Vision loss due to retinopathy of prematurity

Retinopathy of Prematurity

Retinopathy of prematurity (ROP), formerly called retro-lental fibroplasia (RLF), has increased in the 1980s due to a high incidence of premature, low birthweight infants. Apparently, oxygen administration alone does not account for all these ROP babies. Birth-weight, gestational age, and duration of administration of oxygen are primary contributors to ROP development. The stages of severity range from no visual damage to total blindness. Treatments are either pharmacological or surgical. Vitamin E therapy, photocoagulation procedures, cryotherapy, scleral buckling procedures, and vitrectomy are common treatments, but none is totally successful in ameliorating this condition. The educational problems of children with ROP parallel those of other visually impaired children, with deficits found primarily in exploration, mobility, and language. Referral to early intervention programs can provide a comprehensive structured learning situation and support to the entire family.

Retinopathy of Prematurity in Denmark. Epidemiological Considerations and Screening Limits

The epidemiology of retinopathy of prematurity (ROP) in Denmark is analysed based on two sources. Regional experience is presented from 12 years' prospective ophthalmic control of infants at risk, in a Danish county with population 342,000 and 44,805 liveborns over the period 1982-93. Out of 127 subjects with ROP 101 reached stage 1 or 2 only; 26 progressed to at least stage 3. Seven with blindness due to ROP amounted to 15.6/100,000 liveborns, a high frequency. The trend over the twelve years was towards less serious sequelae. Currently, the national screening limits for ROP have been adjusted under guidance from the compulsory registration of childhood visual impairment; with birth years 1974-94 there were 157 ROP-children in the register. Blindness due to ROP is now seen only in the very immature. It is suggested that gestational age 30 weeks will soon replace the present limits of less than 32 weeks/1750 g.

Retinal detachment of regressed retinopathy of prematurity in children aged 2 to 15 years

PURPOSE

To reveal the clinical features and surgical results of retinal detachment of regressed retinopathy of prematurity (ROP) that occur in the children aged 2 to 15 years.

PATIENTS AND METHODS

The records of patient who had a retinal detachment of a regressed ROP were retrospectively reviewed. Sixteen eyes from 15 patients that required surgical treatments due to retinal detachment of a regressed ROP were included.

RESULTS

After treatment of acute phase of ROP, eight eyes showed grade II of cicatricial change and eight eyes showed grade III. We did not find any evidence that the acute stages of ROP and its treatment affect the degree of the cicatricial changes. All eight eyes with grade III of cicatricial ROP showed tractional retinal detachment (TRD) and five of eight eyes (62.5%) with grade II showed rhegmatogenous retinal detachment (RRD). The mean interval between regressed ROP and development of late retinal detachment was 20.7 months (range, 12-61 months) in the TRD group and 85.8 months (range, 33-148) in the RRD group. The mean age at onset of late detachment was 34.1 months (range, 26-73 months) in the TRD group and 98.6 months (range, 45-162) in the RRD group. Anatomical success was achieved at one of five eyes (20%) with RRD and six of 11 eyes (54.5%) with TRD. Compared with the preoperative visual acuity, visual improvement, no change, and decreased visual acuity were achieved, respectively, in two eyes, three eyes, and no eyes in the RRD group and three eyes, six eyes, and two eyes in the TRD group. However, only two of 16 eyes with late retinal detachment achieved a visual acuity of 20/200 or better.

CONCLUSION

Late retinal detachment is the main vision-threatening condition in patients with regressed ROP during childhood. The visual prognoses of these patients are poorer than those with late retinal detachments that occur in adult ROP patients. Therefore, a periodic fundus examination should be performed more frequently during childhood than in adulthood, particularly in nonverbal children.

Visual impairment in children born prematurely from 1972 through 1989

PURPOSE

To investigate the incidence and causes of visual impairment in children born prematurely in Finland from 1972 through 1989, and to determine what conditions and factors were associated with its occurrence.

DESIGN

Retrospective, cross-sectional study.

SUBJECTS

All visually impaired individuals from 0 to 17 years of age who had been born at fewer than 37 gestational weeks in Finland from 1972 through 1989 for whom records were available in the Finnish Register of Visual Impairment were eligible for this study.

METHODS

Data in the Finnish Register of Visual Impairment relating to 556 children were supplemented with data from hospital records, and from the Register of Births, the Register of Congenital Malformations, the Finnish Care Register, and the Finnish Cancer Register. Data relating to causes associated with visual impairment in particular were collected. Data relating to the children born prematurely were compared with data relating to children born at full term. The chi-square test (Mantel-Haenszel), the Mann-Whitney U test, Fisher exact test, and stepwise logistic regression analysis were used in statistical analysis of the data.

MAIN OUTCOME MEASURES

Visual acuity, ophthalmologic diagnoses, associated systemic disease, multiple handicap, gestational age, birth weight, 5-minute Apgar scores, and prenatal, perinatal, and infantile or juvenile disorders or disease and treatment.

RESULTS

One hundred twenty-five of the 556 visually impaired children (23%; 11/100000 children less than 18 years of age) had been born preterm. Retinopathy of prematurity, optic atrophy, and cerebral amblyopia were the main diagnoses associated with visual impairment (in 46%, 28%, and 12% of cases, respectively). Sixty-six percent of those born prematurely with visual impairment were also affected by other handicaps (mental, motor, auditory), 54% by cerebral palsy and 36% by epilepsy. Eighty-eight of the 125 children (70%) born preterm with visual impairment were blind. Very low birth weight (<1500 g), young gestational age (fewer than 30 weeks), prenatal infection, hyperbilirubinemia, respiratory disorders, asphyxia, and lengthy mechanical ventilation were associated with an increased risk of visual impairment.

CONCLUSIONS

Premature birth was a major risk factor of severe visual impairment and blindness in childhood. The visual impairment often was accompanied by cerebral palsy, epilepsy, and other motor and mental handicaps. Retinopathy of prematurity, optic atrophy, and cerebral amblyopia were the main diagnoses associated with visual impairment. During the 18 years covered by the study, the increasing incidence of survival of infants born weighing fewer than 1500 g was associated with increasing incidence of blindness.

Retinopathy of prematurity and bilirubin--no clinical evidence for a beneficial role of bilirubin as a physiological anti-oxidant

The prevention of retinopathy of prematurity (ROP) remains a persistent problem. A previous report has focused on the possible protective effect of bilirubin on the development of ROP. These results still await clinical confirmation by other research groups. Therefore, we undertook a retrospective clinical study trying to confirm this attractive hypothesis. Twelve premature newborns under 32 weeks of gestation with ROP stage 3-4 were matched for gestational age with 12 infants without ROP. Data were collected about the infant's characteristics, medical illnesses, ventilatory settings and treatments. The total serum bilirubin concentrations between the 1st and 8th postnatal day were also gathered. The two matched groups were comparable as to their basic data, clinical characteristics and treatment, except for a slight, but significant longer duration of phototherapy for group ROP 0 (mean, 50.2 h; SD 48,6 vs 31.6 h; SD 42.7 in ROP 3-4; P = 0.02). No statistical difference relative to bilirubin was found between the two groups, neither when expressed as daily mean concentrations, nor as area under the curve (AUC) (mean, ROP 0: 17876.7; SD 6077.3 vs 18888.4; SD 55552.7 in ROP 3-4; P = 0.404) or AUC/h (mean, ROP 0: 135.1; SD 36.3 vs 144.1; SD 23.2 in ROP 3-4; P = 0.515). Our findings do not confirm the hypothesis of a clinically measurable, beneficial role of bilirubin on the development of ROP.

Cryosurgery for acute retinopathy of prematurity: factors associated with treatment success and failure

Cryosurgery for stage 3 plus acute retinopathy of prematurity (ROP) increases the probability of disease regression, but up to 25% of eyes may progress to retinal detachment and blindness in spite of treatment. In a series of 37 eyes in 23 patients treated at the Hammersmith Hospital an overall 75% of eyes reached a favourable outcome. We present these results in detail and analyse the apparent causes of treatment failure. Poor anatomical results (total retinal detachment and traction detachment involving the macula) were associated with inappropriate cryoprobe design and with zone 1 and rush-type disease. Poor functional results in the presence of a largely flat retina (marked macular ectopia and high myopia) appeared to be associated with delayed treatment during the period of evolution of the stage 3 lesion, and with the appearance of a more highly differentiated vascular shunt with early localised forward vitreous invasion. Suggestions for the refinement of existing gradings of acute ROP are made.

Evaluation of bilirubin as possible protective factor in the prevention of retinopathy of prematurity

Retinopathy of prematurity (ROP) appears to be a multifactorial disease, the prevention of which is probably impossible even with the most accurate methods of blood-gas monitoring and oxygen restrictions. The oxidative processes and consequent formation of free radicals are probably influenced by the availability of various antioxidants in the immature retina. Bilirubin, the end product of haem catabolism, has recently been regarded as a potential physiological antioxidant. In order to test the suggestion as to the possible effect of bilirubin in reducing the incidence of ROP a retrospective study was undertaken of the medical records of 151 neonates born between 1984 to 1988 who weighed less than 1500 g. Of these, 78 had various degrees of ROP, whereas 73 had no ROP and served as a control group. The daily mean bilirubin values were analysed in accordance with gestational age and birth weight as well as the severity of ROP, and the results were compared with those obtained for the control group. The results showed no correlation between bilirubin levels and severity of ROP in all subgroups of gestational age and birth weight. These findings indicate that there is no apparent protective effect of bilirubin on the development of ROP.

Eleven years' experience with retinopathy of prematurity: visual results and contribution of cryoablation

We report our 11 years' experience of cryotherapy for retinopathy of prematurity (ROP). Charts of 624 infants weighing under 1250 g who were admitted to our Neonatal Intensive Care Unit during 1977-87 were reviewed. Three hundred and eighty nine babies survived, and the total ROP prevalence was 57.5%. Cryotherapy was applied to 35%. Only one case (0.25%) of blindness was detected, and four babies (1%) had a final visual acuity of less than 20/200 in one eye. The complication rate following cryoablation was very low.

Surveillance for retinopathy of prematurity in practice: experience from one neonatal intensive care unit

We have reviewed the results of a six year surveillance programme for acute Retinopathy of Prematurity (ROP) in order to see how the yield of cases reaching clinically significant stage 3 can safely be maximised, and to assess the effectiveness of an examination technique which does not require a speculum or scleral indentation. An overall 137 (44.8%) developed some signs of ROP and 35 (10.8%) reached stage 3. Seventeen of these were born at 25 weeks or less gestational age, and included four with rush-type disease. None of those born at or over 30 weeks developed stage 3. It is concluded that infants born at 31 weeks or more do not need to be included in a surveillance program, and this protocol will increase the yield of significant disease. In addition, cases of stage 3 which may require cryosurgery will not be missed using an atraumatic examination technique.

Surgical management of late-onset retinal detachments associated with regressed retinopathy of prematurity

The authors report their experience in managing 16 cases of late-onset retinal detachments (RDs) associated with regressed retinopathy of prematurity (ROP). Fourteen (88%) of the 16 eyes were successfully reattached. An initial scleral buckling procedure was successful in 6 of 12 eyes. A pars plana vitrectomy was necessary in a total of eight eyes that either initially presented with proliferative vitreoretinopathy (1 case), posterior retinal breaks (1 case), subretinal fibrosis (1 case), vitreoretinal traction bands (1 case), or had persistent vitreoretinal traction after failed scleral buckling procedures (4 cases). Visual acuity stabilized or improved in 13 of the 14 eyes with successful retinal reattachment. Because these cases often have significant vitreoretinal traction and/or posterior retinal breaks, pars plana vitrectomy in conjunction with scleral buckling may be necessary in order to achieve long-term retinal reattachment.

Iatrogenic disease in the perinatal period

The ever-changing complexion of iatrogenic perinatal disease dictates the following: 1. Neonatologists and pediatric pathologists must be aware of the current spectrum of these lesions and ever alert to the appearance of new ones. 2. The neonatologist and pediatric pathologist within any given institution should be in regular, systematic communication with each other concerning lesions of this type. 3. There must be a national network for rapid dissemination or exchange of information among institutions regarding these lesions. The Study Group for the Complications of Perinatal Care (SGCPC), established in 1984 as an international, multicenter, multidisciplinary study group, is committed to the prevention of complications of perinatal care by individual and collective effort. Its individual members include perinatologists, neonatologists, pediatric pathologists, and obstetricians. There are institutional members as well. Activities to date include the development of a standardized perinatal autopsy protocol and the initiation of a uniform system for the categorization of perinatal deaths. If the reader is interested in obtaining further information about the organization, contact Trevor Macpherson, MD, in the Department of Pathology at the Magee-Womens Hospital in Pittsburgh, Pennsylvania.

Retinopathy of prematurity

Over the last decade major advances have been made in the understanding of the pathogenesis and evolution of retinopathy of prematurity (ROP). The increased survival of very small premature infants in modern neonatal intensive care units has led to the resurgence of this potentially blinding disease. ROP appears to be a multifactorial disease, the prevention of which is probably impossible even now, with the most accurate methods of blood gas monitoring and oxygen restriction. In addition to oxygen, there are a number of significant risk factors, such as birth weight and gestational age, ventilator hours, hyper and hypocarbia, hypoxia and acidosis, xanthine therapy and probably bright light. Current data suggest that the level of antioxidants in the immature retina is relatively low and therefore oxygen radicals which accumulate in the preterm baby's retina may play an important role in the pathogenesis of ROP. The treatment of the disease in both its "active" and "cicatricial" stages emphasizes the need for a new classification which could serve as a common international language through which results may be compared. Vitamin E was suggested in some studies to be helpful in preventing the severe stages of the disease, but its efficacy has yet to be proved. Treatment modalities such as photocoagulation, cryotherapy and vitrectomy are being tried as a means of therapy in the more advanced stages of the disease. Preliminary results of a large multicenter study support the efficacy of cryotherapy.

Visual acuity development in normal and abnormal preterm human infants

The grating acuity of preterm infants was determined by measurements of the visual evoked potential (VEP) produced by phase alternation of sinusoidal luminance gratings. The development of visual acuity in healthy preterm infants appears to be accelerated when compared with full term infants of the same post-conceptual age. Cortical insults and the more advanced stages of retinopathy of prematurity may adversely affect acuity development as indexed by the VEP. Preterm twins also appear to have lower acuity than preterm monoparous infants.

Evolution of the visual prognosis of prematures in the last 20 years

Ophthalmoscopic examinations were performed on 5678 prematures, born between 1964 and 1984, by the same investigator in the same neonatal care unit. Three periods can be differentiated. In the first period (1964-1970) retinal disorders were frequent (20%), a quarter of them severe (stages 3-5). The inspiratory fraction of oxygen was the only oxymetric factor that was monitored. In the second period (1970-1977), less severe forms were observed, but still 4.5% of stage 1 and 8.7% of stage 2 (mild forms) were assessed. During this period, oxygen partial pressure was measured every 6 h in arterial blood whenever the inspiratory fraction of oxygen exceeded 0.3. In the last period (1977-1984), no severe forms were observed and mild forms amounted to only 0.9%. In this period, oxygen partial pressure was continuously monitored transcutaneously, whenever the inspiratory fraction of oxygen exceeded 0.21. Such data show that there is an association between better oxygen monitoring and the dramatically reduced incidence of retinopathy in prematures (RP).

Effect of bright light in the hospital nursery on the incidence of retinopathy of prematurity

The preterm infant is subjected to prolonged exposure to ambient nursery illumination at levels that have been found to produce retinal damage in animals. We prospectively investigated the effect of exposure to light in two intensive care nurseries by comparing the incidence of retinopathy of prematurity among 74 infants from the standard bright nursery environment (median light level, 60 foot-candles [ftc]) with the incidence among 154 infants of similar birth weight for whom the light levels were reduced (median, 25 ftc). There was a higher incidence of retinopathy of prematurity in the group of infants who had been exposed to the brighter nursery lights, particularly in those with birth weights below 1000 g (86 percent vs. 54 per cent, P less than 0.01 by chi-square test). We conclude that the high level of ambient illumination commonly found in the hospital nursery may be one factor contributing to retinopathy of prematurity and that safety standards with regard to current lighting practices should be reassessed.

Retinopathy of prematurity: incidence and treatment

The incidence of retinopathy of prematurity in infants with a birthweight less than or equal to 2500 g admitted to a tertiary neonatal intensive care unit between 1977 and 1983 was 20% of all survivors. There was a reciprocal relation between birthweight and the incidence of the disease, with an incidence of 68% in infants weighing less than or equal to 1000 g at birth. Cryotherapy of the avascular retina was performed if the acute disease progressed rapidly during stage 3 and the amount of fibrovascular proliferation was mild to moderate with signs of plus disease (presence of appreciable posterior pole vascular tortuosity and dilatation and the presence of engorgement of iris vessels). This method of treatment was performed in 4% of all survivors: in 26% of infants weighing less than or equal to 1000 g at birth and 5% of infants weighing 1001-1500 g. No infants had cicatricial disease greater than stage 2 on follow-up. The absence of any severe cicatricial disease or blindness in this large group of high risk infants suggests that when indicated and performed on the avascular retina cryotherapy may be an important method of treatment.

Observations on the retinopathy of prematurity

The fourfold to fivefold increased survival rate since 1950 of premature infants with birthweights of less than 1,000 g apparently explains the increase in cases of retinopathy of prematurity in recent years. A new international classification permits standardized grading of the retinopathy of prematurity based on severity, anterior-posterior location, and the meridians involved. Previously reported clinical trials on the role of vitamin E in the prevention of retinopathy of prematurity have given conflicting results.

The retinopathy of prematurity: medicolegal aspects

The incidence of medicolegal claims based on retinopathy of prematurity (ROP) diminished in the 1960s after the role of oxygen was presumed to be understood. It has since increased again for a number of reasons. More very premature infants are being saved. The causes of ROP are multifactorial, not well understood, and the role of oxygen as a significant factor is not always clear. Moreover, the risk/benefit ratio of supplemental oxygen is not always easy to evaluate. The morphologic features of ROP are common to a number of disorders, which may be misdiagnosed as ROP. In the series of 500 medicolegal claims that I have studied, no ophthalmologists have been sued in cases concerning ROP. However, they are routinely called as expert witnesses and it is to guide them in that role that I am reviewing the subject.

Current concepts of the effect of oxygen on the developing retina

The role of oxygen in the development of retrolental fibroplasia and the mechanism of oxygen changes in the developing retina are discussed. The primary effect of oxygen is one of Vascular closure and the secondary response, which occurs after removal from increased oxygen, is retinal neovascularization. A brief discussion of recent observations on the potential role of vitamin E in the prevention of retrolental fibroplasia is presented.

Spastic diplegia among children of low and normal birthweight

Data from a population-based Cerebral Palsy Register in Western Australia were analysed for children born between 1956 and 1975, and low birthweight (LBW) and normal birthweight (NBW) infants were compared. Control populations of similar birthweight to the cases were available from Western Australia live births. The incidence of spastic diplegia among LBW infants was higher than among those of NBW. The relative risk for LBW infants increased from 12- to 26-fold between 1961 and 1975, and those who previously would have died were surviving to be more severely disabled, both physically and intellectually. For LBW infants the risk of spastic diplegia increased both with increasing maternal age and with birth order; for NBW infants birth order was of main importance. LBW singletons, NBW twins and those born in rural hospitals had increased risk of spastic diplegia. More antenatal problems were seen in the LBW group, whereas the NBW group had higher rates of perinatal problems. Thus the groups may differ aetiologically, the LBW group having a greater likelihood of being damaged in utero, whereas the NBW group may have become brain-damaged as a result of traumatic deliveries.

Current therapy of retrolental fibroplasia. Retinopathy of prematurity

Retrolental fibroplasia, frequently referred to now as the "retinopathy of prematurity," has shown an increased incidence in recent years. This is apparently due to advances in neonatal care, which have resulted in a four- to five-fold improvement in the survival of the extremely low birthweight infants and it is these infants who are at the highest risk of developing retrolental fibroplasia. The use of large supplements of vitamin E, a known antioxidant, is discussed along with other forms of therapy.

Visual defects in children of low birthweight

The prevalence of visual defects at ages 7 to 9 in 1485 children of birthweight 2000 g or less is reported. These children were born in 1970, 1971, and 1973 to parents resident in what is now the South East Thames Regional Health Authority area, and comprise 73.9% of all survivors of births of this weight, 81% of those whose present address is known. Only 16 (1%) children were reported to have serious visual defects; 5 had retrolental fibroplasia. For the children attending normal schools there was a significant excess of both mild and more severe visual defects compared with matched controls. A distant visual acuity of 6/6 was reported in the better eye of 89%, and in both eyes of 83% of the low birthweight group.