Decreased incidence of retinopathy of prematurity, 1995-1997

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.

A Retrospective Analysis of Retinopathy of Prematurity (ROP) in a Tertiary Newborn Intensive Care Unit: Incidence and Risk Factors of ROP

Background Retinopathy of prematurity (ROP) is the most frequent problem which causes blindness in preterm babies. In our study we evaluate the frequency of retinopathy, the risk factors, and their effects on disease development in premature newborns admitted to our neonatal intensive care unit (NICU).

Methods A total of 139 premature infants with gestational ages less than 34 weeks followed in our NICU between January 1, 2008 and January 1, 2011. The infants were divided into two groups as group 1 (no ROP/mild ROP) and as group 2 (severe ROP).

Results The demographics of 139 patients were as follows: 79 (56.83%) were female and 60 (43.17%) were male. Overall, 104 (74.8%) patients were found to have no or mild ROP and 35 (25.2%) had severe ROP. Among the patients in the severe ROP group, 25 of them had plus disease. With logistic regression analysis, lower gestational age (odds ratio [OR]: 4.1, confidence interval [CI]: 1.9–9.2), the central catheter usage (OR: 13.4, CI: 1.2–146.6), hypotension (OR: 7.5, CI: 1.1–49.6), perinatal asphyxia (OR: 261.3, CI: 8.8–7725.4), apnea (OR: 18.1, CI: 1.6–202.6), and high FiO2 (OR: 1.2 CI: 1.0–1.5) were found to be related to severe ROP.

Conclusion Among the preterms with very low body weight included in our study, we found that the frequency of severe ROP requiring treatment was low. The most important factors related to severe ROP were found to be low gestational age and birth weight. Being aware of the risk factors related to severe ROP in addition to screening every preterm infant carrying these risk factors is extremely important for the early diagnosis and treatment to prevent blindness due to severe retinopathy.

Clinico-demographic profile and outcomes of 25-gauge vitrectomy in advanced stage 5 retinopathy of prematurity

BACKGROUND

Stage 5 retinopathy of prematurity is a difficult condition to treat despite technological advances in vitreous surgery.

METHODS

A retrospective chart review of all consecutive cases of stage 5 ROP was performed between December 2016 and December 2018, and 21 babies were included for assessment of surgical outcomes using a modified vitrectomy technique. Data extracted from documents included demography, ROP screening status, preoperative prophylactic therapy, clinical presentation, surgery performed, and postsurgical outcomes.

RESULTS

Out of the 21 babies, ophthalmologist screening was done in 42.9%. Mean birth weight was 1185 ± 222.4 g with a mean gestational age of 29.86 ± 2.0 weeks and mean post-menstrual age of 44.55 ± 9.82 weeks. Lesser than stage 5 disease was seen in 16.7% of eyes and they were managed accordingly. Seventy percent of babies had bilateral disease. 21 eyes underwent 25-gauge pars plicata vitrectomy using a modified technique. After an average follow-up duration of 6.33 ± 2.18 months, the final macular attachment rate was 19%. Anteriorly closed-posteriorly closed type configuration of retinal detachments had a poorer outcome. Fix and follow visual acuity was achieved in 23.8% of eyes, while 57.1% of eyes had a perception of light.

CONCLUSIONS

Management of stage 5 ROP is mostly surgical; however, the risk of ending up with a poor vision or vision loss is high, irrespective of whether surgery is performed. The modified surgical technique with a spacer described in this study may help in better manipulation of instruments inside the vitreous cavity.

The efficacy of propranolol in very preterm infants at the risk of retinopathy of prematurity: Which newborn and when?

PURPOSE

Retinopathy of prematurity (ROP), a proliferative vitreoretinopathy resulting from the vascular disorder of the retina, is the most frequent cause of blindness in childhood. In our time, ROP in advanced stage, a serious problem in premature infants, has no other treatment more effective and with fewer side effects than laser photocoagulation (LPC) treatment, which narrows visual field. The search for methods with fewer side effects than LPC has increased in recent times for the treatment of ROP. We aimed to investigate the effects in question of propranolol on ROP in various stages (stages 1, 2, and 3 ROP).

METHODS

This study is designed as a randomized, placebo-controlled, single-centered, double-blind clinical trial with parallel groups. A total of 126 very preterm infants, followed up in our unit from April 2011 to January 2013, were randomly selected and included in our study. They were separated into the groups of 0, 1, and 2 depending on their stage of ROP. In addition, all the patients were divided into control group (CG) and propranolol treatment group (PTG). While the cases in the CG were administered physiological saline solution, the cases in the PTG were administered propranolol (2 mg/kg/day) in the neovascularization phase (second phase) of the ROP.

RESULTS

Propranolol given to the group of stage 0-1 ROP was observed to have had no effect on the level of statistical significance between the CG and PTG in terms of increase in ROP stages (p > 0.05). However, propranolol was found to be more useful in patients with stage 2 ROP (p < 0.05).

CONCLUSION

When given in the neovascularization phase of the ROP, propranolol was found to be effective in the stage 2 (advanced stage) ROP patients but in stage 0-1 (early-stage) ROP patients, its efficacy was not sufficient.

Changes in Course of Retinopathy of Prematurity from 1986 to 2013: Comparison of Three Studies in the United States

PURPOSE

To compare infant and retinopathy of prematurity (ROP) characteristics from 3 clinical studies conducted over a 27-year period in the United States.

DESIGN

Secondary analysis of results of 3 clinical studies.

PARTICIPANTS

Infants with birth weight (BW) <1251 g.

METHODS

Analysis of data from the Cryotherapy for Retinopathy of Prematurity (CRYO-ROP) and Early Treatment for Retinopathy of Prematurity (ETROP) trials and the primary data from the Telemedicine Approaches for the Evaluation of Acute-Phase Retinopathy of Prematurity (e-ROP) study.

MAIN OUTCOME MEASURES

Infant characteristics and onset, severity, and time course of ROP.

RESULTS

Across the 3 studies, mean (standard deviation) BW and mean gestational age (GA) decreased over time from CRYO-ROP (954 g [185 g], 27.9 weeks [2.2 weeks]) to ETROP (907 g [205 g], 27.4 weeks [2.2 weeks]) to e-ROP (864 g [212 g], 27.0 weeks [2.2 weeks]), with an increase in the percentage of infants enrolled weighing <750 g (15.8% CRYO, 24.9% ETROP, 33.4% e-ROP; P<0.0001). The percentage of infants who developed ROP varied only minimally (65.8% CRYO, 68.0% ETROP, 63.7% e-ROP; P = 0.003). Moderately severe ROP (defined as prethreshold or referral warranted) varied (17.8% CRYO, 12.3% ETROP, 19.4% e-ROP; P<0.0001), whereas the time of onset of any ROP did not vary (34.3 weeks CRYO, 34.1 weeks ETROP, 34.8 weeks e-ROP).

CONCLUSIONS

The BW and GA of infants enrolled in ROP studies in the United States have decreased over the past 27 years, whereas ROP prevalence and onset of disease are stable.

The Efficacy of Propranolol in Retinopathy of Prematurity and its Correlation with the Platelet Mass Index

PURPOSE

Retinopathy of Prematurity (ROP) is a proliferative vitreoretinopathy which is one of the most frequent causes of blindness in children. In an attempt to find a solution to this important problem in preterm children, the search for new, effective treatment modalities with fewer side effects is underway. In our study, which was planned for this reason, we aimed to investigate the effects of propranolol treatment applied to cases of ROP in various stages during the second phase (known as the neovascularization-hypoxia phase) and to determine the correlation of these effects with the platelet mass index (PMI).

METHOD

A total of 171 preterm infants at risk of ROP were selected randomly for inclusion in the study. All of the patients were classified according to their stage of ROP and were divided into control and treatment groups. While the cases in the control group were administered physiological saline solution, those in the treatment group were administered propranolol in the period that corresponded to the second stage of the disease. The thrombocyte and PMI values in the first and second stages of each study group were recorded.

RESULTS

A significant difference was found between the control and treatment groups of the stage 2 ROP study subjects. In the stage 2 ROP study group, no significant difference was detected between the control and treatment cases in terms of platelet counts in phase 1 or in the PMI values and the thrombolytic counts in phase 2. On the other hand, in phase 2 of the stage 2 ROP study subjects significant differences were detected between the control and treatment group in terms of PMI values.

CONCLUSION

In the study, it was found in the stage 2 ROP study group that propranolol reduced the need for laser photocoagulation significantly. Also, in parallel to the efficacy of propranolol in this study group, a decrease was observed in PMI values.

Incidence of retinopathy of prematurity and risk factors among premature infants at a neonatal intensive care unit in Canada

PURPOSE

To study the incidence of retinopathy of prematurity (ROP) in a neonatal intensive care unit and obtain information on risk factors associated with ROP.

METHODS

Four hundred twenty-three infants were screened for ROP between July 2006 and July 2010. Demographic information, clinical data, and risk factors were reviewed.

RESULTS

The incidence was 40.4% (171 infants) for ROP, 9.2% (39 infants) for severe ROP, and 5.67% (24 infants) for laser treatment. Mean gestational age and birth weight were significantly lower among infants with ROP versus those without ROP (26 ± 0.13 vs 28.55 ± 0.12 weeks, P < .0001 and 840.5 ±17.49 vs 1,190.24 ± 20.20 g, P < .0001, respectively). Birth weight (P < .001), gestational age (P < .001), mechanical ventilation therapy (P = .039), and necrotizing enterocolitis (P = .019) were independent risk factors for ROP.

CONCLUSION

Gestational age and birth weight were the most significant risk factors for developing ROP. The study population had an elevated percentage of infants with birth weight less than 1,000 g (extremely low birth weight), yet there was no corresponding increase in severe ROP incidence and treatment when compared to other studies.

Analysis of incidence and risk factors of retinopathy of prematurity among very-low-birth-weight infants in North Taiwan

BACKGROUND

Although significant advances have been made in perinatal care, retinopathy of prematurity (ROP) remains a serious complication in prematurely born individuals. There have been limited studies on ROP in Taiwan, and most of those existing reports are outdated.

METHODS

This retrospective study included 252 very-low-birth-weight (VLBW) infants admitted to the neonatal intensive care unit of Chang Gung Children's Hospital over a 2-year period between July 2005 and June 2007. All infants were examined for ROP according to the guidelines published by the American Academy of Pediatrics. The relationship between clinical risk factors and the development of ROP was analyzed.

RESULTS

Of the 252 VLBW infants, 216 met the screening criteria. Of the 216, 99 (45.8%) had ROP. Compared with neonates born at 29 weeks of gestational age (GA) or later, those very premature infants of ≤25 weeks' and 26-28 weeks' GA had increased odds ratios (OR) of 8.49 and 3.19, respectively, for the development of severe ROP. No ROP was detected in infants of greater than 33 weeks' GA. The simultaneous presence of a low GA, low birth weight (LBW), lower Apgar scores, hypotension, patent ductus arteriosus, septicemia, intraventricular hemorrhage, ventilator dependence, and use of postnatal steroids was associated with severe ROP. Using multiple logistic regression analyses for ROP, only maternal preeclampsia [OR, 2.52; confidence interval (CI), 1.32-4.7]; duration of mechanical ventilation (OR, 1.06; CI, 1.04-1.08); and LBW (OR, 2.62; CI, 1.370-3.375) predicted the development of threshold ROP.

CONCLUSION

The incidence of ROP among VLBW infants was 45.8%; 19.0% had severe ROP. Infants of lower GAs and/or with LBW, whose mother had preeclampsia or who had a long duration of mechanical ventilation are at risk for the development of threshold ROP.

Effectiveness of ketorolac tromethamine in prevention of severe retinopathy of prematurity

PURPOSE

This study assessed the effectiveness of the use of ketorolac tromethamine to reduce retinopathy of prematurity (ROP) incidence and its progression to more severe forms.

METHODS

Forty-seven preterm newborn infants with a birth weight (BW) of 1,000 grams or less and/or a gestational age (GA) of 29 weeks or less were enrolled in the study when avascular retina zone I or ROP any stage were diagnosed at screening. Studied infants were randomized to receive ketorolac tromethamine ophthalmic solution in one eye and a drop of placebo in the other eye, until ROP requiring treatment or full retinal vascularization was diagnosed.

RESULTS

Only 2 newborn infants did not develop ROP. Among 45 newborn infants who developed ROP, 6 showed different ROP staging between the two eyes, 4 of which had a better outcome in the eye receiving ketorolac tromethamine. The differences between ROP stagings were not significant even when analyzed by GA and BW subgroups. No significant treatment-related side effects occurred.

CONCLUSION

This report suggests that ketorolac tromethamine ophthalmic solution cannot reduce the risk of developing severe ROP in preterm infants.

Erythropoietin and retinopathy of prematurity

Erythropoietin (EPO) is a glycoprotein that regulates many functions of an organism: It stimulates the production of red blood cells and it has angiogenic and neuroprotective properties in newborn infants. Retinopathy of prematurity (ROP) is a frequent cause of visual impairment in preterm newborn infants and it has two distinct phases in which hypoxia-induced angiogenic factors are involved. The relationship between EPO and ROP is derived from the observation of studies done on the haematopoietic effect of EPO. The first observations suggested that a precocious treatment with EPO increases the risk of ROP, while the most recent reports suggested that the late treatment with high doses of rhEPO can increase the risk of ROP. All these studies were not designed to demonstrate the relationship between EPO and ROP. Further studies specifically designed should be performed. New ongoing studies on the neuroprotective role of EPO should consider this objective. In the mean time the use of EPO in the neonatal period should be cautious, mainly in very low birth weight infants.

Risk factors and growth factors in ROP

Retinopathy of prematurity (ROP) is a multifactorial disease which incidence is increasing with increasing survival of very preterm infants. Pathogenic pathway is characterised by abnormal retinal vascular development modulated by vascular growth factors: low IGF-1 in the first phase and high VEGF in the second phase. Many causal factors are able to influence retinal vascularization: gestational age, birth weight, oxygen administration, perinatal bacterial or fungal infections, and blood transfusions. All risk factors, both oxygen and not-oxygen-regulated, have been studied considering the whole period from hospital birth to the hospital discharge, but it is possible that postnatal risk factors may be determinant in a time-dependent way. Analysis of factors involved in the pathogenesis of ROP suggests that their action begins long before anatomical clinical features become appreciable and this is strengthened by the essential role of risk factors from the first two to four weeks of life, thus preventive strategies in very preterm infants should be carried out since birth.

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.

Risk factors for acute retinopathy of prematurity

We prospectively studied the risk factors and the incidence of retinopathy of prematurity (ROP) in 195 consecutive preterm infants. Birth weight and duration of mechanical ventilation were the only factors that were significantly associated with the incidence of ROP. While indomethacin increases the risk of developing ROP, maternal antenatal steroids have a protective effect against the development of severe stages of ROP. The presence of intraventricular hemorrhage increases the risk of severe ROP.

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.

Risk factors for acute retinopathy of prematurity

We prospectively studied the risk factors and the incidence of retinopathy of prematurity (ROP) in 195 consecutive preterm infants. Birth weight and duration of mechanical ventilation were the only factors significantly associated with the incidence of ROP. While indomethacin increases the risk of developing ROP, maternal antenatal steroids have a protective effect against the development of severe stages of ROP. The presence of intraventricular hemorrhage increases the risk of severe ROP.

ANATOMICAL AND VISUAL RESULTS OF VITREORETINAL SURGERY FOR STAGE 5 RETINOPATHY OF PREMATURITY

PURPOSE

To provide a historical perspective on outcomes of surgery for infants with stage 5 retinopathy of prematurity (ROP) as performed by a single surgeon over a 24-year period.

DESIGN

Retrospective observational cohort study.

METHODS

SETTING

Clinical practice of the Charles Retina Institute.

PATIENTS

The 601 infants with stage 5 ROP in at least one eye who were referred for surgery between 1977 and 2001. Charts were reviewed for demographic data and postoperative anatomical and visual acuity outcomes in eyes that underwent surgery.

MAIN OUTCOME MEASURES

The postoperative anatomical status of the retina and visual function were assessed after surgery. Anatomical outcome was categorized as success (macula attached), partial success (macula detached), failure (total retinal detachment), or lost eye (opaque cornea, secluded pupil, or phthisis). Visual function was classified as>20/200, 20/200-5/200, hand movement, light perception, or no light perception. Multivariable logistic regression was used to explore relationships between outcomes and baseline characteristics.

RESULTS

Only a minority of eyes had prior cryotherapy (15%) or laser photocoagulation (7%) therapy. The mean follow-up was 44 months for the 956 eyes treated surgically. The 608 eyes with available follow-up data were classified as follows: 28% success, 5% partial success, 55% failure, and 11% lost eye. Visual function of light perception or better was achieved in 74% of the 183 eyes with data on visual acuity. Controlling for other baseline factors, early postpartum age at the time of surgery was a statistically significant predictor of failure/lost eye (OR=2.08, 95% CI 1.09-3.97) and no light perception (OR=5.13, 95% CI 1.45-18.14). Surgery for stage 5 ROP on the fellow eye was also a predictor of failure/lost eye (OR=2.38, 95% CI 1.39-4.08).

CONCLUSIONS

Surgery resulted in anatomical success for approximately one third of infant eyes with stage 5 ROP, and only a minority of eyes (8 of 183) achieved visual acuity better than 5/200. However, some initially successfully attached retinas redetached. Although this study is limited by follow-up and may represent a group of patients with a more vascularly active disease state due to the low proportion of patients with prior peripheral ablation, this cohort of infants provides results against which future interventions may be compared.

The incidence and course of retinopathy of prematurity: findings from the early treatment for retinopathy of prematurity study

OBJECTIVES

To estimate the incidence of retinopathy of prematurity (ROP) in the Early Treatment for Retinopathy of Prematurity (ETROP) Study and compare these results with those reported in the Cryotherapy for Retinopathy of Prematurity (CRYO-ROP) Study.

METHODS

The ETROP Study, as part of its protocol, screened 6998 infants at 26 centers throughout the United States. Serial eye examinations were conducted for infants born weighing <1251 g, making it possible to estimate the frequency of ROP in different birth weight and gestational age categories. ROP was categorized according to the International Classification for ROP.

RESULTS

The incidence of any ROP was 68% among infants of <1251 g. The findings were compared with those for infants born in 1986 and 1987 in the CRYO-ROP Study. The overall incidences of ROP were similar in the 2 studies, but there was more zone I ROP in the ETROP Study. Among infants with ROP, more-severe ROP (prethreshold) occurred for 36.9% of infants in the ETROP Study and 27.1% of infants in the CRYO-ROP Study. The gestational age of onset of ROP of different severities has changed very little since the CRYO-ROP Study was conducted.

CONCLUSIONS

ROP remains a common important problem among infants with birth weights of <1251 g. The incidence of ROP, time of onset, rate of progression, and time of onset of prethreshold disease have changed little since the CRYO-ROP natural-history study.

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.

Retinopathy of prematurity--risk factors

OBJECTIVE

Improved survival of low birth weight, premature babies have increased the incidence of retinopathy of prematurity. This hospital-based, prospective, study was undertaken to determine its incidence and risk factors in our neonatal unit.

METHODS

Neonates with gestational age < or = 35 weeks and/or birth weight < or = 1500 gm born over a one-year period were examined by indirect ophthalmoscopy between 2 to 4 weeks after birth, and followed up till retinal vascularisation was complete. Maternal and neonatal risk factors were noted and data analyzed by statistical package SPSS-10.0.

RESULTS

Sixty babies were thus examined. The incidence of retinopathy was 21.7% in the cohort, 33.3% in babies < or = 32 weeks gestation and 36.4% in babies weighing < or = 1250 gm. Oxygen (p=0.01), sepsis (p=0.04) and apnoea (p=0.02) were independent risk factors. Retinopathy was significantly more severe in babies with hyaline membrane disease (p=0.02) and lower birth weight (p=0.02). Severe disease was never seen before 6.5 weeks of age.

CONCLUSION

Indirect ophthalmoscopy should be performed at 4 weeks of post natal age in all preterm babies with birth weight < or = 1500 gm, and intensified in the presence of risk factors like oxygen administration, apnoea and septicemia.

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.

Ethical considerations in the management of infants born at extremely low gestational age

With ongoing improvements in technology and the understanding of neonatal physiology, there has been increasing debate regarding the gestational age and birth weight limits of an infants' capability of sustaining life outside the womb and how this is to be determined. The objective of this review was to address this issue with an analysis of current data (following the introduction of surfactant therapy in 1990) from published studies of survival in extremely low gestational age infants. We found that survival was possible at 22 completed weeks of gestation but only in < 4% of live births reported. Survival increased from 21% at 23 weeks gestational age to 46% at 24 weeks gestational age. Historically, despite continual advances in neonatology, the mortality at 22 weeks has not improved over the past three decades. Combining the data from studies on survival with evidence from developmental biology, we believe that it is not worthwhile to pursue aggressive support of infants born at < 23 weeks gestational age. Given the complicated issues related to morbidity and mortality in infants born at 22 to 25 weeks gestational age and the ethical implications of the available evidence, we propose the need for a consensus derived framework to help in decision-making.

[Retinopathy of prematurity: casuistics between 1996 and 2001]

BACKGROUND

Retinopathy of prematurity (ROP) is a cause of neurosensorial morbidity.

OBJECTIVES

To study the incidence, associated risks factors, treatment, and outcome of ROP in premature infants born at less than 32 weeks in our hospital.

METHODS

We performed a descriptive study of patients born between the January 1, 1995, and December 31, 2001, in Sant Joan de Déu Hospital in Barcelona (Spain) at <= 32 weeks of gestation who survived until their first month of life. An ocular evaluation was performed between weeks 4 and 6 of life and was repeated every 1-2 weeks until retinal vascularization was complete. Ocular sequelae and visual function were evaluated. Bivariate comparison of groups with and without ROP was performed.

RESULTS

Of the 324 patients evaluated, 74 presented ROP (22.8 %), of which 63 patients (21.7 %) were classified as stage 1 or 2 and 11 (3.7 %) as stage 3. An inverse correlation between the incidence of retinopathy and weight and gestational age was found. Threshold disease (3 plus) was detected in 9 patients (16 eyes; 3.1 % of the study sample and 12.1 % of the neonates with retinopathy). All of these neonates were treated with laser therapy. Ocular sequelae were mild in 2.7 % of the patients, moderate in 0.6 % and severe in 0.6 %. The visual function (n 236) of infants with ROP (n 74) was altered in 4 patients (1.7 %). Of these, alterations were severe in 2 patients (0.8 %). Bivariate analysis revealed significant differences (p < 0.001) in low birth weight, gestational age, days of oxygen therapy, days of mechanical ventilation, days of antibiotic therapy, and number of blood transfusions.

CONCLUSIONS

In this study the incidence of ROP was similar to that in other centers. Development of ROP was strongly associated with its various risk factors. Severe stages were not seen above 30 weeks of gestational age. The results of laser therapy were optimal, with fewer alterations in ocular examination and visual function than those estimated in patients without treatment.

Improved outcomes for very low birthweight infants: evidence from New Zealand national population based data

OBJECTIVE

To compare the survival and short term morbidity of all New Zealand very low birthweight (VLBW) infants born in two epochs, 1986 and 1998-1999.

SETTING

All level III and level II neonatal intensive care units (NICUs) in New Zealand.

METHODS

In 1986, data were prospectively collected for a study of retinopathy of prematurity (ROP). In 1998-1999, prospective data were collected by the Australian and New Zealand Neonatal Network (ANZNN). Both cohorts included all VLBW infants born during the calendar year and admitted to a NICU. Data were collected from birth until discharge home or death.

RESULTS

More VLBW infants were admitted for care in 1998-1999 (n = 1084, 0.96% of livebirths) than in 1986 (n = 413, 0.78% of livebirths; p < 0.001), including a higher proportion of VLBW infants of < 1000 g birth weight (38% v 32% respectively; p < 0.05). Survival to discharge home increased from 81.8% in 1986 to 90.3% in 1998-1999 (p < 0.001). The 1998-1999 cohort had a higher proportion of infants born in a hospital with a level III NICU (87% v 72% in 1986; p < 0.001) and receiving antenatal corticosteroids (80% v 58% in 1986; p < 0.001). In 1998-1999, the incidence of several morbidities had decreased compared with 1986, including oxygen dependency at 28 days (29% v 39% respectively; p = 0.001) and at 36 weeks postmenstrual age (16% v 23%; p = 0.002), grade 1 intraventricular haemorrhage (IVH) (8% v 24%; p < 0.001), grade 2/3 IVH (5% v 11%; p < 0.001), and stage 3/4 ROP for infants < 1000 g (6% v 13%; p < 0.001).

CONCLUSIONS

The outlook for VLBW infants in New Zealand has improved since 1986.

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.

Retinopathy of prematurity: causation

The incidence of ROP is birth weight dependent and restricting therapeutic oxygen levels has dramatically reduced the incidence of ROP in infants of birth weight >1000 g. However, the incidence of ROP has remained high in very low birth weight (VLBW) infants and this appears to be related to these babies being more ill. Several risk factors have been identified in this group, however oxygen variability, rather than high levels, has been correlated with severity of disease in recent clinical and animal studies. Difficulties in defining 'normal' oxygen in this group has meant the optimal range of oxygen therapy has not yet been defined. Clinical studies are now underway using even lower oxygen therapy ranges. The impact this may have on ROP, neurological and respiratory outcomes will require further study.