A capture-recapture model to estimate prevalence of children born in Scotland with developmental eye defects

BACKGROUND

Microphthalmia, anophthalmia and coloboma (MAC) are closely related structural developmental eye defects that have caused public concern in the UK following media reports of apparent clusters of cases. An extensive search was carried out to identify potential cases, and diagnoses were confirmed by ophthalmological review. Despite this effort, it was recognised that some cases would remain unidentified. Capture-recapture methods could improve the accuracy of the study's birth prevalence estimate.

METHODS

A register of all children born with the developmental eye defects of MAC in Scotland (1981-96) was compiled. This identified 188 cases from eight national ascertainment sources. The methods described by Hook and Regal were used to determine possible estimates for each source. A log-linear method of capture-recapture was used to fit a model to the number of children identified by the different combinations of the eight national sources, and the individual sources were included in the model as main effects.

RESULTS

Maximum-likelihood estimates were calculated for tables of captured/not captured by one source versus any other source. The estimated number of unobserved cases for the most complete source, the register of congenital anomalies for Scotland, and the seven others combined is 78 (95% CI 53-115). Estimates calculated from two different log-linear models of the numbers of cases unobserved by all sources were 61 (95% CI 43-86) and 175 (95% CI 106-287). An external check with an independent congenital-anomalies register in one region, which is known to have high completeness, gave an estimate of 120. The study found a birth prevalence of MAC in Scotland of 1.9/10000, based on total live births during the study period. The capture-recapture analysis suggests that the true birth prevalence lies between 2.4/10 000 and 3.5/10000.

DISCUSSION

Our experience shows that, even with multiple sources of ascertainment and considerable resources directed at case identification, a considerable level of under-ascertainment of congenital eye-anomalies still results, and suggests that the use of capture-recapture analysis would be a useful addition to congenital anomalies registers for needs assessment, disease-burden estimates and health-service planning.

Is there an association between maternal carbamazepine use during pregnancy and eye malformations in the child?

PURPOSE

To check for an association between carbamazepine (CBZ) use by the mother during pregnancy and congenital eye malformations (i.e., anophthalmia, microphthalmia, and coloboma) in the child, as suggested by Sutcliffe et al. (1998), who reported four cases.

METHODS

We checked all the cases with these eye malformations for CBZ use by the mother in the EUROCAT Northern Netherlands dataset, which registers infants with congenital malformations and records possible teratogenic exposures (including medication taken by the mother). We also reviewed 13 studies in the literature.

RESULTS

The EUROCAT dataset recorded 77 cases of anophthalmia, microphthalmia, or coloboma, but none with prenatal exposure to CBZ. Prenatal CBZ exposure was recorded in seven other cases without congenital eye malformation. Large studies in the literature on the teratogenic effects of CBZ (and other antiepileptic drugs), including data from the MADRE database, revealed no association between these congenital eye malformations and prenatal CBZ exposure. One case reported bilateral anophthalmia and other congenital anomalies after prenatal exposure to CBZ in combination with vigabatrin and dexamethasone.

CONCLUSIONS

Our data do not support Sutcliffe's suggestion that prenatal CBZ exposure may result in congenital eye malformations. However, despite the large population represented, both the low birth prevalence of these congenital eye malformations and the low prevalence of CBZ exposure during pregnancy make it difficult to exclude an increased relative risk. The many large prospective and retrospective studies in the literature seem to agree with our findings, although there is still uncertainty about the teratogenic effect of CBZ in polytherapy.

Menkes' syndrome: ophthalmic findings

PURPOSE

To report the prevalence and clinical significance of ocular findings in 20 patients with Menkes' syndrome recruited for a clinical trial at the National Institute of Child Health and Human Development (NICHHD).

DESIGN

Retrospective observational case series.

PARTICIPANTS

Twenty patients with Menkes' syndrome enrolled in a clinical trial at the NICHHD, who underwent ophthalmic evaluation at the National Eye Institute from 1990 through 1997.

METHODS

Review of clinical ophthalmic examination records, photographs, and visual evoked potential recordings.

MAIN OUTCOME MEASURES

Prevalence of ophthalmic signs of unusual frequency in patients with Menkes' syndrome.

RESULTS

There was a high prevalence of very poor visual acuity (8 patients), myopia at 21 months old or younger (5 of 9 patients this age who underwent cycloplegic refraction), strabismus (11 of 18 patients whose motility was evaluated), blue irides (15 of 16 patients whose iris color was documented), iris stromal hypoplasia and bilateral peripheral transillumination (7 and 3 patients, respectively), peripheral retinal hypopigmentation (7 of 18 patients whose retinal periphery was noted at the initial examination), and aberrant eyelashes (5 patients).

CONCLUSIONS

Patients with Menkes' syndrome exhibit a high prevalence of several ocular findings, including some (very poor visual acuity, myopia, strabismus) that may warrant special care. Early ocular examination is thus indicated for patients with Menkes' syndrome, particularly those with mild variants of the disease, whose neurologic status is better and lifespan is longer.

Optic nerve hypoplasia: Risk factors and epidemiology

OBJECTIVES

To study the epidemiology of optic nerve hypoplasia.

DESIGN AND METHODS

Children with optic nerve hypoplasia and visual impairment were identified through the Swedish Register of Visually Impaired Children. Pre- and perinatal characteristics were obtained from the Medical Birth Registry and by scrutinizing pregnancy and delivery records. Clinical characteristics of children with optic nerve hypoplasia are described. The following risk factors were studied: maternal age, parity, maternal smoking, gestational duration, birth weight, delivery method, Apgar score, maternal disease during pregnancy, drugs used in early pregnancy.

RESULTS

Young maternal age, first parity, maternal smoking, preterm birth and factors associated with preterm birth were risk factors for optic nerve hypoplasia. There was an indicated association with the use of fertility drugs and antidepressant drugs.

CONCLUSIONS

Optic nerve hypoplasia is apparently associated not only with other anomolies, notably of the central nervous system, but also with signs of general disturbance in fetal development.

Population prevalence of tilted optic disks and the relationship of this sign to refractive error

PURPOSE

To assess the prevalence of tilted disks and its association with refractive error and visual field defects.

DESIGN

Population-based cohort study.

METHODS

The Blue Mountains Eye Study examined urban Australians aged 49 years or older between 1992-1994. Of 4,433 eligible participants, 3,654 (82.4%) participated. The eye examination included logMAR visual acuity, standardized refraction, cover testing, stereoscopic optic disk photography, and Humphrey automated perimetry. Inferior or nasal optic disk tilting was graded from stereoscopic photographs.

RESULTS

Of 3,583 participants with gradable photographs, inferior or nasal optic disk tilting was observed in 77 eyes of 56 participants (1.6%). The prevalence of tilted disks increased from 0.4% in eyes with astigmatism < 1.0 diopters to 17.9% in eyes with astigmatism >or= 5.0 diopters. The mean astigmatic error was 2.2 diopters in eyes with tilted disks compared with 0.7 diopters in eyes with normal disk appearance, P <.001. Myopia was present in 66.2% of eyes with tilted disks compared with 12.4% of eyes with a normal disk appearance, P <.001. The most common associated features were astigmatism (93.5%), pallor, and tessellation of the adjacent chorioretinal tissues (74.0%), situs inversus of the retinal vessels (70.1%), beta-peripapillary atrophy (64.9%), strabismus (30.4%), visual field defects (19.4%), posterior staphyloma (18.2%), inferonasal pigmentary accumulation (9.1%), and chorioretinal atrophy (5.2%). Superotemporal (33.3%) and superior (25.0%) visual field defects were most frequent.

CONCLUSIONS

A tilted disk appearance was not a rare finding in our study population and was strongly associated with astigmatism and higher levels of spherical refractive error, particularly myopia. The tilted disk and its associated visual field defect should be distinguished from other sinister causes.

[A clinical analysis of 25 cases with Duane's retraction syndrome combined with congenital crocodile tears]

OBJECTIVE

To analyze the clinical manifestations of Duane's retraction syndrome (DRS) combined with congenital crocodile tears or gustatory-lacrimal reflex.

METHODS

Twenty-five cases of DRS associated with congenital crocodile tears were retrospectively summarized. The clinical features, including sex, age at first visit, chief complaints, laterality, types of DRS, features of abnormal lacrimation and its associated ocular and non-ocular anomalies were analyzed.

RESULTS

There were 8 males and 17 females with a male-to-female ratio of 1:2. Fifteen cases had binocular involvement and the remaining 10 cases were monocular involvement. In general, the association of the abnormal lacrimation and eye movement disorder in unilateral cases was ipsilateral, while in bilateral cases the abnormal lacrimation and the movement disorder were also bilateral except 3 cases of bilateral DRS with monocular crocodile tears and one case of unilateral DRS with binocular crocodile tears.

CONCLUSIONS

Clinically, cases with Duane's syndrome combined with crocodile tears are relatively few. That sufficiently pay attention to and master its clinical characteristics is the basis for its correct diagnosis.

A population-based study on the frequency of additional congenital malformations in infants with congenital hypothyroidism: data from the Italian Registry for Congenital Hypothyroidism (1991-1998)

In the last decade a high frequency of other congenital anomalies has been reported in infants with congenital hypothyroidism (CH) detected by neonatal screening. In the present study the occurrence of additional congenital malformations (CM) in the population of CH infants detected in Italy between 1991 and 1998 (n = 1420) was investigated. In Italy all of the centers in charge of screening, treatment, and follow-up of CH adhere to the Italian National Registry of infants with CH. In this study a high prevalence of additional CM (8.4%), more than 4-fold higher than that reported in the Italian population (1-2%), was found in the population of CH infants. Cardiac anomalies represented the most frequent malformations associated with CH, with a prevalence of 5.5%. However, a significant association between CH and anomalies of nervous system, eyes, and multiple CM was also observed. In conclusion, the significantly higher frequency of extrathyroidal congenital malformations reported in the CH infants than in the general population represents a further argument supporting the role of a genetic component in the etiology of CH. Investigations of the molecular mechanisms underlying developmental events of formation of thyroid and other organs represent critical steps in the knowledge of CH etiology.

A comparison of the clinical, histopathologic, and ultrastructural phenotypes in carriers of X-linked and autosomal recessive Alport's syndrome

Previous series that described phenotypes in carriers of Alport's syndrome did not distinguish genetically between carriers of X-linked and autosomal recessive disease. In this study, modes of inheritance in unselected families with Alport's syndrome associated with two city and two provincial hospitals were determined using microsatellite markers, and carriers of disease haplotypes were identified within these families. All 47 carriers (100%) from 18 families with X-linked Alport's syndrome had dysmorphic hematuria on phase-contrast microscopy, but few developed renal failure (3 of 40 carriers; 8%), clinical hearing loss (2 of 45 carriers; 4%), retinopathy (1 of 30 carriers; 3%), or lenticonus (0 of 30 carriers; 0%). Eleven of the 14 carriers (79%) from 2 families with autosomal recessive disease had dysmorphic hematuria, but none had renal failure, clinical hearing loss, retinopathy, or lenticonus. Urinary red blood cell counts in carriers of X-linked Alport's syndrome were greater than those in carriers of autosomal recessive disease (P < 0.0001), but the frequency of proteinuria and hypertension and levels of proteinuria were not different. There was more tubulointerstitial damage in carriers of X-linked disease (P = 0.012); however, carriers of autosomal recessive disease had more widespread and more uniform thinning of the glomerular basement membrane (P < 0.0001) and less lamellation (P < 0.04).

Ocular manifestations in children born after in vitro fertilization

OBJECTIVE

To report the ocular abnormalities found in children born after in vitro fertilization.

METHODS

Forty-seven children (25 girls and 22 boys) born after an in vitro fertilization pregnancy (mean +/- SD birth weight, 2335 +/- 817 g; range, 924-4300 g) and referred for ophthalmic evaluation were included in the study. All underwent a thorough ocular examination. Obstetric history was gathered following a detailed questionnaire with the mothers.

RESULTS

Of 70 eyes among nonverbal children, visual acuity was "normal for age" in 60 (86%), "fair" in 4 (6%), and "poor" in 6 (9%). Visual acuity in 24 eyes in verbal children ranged from 6/6 to no light perception, with 4 (17%) having poor vision. Cycloplegic refraction disclosed an emmetropia in 22 (27%), hypermetropia in 47 (57%), and myopia in 13 (16%) of the eyes. Anisometropia of more than 1.0 diopters was found in 8 children. Major ocular malformations were observed in 12 (26%) of the 47 children. These malformations included Coats disease, congenital cataract, congenital glaucoma, hypoplastic optic nerve head, idiopathic optic atrophy, coloboma with microphthalmos, and retinoblastoma.

CONCLUSIONS

Ocular anomalies were frequently observed in this cohort of offspring born after in vitro fertilization. A diligent and prospective prenatal search for such malformations should unveil the real prevalence of ocular malformations in children born after in vitro fertilization.

Measuring and interpreting the incidence of congenital ocular anomalies: lessons from a national study of congenital cataract in the UK

PURPOSE

Prevention of visual impairment due to congenital cataract is an international priority. Estimates of incidence are required for implementation and assessment of preventive strategies, but are not widely available, despite routine monitoring of birth defects at a national level in many industrialized countries. The purpose of this study was to determine the incidence of new diagnosis of congenital and infantile cataract in the United Kingdom.

METHODS

All children with newly diagnosed congenital and infantile cataract in the United Kingdom in 1 year from October 1995 through September 1996 were identified using independent ophthalmic and pediatric national active surveillance schemes. Capture-recapture analysis was used to estimate completeness of ascertainment. Annual age-specific and cumulative incidence were estimated and adjusted for ascertainment.

RESULTS

Two hundred forty-eight children with newly diagnosed congenital or infantile cataract were identified-an estimated 92% of eligible cases. The adjusted annual age-specific incidence of new diagnosis of congenital and infantile cataract was highest in the first year of life, being 2.49 per 10,000 children (95% confidence interval [CI], 2.10-2.87). Adjusted cumulative incidence at 5 years was 3.18 per 10,000 (95% CI, 2.76-3.59), increasing to 3.46 per 10,000 by 15 years (95% CI, 3.02-3.90). Incidence of bilateral cataract was higher than that of unilateral, but incidence did not vary by sex or country of residence.

CONCLUSIONS

These estimates of congenital and infantile cataract incidence were higher than reported previously from routine sources relying on passive notification around the time of birth. Studies of congenital ocular anomalies that are not always readily diagnosed at birth should consider the potential influence on disease frequency of diagnostic practices as well as of underlying disease risk.

Ophthalmologic abnormalities in mentally retarded

PURPOSE

To determine the prevalence and types of ophthalmologic abnormalities in mentally retarded subjects.

METHODS

Seventy-three institutionalized mentally retarded subjects (41 boys and 32 girls) aged 5 to 19 years (mean: 11.5 years) were examined ophthalmologically during a three month period (from May to July 1999). The eye examination consisted of visual acuity testing (illiterate Snellen E-chart or acuity card procedures), pupillary reflex and motility evaluation, cover test for phoria and tropia, examination of adnexa and anterior segment (magnifying glass or slit-lamp biomicroscopy if indicated and possible), retinoscopy and direct ophthalmoscopy. All subjects were evaluated pediatrically, neurologically, psychologically and otorhinolaryngologically if indicated.

RESULTS

Ophthalmologic abnormalities were found in 60.2% of the subjects. Eyelid abnormalities accounted for 21.7%, fundus abnormalities for 21.6%, refractive errors for 15% and ocular motility disorders for 13.6%. Taken separately, optic atrophy (16.4%) was the most frequent disorder, followed by refractive errors (15%), hypertelorism (12.3%), epicanthus (10.9%) and nystagmus (8.2%). Strabismus and mongoloid obliquity of lids were seen in 5.4% each other while ptosis was disclosed in 4.2% of cases. Visual acuity tested in 60 subjects revealed that 25 (41.6%) had visual impairment. Of all subjects 10.9% required corrective glasses while 9.6% needed corrective surgery for strabismus and ptosis.

CONCLUSION

This study shows a high prevalence of ophthalmologic abnormalities in mentally retarded subjects. This is in agreement with the results of several other previous studies. It's therefore essential to screen mentally disabled subjects ophthalmologically.

Collie eye anomaly in the rough collie in Sweden: genetic transmission and influence on offspring vitality

Between 1989 and 1997, 8204 rough collies were examined for collie eye anomaly (CEA) at up to 10 weeks of age. All dogs were positively identified and the results were registered under the Swedish Kennel Club genetic health programme. A significant decrease in litter size occurred if one of two affected parents had coloboma (3.8 pups) compared with litters from two chorioretinal dysplasia- (CRD-) affected collies (5.2 pups) or litters by two normal collies (5.0 pups), indicating an influence of the coloboma genotype on offspring vitality. The prevalence of CRD in pups from normal x normal matings and CRD x CRD matings was significantly different from that expected under simple autosomal recessive inheritance (43 per cent versus 25 per cent and 85 per cent versus 100 per cent). The results are compatible with polygenic inheritance but not with simple autosomal recessive inheritance. CRD prevalence in offspring of CRD x coloboma matings was significantly lower than in pups of CRD x CRD matings, reflecting effects of the coloboma genotype on vitality. These results have important implications for breeding programmes and the genetic control of CEA.

Ocular findings in children with homozygous sickle cell disease in the Democratic Republic of Congo

OBJECTIVE

The purpose of the study is to determine the frequency of ocular manifestations in Congolese children with homozygous sickle cell disease.

METHODS

Sixty-six children with homozygous sickle cell disease were examined for ocular abnormalities between March 1 and August 31, 1998. The ages of children ranged from two to 18 years. Routine ophthalmic examination included measurement of visual acuity, inspection of the adnexa and cornea, refraction, silt-lamp examination and dilated ophthalmoscopy.

RESULTS

Ocular abnormalities were found in 47 (71%) children of 66 subjects. Ophthalmologic abnormalities included conjunctival signs (32%), retinal vascular tortuosity (29%) and dilatation (26%), AV crossing (29%).

CONCLUSIONS

Ocular findings in this study were similar to those previously published in Africa, which showed a low frequency of retinal changes.

CHARGE Association in newborns: a registry-based study

The CHARGE Association is a nonrandom occurrence of congenital malformations that has been described in clinical series. Reported patients have been selected on the basis of certain prior criteria. In this article, we try to identify a congenital malformation pattern corresponding to the CHARGE Association, using statistical methods and analyzing 5,260 infants with multiple malformations collected from four large registries of congenital malformations. Care was taken to identify a number of confounding characteristics that can influence the ascertainment and registration of specific congenital malformations. We have identified a cluster of malformations that generally agreed with the current clinical definition of the CHARGE Association and have added some further malformations (e.g., facial clefts). We demonstrate that others (e.g. , esophageal atresia) are probably not part of the pattern. Heart defects (H in the acronym) seems to be less helpful in identifying infants with the association. We suggest a method to select infants who probably represent the CHARGE Association for analyses of possible risk factors.

Spontaneous ophthalmic lesions in young Swiss mice

BACKGROUND AND PURPOSE

Outbred mice are frequently used in toxicity evaluation. Due to their small size, ophthalmologic examination of such animals is difficult with regard to restraint and use of instruments designed for human medicine. The clinical appearance and incidence of spontaneous ophthalmic lesions should be helpful in selecting mice for toxicity studies and allow distinction between intercurrent spontaneous ocular changes and those attributable to drugs or chemicals.

METHODS

Pretest ophthalmologic examinations of about 3,000 4- to 5-week-old Swiss mice, Crl:CD1 (ICR)BR, conducted in 1995 and 1996, provided information about spontaneous ocular changes and their incidence. Eye evaluations were performed after pupil dilatation (0.5% tropicamide instillation), using indirect ophthalmoscopy, and when indicated, a portable slit lamp.

RESULTS

Lenticular opacities and heterogeneity/prominence were the most common findings (up to 19%) in the anterior segment. Abnormalities of the cornea and iris were detected in up to 4% of mice. Hyaloid artery remnant, as well as isolated cases of floating bodies or hemorrhage, was observed in the vitreous of 12 to 17% of mice. Approximately 2 to 4% of mice had colobomatous fundus, retinal fold, or retinal atrophy. A few mice had chorioretinal atrophy, hemorrhage, or abnormal pattern of the retinal vasculature. Remaining findings consisted of incomplete palpebral fissure, microphthalmia, exophthalmia, ophthalmic hemorrhage, and scleral mass.

CONCLUSIONS

Due to severity of the condition or interference with ocular examination, affected mice should be eliminated from experimental studies. Hence, pretest ocular examinations of mice are indicated in safety-assessment toxicity studies.

Bias due to incomplete follow up in a cohort study

AIM

To investigate the bias introduced by incomplete follow up in a cohort study of ocular outcome after premature birth.

METHODS

A geographically defined cohort of children born before 32 weeks' gestation was prospectively recruited at birth to study the ocular outcome at 2 years. On the basis of attendance at 2 years, the children's families were allocated to one of three groups: group 1 attended for follow up, group 2 were difficult to trace, and group 3 were very reluctant for assessment. All children were examined by a single ophthalmologist, masked to these groupings.

RESULTS

558 children (98.8% of study group) were examined, of whom 505 were in group 1, 20 in group 2, and 33 in group 3. The groups which were more difficult to study (groups 2 and 3) showed a significantly higher prevalence of ocular abnormalities, including strabismus (p=0. 02) and cicatricial retinopathy of prematurity (p=0.002) compared with those attending for follow up. Further, not all of these cases could have been identified by review of the children's previous records. Ocular abnormalities would be underestimated by 16% (11.3% in group 1 compared with 13.4% in the total cohort, p=0.77).

CONCLUSIONS

This study suggests that the prevalence of abnormalities would be underestimated by incomplete follow up, as those subjects who were most difficult to obtain for study had a significantly higher prevalence of abnormalities.

Compiling a national register of babies born with anophthalmia/microphthalmia in England 1988-94

AIM

To describe the prevalence of anophthalmia/microphthalmia in babies born in England 1988-94, as well as their overall survival, and the incidence of associated eye and non-eye malformations; to determine the usefulness of different sources of medical and health service information for establishing a retrospective register of anophthalmia/microphthalmia.

METHODS

Multiple sources for initial (retrospective) case ascertainment were surveyed, followed by questionnaires to clinicians to establish severity, associated malformations, and aetiology for England, 1988-94. The population surveyed was all births in England for this time period (4,570,350 births). Cases included live births, stillbirths, or terminations after prenatal diagnosis of congenital anomaly, with anophthalmia/microphthalmia, with or without other malformations and syndromes. Trisomy 13 was subsequently excluded.

RESULTS

The proportion of cases notified by any one information source was not more than 26% (Office for National Statistics Register 22%, paediatricians 26%, district sources 25%). Sixty nine per cent of cases (51% of severe cases) were notified by only one source. A total of 449 cases were reported, prevalence 1.0 per 10,000 births. The prevalence was stable over time, although the proportion notified by clinicians rose in more recent years. Thirty four per cent of affected babies had mild microphthalmia. Of those with severe anophthalmia/microphthalmia, 51% were bilateral, other eye malformations were present in 72%, non-eye malformations in 65%, and a "known aetiology" was attributed in 22%. Three quarters of those severely affected survived infancy.

CONCLUSIONS

Despite high response rates from the sources of information contacted, the lack of duplication between sources indicates the difficulties of retrospective ascertainment and the need for multiple sources when establishing a register. Anophthalmos/microphthalmos is usually associated with other malformations. Most cases are of unknown aetiology.

Ocular status of boys with fragile X syndrome: a prospective study

PURPOSE

The purpose of this study was to determine whether the high rates of ocular problems described in previous retrospective reports of individuals with fragile X syndrome were present in a prospective sample of young boys. Fragile X syndrome is currently considered the leading hereditary cause of mental retardation, with prevalence estimates of 1:2500 to 1:5000 males.

METHODS

Forty-eight boys with fragile X syndrome between the ages of 2.5 and 11 years were evaluated for ocular abnormalities. They received complete ophthalmic evaluations including assessment of visual acuity, cycloplegic refraction, ocular motility assessment, and dilated fundus examination.

RESULTS

Approximately 25% of the children had clinically significant ocular findings that included refractive errors (17%, primarily hyperopia and astigmatism) and strabismus (8%). Of the 42 children with quantifiable visual acuities, only 1 child, with diagnoses of nystagmus and hyperopia, had a Snellen visual acuity that was not within normal limits for his age. Three of the 5 children with gross measures of visual acuity had clinically significant findings: 2 had hyperopia greater than 3.5 diopters and 1 had esotropia. The other 2 children with gross measures of acuity and the 1 child without visual acuity assessment had cycloplegic refractions of +1.25 to +1.5 and ocular motility appeared normal.

CONCLUSIONS

These results suggest that previous reports of high rates of vision problems, particularly strabismus, in boys with fragile X syndrome may have resulted from selection bias. Although we did observe a higher prevalence of strabismus than that found in the general population (8% vs 0.5% to 1%), the proportion of children having strabismus in our sample was much smaller than that reported in other studies of children with fragile X syndrome (30% to 40%). However, 17% of the sample did have significant refractive errors. In addition to evaluating the ocular motility of children with fragile X syndrome, cycloplegic refraction should also be performed to determine whether refractive problems are present.

Acquired pits of the optic nerve in glaucoma: prevalence and associated visual field loss

PURPOSE

This study was performed to determine the prevalence of acquired pits of the optic nerve (APON) in glaucoma and the characteristics of associated visual field loss.

SUBJECTS AND METHODS

Stereoscopic optic disc photos from 235 patients with a low-tension variety of primary open-angle glaucoma (LTG) and 251 primary open-angle glaucoma patients with intraocular pressures higher than 21 mmHg (HTG) were examined for the presence of typical APON as defined by a standard photograph (Fig 1). Associated visual field loss was evaluated with automated perimetry and patterns of field loss were identified.

RESULTS

Out of a total of 486 patients, 63 APON were found in 51 eyes of 44 glaucoma patients. APONs were more prevalent in women. Acquired pits were more frequently (p<0.001) located inferiorly (70%) than superiorly (30%). There was a significantly higher prevalence (p<0.001) of APON in LTG patients (12.7%) than in HTG patients (5.6%). Dense visual field defects within five degrees of fixation occurred in 96% of patients with APON.

CONCLUSION

Acquired pits of the optic nerve are more often located at the inferior optic disc than at the superior disc and are nearly always associated with visual field loss close to fixation. In a glaucoma referral center setting, APON are more prevalent in lower pressure glaucoma than in higher pressure glaucoma.

Congenital eye malformations: clinical-epidemiological analysis of 1,124,654 consecutive births in Spain

We analyzed Spanish Collaborative Study of Congenital Malformations (ECEMC) data on a series of 1,124,654 consecutive births to study congenital eye malformations from an epidemiological standpoint. We studied their frequencies as well as some causal and clinical aspects. Four hundred fourteen infants had eye malformations, for an overall prevalence of 3.68/10,000 newborns. Most frequent were: anophthalmia/microphthalmia (21.34/100,000), congenital cataract (6.31), coloboma (4.89), corneal opacity (3.11), and congenital glaucoma (2.85). In our data, the tendency of eye malformations to be associated with other congenital abnormalities is evident (only 21.01% of cases were isolated). Eye defects are heterogeneous, since we have observed them in clinical patterns with all modes of inheritance or caused by different environmental agents. Chromosomal syndromes represent 60% of total syndromes, followed by syndromes of autosomal-recessive inheritance (15%), environmental syndromes (10%), autosomal-dominant syndromes (5.83%), and other types which have a lower frequency. Regarding defects associated with eye malformations, most frequent are limb anomalies (affecting 59.3% of multiply malformed cases), auricular/facial (47.1%), central nervous system (42.5%), osteomuscular excluding limbs (42.2%), genital defects (30.6%), oral clefts (29.4%), and the rest of the body systems, which are less frequent. Using the method outlined by Prieto and Martínez-Frías [1996: Am J Med Genet 62:61-67], it was demonstrated that the association of coloboma and anophthalmia/microphthalmia was specific, as was the combination of cataract and anophthalmia/microphthalmia, and that of anophthalmia/microphthalmia with holoprosencephaly. From these statistical associations some pathogenetic relationships in human embryos can be inferred, supporting several previously proposed mechanisms.

Epidemiology of holoprosencephaly and phenotypic characteristics of affected children: New York State, 1984-1989

Holoprosencephaly is a congenital defect of the median structures of the brain and face. The epidemiology is poorly known due to the paucity of population-based studies. This study describes the epidemiology of holoprosencephaly in a large population, using cases identified through the New York State Congenital Malformations Registry, and born in 1984-1989. We describe the craniofacial abnormalities present, their frequency, and their cooccurrence, and we examine the correspondence between the severity of craniofacial abnormalities, chromosomal abnormalities, and severity of the brain defect. Liveborn cases totaled 78, yielding a prevalence of 4.8 per 100,000 live births. Prevalence among girls was nearly double that in boys, and was 4.2 times higher among infants of mothers under age 18 compared to infants of older mothers. Only 9.8% of all cases had no craniofacial abnormalities other than the brain defect. Eye malformations were present in 76.8%, nose malformations in 69.5%, ear malformations in 50%, and oral clefts in 41.5%. These malformations arise at different times during gestation. The variability in patterns of cooccurrence suggests variability in the developmental pathways and/or timing of developmental derangements which result in holoprosencephaly. This, in turn, is consistent with a model of multiple causes. Children with alobar holoprosencephaly tended to have the most severe craniofacial anomalies, but the correspondence was not 100%. Craniofacial phenotype does not consistently discriminate between cytogenetically normal and abnormal cases.

Clinical evaluation of posterior embryotoxon in one institution

To elucidate the pathogenesis of posterior embryotoxon, we estimated its incidence in our clinic and evaluated its associated ocular and systemic anomalies. Slit-lamp and gonioscopic examinations were performed on 440 randomly selected patients at Nagoya City University Hospital over a 10-month period. Posterior embryotoxon was detected in 107, 50 bilateral and 57 unilateral, cases (24.3%). Twelve (11.2%) of the 107 cases had open-angle glaucoma. Accompanying ocular anomalies included six cases of sclerocornea, two each of persistent pupillary membrane and familial exudative vitreoretinopathy, and 1 each of melanocytoma of the optic nervehead, choroidal nevus and subconjunctival dermoid cyst. Associated systemic anomalies included three cases of Alagille syndrome, two of congenital biliary atresia, and one each of congenital facial palsy with microtia, congenital adrenal hyperplasia, empty sella syndrome, Hirschsprung disease and Wilson disease. Many of these ocular and systemic anomalies were caused by the maldevelopment of neural crest cells. Patients with posterior embryotoxon should be examined for the possible presence of open-angle glucoma and for ocular and systemic anomalies related to maldevelopment of neural crest cells.

Down syndrome associated malformations

This paper reports the associated malformations and the clinical findings that were observed in 417 cytogenetically confirmed Down Syndrome patients. Among them congenital heart defects have occurred more frequently [75; 17.98%] than osteoarticular malformations [23; 5.52]; eye anomalies [22; 5.27%]; and gastroenterological malformations [n 16; 3.84%]. With regard to prognosis and treatment appropriate counselling has been given to Down Syndrome patients and their families.

Ocular abnormalities in Down syndrome: an analysis of 140 Chinese children

One hundred forty Chinese children with Down syndrome (DS) treated in the Child Assessment Centre of the Duchess of Kent Children's Hospital in Hong Kong between 1985 and 1996 underwent a detailed ophthalmologic evaluation, including test of visual acuity by behavioral testing or retinoscopy, determination of ocular motility, visual field examination, binocular examination for strabismus, determination of near point convergence and pupillary reflex, and/or slit lamp bimicroscopy and ophthalmoscopy to assess ocular health. Only 43 children (31%) had no ocular abnormalities. The overall incidence of ocular abnormalities was 69%, and included refractive error (58%), strabismus (20%), nystagmus (11%), blepharitis/conjunctivitis (7%), lens opacities (4%), and glaucoma (0.7%). No child had Brushfield spots or keratoconus. The incidence of refractive errors increased with increasing age and nearly doubled at school age. As compared with white children with DS, the Chinese children with DS exhibited a higher incidence of refractive error and a similar incidence of lens opacities but a lower incidence of strabismus, nystagmus, blepharitis, Brushfield spots, and keratoconus. Regular visual surveillance, especially of visual acuity, in children with DS as they mature is important in preventing amblyopia.

Congenital eye malformations in 212,479 consecutive births

Congenital eye malformations were studied in a small geographical area in 212,479 consecutive births. For each of the 145 new cases studied during the period 1979 to 1994, more than 50 factors were compared in probands and in controls. The prevalence rate of congenital eye malformations was 6.8 per 10,000 for microphthalmia 1.7, anophthalmia 0.23, cataract 2.7 and coloboma 1.4 respectively. Sex ratio was 0.82. Prenatal diagnosis was performed in 18 cases and 7 cases were induced abortions. The more common types of associated malformations in the 81 affected cases (53.8%) with at least one anomaly other than an eye malformation were clubfeet, microcephaly, hydrocephaly, cleft lip/palate and facial dysmorphia. At birth infants with eye malformations and other malformations were smaller, weighted less and their head circumference was lower than in controls. Placental weight was also lower than in controls. Pregnancies with eye malformations were more often complicated by threatened abortion, oligoamnios and polyhydramnios. Mothers of children with congenital eye malformations took more often drugs during pregnancy than mothers of controls. Fathers of children with congenital eye malformations were more often exposed to occupational hazards than fathers of controls. There was a significant association between eye malformations and consanguinity of parents. The recurrence risk for first degree relatives of probands was 8.9%. First degree relatives of probands had more than three times the prevalence of non-eye malformations than controls. These results are of relevance to genetic counseling.

Ocular defects in children and adolescents with severe mental deficiency

To assess the need for eye care in children and adolescents with severe mental deficiency, a cross-sectional study of the prevalence and causes of ocular defects amongst these individuals was conducted. Two hundred and sixty residents in a mental handicap unit were examined from January 1992 to June 1993. It was found that there was an unusually high prevalence of severe visual impairment (25%), refractive errors (24%), squint (8%) and a number of organic ocular diseases (8%). All the patients studied were non-verbal and 18% of them were deaf. Only 23 patients could walk. The results emphasize the need for establishing an efficient system to provide regular ophthalmic care for children with severe mental deficiency.

Ocular abnormalities in congenital cytomegalovirus infection

BACKGROUND

Congenital cytomegalovirus (CMV) infection often results in damage to the brain, auditory system and visual system that leads to debility. This report describes the frequency, severity and effect on vision function of ocular abnormalities in a large cohort of children with congenital CMV infection.

METHODS

Serial eye examinations were performed on 445 infants and children with congenital CMV infection from one month to 9 years of age, assessing anatomic integrity, motor sensory function, retina and posterior pole.

RESULTS

Ocular disease was manifest principally by chorioretinitis, optic atrophy, pigmentary retinopathy and strabismus; each of these findings occurred more frequently (p < 0.05) among children who were symptomatic at birth than among those who were initially asymptomatic. These same findings were also more common among patients born after a primary maternal infection than among those born after a recurrent maternal infection. More than half of the patients with symptomatic congenital CMV infection with chorioretinitis or optic atrophy had significant binocular vision impairment.

CONCLUSIONS

Ocular disease is an important sequela of congenital CMV infection that can lead to impaired vision. In order to allow for early intervention, patients with congenital CMV infection should have eye examinations beginning in early infancy.

The geographical epidemiology of ocular diseases: some principles and methods

With the increasing availability of geographically referenced data in health research the time is ripe to review the use of particular geographical and spatial analysis techniques in ophthalmic research. Analysis of the geographical distribution of ocular diseases, particularly in Britain, has not had a high profile, but there are certain diseases, such as congenital eye malformations in children, where such analysis methods are particularly appropriate. We review the data requirements and then a variety of analytical techniques, some of which partition geographical space into areal units (such as counties or electoral wards), others of which treat space as continuous. We conclude with some comments on software that is available for such analyses.

Minor physical anomalies in schizophrenia

Using the Waldrop scale, minor physical anomalies were studied in 82 Caucasian subjects, including 41 schizophrenic and 8 bipolar adults, as well as 14 normal and 19 mentally retarded adults. An increased incidence of minor physical anomalies was found in the mentally retarded adults relative to the other groups. Consistent with previous studies, there was a trend for the total mean Waldrop score of the schizophrenic group to be higher than the mean score of the normal group. Minor physical anomalies (assessed by the Waldrop scale), however, appear to be of questionable utility in identifying "congenital" schizophrenia, at least as this putative subgroup of schizophrenia is currently conceptualized.

[Incidence of ocular congenital anomalies in clinical material]

The aim of the study was to analyse, basing on the clinical material of the years 1987-1992, the congenital ocular anomalies and to compare the results with the observations made 20 years ago. Among the total clinical material of 7333 examined patients in the age from 3 days to 18 years congenital anomalies, including high myopia, were found in 3882 cases (group A). There were 2201 boys and 1681 girls. Group B, without high myopia, comprised 2639 cases of congenital anomalies, 1539 boys and 1100 girls. It was established that the incidences of congenital retinal degenerations and optic nerve atrophy were now higher than in the 1970-s years. About 1/3 of cases with congenital anomalies were those with high myopia.

Ocular abnormalities in children from a Malaysian school for the deaf

The prevalence of ocular abnormalities was studied in 165 children from a Malaysian school for the deaf. Ninety-five children (57.6%) had one or more ocular abnormalities. Rubella retinopathy was the commonest form of ocular abnormality (35.2%). Refractive errors were found in 23 children (13.9%). Refractive errors in the rubella group were significantly more common than in the non-rubella group of deaf children (p < 0.001) (chi 2 test). Thirteen children had congenital anomalies causing significantly impaired vision. Ophthalmological examination of deaf children helps in the detection of cases with rubella eye signs and thus helps to identify the cause of deafness. Since deaf children are at greater risk of visual and ocular abnormalities, periodical ophthalmological examination should be carried out in these children.

Ocular manifestations of frontonasal dysplasia

The ophthalmologic findings associated with frontonasal dysplasia have not been defined previously in a large series of untreated children. We reviewed the ophthalmic manifestations of a series of patients with frontonasal dysplasia who were seen as part of their craniofacial evaluation. All had undergone a complete ophthalmologic examination before any manipulation of either the orbits or the soft tissues of the orbital contents. From 1986 to 1991, 23 patients with frontonasal dysplasia were seen; ophthalmologic abnormalities were found in 20 (87 percent). Abnormalities included significant refractive errors, strabismus, nystagmus, and eyelid ptosis. Three patients had amblyopia, a treatable cause of visual loss, from strabismus or anisometropia. Ten eyes in seven patients (30 percent) had severe structural anomalies, such as optic nerve hypoplasia, optic nerve colobomas, microphthalmia, cataract, corneal dermoid, or inflammatory retinopathy, that resulted in an acuity of 20/100 or worse. The high incidence of ocular abnormalities indicates that early assessment by an ophthalmologist should be part of the initial evaluation of patients with frontonasal dysplasia to detect treatable visual or ocular problems.

Fraser syndrome

Fraser Syndrome is a rare disorder with only a few cases having been described in Indian literature. We report here a case of a patient aged 16 yr present with primary amenorrhea which is a very unusual mode of presentation. Multiple associated anomalies were present including those of eyelids, eyebrow, face, fingers and genitalia. Chromosome analysis revealed a normal female karyotype. Pituitary gonadotropins were within normal range.

[Malformation syndromes: the diagnostic approach and follow-up in ocular pathology]

Ocular defects are often found in association with many systemic disorders. Some are already present at birth, but in other cases they develop in early infancy or later in life. They are found associated with connective tissue disorders, neurological conditions, chromosomal abnormalities and dermatological disorders. Some of these syndromes have a genetic basis but often it is uncertain whether they are inherited and their cause is unknown.

Epidemiology of congenital eye malformations in 131,760 consecutive births

The epidemiology of eye malformations was studied in the geographical area covered by the authors' registry of congenital malformations. For each of the 78 new cases studied during the period 1979 to 1988, more than 50 factors were compared in probands and in controls. The prevalence rate of congenital eye malformations was 7.5 per 10,000 with microphthalmia 1.8, anophthalmia 0.3, cataract 2.3 and coloboma 0.7 respectively. Sex ratio was 0.82. Prenatal diagnosis was performed in ten cases and three cases were induced abortions. The more common types of associated malformations in the 42 affected cases (53.8%) with at least one anomaly other than an eye malformation were clubfeet, microcephaly, hydrocephaly and facial dysmorphia. At birth infants with eye malformations and other malformations were smaller, weighed less and their head circumference was lower than in controls. Placental weight was also lower than in controls. Pregnancies with eye malformations were more often complicated by threatened abortion, oligoamnios and polyhydramnios. Mothers of children with congenital eye malformations took more often drugs during pregnancy than mothers of controls. Fathers of children with congenital eye malformations were more often exposed to occupational hazards than fathers of controls. There was a significant association between eye malformation and consanguinity of parents. First degree relatives of probands had more than three times the prevalence of non-eye malformations than controls. These results are of relevance to genetic counseling.

The study of malformations "by the company they keep"

Our study of individuals with thalidomide embryopathy reaffirms many of the principles of clinical teratology concerning sensitivity of developing structures and specificity of action. It also highlights important features of ocular teratology that differ from those of other organ systems. Because malformations of the eye and associated structures do not significantly threaten the survival of the embryo, fetus, or neonate, any variation in prevalence in older individuals is not due to the nature of the ocular malformation but may be significantly modified by "the company they keep," the systemic malformations occurring at the same time as the original insult, whether it be an environmental, a genetic, or a local disturbance. Additionally, the presence of clusters of malformations caused by a teratogen at a specific time supports the concept of a common pathogenic mechanism and provides suggested avenues for further research into the cause of these malformations.

The cyclops and the mermaid: an epidemiological study of two types of rare malformation

Infants with cyclopia or sirenomelia are born at an approximate rate of 1 in 100,000 births. Eight malformation monitoring systems around the world jointly studied the epidemiology of these rare malformations: 102 infants with cyclopia, 96 with sirenomelia, and one with both conditions were identified among nearly 10.1 million births. Maternal age is somewhat increased for cyclopia, indicating the likely inclusion of some chromosomally abnormal infants which were not identified. About half of the infants are stillborn. There is a female excess among infants with cyclopia. Excess twinning occurred for cyclopia and possibly also for sirenomelia. An analysis of associated malformations indicates the similarity between the two conditions, which is in agreement with recent embryological analysis.

[Clinico-morphological characteristics of developmental defects of the eye]

Analysis of the records of the ophthalmologic pathoanatomic laboratory of the Kazakh Research Institute of Ophthalmic Diseases has shown that the incidence of developmental abnormalities due to disorders in the embryonal period and organogenesis have made up 3.7 percent of the total number of ocular tumors and 6.0 percent of benign tumors over the past 34 years. More than 60 percent of the patients with developmental defects were residents of South-Eastern Kazakhstan, equally frequently aborigens and representatives of other nationalities (41 and 43 patients, respectively), with male patients predominating (46 of 84 subjects). The patients' ages varied from 3 months to 70 years, children under 14 (50 patients) and young subjects aged 14 to 30 (24) prevailing. The most frequent developmental defects were dermoid cysts (61.9 percent) localized mainly in the orbit, less frequently dermoids and lipo-dermoids (20.2 percent) in the cornea, and dystrophic lacrimal gland in scleral conjunctiva (14.3 percent). Teratoma, brain hernia, and cystic eyes occurred in 1.2% of cases each; these conditions and dystopic lacrimal gland were histologically diagnosed.

[Congenital developmental anomalies of the visual system in children in our 13-year observations]

Cases of congenital anomalies of the visual system in children hospitalized in the period 1974-1986 were analyzed. Together 305 cases were analyzed. The most frequently seen congenital anomaly was an unilateral or bilateral cataract (107 cases), further glaucoma (50 cases) and pathological changes caused by Toxoplasma Gondii (33 cases). Among principal causes of these anomalies the author ++ is citing the rubella and toxoplasmosis.

Nitrosatable drug exposure during pregnancy and adverse pregnancy outcome

Recent investigations have suggested that drugs that are amines can undergo endogenous or exogenous nitrosation reactions to form N-nitroso compounds. These compounds have been extensively characterized in animal models as carcinogens, mutagens and teratogens. In order to examine the possible effects of exposure to nitrosatable drugs during gestation on pregnancy outcome, data were utilized from the Collaborative Perinatal Project of the National Institute of Neurological and Communicative Disorders and Stroke. Pregnancy outcomes for 6061 pregnancies in which the mother ingested a drug known to undergo nitrosation were compared with 6921 randomly sampled pregnancies without such exposure. The major outcome factors of interest were birth defects, fetal, neonatal and infant death and birthweight. Our findings suggest that no significant increases in risk of fetal, neonatal and infant death or low birthweight were associated with nitrosatable drug exposure during pregnancy. However, the risk of a tumour in the offspring of exposed mothers was increased (relative risk, RR = 2.29; 95% Cl 0.99-5.26). Increases in relative risk of major malformations was also observed and this increase was greater when exposure during the first four months of pregnancy was examined separately (RR = 1.33; 1.11-1.58). There were specific individual malformations that were observed to have increased relative risks (for example: eye malformations, hydrocephaly, craniosynostosis and meningomyelocoele/meningocoele) but interpretation was difficult due to multiple comparisons and some of these observations were associated with wide confidence intervals. These types of adverse pregnancy outcomes were consistent with animal study outcomes.