity (ROP) is a major problem in both highly developed countries and countries with emerging technology. The incidence of ROP has been stable over the last 2 decades despite improvements in neonatology. Threshold ROP occurs in about 5% of premature infants in the US with birthweights <1.25kg. Despite treatment, a sizable minority will become blind (up to 20 to 30%). The pathophysiology of ROP can be separated into 2 phases. Phase I is hyperoxia-vasocessation. Phase II is hypoxia-vasoproliferation. The former occurs immediately following premature birth. The provision of supplemental oxygen causes retinal hyperoxia, a down regulation of vascular endothelial growth factor (VEGF) and a consequent cessation of normal retinal vascularisation. Systemic factors and increasing retinal metabolic demands cause a shift to phase II when a relative retinal hypoxia develops. This hypoxia stimulates VEGF production, leading to renewed vascularisation. This can be the resumption of normal vascularisation or abnormal neovascularisation, depending on local retinal responses. The management of ROP begins with a reliable evidence-based screening protocol. All interested parties must cooperate in developing and implementing foolproof screening protocols. Hospital officials, nursery personnel, neonatologists and ophthalmologists all have areas of responsibility in ensuring adequate screening. ROP management involves prevention, interdiction and correction. Prevention includes: adequate prenatal care which minimises premature birth, and appropriate systemic intensive care which lessens the tissue hyperoxia/hypoxia swings. Pharmacological vitamin E supplementation has largely been abandoned and ambient light reduction has been shown to be ineffective. The value of inositol supplementation and angiogenesis inhibitors in preventing ROP is presently under investigation. Interdiction concentrates on ablation of the peripheral avascular retina, thus dramatically decreasing VEGF production. Both cryotherapy and laser photocoagulation are effective; however, unfortunately, poor outcomes persist despite treatment. Supplemental oxygen administration has so far proven ineffective in limiting ROP progression. Finally, correction focuses on vitrectomy/retinal detachment repair. While anatomically successful, this procedure is often unsuccessful in terms of restoration of vision (<5% success rate). In conclusion, despite improvements in neonatology, ROP, potentially leading to blindness, continues to be a common problem associated with prematurity. Future management success must concentrate on discovering new modes of treatment, especially prevention.

Decreased incidence of retinopathy of prematurity, 1995-1997

PURPOSE

To report a significant decrease in the incidence of retinopathy of prematurity (ROP), both in our neonatal intensive care unit (NICU) and internationally, and review factors in patient care that may be contributory.

METHODS

We retrospectively reviewed the records of all neonates weighing less than 1251 g admitted to our NICU from 1995 to 1997 and evaluated the incidence and stage of ROP. These data on 191 neonates were compared with an international NICU database of 9989 similar neonates, which represents all infants who received an ophthalmologic examination in the Vermont-Oxford Network Database (VOND) in 1997, except those from our institute (the University of Kentucky). In addition to investigating the incidence of ROP, we looked at the use of antenatal corticosteroids given 1 to 7 days prepartum, the use of oxygen at 36 weeks' postconceptional age, and the use of oxygen at home upon discharge.

RESULTS

In our center, we had a 36.1% incidence of ROP compared with an international incidence of 57.2% for the VOND in 1997 (P <.0001). Antenatal corticosteroids were given to 62.6% of infants in our center compared with 48.6% in the VOND (P <.005). In addition, 48.5% of our infants weighing less than 1500 g received oxygen at 36 weeks' postconceptional age versus 29.5% of the VOND infants (P <.001). Upon discharge to home, 37.5% of our infants were on oxygen compared with 15.6% of infants from all VOND centers, excluding the University of Kentucky (P <.001).

CONCLUSION

The incidence of ROP in our center from 1995 to 1997 and in the VOND in 1997 show a significant decrease from the 65.8% incidence from 1986 to 1987 reported by the Multicenter Trial of Cryotherapy for ROP.

New developments in neonatology: less severe retinopathy of prematurity?

PURPOSE

To determine the effects of surfactant replacement therapy (SRT), high-frequency oscillatory ventilation (HFOV), and general improvements in quality of care on the incidence of severe retinopathy of prematurity (ROP).

METHODS

Retrospective comparison of the incidence and severity of ROP in two groups of preterm infants admitted to our neonatal intensive care unit (NICU) in two consecutive 5-year periods (1986-1995) and screened for ROP. During the second study period, natural surfactant was introduced in the treatment of respiratory distress syndrome (RDS) and HFOV was used for treatment of respiratory insufficiency of any origin. The effects of these developments and general improvements on the incidence of severe ROP were analyzed with stepwise logistic regression.

RESULTS

The overall incidence of ROP from 1986-1990 was not significantly different from the incidence of ROP from 1991-1995. The incidence of severe ROP (ROP stage 3 or greater) was significantly lower in the second period (15.7% versus 6.4%, P=.015). For infants <1000 g, the incidence of overall ROP was increased significantly during the second study period (47.6% versus 60.1 %, P=.045), although the incidence of severe ROP remained unchanged. Only SRT was associated with a decreased risk for severe ROP; HFOV and general improvements in quality of care had no influence on the outcome. In patients with RDS, the incidence of severe ROP decreased significantly during the second period.

CONCLUSION

Of the recent new developments in neonatology, only SRT was associated with a decreased risk for severe ROP.

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

OBJECTIVE

To study the incidence and severity of retinopathy of prematurity (ROP) in infants < 32 weeks' gestation.

DESIGN

Review of the records maintained in the New South Wales Neonatal Intensive Care Unit Study (NICUS) database on infants admitted to the neonatal intensive care units (NICU) in NSW from 1 January 1993 to 31 December 1994.

RESULTS

In the more premature infants, 23-26 weeks' gestation, 65% developed ROP (102 of 157 examined for ROP). Forty-four infants (28%) developed severe ROP (Stage ≥ 3 ROP), 19 infants (12.1%) required cryo/laser therapy and one infant (0.6%) in this group had a retinal detachment. One hundred and fifty-seven of 159 surviving infants (98.7%) were examined for ROP. In the infants 27-28 weeks' gestation, 38.3% developed ROP (103 of 269 examined for ROP). Fifteen infants (5.6%) developed severe ROP, seven infants (2.6%) required cryo/laser therapy for threshold ROP and three infants (1.1%) in this group had a retinal detachment. Two hundred and sixty-nine of 299 surviving infants (90%) were examined for ROP. In the infants 29-31 weeks' gestation, 10.8% developed ROP (48 of 443 examined for ROP). Six infants (1.4%) developed severe ROP, one infant (0.2%) required cryo/laser therapy for threshold ROP and no infant in this group had a retinal detachment. However, only 443 of 681 surviving infants (65.1%) in this group were examined for ROP. Of the four infants with detached retinas, one was a 25 week gestation infant weighing 840 g, two were 27 weeks' gestation weighing 960 and 980 g and one infant was a 28 week gestation infant weighing 620 g. No infant developed Stage 5 ROP.

CONCLUSION

In the more mature infants 29-31 weeks' gestation, the rate of ROP is low, although severe ROP still occurs. However, only 65.1% of these infants were examined for ROP and we should be diligent in screening for ROP in the sicker infants in this group. The incidence of severe ROP as well as the rate of cryo/laser therapy in premature infants 23-26 weeks' in NSW has not changed since the increases seen in the early 1990s. Retinal detachment also occurs in the infants 27-28 weeks' gestation and it is important that all these infants are screened for ROP.

Dexamethasone reduces oxygen induced retinopathy in a mouse model

Dexamethasone is widely used in the postnatal period. Its impact on retinopathy of prematurity (ROP) is extremely controversial; published studies have found a detrimental, protective, or no effect on ROP. The goal of this study was to test the hypothesis that use of dexamethasone during the injury phase (oxygen exposure) reduces the severity of oxygen-induced retinopathy (OIR) in a mouse model. C57BL6 mice pups were exposed to either room air or hyperoxia (75% FiO2) from postnatal d 7 through 12 (PN7-12) with or without dexamethasone (0.5 mg/kg/d s.c.) and killed on PN17-21. Retinopathy was assessed by a scoring system of retinal flat mount preparations and periodic acid-Schiff (PAS) staining of retinal sections. Pups exposed to dexamethasone and oxygen had a lower median retinopathy score of 5 (4, 6) [median (25th, 75th quartile)] compared with animals exposed to oxygen alone with median score of 9 (6, 10) with p < 0.001. PAS staining for extra retinal neovascularization in the dexamethasone and oxygen treated animals showed a significant reduction in number of nuclei extending beyond the inner limiting membrane when compared with oxygen exposed alone (p = 0.04). Animals treated with dexamethasone had decreased weight gain compared with control animals. Dexamethasone did not appear to affect the normal development of retinal vasculature as assessed by the scoring system when compared with control animals. Thus, dexamethasone decreases severity of OIR without having an adverse effect on normal retinal vascular development in the mouse model. We speculate that dexamethasone decreases the injury response that occurs during the hyperoxic phase, thus protecting the developing vasculature and improving the subsequent retinopathy.

The decreasing incidence and severity of retinopathy of prematurity

PURPOSE

We sought to determine whether the incidence of retinopathy of prematurity (ROP) at our institution has changed since the Cryo-ROP recruitment period 10 years ago.

METHODS

We determined the incidences of threshold ROP, prethreshold ROP, less-than-prethreshold ROP, and no disease for each of 3 birth weight classes (<750 g, 750 to 999 g, and 1000 to 1250 g) of infants born between July 1, 1995, and June 30, 1996, and cared for in the Vanderbilt Neonatal Intensive Care Unit. We then compared these with the rates from our institution during the Cryo-ROP study recruitment period (January 1, 1986, to November 30, 1987).

RESULTS

The current incidence and severity of ROP have decreased substantially overall and for each weight group compared with the 1986-87 incidence (P < .001, Cochran-Mantel-Haenszel test). The incidence of "any ROP" decreased by 27% for infants with birth weights less than 750 g, by 51% for infants 750 to 999 g, and by 71% for infants 1000 to 1250 g. The incidence of "prethreshold or greater ROP" decreased by 70% for the 750 to 999 g and 77% for the 1000 to 1250 g weight groups. Although the decrease in "prethreshold or greater ROP" was not as dramatic (25%) for the infants less than 750 g, only 1 infant (10%) progressed to threshold disease in this group, whereas 7 (47%) did in 1986-87. The incidence of threshold ROP decreased by 84% for infants less than 750 g and by 66% for infants 750 to 999 g. No infant with birthweight greater than 999 g progressed to threshold ROP.

CONCLUSIONS

The incidence of all levels of ROP has decreased substantially for all infants with birth weights less than 1251 g at Vanderbilt University Medical Center during the past decade. Putative factors responsible for this decrease may include surfactant use, continuous pulse oximetry, aggressive use of antenatal steroids, and improved neonatal nutritional support.