Retinopathy of prematurity in middle-income countries

Speed of telemedicine vs ophthalmoscopy for retinopathy of prematurity diagnosis

PURPOSE

To compare the speed of retinopathy of prematurity (ROP) diagnosis using standard indirect ophthalmoscopy with that of telemedicine.

DESIGN

Prospective, comparative study.

METHODS

Three study examiners (2 pediatric retinal specialists [R.V.P.C., T.C.L.] and 1 pediatric ophthalmologist [M.F.C.]) conducted ROP diagnosis via standard indirect ophthalmoscopy and telemedicine. Each examiner performed: 1) standard ophthalmoscopy on 72 to 150 consecutive infants at his respective institution and 2) telemedical diagnosis on 125 consecutive deidentified retinal image sets from infants from an at-risk population. Time for ophthalmoscopic diagnosis was measured in 2 ways: 1) time spent by the examiner at the infant's bedside and 2) mean total time commitment per infant. Time for telemedicine diagnosis was recorded by computer time stamps in the web-based system. For each examiner, nonparametric statistical analysis (Mann-Whitney U test) was used to compare the distribution of times for examination by ophthalmoscopy vs telemedicine.

RESULTS

Mean (+/- standard deviation [SD]) times for ophthalmoscopic diagnosis ranged from 4.17 (+/- 1.34) minutes to 6.63 (+/- 2.28) minutes per infant. Mean (+/- SD) times for telemedicine diagnosis ranged from 1.02 (+/- 0.27) minutes to 1.75 (+/- 0.80) minutes per infant. Telemedicine was significantly faster than ophthalmoscopy (P < .0001). The total time commitment by ophthalmologists performing bedside ophthalmoscopy for ROP diagnosis, including travel and communication with families and hospital staff, was 10.08 (+/- 2.53) minutes to 14.42 (+/- 2.64) minutes per infant.

CONCLUSIONS

The ophthalmologist time requirement for telemedical ROP diagnosis is significantly less than that for ophthalmoscopic diagnosis. Additional time requirements associated with bedside ROP diagnosis increased this disparity. Telemedicine has potential to alleviate the time commitment for ophthalmologists who manage ROP.

Wide-field digital imaging based telemedicine for screening for acute retinopathy of prematurity (ROP). Six-year results of a multicentre field study

Objective

To report on a 6-year experience with wide-field digital imaging based telemedicine (WFDI telemedicine) to reduce the risk for blindness from retinopathy of prematurity (ROP).

Methods

Wide-angle digital fundus cameras (RetCam 120, Massie Lab, Pleasanton, CA, USA) were installed in five neonatal intensive care units (NICUs) in Germany. All prematures at risk were screened with WFDI, and the local ophthalmologists were asked to continue binocular indirect ophthalmoscopy (BIO) according to the German guidelines. Image data were coded and transferred to the Reading Centre in Regensburg. Image evaluation and additional BIO of infants with suspected treatment-requiring ROP (STR-ROP i.e. threshold ROP zone II, prethreshold ROP zone I (type-1 ROP according to ETROP), and ROP possibly requiring treatment but not reliably classifiable from the images) were performed by paediatric ophthalmologists at the Reading Centre. ROP was classified following ICROP, ETROP, and revised ICROP criteria. Outcome measures were incidence of clinically relevant ROP (CR-ROP, i.e. any ROP up to mid-peripheral zone III, ≤ stage 3+), sensitivity to detect STR-ROP, and positive predictive value to detect treatment-requiring ROP (TR-ROP).

Results

In total, 1,222 prematures at risk were screened (mean BW 1395 g, SD ±507 g; mean GA 30 wks, SD ±3 wks). The overall incidence of CR-ROP was 27.6% (71.8% mild = stage 1 to 3 without plus disease, 15.7% prethreshold = type-1 ROP according to ETROP, 12.5% threshold according to ICROP). Zone I disease was present in 3.3%, zone II disease in 76.5%, and zone III disease in 20.2%. According to ETROP, 95 infants were type-1 or type-2 ROP; 67.4% type-1 ROP, and 32.6% type-2 ROP. Of all 1,222 infants, 3.5% received treatment. Following ETROP (not applied in the study), 5.3% would have been treated. The sensitivity for detecting STR-ROP was 100%, and the positive predictive value for TR-ROP 82.4% (28/34) at the time of the first referral (28 infants, ≤ stage 3+ in zone I or II).

Conclusion

All TR-ROP was detected in time, showing the potential of our telemedical screening program. The overall incidence of CR-ROP was comparable to ROP incidences reported in other West European countries.

The Impact of War and Economic Sanction on the Incidence of Retinopathy of Prematurity in Serbia

This study compared the distribution of various types of visual impairments among Serbian children who were born prior to the imposed economic sanctions and wars of the 1990s in the former Yugoslavia to that of children who were born during the years of economic sanctions and active war.

SNPs: impact on gene function and phenotype

Single nucleotide polymorphism (SNP) is the simplest form of DNA variation among individuals. These simple changes can be of transition or transversion type and they occur throughout the genome at a frequency of about one in 1,000 bp. They may be responsible for the diversity among individuals, genome evolution, the most common familial traits such as curly hair, interindividual differences in drug response, and complex and common diseases such as diabetes, obesity, hypertension, and psychiatric disorders. SNPs may change the encoded amino acids (nonsynonymous) or can be silent (synonymous) or simply occur in the noncoding regions. They may influence promoter activity (gene expression), messenger RNA (mRNA) conformation (stability), and subcellular localization of mRNAs and/or proteins and hence may produce disease. Therefore, identification of numerous variations in genes and analysis of their effects may lead to a better understanding of their impact on gene function and health of an individual. This improved knowledge may provide a starting point for the development of new, useful SNP markers for medical testing and a safer individualized medication to treat the most common devastating disorders. This will revolutionize the medical field in the future. To illustrate the effect of SNPs on gene function and phenotype, this minireview focuses on evidences revealing the impact of SNPs on the development and progression of three human eye disorders (Norrie disease, familial exudative vitreoretinopathy, and retinopathy of prematurity) that have overlapping clinical manifestations.

Weight gain measured at 6 weeks after birth as a predictor for severe retinopathy of prematurity: study with 317 very low birth weight preterm babies

BACKGROUND

Recent studies suggest that postnatal weight gain can play an important role in the development of retinopathy of prematurity (ROP).

AIM

To analyze the low weight gain (WG) from birth to 6 weeks of life to predict the development of severe retinopathy of prematurity (ROP) among very low birth weight preterm babies (VLBW).

METHODS

A prospective cohort study included 317 newborns with birth weight (BW) <or=1,500 g and gestational age (GA) <or=32 weeks. The main outcome was the development of severe ROP (defined as threshold ROP and higher stages of ROP). In all patients, the proportion of the WG was defined as the preterm weight measured at 6 weeks of life minus the BW divided by the BW. Seventeen risk factors for ROP were studied by univariate analysis. Chi-square test and Student's t-test were used to compare no-ROP/mild ROP patients and severe ROP patients. Logistic regression and receiver operating characteristic (ROC) curve were used to determine if the WG proportion was independently related to severe ROP development and if it was capable of predicting severe ROP. Ophthalmological examinations started between the fourth and sixth week of life, and were repeated until the 45th week of postmenstrual age. Weight gain proportion was always calculated at completed 6 weeks of life.

RESULTS

Mean GA and mean BW of the whole cohort were 29.6 weeks (+/-1.9) and 1,124 grams (+/-239.5) respectively. After logistic regression, the low WG proportion under 51.2% from the BW, measured at 6 weeks of life, showed OR 3.007 (95%CI: 1.195-7.566; P = 0.019), for severe ROP, when adjusted for BW and for any stage intraventricular hemorrhage. Area under the ROC curve was 0.63 (95%CI: 0.495-0.761; P = 0.037). For the discriminative cutoff of 51.2% of the WG proportion, sensitivity and specificity values were 66.3% and 62.6% respectively. Positive and negative predictive values were 10.2% and 94.7% respectively.

CONCLUSIONS

Low WG by six weeks of life is an important and independent risk factor for severe ROP and is capable to predict the development of severe ROP in most patients that needed treatment.

Structural sequelae and refractive outcome after successful laser treatment for threshold retinopathy of prematurity

PURPOSE

To study the structural sequelae and refractive outcome in eyes with a favorable structural outcome following laser treatment for threshold retinopathy of prematurity (ROP).

METHODS

Premature infants with threshold ROP had laser treatment with a minimum follow-up of 1 year. Complete ocular examination and refraction was done. Analysis and correlation of structural sequelae and refractive outcome was done.

RESULTS

One hundred eighty-four eyes of 93 preterm infants were followed up. Structural changes such as vascular tortuosity, narrowing of arcades, temporal crescent, disc drag, and macular heterotopia were seen. Mean refractive error observed was -4.71 D spherical equivalent. Myopia was seen in 80.43% of eyes.

CONCLUSIONS

The study revealed various structural sequelae and their correlation with refractive outcome.

Pediatric ophthalmology in the developing world

PURPOSE OF REVIEW

It is estimated that of the 45 million people who are blind worldwide in 2000, 1.4 million are children from middle-income and low-income countries, the majority of whom live in the poorest regions of Africa and Asia. The focus of this paper is to discuss the status of pediatric ophthalmology in developing countries and the progress that has been made in the areas of avoidable childhood blindness and visual impairment, particularly corneal scarring as a result of vitamin A deficiency, congenital cataract and retinopathy of prematurity. In addition, we will review the prevalence of uncorrected refractive error and discuss the access to pediatric ophthalmologists in developing countries.

RECENT FINDINGS

Some developing countries have begun incorporating vitamin A supplementation and measles immunizations and have seen a decrease in xerophthtalmia. With improvement in vitamin A status, cataract is becoming a more apparent cause of treatable childhood blindness. Amblyopia and uncorrected refractive errors are important and inexpensively treatable causes of visual impairment, with myopia being most common. As neonatal intensive care services in middle-income developing countries improve the survival of premature infants, retinopathy of prematurity is emerging as a significant cause of childhood blindness.

SUMMARY

Childhood blindness and visual impairment in developing countries remains a significant public health issue, but recent initiatives have shown promise of future improvements.

Retinopathy of prematurity in Bangladeshi neonates

BACKGROUND

Retinopathy of prematurity (ROP) is a potentially blinding eye disorder that primarily affects premature infants. Increased survival of extremely low birth weight infants following advances in antenatal and neonatal care has resulted in a population of infants at high risk of developing ROP. Long term morbidity of ROP has a spectrum ranging from myopia to blindness. Screening programs and early intervention can provide enormous economic and social benefits.

MATERIALS AND METHODS

Preterm infants of gestational age <33 weeks admitted to the Special Care Nursery of Dhaka Shishu Hospital for a trial of topical emollient therapy during December 1998-July 2003 were followed-up after hospital discharge, including detailed ophthalmologic examination. Detailed history regarding risks during pregnancy, delivery and hospital stay was documented. ROP cases were managed according to the stage of the disease at diagnosis.

RESULTS

Five out of the 114 (4.4%) children seen in follow-up were diagnosed with ROP. Low gestational age, low birth weight, administration of oxygen, apneic spells, sepsis and blood transfusions were common factors among cases who developed ROP.

CONCLUSION

As survival of preterm infants in low resource settings increases, ROP will become increasingly important as a potential cause of blindness, emphasizing the critical need for ophthalmologic examination in premature infants, with immediate initiation of treatment when ROP is diagnosed.

Childhood blindness in a rural population of southern India: prevalence and etiology

PURPOSE

To determine the prevalence and etiology of childhood blindness in a rural population in southern India through a population based study.

METHODS

A cross sectional, house-to-house survey to screen for childhood blindness included 14,423 children < 16 years. Blindness was defined as best corrected visual acuity < 3/60 in the better eye. The first stage of screening for blindness was done by interns under supervision of ophthalmology residents. Senior residents examined the referred cases from the first stage. Those detected to be blind were brought to a tertiary care hospital for detailed examination.

RESULTS

Fifty-four children were referred after first stage of screening of 13,241 children. Of these 14 were bilaterally blind giving a prevalence of 1.06/1000 (95% confidence interval (CI), 0.50 to 1.61); 6 (42.9%) had lens and related complications, 4 (28.6%) had globe anomalies (2 Microphthalmos and 2 Anophthalmos), 2 (14.3%) had retinal dystrophy and 1 (7.1%) each of glaucoma and optic atrophy. Among the parents of blind children, 71.4% (p = 0.002) had consanguineous marriage (83.3% in cataract blind children).

CONCLUSIONS

More than half of the blindness detected was potentially avoidable. Genetic counseling, early identification and access to tertiary care would reduce the burden of childhood blindness in the local community.

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.

Retinopathy of prematurity management using single-image vs multiple-image telemedicine examinations

PURPOSE

To compare performance of single-image vs multiple-image telemedicine examinations for retinopathy of prematurity (ROP) diagnosis.

DESIGN

Prospective comparative study.

METHODS

A total of 248 eyes from 67 consecutive infants underwent wide-angle retinal imaging by a trained neonatal nurse at 31 to 33 weeks and/or 35 to 37 weeks postmenstrual age (PMA) at a single academic institution. Data were uploaded to a web-based telemedicine system and interpreted by three masked retinal specialists. Diagnoses were provided based on single images, and subsequently on multiple images, from both eyes of each infant. Findings were compared to a reference standard of indirect ophthalmoscopy by a pediatric ophthalmologist. Primary outcome measures were recommended follow-up interval, presence of plus disease, presence of type-2 or worse ROP, and presence of visible peripheral ROP.

RESULTS

Among the three graders, mean sensitivity/specificity for detection of infants requiring follow-up in less than one week were 0.85/0.93 by single-image examination and 0.91/0.88 by multiple-image examination at 35 to 37 weeks PMA. Mean sensitivity/specificity for detection of infants with type-2 or worse ROP were 0.82/0.95 by single-image examination and 1.00/0.91 by multiple-image examination at 35 to 37 weeks PMA. Mean sensitivity/specificity for detection of plus disease were 1.00/0.86 by single-image examination and 1.00/0.87 by multiple-image examination at 35 to 37 weeks PMA. There were no statistically-significant intragrader differences between accuracy of single-image and multiple-image telemedicine examinations for detection of plus disease.

CONCLUSIONS

Single-image and multiple-image telemedicine examinations perform comparably for determination of recommended follow-up interval and detection of plus disease. This may have implications for development of screening protocols, particularly in areas with limited access to ophthalmic care.

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.

Three-year anatomic and visual outcomes after vitrectomy for stage 4B retinopathy of prematurity

PURPOSE

To assess anatomic and visual outcome following vitrectomy for stage 4B retinopathy of prematurity (ROP) after 3 years follow-up.

METHODS

Retrospective analysis of 56 eyes (46 infants) with stage 4B ROP-related retinal detachment. Eyes underwent either lens-sparing vitrectomy (LSV) or combined lensectomy and vitrectomy (LV). Visual outcome after a minimum follow-up of 36 months was ascertained by using either Teller or Snellen acuities, or sweep visual evoked potential.

RESULTS

LSV was performed in 42.9% and LV in 57.1% of eyes. Retinal reattachment was achieved in 73.2% overall (LV 71.8% versus LSV 75%) (P = 0.96). Ambulatory vision (VA better than 20/1900) and near reading vision (better than 20/800) were attained in 97.4% and 42.8% of eyes respectively. Attached retina, LSV, and pretreatment with retinal ablation were associated with a higher incidence of near reading or better vision compared to detached (P < 0.001), undergoing LV (P < 0.001), and non pretreated eyes (P = 0.011).

CONCLUSION

After 3 years, more than 40% of eyes operated for ROP stage 4B in this series had a visual acuity compatible for near reading or better. Eyes undergoing LSV and with prior peripheral retinal ablation had better visual outcomes.

Clinical practices in neonatal oxygenation: where have we failed? What can we do?

INTRODUCTION

Oxygen is among the most frequently used therapies in neonates worldwide. Nevertheless, many times it is used unnecessarily. Neonatal practices have changed over the last several years; treatments originally believed to be beneficial have been discarded.

STUDY DESIGN

Oxygen utilized 'just in case' or 'prophylactically' can lead to great damage previously ignored and/or unseen by healthcare providers. It is imperative to improve education on neonatal oxygenation and saturation monitoring. It is also important not to depend on old assumptions, which were not based on evidences. The potential for unseen damage at the cellular and tissue levels cannot be ignored. Therapies that prove to be outdated or even dangerous must be eliminated while further research and confirmation of the best practices are determined. Freedom to choose can come at a price.

Changing challenges in the control of blindness in children

One cannot address issues of control of blindness in children without first considering the epidemiology, as this allows priorities to be determined and appropriate strategies to be delineated. Control does not occur within a vacuum, and so it is also important to understand the context in which programmes are to be implemented, particularly in relation to development and poverty--the distal risk factors that are powerful determinants of the incidence of disease in populations. Interventions need to be considered from the perspective of patients as well as providers if services are to be acceptable and appropriate.

Screening for retinopathy of prematurity

The CRYO-ROP study confirmed the success of treatment for ROP and made screening mandatory. National based screening has been influenced by the varied incidence of disease in developed and developing countries. Most ophthalmologists in developed countries screen infants born between 1000 and 1500 g and between 28 and 31 weeks gestation post menstrual age. The 1984 classification has been updated to highlight the importance of plus disease. The ETROP study findings have resulted in earlier treatment and elevated the importance of screening. Measures such as nesting may help to reduce infant distress during examination. It is important for neonatal units to have an agreed policy on screening and both neonatologist and neonatal nurses have an invaluable role. Diagnostic retinal imaging and telemedicine may have an increasing role in future screening. Timely and accurate screening is the most important first step as earlier treatment results in improved visual prognosis.

Retinopathy of prematurity: a global perspective of the epidemics, population of babies at risk and implications for control

Globally at least 50,000 children are blind from retinopathy of prematurity (ROP) which is now a significant cause of blindness in many middle income countries in Latin American and Eastern Europe. Retinopathy of prematurity is also being reported from the emerging economies of India and China. The characteristics of babies developing severe disease varies, with babies in middle and low income countries having a much wider range of birth weights and gestational ages than is currently the case in industrialized countries. Rates of disease requiring treatment also tend to be higher in middle and low income countries suggesting that babies are being exposed to risk factors which are, to a large extent, being controlled in industrialised countries. The reasons for this "third epidemic" of ROP are discussed as well as strategies for control, including the need for locally relevant, evidence based criteria which ensure that all babies at risk are examined.

[Hypercapnia- and trans-arachidonic acid-induced retinal microvascular degeneration: implications in the genesis of retinopathy of prematurity]

High oxygen tension is a major factor in the genesis of retinopathy of prematurity (ROP). However, clinical and experimental evidence also suggest a significant role for high levels of carbon dioxide (CO(2)). Hypercapnia is a facilitator of nitration in vitro, and nitrative stress is known to have an important role in microvascular degeneration leading to ischemia in conditions such as ROP. We hereby present evidence that prolonged exposure to CO(2) impairs developmental retinal neovascularisation through a mechanism involving increased endothelial nitric oxide synthase and induction of a nitrative stress; effects of hypercapnia are independent of its hyperaemic effects. Moreover, in a model of oxygen-induced retinopathy, we demonstrate that an in vivo nitrative stress associated with retinal vasoobliteration results in nitration of cis-arachidonic acids into trans-arachidonic acids (TAAs). TAAs act in turn as mediators of nitrative stress by causing microvascular degeneration by inducing expression of the anti-angiogenic factor thrombospondin-1. These recent findings establish a previously unexplored means by which hypercapnia hinders efficient neovascularisation and provide new insight into the molecular mechanisms of nitrative stress on microvascular injury involving TAA, therefore opening new therapeutic avenues in the management of nitrative stress disorders such as in ischemic retinopathies (of prematurity and of diabetes) and encephalopathies.

Retinopathy of prematurity in Asian Indian babies weighing greater than 1250 grams at birth: ten year data from a tertiary care center in a developing country

Background:

Retinopathy of prematurity (ROP) is an important cause of childhood blindness in developing countries.

Aim:

To report the spectrum of ROP and associated risk factors in babies weighing > 1250 g at birth in a developing country.

Setting and Design:

Institutional, retrospective, non-randomized, observational clinical case series.

Materials and Methods:

Retrospective analysis (10 years) of 275 eyes (138 babies) with ROP.

Statistical Analysis:

Qualitative data with the Chi-square test. Quantitative data using the unpaired t test or the ANOVA and further tested using multivariate logistic regression.

Results:

The mean birth weight was 1533.9 g (range 1251 to 2750 g) and the mean period of gestation was 30.9 weeks (range 26 to 35). One hundred and twenty-four of 275 eyes (45.1%) had threshold or worse ROP. Risk factors for threshold or worse disease were, ′outborn babies′ ( P < 0.001), respiratory distress syndrome ( P = 0.007) and exchange transfusion ( P = 0.003). The sensitivity of the American and British screening guidelines to pick up threshold or worse ROP in our study group was 82.4% and 77.4% respectively.

Conclusions:

Severe ROP is often encountered in babies weighing greater than 1250 g at birth in developing countries. Western screening guidelines may require modifications before application in developing countries.

Visual outcomes and perinatal adversity

Preterm birth per se, the neonatal environment, retinopathy of prematurity (ROP) and neurological damage are all causes of visual impairment and the impact of these factors is discussed in relation to the resultant ophthalmic deficits. Visual acuity impairments range from blindness, due to ROP or cortical visual impairment, which can be identified at an early age, to subtle deficits related to preterm birth only identified at a later age. Visual function deficits are not limited to visual acuity but can affect contrast sensitivity, field of vision and colour vision. Strabismus and refractive errors are also very common in children following perinatal adversity. Although more is now known about the types of deficits affecting these children, there is still a poor understanding of how these deficits impact on a child's functional ability. The impact of these ophthalmic deficits on the long term ophthalmic care required, and the role of perinatal factors, is discussed.

Incidence and risk factors for retinopathy of prematurity in very low and in extremely low birth weight infants in a unit-based approach in southern Brazil

AIMS

To analyse the incidence and risk factors for retinopathy of prematurity (ROP) and survival rates among extremely low birth weight (ELBW) and very low birth weight (VLBW) preterm infants.

METHODS

A prospective cohort study of 352 infants admitted at a teaching hospital, Hospital de Clinicas de Porto Alegre, Brazil, between October 2002 and December 2006, was screened for ROP. The ELBW group comprised infants whose birth weight (BW) was < or = 1000 g and the VLBW group comprised those infants whose BW were > 1000 g and < or = 1500 g. Perinatal risk factors for ROP were assessed using univariate and multivariate analysis.

RESULTS

Of the 352 neonates screened, 88 were ELBW babies. Survival rates among ELBW and VLBW were 47.8 and 88.7%, respectively. ROP affected 48.9% of ELBW infants and 18.2% of VLBW babies. Threshold disease occurred in 21 patients, 15 of whom were born weighing < 1000 g. Only 2.3% of the neonates born with more than 1000 g developed treatable disease. Univariate analysis showed that gestational age (GA), BW, use of indomethacin and erythropoietin, blood transfusions, and intraventricular haemorrhage were associated with ROP. After logistic regression, the most important adjusted risk factors were BW (OR: 1.002;95% CI: 1.001-1.003; P=0.003), GA (OR: 1.254;95% CI: 1.082-1.455; P=0.003), and use of erythropoietin (OR: 2.486;95% CI: 1.182-5.231; P=0.016).

CONCLUSION

This study showed reduced survival rates, high incidence of ROP, and a greater need of treatment among ELBW infants as compared to VLBW babies admitted in this institution.

Oxygen as a neonatal health hazard: call for détente in clinical practice

Education in oxygenation and in how oxygen is given to newborns needs to increase. Treatment with oxygen should no longer be considered proverbial and customary, regardless of our 'past experience' or consensus recommendations in clinical guidelines, since oxygen may lead to acute or chronic health effects.

CONCLUSION

Inappropriate oxygen use is a neonatal health hazard associated with aging, DNA damage and cancer, retinopathy of prematurity, injury to the developing brain, infection and others. Neonatal exposure to pure O2, even if brief, or to pulse oximetry >95% when breathing supplemental O2 must be avoided as much as possible.

Morphine analgesia as an alternative to general anaesthesia during laser treatment of retinopathy of prematurity

PURPOSE

To determine the feasibility and efficacy of morphine sedation/analgesia in the laser treatment of retinopathy of prematurity (ROP).

METHODS

A retrospective study was carried out on all infants who underwent laser treatment for ROP over a 7 year period. Morphine infusion commenced 6 hrs prior to treatment at a rate of 10 microg/kg/hr. This rate increased to 20 microg/kg/hr at the start of laser treatment. Subsequent infusion rate was titrated according to tolerance of the laser and cardio and respiratory system changes and evidence of infant distress (truncal and limb movements) up to a maximum rate of 40 microg/kg/hr. Following treatment, morphine was weaned over 6 hrs. Infant ventilation status was recorded prior to and during morphine infusion and during laser treatment. The incidences of adverse cardiac or respiratory events occurring during laser treatment were determined.

RESULTS

One hundred and nine infants treated from 1998 to 2005 were involved in the study. One hundred and thirty-six treatments were performed and mean gestational age at the time of treatment was 36 weeks. In 130 treatments, respiratory status remained stable and was not adversely affected. Infants were mechanically ventilated because of morphine-induced apnoea during three treatments, because of poor laser tolerance during two treatments and because of post-procedure apnoea in one case. In 65 treatments, minor alterations in oxygen saturation (< 90%), bradycardia or tachycardia occurred.

CONCLUSION

This study demonstrates that morphine analgesia can be used as an alternative to general anaesthesia.

Retinopathy of prematurity in South Africans at a tertiary hospital: a prospective study

BACKGROUND AND OBJECTIVES

World Health Organization's vision 20/20 programme has recognized retinopathy of prematurity (ROP) as an important cause of childhood blindness in industrialized and middle-income countries. While ROP is virtually nonexistent in many African countries, ROP is seen in urban areas where facilities for neonatal care exist. The aim of this study is to establish the frequency of ROP in a cohort of patients screened for ROP and to establish if current screening criteria apply to our patients.

PATIENTS AND METHODS

Infants with birth weight (BW) of 1500 g or less and/or gestational age of 32 weeks or less were screened for ROP over a 2(1/2)-year period by a single examiner.

RESULTS

ROP was observed in 84 of 514 (16.3%) of infants included for analysis. Threshold disease (tROP) was noted in 1.6% of the total cohort although 41/84 babies with ROP were lost prior to regression or progression to tROP. Of the 43/84 adequately followed up, eight (18.6%) developed tROP. An estimated frequency of tROP was more likely to be 2.9%. There was no tROP noted in babies of BW greater than 1250 g. Gestational age was an unreliable risk parameter in our population.

CONCLUSION

The projected occurrence rate of tROP is similar to that found in black population in the Multicentre Cryotherapy for ROP Trial. Our data suggest that the screening criterion based on BW can safely be lowered to 1250 g in our population.

Regulation of human male germ cell death by modulators of ATP production

The understanding of testicular physiology, pathology, and male fertility issues requires knowledge of male germ cell death and energy production. Here, we induced human male germ cell apoptosis (detected by Southern blot analysis of DNA fragmentation, TUNEL, activation of caspases-3 and -9, and electron microscopy) by incubating seminiferous tubule segments under hormone- and serum-free conditions. Inhibitors of complexes I to IV of mitochondrial respiration, exposure to anoxia, and inhibition of F0F1-ATPase (with oligomycin) decreased the ATP levels (analyzed by HPLC) and suppressed apoptosis at 4 h. Uncoupler 2,4-dinitrophenol (DNP) and oligomycin combination also suppressed death at 4 h, as did the DNP alone. Inhibition of glycolysis by 2-deoxyglucose neither suppressed nor further induced apoptosis nor altered the antiapoptotic effects of the mitochondrial inhibitors. Furthermore, Fas system activation did not modify the effects of mitochondrial modulators. After 24 h, delayed male germ cell apoptosis was observed despite the presence of the mitochondrial inhibitors. We conclude that the mitochondrial ATP production machinery plays an important role in regulating in vitro-induced primary pathways of human male germ apoptosis. The ATP synthesized by the F0F1-ATPase seems to be the crucial death regulator, rather than any of the complexes (I-IV) alone, the functional electron transport chain, or the membrane potential. We also conclude that there seem to be secondary pathways of human testicular cell apoptosis that do not require mitochondrial ATP production. The present study emphasizes the role of the main catabolic pathways in the complex network of regulating events of male germ cell life and death.

Modification of screening criteria for retinopathy of prematurity in India and other middle-income countries

PURPOSE

To determine the gestational age and birth weight of premature babies who developed vision-threatening severe retinopathy of prematurity.

DESIGN

Prospective observational study of babies at risk of blindness due to retinopathy of prematurity.

METHODS

Data pertaining to all babies who underwent laser treatment or surgery for acute retinopathy of prematurity and those who had cicatricial retinopathy of prematurity were prospectively collected. The gestational age and birth weight were evaluated to establish screening criteria.

RESULTS

In 120 babies, the mean gestational age was 29.6 weeks (range 26 to 36 weeks). The birth weight of 115 babies ranged from 710 to 2000 g (mean 1254.5 g, SD 280.8). Birth weight was not available for five babies. Only one baby had a gestational age of >35 weeks.

CONCLUSIONS

Ocular morbidity related to retinopathy of prematurity was seen in bigger and more mature babies. This study provides a scientific basis for establishing screening criteria for retinopathy of prematurity in South India and other middle-income countries.

Diode laser versus cryotherapy in treatment of ROP

Advantages of laser therapy

Characteristics of severe retinopathy of prematurity patients in China: a repeat of the first epidemic?

AIM

To describe the characteristics of babies treated for severe retinopathy of prematurity (ROP) in a tertiary referral unit in China, to provide information to assist in determining screening criteria.

METHODS

Information on consecutive babies referred to one eye department for treatment of stage 3 (prethreshold and threshold disease), and stages 4 and 5 ROP between January 2001 and May 2005 were retrieved from medical records.

RESULTS

Data from 114 babies were analysed. The number of babies treated increased from nine in 2001 to 52 in 2004. The numbers of infants in each stage of ROP were as follows: stage 3, 40 babies; stage 4, 19 babies, and stage 5, 55 cases. The mean gestational age (GA) was 29.8 (SD 1.9) weeks (range 26-34 weeks) and the mean birth weight (BW) was 1432 (319) g (range 760-2500 g). 31 babies had BWs more than 1500 g (27.2%). 10 cases (8.8%) had GAs more than 32 weeks, and 82 (71.9%) had GAs more than 28 weeks. Overall, 18 (16.2%) infants exceeded UK screening criteria, and 34 (30.4%) exceeded the criteria used in the United States. The median age at presentation was 5.5 months (range 1-72 months).

CONCLUSION

Comprehensive screening programmes for ROP are urgently needed in China. Screening criteria recommended by the American Academy of Pediatric Ophthalmology and Strabismus and the Royal College of Ophthalmologists, United Kingdom, may not be suitable for China where bigger, more mature babies are developing severe disease.

Outcome of the Treatment of Retinopathy of Prematurity in Qatar

To evaluate the results of the treatment of Retinopathy of Prematurity (ROP) patients in Qatar a retrospective analysis was made of 43 infants treated between January 1999 and December 2002 initially with indirect laser transpupillary photocoagulation. Cryotherapy was used only on those needing re-treatment. A favorable outcome overall was obtained in 40 cases (90%) after ten received re-treatment. The statistical interpretation, complicating factors and outcomes are discussed. It is concluded that the results of threshold ROP treatment in Qatar are encouraging.

The ‘ideal’ management of retinopathy of prematurity

AIM

Retinopathy of prematurity continues to be a serious, but largely preventable cause of blindness and its detection and treatment is of increasing importance as survival rates of premature babies increase. This is particularly important in Medium Human Development Countries where the guidelines for detection used in the US or UK may not be appropriate.

METHOD

This report addresses identification of infants at risk for retinopathy of prematurity, detection, and treatment of serious disease, and what to do when treatment fails.

RESULTS AND CONCLUSIONS

Retinopathy of prematurity occurs almost exclusively in small premature babies, but the demographic characteristics of these babies vary depending on where they are born. Detection of serious retinopathy requires carefully timed examinations and the treatment criteria will continue to evolve as new therapies are developed. Timely detection and treatment of serious retinopathy of prematurity minimizes the likelihood of blindness, but it is not always successful.

Characteristics of infants with severe retinopathy of prematurity in countries with low, moderate, and high levels of development: implications for screening programs

OBJECTIVE

Retinopathy of prematurity (ROP) is a potentially avoidable cause of blindness in children. The proportion of blindness as a result of ROP varies greatly among countries depending on their level of development, being influenced by the availability of neonatal care, neonatal outcomes, and whether effective screening and treatment programs are in place. The objective of this study was to compare characteristics of premature infants who developed severe ROP between 1996 and 2002 in highly developed countries with less developed countries.

METHODS

This was an observational study. A questionnaire was completed by ophthalmologists in countries with low, moderate, and high development rankings (3 highly developed countries and from 10 less well-developed countries) who screen for ROP in which they supplied birth weights and gestational ages (GAs) of infants who were treated for threshold ROP or identified with more advanced stages of the disease. Birth weights and GAs of infants with severe ROP were measured.

RESULTS

The mean birth weights of infants from highly developed countries ranged from 737 to 763 g compared with values ranging from 903 to 1527 g in less developed countries. Mean GAs of infants from highly developed countries ranged from 25.3 to 25.6 weeks compared with 26.3 to 33.5 weeks in less developed countries. A total of 13.0% of 1091 infants from poorly developed countries exceeded United Kingdom screening criteria; 3.6% exceeded a criteria of <34 weeks' GA and/or <1750 g birth weight.

CONCLUSIONS

These findings suggest that larger, more mature infants are developing severe ROP in countries with low/moderate levels of development compared with highly developed countries. ROP screening programs need to use criteria that are appropriate for their local population.

UK population based study of severe retinopathy of prematurity: screening, treatment, and outcome

BACKGROUND

Retinopathy of prematurity (ROP) is one of the few causes of childhood blindness in which severe vision impairment is largely preventable. Ophthalmic screening for ROP is required to identify disease that requires treatment whereby the development of potentially blinding disease can be minimised.

OBJECTIVES

To make the first UK population based estimate of the incidence of babies with severe ROP (stage 3 or more); to document their clinical characteristics and management and to evaluate the appropriateness of current ROP screening guidelines in the UK.

PATIENTS

Cases were recruited through a national surveillance programme with 1 year ophthalmic follow up and data from clinician completed questionnaires.

RESULTS

Between 1 December 1997 and 31 March 1999, 233 preterm babies with stage 3 ROP were identified. Severity (location, extent, and presence of plus disease) was associated with degree of prematurity, most severe in the most premature babies. Fifty nine percent were treated. The UK screening protocol was followed in two thirds of cases, but in the remainder it was begun too late or was too infrequent. Three quarters of the cases were followed up at 1 year, and 13% had a severe vision deficit as a result of ROP.

CONCLUSIONS

Visual deficit as a result of ROP in premature babies continues to be a severe disability in some of the survivors of neonatal intensive care. Further efforts are needed to organise treatment regionally to improve outcome and standards of practice.

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.

Prise en charge de la rétinopathie du prématuré en service spécialisé

INTRODUCTION

Retinopathy of prematurity is a complication of prematurity whose risk factors are well known. Its prognosis remains fearsome and its treatment is difficult.

PATIENTS AND METHODS

Fifty-four children were managed (108 eyes analyzed) for retinopathy of prematurity in the Ophthalmology Ward of Necker-Enfants-Malades Hospital between 1996 and 2002. A retrospective review of those cases was performed to describe their clinical features, their treatment and their outcome.

RESULTS

Mean gestational age was 26.75 weeks after the mother's last period (24-32.5 weeks) and mean birth weight was 842 g (530-2260 g). Stage zero occurred in ten eyes, stage 1 in two eyes, stage 2 in seven eyes, stage 3 in 42 eyes, stage 4 in ten eyes, stage 5 in 24 eyes, and after-effects stage in 13 eyes. Initial treatment (combined treatments possible) was abstention in 45 eyes, cryotherapy in 16 eyes, laser photocoagulation in 43 eyes, surgical treatment of 13 eyes (scleral buckling or vitrectomy). Cryotherapy was effective in 71.5% of cases, photocoagulation was effective in 77%, and scleral buckling was effective in 25%. Vitrectomy failed in the five eyes treated. Outcome was complicated by legal blindness in 33 eyes.

DISCUSSION AND CONCLUSION

The cases of retinopathy of prematurity that we manage are often severe, stage 3 or above, which explains the outcome of the patients. The 7-year experience reported herein shows how difficult it is to manage this condition, though the need for its detection, diagnosis criteria, and therapeutical indications are well known. Because younger and smaller premature newborns are successfully managed by pediatricians, retinopathy of prematurity is far from having vanished and its morbidity is considerable.

Cost-effectiveness of digital photographic screening for retinopathy of prematurity in the United Kingdom

OBJECTIVES

To compare the cost-effectiveness of alternative methods of screening for retinopathy of prematurity (ROP) in the United Kingdom, including the existing method of indirect ophthalmoscopy by ophthalmologists and digital photographic screening by nurses.

METHODS

A decision tree model was used to compare five screening modalities for the UK population of preterm babies, using a health service perspective. Data were taken from published sources, observation at a neonatal intensive care unit (NICU), and expert judgment.

RESULTS

We estimated that use of standard digital cameras by nurses in NICUs would cost more than current methods (pound 371 compared with pound 321 per baby screened). However, a specialist nurse visiting units with a portable camera would be cheaper (pound 172 per baby). These estimates rely on nurses capturing and interpreting the images, with suitable training and supervision. Alternatively, nurses could capture the images then transmit them to a central unit for interpretation by ophthalmologists, although we estimate that this would be rather more expensive (pound 390 and pound 201, respectively, for NICU and visiting nurses). Sensitivity analysis was used to examine the robustness of estimates.

CONCLUSIONS

It is likely that there is an opportunity to improve the efficiency of the ROP screening program. We estimate that screening by specialist nurses trained in image capture and interpretation using portable digital cameras is a cost-effective alternative to the current program of direct visualization by ophthalmologists. This option would require the development of a suitable portable machine. Direct comparative research is strongly needed to establish the accuracy of the various screening options.

Semiautomated computer analysis of vessel growth in preterm infants without and with ROP

AIMS

To measure characteristics of the retinal blood vessels close to the optic disc in full term and preterm infants, with and without retinopathy of prematurity (ROP), using digital imaging. To determine whether these measures are indicative of the presence or severity of ROP in the retinal periphery.

METHODS

52 digital fundus images from 42 babies were analysed with a semiautomated analysis program developed at Imperial College London. Analysis was limited to the principal temporal vessels close to the optic disc: recording venular diameter and arteriolar diameter and tortuosity.

RESULTS

Each result was categorised by the gestational age of the infant ("very premature" 24-27 weeks, "moderately premature" 28-31 weeks, and "near term" > or =32 weeks) and by the highest stage of ROP present ("no ROP," "mild ROP" stage 1 or 2, and "severe ROP" stage 3). Arteriolar tortuosity was found to vary significantly (Kruskal-Wallis p=0.002) with ROP severity. Although venular and arteriolar diameters increased monotonically with ROP severity the differences were not significant. Venular diameter, arteriolar diameter, and arterial tortuosity did not vary significantly between gestational age groups.

CONCLUSIONS

This study confirms it is possible to quantify the size and tortuosity of retinal blood vessels in term and preterm babies using digital image analysis software. This method detected significant increases in arteriolar tortuosity with increasing ROP severity.

Hypoxic oxygen fluctuations produce less severe retinopathy than hyperoxic fluctuations in a rat model of retinopathy of prematurity

The aim of this study was to investigate whether the mean around which arterial oxygen fluctuations take place was important in a unique animal model of oxygen-induced retinopathy. Retinopathy of prematurity (ROP) is associated with fluctuating arterial oxygen. A recent retrospective study suggested that management of high-risk preterm infants at lower oxygen saturations was associated with less severe ROP. Rat pups were raised in a variable oxygen environment around a high (24%), normal (21%) or low (17%) mean inspired oxygen for 14 d. Rat pups raised in the high (24%) mean variable oxygen environment had more retarded retinal vascular development than did rats raised in an environment that fluctuated around 21% mean oxygen. In contrast, rats raised in a lower mean (17%) but still variable oxygen environment had no discernible retinal differences from controls raised in constant room air. Rats raised in a relatively hypoxic but variable oxygen environment develop less severe retinal vascular abnormalities than those raised in variable oxygen around higher oxygen means.

Outcome of zone 1 retinopathy of prematurity

PURPOSE

To describe the outcome in a series of patients with pre-threshold and threshold zone 1 retinopathy of prematurity.

METHODS

We performed a retrospective analysis of 12 babies, 24 eyes, with zone 1 retinopathy of prematurity, treated between 1992 and 2002 with diode laser treatment.

RESULTS

Ten out of the 12 babies had an unfavourable outcome. The only patients with successful anatomical outcomes were those treated before threshold disease occurred. All babies had developmental delay or neurological disability.

CONCLUSION

Zone 1 retinopathy of prematurity has a poor anatomical and visual prognosis and many of the babies in our study had developmental delay and neurological disability. Earlier treatment may improve the visual outcome.

Incidence and severity of retinopathy of prematurity in Vietnam, a developing middle-income country

BACKGROUND

Although retinopathy of prematurity (ROP) is a leading cause of childhood blindness, its impact in lower income countries is not well documented. The World Health Organization has proclaimed that infants at risk for ROP should have screening eye examinations and access to treatment.

PATIENTS AND METHODS

A prospective study was conducted from January 1 through December 31, 2001, at Tu Du Hospital in Ho Chi Minh City for premature infants who weighed 1,500 g or less at birth or were 33 gestational weeks or younger. Serial examinations were used to classify ROP, and treatment outcomes were noted.

RESULTS

Two hundred twenty-five consecutive infants were included in the data analysis. Birth weights ranged from 900 to 2,000 g (mean, 1,512 g). Gestational ages ranged from 26 to 36 weeks (mean, 31 weeks). ROP was present in 103 (45.8%) of the 225 infants. In infants who weighed 1,250 g or less at birth, the ROP rate was 81.2% (26 of 32 infants). Threshold ROP was present in 9.3% of the 225 infants but in 25% of the 32 infants. Twenty-four eyes received treatment, whereas 16 lacked the family resources. Of the 24 treated eyes, 18 (75%) had a favorable outcome. Of the 16 untreated eyes, only 3 had a favorable outcome.

CONCLUSIONS

ROP incidence is high in Vietnam, similar to that in the United States. However, larger, older infants are at risk in Vietnam and the rate of severe ROP seems to be higher. This necessitates an ROP screening paradigm different from that currently used in the United States.