The clinical and morphologic spectrum of optic nerve hypoplasia

Peripheral Retinal Nonperfusion in Pediatric Patients with Optic Disc Hypoplasia

PURPOSE

This study aims to report the association of optic nerve hypoplasia (ONH), peripheral retinal nonperfusion, and secondary complications in pediatric patients.

DESIGN

Retrospective case series.

METHODS

The study was conducted between January 2015 and January 2022 at the Bascom Palmer Eye Institute. Inclusion criteria were clinical diagnosis of optic disc hypoplasia, age <18 years, and a fluorescein angiography (FA) of acceptable quality.

RESULTS

Seven patients (11 eyes) met inclusion criteria. Average age at presentation was 3.5 years (range 1 month-8 years) and the mean follow-up time was 34.28 months (range 2-87 months). Four patients (57.14%) showed bilateral optic disc hypoplasia. All eyes exhibited peripheral retina nonperfusion on FA, in which mild severity was found in 7 eyes (63.63%), moderate in 2 eyes (18.18%), severe in 1 eye (9.09%) and extreme in 1 eye (9.09%). Eight eyes (72.72%) showed evidence of 360 degrees of retinal nonperfusion. Two patients (18.18%) were diagnosed with concurrent retinal detachment that were deemed inoperable at the time of diagnosis. All cases were observed without intervention. None of the patients were observed to have complications during follow-up.

CONCLUSION

Among pediatric patients with ONH, there appears to be a high rate of concurrent retinal nonperfusion. In these cases, FA is a helpful tool to detect peripheral nonperfusion. Retinal findings are subtle in some cases and may not be detectable in children with suboptimal imaging performed without examination under anesthesia.

Comparison of Cirrus spectral domain OCT with disc-macula distance to disc diameter ratio in diagnosing congenital optic nerve hypoplasia

PURPOSE

Diagnosis of congenital optic nerve hypoplasia (CONH) can be challenging in children or uncooperative individuals. Misdiagnosis can lead to inappropriate treatment; thus, it is important to identify an objective and reliable measurement. The purpose of this study was to evaluate whether Cirrus spectral domain optical coherence tomography (SD-OCT) is a valid test for diagnosing CONH by comparing it to the disc-macula distance to disc diameter (DM:DD) ratio.

METHODS

A total of 93 participants (64 controls and 29 CONH) underwent comprehensive eye examinations, fundus photography and Cirrus SD-OCT. Receiver operating characteristic (ROC) curves for the DM:DD ratio and OCT disc area were constructed for CONH and control eyes.

RESULTS

Mean (±SD) OCT disc area was 1.46 (±0.42) mm² and 1.89 (±0.38) mm² for CONH and control eyes, respectively (p < 0.0001). The area under the curve for the DM:DD ratio was 0.97 (95% confidence interval: 0.91-0.99) and 0.79 for OCT disc area (95% confidence interval: 0.70-0.86), which were significantly different (p = 0.0005). The optimal cut-off value for OCT disc area was 1.66 mm² (76% sensitivity, 70% specificity), while the optimal cut-off for DM:DD ratio was 3.10 (85% sensitivity and 95% specificity). The Cirrus SD-OCT showed a tendency to overestimate disc size, especially in cases with no light perception (NLP) or segmental CONH.

CONCLUSIONS

Although the DM:DD ratio is superior to OCT in diagnosing CONH with a higher sensitivity and specificity, the ratio is subject to inter-examiner variability and can be challenging to obtain. We found the Cirrus SD-OCT to be a valid objective test for diagnosing CONH. Caution is advised when using SD-OCT in segmental CONH or in an eye with NLP. We suggest 1.66 mm² as the optimal cut-off value for Cirrus SD-OCT disc area to differentiate a hypoplastic from a normal optic disc.

Vascular Contributions to the Neurobiological Effects of Prenatal Alcohol Exposure

Fetal alcohol spectrum disorders (FASD) are often characterized as a cluster of brain-based disabilities. Though cardiovascular effects of prenatal alcohol exposure (PAE) have been documented, the vascular deficits due to PAE are less understood, but may contribute substantially to the severity of neurobehavioral presentation and health outcomes in persons with FASD.

Methods

We conducted a systematic review of research articles curated in PubMed to assess the strength of the research on vascular effects of PAE. 40 pertinent papers were selected, covering studies in both human populations and animal models.

Results

Studies in human populations identified cardiac defects, and defects in vasculature, including increased tortuosity, defects in basement membranes, capillary basal hyperplasia, endarteritis, and disorganized and diminished cerebral vasculature due to PAE. Preclinical studies showed that PAE rapidly and persistently results in vasodilation of large afferent cerebral arteries, but to vasoconstriction of smaller cerebral arteries and microvasculature. Moreover, PAE continues to affect cerebral blood flow into middle-age. Human and animal studies also indicate that ocular vascular parameters may have diagnostic and predictive value. A number of intervening mechanisms were identified, including increased autophagy, inflammation and deficits in mitochondria. Studies in animals identified persistent changes in blood flow and vascular density associated with endocannabinoid, prostacyclin and nitric oxide signaling, as well as calcium mobilization.

Conclusion

Although the brain has been a particular focus of studies on PAE, the cardiovascular system is equally affected. Studies in human populations, though constrained by small sample sizes, did link pathology in major blood vessels and tissue vasculature, including brain vasculature, to PAE. Animal studies highlighted molecular mechanisms that may be useful therapeutic targets. Collectively, these studies suggest that vascular pathology is a possible contributing factor to neurobehavioral and health problems across a lifespan in persons with a diagnosis of FASD. Furthermore, ocular vasculature may serve as a biomarker for neurovascular health in FASD.

Selected Ophthalmological Features in Children with Septo-Optic Dysplasia and Optic Nerve Hypoplasia

Septo-optic dysplasia (SOD) and optic nerve hypoplasia (ONH) cause congenital visual impairment. Their aetiology is mostly unknown. Our aim was to investigate the prevalence of selected ophthalmological features in patients with these disorders. A chart review was performed on patients with SOD/ONH. Ophthalmological data were extracted. There were 102 patients (56 males). The median age at the end of the study was 12.7 years. Best-corrected visual acuity ranged from normal to no light perception. Bilateral ONH was more common than unilateral ONH. Strabismus (85%) and to a lesser extent nystagmus (52%) were both very common in our cohort. Patients with esotropia had worse visual acuity than those who had exotropia. The presence of nystagmus was more likely in cases with bilateral ONH. Therefore, patients with SOD/ONH may have normal visual acuity. Many have strabismus, which may cause amblyopia thereby further decreasing visual acuity. Nystagmus occurs commonly and its presence typically indicates bilateral ONH.

FEVR phenotype associated with septo-optic dysplasia

Background: Septo-optic dysplasia, also known as de Morsier syndrome, is a disorder of brain development characterized by optic nerve hypoplasia, hypopituitarism, and midline brain defects.Materials and Methods: Single retrospective case report.Results: An infant born at 38 5/7 weeks gestation age weighing 3125 g developed respiratory distress shortly after birth. Systemic findings included myocardial dysfunction, hypopituitarism, feeding intolerance, microphallus, and dysmorphic features. Eye examination revealed tractional retinal detachments and optic nerve hypoplasia. In addition, peripheral non-perfusion and peripheral neovascularization were consistent with Familial Exudative Vitreoretinopathy (FEVR) phenotype. MRI showed hypoplastic optic nerves, ectopic posterior pituitary with hypoplastic pituitary infundibulum, and slightly thin corpus callosum, diagnostic of septo-optic dysplasia. Genetic testing revealed no pathogenic variants and two variants of uncertain significance.Conclusion: FEVR findings can be associated with septo-optic dysplasia and may point to an etiologic connection between neural development and subsequent vascular development.

High prevalence of pituitary hormone deficiency in both unilateral and bilateral optic nerve hypoplasia

AIM

This study examined the prevalence of neurological impairment and pituitary hormone deficiency (PHD) in patients with unilateral and bilateral optic nerve hypoplasia (ONH).

METHODS

A population-based cross-sectional cohort study of 65 patients (51% female) with ONH was conducted in Stockholm. Of these were 35 bilateral and 30 unilateral. The patients were below 20 years of age, living in Stockholm in December 2009 and found through database searching. The median age at the analysis of the results in January 2018 was 16.1 years (range 8.1-27.5 years). Neurological assessments and blood sampling were conducted, neuroradiology was reviewed and growth curves were analysed. Diagnoses of PHDs were based on clinical and biochemical evidence of hormone deficiency.

RESULTS

Neurological impairments were identified in 47% of the patients and impairments in gross and fine motor function were more prevalent in bilateral ONH (p < 0.001). In addition, 9% had cerebral palsy and 14% had epilepsy. The prevalence of PHD was 29 and 19% had multiple PHD.

CONCLUSION

Children with ONH had a high risk of neurological impairment, especially in bilateral disease. Both unilateral and bilateral ONH signified an increased prevalence of PHD and all these children should be endocrinologically followed up until completed puberty.

Optic Nerve Hypoplasia and Crouzon Syndrome

Crouzon syndrome is the most common cause of syndromic craniosynostosis. The authors present a previously unreported association between Crouzon syndrome and optic nerve hypoplasia. A male infant was transferred to the center for treatment of respiratory distress. He was diagnosed as having dysmorphic features, a membranous choanal stenossi bilaterally, and bilateral optic nerve hypoplasia. Genetic testing confirmed a molecular diagnosis of Crouzon syndrome. He had a complicated course in relation to choanal stenosis management, and was discharged home at 10 weeks of age. Although uncommon in Crouzon syndrome, the association with optic nerve hypoplasia changes the initial work-up and the management of parental expectations. [J Pediatr Ophthalmol Strabismus. 2018;55:e45-e48.].

Congenital anomalies of the optic disc: insights from optical coherence tomography imaging

PURPOSE OF REVIEW

Congenital anomalies of the optic nerve are rare but significant causes of visual dysfunction in children and adults. Accurate diagnosis is dependent on a thorough funduscopic examination, but can be enhanced by imaging information garnered from optical coherence tomography (OCT). We review common congenital optic nerve anomalies, including optic disc pit, optic nerve coloboma, morning glory disc anomaly, and hypoplasia of the optic nerve, review their systemic associations, and discuss insights from OCT imaging.

RECENT FINDINGS

Optic disc pits are a result of a defect in the lamina cribrosa and abnormal vitreomacular adhesions have been shown to cause maculopathy. In patients with optic nerve colobomas, OCT can be instrumental in diagnosing choroidal neovascularization, a rare but visually devastating complication. The pathogenesis of morning glory disc anomaly has been more clearly elucidated by OCT as occurring from a secondary postnatal mesenchymal abnormality rather than only the initial neuroectodermal dysgenesis of the terminal optic stalk in isolation. OCT studies of optic nerve hypoplasia have demonstrated significant thinning of the inner and outer retinal layers of the perifoveal region and thicker layers in the fovea itself, resulting in a foveal hypoplasia-like pathology, that is, significantly correlated to poorer visual outcomes.

SUMMARY

OCT provides detailed in-vivo analysis of these anatomic anomalies and their resulting pathologies, shedding new insights on the pathogenesis, diagnosis, and potential visual outcomes of these conditions in children. Further study employing OCT to elucidate structure-function relationships of congenital optic nerve anomalies will help expand the role of OCT in clinical practice related to diagnosis, prognosis, and management of these entities.

Retinal Structure and Function in Eyes with Optic Nerve Hypoplasia

We investigated retinal structure and function in eyes with optic nerve hypoplasia (ONH). Twenty-nine eyes of 18 patients with ONH and 21 eyes of 21 control patients were analyzed. Spectral-domain optical coherence tomography (SD-OCT), full-field electroretinography (FF-ERG), and focal macular ERG (FM-ERG) were performed. SD-OCT analysis of the macular region showed significant ganglion cells complex (GCC) thinning nasally and temporally (P < 0.05), but the thickness from the inner nuclear layer (INL) to the retinal pigment epithelium (RPE) became thinner only nasally (P < 0.05). SD-OCT analysis of the circumpapillary region showed significant thinning in the retinal nerve fiber layer and from the INL to the RPE (P < 0.05). The horizontal SD-OCT images showed variable foveal abnormalities. FF-ERG analysis showed significantly reduced amplitudes (P < 0.05) and preserved implicit time in the photopic negative response. The amplitudes and implicit times of the other FF-ERG components did not differ significantly. FM-ERG analysis showed significantly reduced amplitudes (P < 0.05) but preserved implicit times in all components. The current study showed the change of retinal structure and function in eyes with ONH compared with those with control, representing by decreased retinal ganglion cells (RGCs) and their axons, foveal abnormalities, and preserved peripheral retina except for the RGCs and their axons.

Congenital optic nerve anomalies

OBJECTIVE

To update the current knowledge about congenital optic disc anomalies.

METHODS

A comprehensive literature search was performed in the major biomedical databases.

RESULTS

Patients with these anomalies usually have poor vision in infancy. Refractive errors are common, and serous retinal detachment may develop in some of these anomalies. It is critically important to clinically differentiate between these congenital optic disc anomalies, as central nervous system malformations are common in some, whereas others may be associated with systemic anomalies.

CONCLUSIONS

Congenital optic disc anomalies are a heterogeneous group of pathologies with characteristic fundus appearance and systemic associations. We should always try to make a correct diagnosis, in order to ask for specific tests, as well as to provide an adequate follow-up.

VEP analysis methods in children with optic nerve hypoplasia: relationship to visual acuity and optic disc diameter

PURPOSE

Assessing vision in young children with optic nerve hypoplasia (ONH) is challenging due to multi-directional infantile nystagmus, the range of optic nerve loss, and cognitive delay. This study examined visual evoked potential (VEP) responses and averaging techniques in children with ONH. The assumption is that EEG epochs with inconsistent temporal phase would be associated with nystagmus, signal reduction due to axon loss, and visual inattention.

METHODS

A retrospective chart review was performed on 44 children (average age 2.2 years; SD 1.9). Optic disc diameter was estimated by ophthalmoscopy. Visual function was measured under binocular viewing and then compared to the eye with the larger optic disc to exclude secondary amblyopia. Visual acuity was measured by Teller cards or by recognition optotypes, and both measures were converted into log minimum angle of resolution (logMAR). VEPs were recorded to onset/offset of horizontal gratings and to reversing checkerboards. Signal-to-noise ratios (SNRs) were estimated from phase consistency across epochs in the Fourier domain. VEPs were also averaged after (1) correction of epochs for phase shifts across a limited bandwidth, or (2) selection of only epochs showing phase consistency.

RESULTS

Optic disc diameter, logMAR, VEP amplitudes, and VEP SNR were all significantly inter-correlated. Optic disc diameter correlated best with VEP SNR (Spearman rho = 0.82; p < 0.001). Age-corrected logMAR correlated with optic disc diameter and VEP SNR (Spearman rho = -0.695 and 0.70, respectively; p < 0.001). VEP latency poorly correlated with optic disc diameter or logMAR. Correction of phase shifts or selection of epochs based on phase consistency significantly increased VEP amplitude and SNR for children with optic disc diameters <1000 microns. Correction of phase inconsistency did not improve the correlation of VEP parameters with optic disc diameter or with logMAR.

CONCLUSIONS

In ONH, the size of the optic nerve is correlated with VEP SNR and logMAR. The results imply a direct relationship between the reduction in optic nerve axons and generalized reduction in visual function. Our calculation of VEP SNR provides objective assessment of optic nerve function that is independent of subjective scoring of VEP peaks.

Association of refractive error with optic nerve hypoplasia

PURPOSE

To evaluate the association of refractive error with optic nerve hypoplasia (ONH).

METHODS

A total of 30 ONH subjects were recruited and underwent comprehensive eye exams. Refractive error data from this group was compared to data from a group of 3232 non-ONH subjects from the same facility. Spherical equivalent was calculated to assess refractive error. Multiple logistic regression was used to evaluate the relationship between ONH and refractive error while controlling for age, race, and gender.

RESULTS

The prevalence of hyperopia (≥+1.00 D), myopia (<-0.75 D), and anisometropia (≥1.00 D) was higher in ONH subjects than in controls. ONH subjects were 9.1 times more likely to be hyperopic than emmetropic (OR = 9.1, 95% CI = 2.9-28.4, p < 0.001) and 3.8 times more likely to be myopic than emmetropic (OR = 3.8, 95% CI = 1.2-11.5, p = 0.02). Unilateral ONH subjects were 10.0 times more likely to have anisometropia than controls (OR = 10.0, 95% CI = 3.9-25.6, p < 0.0001). Bilateral ONH subjects were 3.8 times more likely to have anisometropia than controls (OR = 3.8, 95% CI = 1.1-12.7, p = 0.03).

CONCLUSIONS

Optic nerve hypoplasia subjects were more likely than control subjects to exhibit significant refractive errors, particularly hyperopia. Anisometropia tended to be more likely to occur in subjects with unilateral ONH than in bilateral ONH. Based on our findings, we recommend that clinicians perform a comprehensive eye examination on all patients with ONH and prescribe for existing refractive error when visual acuity or general visual function can realistically be improved.

Size of the intracranial optic nerve and optic tract in neonates at term-equivalent age at magnetic resonance imaging

BACKGROUND

The expected MRI-based dimensions of the intracranial optic nerve and optic tract in neonates are unknown.

OBJECTIVE

To evaluate the sizes of the intracranial optic nerve and optic tract in neonates at term-equivalent age using MRI.

MATERIALS AND METHODS

We retrospectively analyzed brain MRI examinations in 62 infants (28 boys) without intracranial abnormalities. The images were obtained in infants at term-equivalent age with a 1.5-tesla MRI scanner. We measured the widths and heights of the intracranial optic nerve and optic tract and calculated the cross-sectional areas using the formula for an ellipse.

RESULTS

The means ± standard deviation of the width, height and cross-sectional area of the intracranial optic nerve were 2.7 ± 0.2 mm, 1.7 ± 0.2 mm and 3.5 ± 0.5 mm(2), respectively. The width, height and cross-sectional area of the optic tract were 1.5 ± 0.1 mm, 1.6 ± 0.1 mm and 2.0 ± 0.2 mm(2), respectively. Using univariate and multivariate analyses, we found that postmenstrual age showed independent intermediate positive correlations with the width (r = 0.48, P < 0.01) and cross-sectional area (r = 0.40, P < 0.01) of the intracranial optic nerve. The lower bounds of the 95% prediction intervals for the width and cross-sectional area of the intracranial optic nerve were 0.07 × (postmenstrual age in weeks) - 0.46 mm, and 0.17 × (postmenstrual age in weeks) - 4.0 mm(2), respectively.

CONCLUSION

We identified the sizes of the intracranial optic nerve and optic tract in neonates at term-equivalent age. The postmenstrual age at MRI independently positively correlated with the sizes.

Ocular, Neurologic and Systemic Findings of the Cases with Optic Nerve Hypoplasia

Aim:

To describe the associated ocular, neurologic, and systemic findings in a population of children with optic nerve hypoplasia (ONH) and to evaluate the relationship between ocular signs and neurologic findings.

Method:

A retrospective chart review of 53 patients with the diagnosis of ONH seen between December 1998 and September 2012 was performed. All neurodevelopmental anomalies, neuroradiologic findings, endocrinologic and systemic findings were recorded. Poor vision was defined as the visual acuity poorer than logMAR 1.0 or inadequate central steady maintained fixation.

Results:

Thirty (56.6%) of the 53 children with ONH were boys. Mean age at presentation was 56.2±46.8 months (range; 3 months to 18 years). Poor vision defined for the purpose of this study was found in 47.2% of 53 patients. Thirty-three (62.3%) children had nystagmus. Thirty-four (64.2%) children had strabismus. Thirteen (38.2%) of those with strabismus had esotropia, 20 (58.8%) had exotropia. The total number of the children with neurodevelopmental deficit was 22 (41.5%) in our study.

Conclusion:

The vision of young children with ONH should be monitored at least annually, and any refractive errors should be treated. Neuroimaging of the brain and endocrinologic evaluation is necessary in all cases with ONH.

Comparison of Heidelberg Retina Tomograph with disc-macula distance to disc diameter ratio in diagnosing optic nerve hypoplasia

PURPOSE

To evaluate whether Heidelberg Retinal Tomograph (HRT) is a valid test for diagnosing congenital optic nerve hypoplasia (CONH) compared to the ratio of the distance between the centre of the optic disc and the centre of the macula and the mean optic disc diameter (DM:DD ratio). Furthermore, to determine the optimal cut-off value of HRT disc area to differentiate a hypoplastic disc from a normal optic disc.

METHODS

A total of 33 subjects with CONH (4-67 years old) and 160 normal subjects (5-65 years old) were recruited and underwent comprehensive eye examinations, fundus photography and HRT. Receiver operating characteristic curves for DM:DD ratio and HRT disc area were constructed based on data from the 46 CONH eyes and 160 control eyes.

RESULTS

Mean (±S.D.) HRT disc area was 1.94 (±0.54) mm(2) for the control eyes and 0.84 (±0.35) mm(2) for the CONH eyes (p < 0.0001). The area under the curve (AUC) for DM:DD ratio was 0.83 (95% confidence interval: 0.76-0.90). The AUC for HRT disc area was 0.96 (95% confidence interval: 0.94-0.99). A statistically significant difference was found between AUC for HRT disc area and that for DM:DD ratio (p = 0.0004). The optimal cut-off value for HRT disc area was 1.42 mm(2) with 95% sensitivity and 85% specificity. The optimal cut-off value for DM:DD ratio was 3.20 with 78% sensitivity and 78% specificity.

CONCLUSIONS

Both HRT and the DM:DD ratio are valid tests to aid diagnosis of CONH. HRT is superior to DM:DD ratio in diagnosing CONH with higher sensitivity and specificity. We suggest the optimal cut-off value for HRT disc area as 1.42 mm(2) in order to discriminate a hypoplastic disc from a normal optic disc.

Macular optical coherence tomography in patients with unilateral optic nerve hypoplasia

PURPOSE

To characterize the extent and location of macular thinning in patients with unilateral optic nerve hypoplasia (ONH) as compared to the contralateral normal eye.

METHODS

The medical records of patients with unilateral ONH who underwent spectral domain optical coherence tomography (SD-OCT) of the macula were retrospectively reviewed. SD-OCT scans were manually segmented by 3 observers in 3 macular regions (superior, central, inferior). Boundaries identified included the inner limiting membrane, the junction between the inner nuclear layer and outer plexiform layer, and the neural retina-retinal pigment epithelium interface. Using custom MATLAB software, inner and outer retinal thickness profiles were quantified. A paired t test was used to compare the retinal thickness between the ONH eye and the contralateral normal eyes.

RESULTS

Inner retinal thickness of the ONH eye was decreased in all areas of the macula (superior, central, and inferior) compared to the contralateral normal eye (P < 0.05). Outer retinal thicknesses were also decreased in the central and inferior sections compared with the normal eye (P < 0.05).

CONCLUSIONS

Optic nerve hypoplasia is a congenital disease known to result in thinning of the nerve fiber and ganglion cell layer. Our small cohort demonstrated thinning of the inner retinal layers as well as the outer retinal layers in the ONH eye compared with the contralateral normal eye.

Optic nerve hypoplasia in children and adolescents; prevalence, ocular characteristics and behavioural problems

PURPOSE

To report prevalence, ocular characteristics and coexisting behavioural problems in children and adolescents with optic nerve hypoplasia (ONH), which is a common cause of visual impairment in children in western countries, often associated with neurological or endocrinological problems and where autism has been reported in severe cases with blindness.

METHODS

This is a population-based cross-sectional study of patients <20 years of age who had been diagnosed with ONH and lived in the county of Stockholm in December 2009. Ophthalmological assessments including fundus photographs with optic disc analyses were made. A questionnaire was used to screen for behaviour and development.

RESULTS

The prevalence of ONH in all living children <18 years of age in Stockholm was 17.3/100 000 with a prevalence of visual impairment (<0.3) of 3.9/100 000. In total, 66 patients, median age 9.3 years (0.6-19.4), 36 with bilateral and 30 with unilateral ONH, were included in the current study; 53 were re-examined clinically, group A, and 13 agreed to retrospective analyses of existing medical records, group B. Analyses of the optic discs were made in fundus photographs from 53 patients comparing a semi-automated (Retinal Size Tool) and a manual method (Zeki). There was a strong curvilinear correlation (r(S)  = -0.91 p < 0.0001 for both eyes). Behavioural problems were more common (p < 0.05) in bilateral ONH.

CONCLUSION

Optic nerve hypoplasia is a common ocular malformation with a prevalence of 17.3/100 000 children and adolescents <18 years of age in Stockholm. Unilateral ONH seems as common as bilateral.

Prenatal determinants of optic nerve hypoplasia: review of suggested correlates and future focus

Optic nerve hypoplasia (ONH), a congenital malformation characterized by an underdeveloped optic nerve, is a seemingly epidemic cause of childhood blindness and visual impairment with associated lifelong morbidity. Although the prenatal determinants of ONH are unknown, early case reports have led to a longstanding speculation that risky health behaviors (e.g., prenatal use of recreational drugs, alcohol) are a likely culprit. There has yet to be a systematic review of the epidemiology of ONH to assess the common prenatal features that may help focus research efforts in the identification of likely prenatal correlates. A review of the past 50 years of epidemiologic research was conducted to examine the prenatal features linked with ONH and provide direction for future research. There are select prominent prenatal features associated with ONH: young maternal age and primiparity. Commonly implicated prenatal exposures (recreational or pharmaceutical drugs, viral infection, etc.) were rare or uncommon in large cohort studies of ONH and therefore unlikely to be major contributors to ONH. Familial cases and gene mutations are rare. The preponderance of young mothers and primiparity among cases of ONH is striking, although the significance is unclear. Recent research suggests a potential role for prenatal nutrition, weight gain, and factors of deprivation. With the rapidly increasing prevalence of ONH, future research should focus on investigating the relevance of young maternal age and primiparity and exploring the recently suggested etiologic correlates in epidemic clusters of ONH.

Incidence and associated endocrine and neurologic abnormalities of optic nerve hypoplasia

IMPORTANCE

Optic nerve hypoplasia (ONH) is an increasingly recognized cause of congenital blindness in children; however, there is significant discord regarding its incidence and the rate of associated conditions.

OBJECTIVE

To determine the incidence of ONH and the rate of associated endocrine, neurologic, and developmental abnormalities among a population-based cohort of pediatric patients.

DESIGN

Retrospective, population-based study.

SETTING

Olmsted County, Minnesota (95.7% white in 1990).

PARTICIPANTS

All pediatric residents (aged <19 years) of Olmstead County, diagnosed as having ONH from January 1, 1984, through December 31, 2008.

MAIN OUTCOMES AND MEASURES

Incidence of ONH and the rate of associated endocrine, neurologic, and developmental abnormalities.

RESULTS

Optic nerve hypoplasia was diagnosed in 19 pediatric patients during the 25-year study period, for an annual incidence of 2.4 (95% CI, 1.2-3.5) per 100,000 residents younger than 19 years or 1 in 2287 live births. The mean age at diagnosis was 2.1 years, and 10 (53%) patients were male. Commonly associated perinatal conditions included primiparity in 8 patients (42%), premature birth in 6 (32%), and maternal diabetes mellitus in 3 (16%). Of the 19 study patients, 16 (84%) had bilateral involvement at initial examination, 9 (47%) had decreased visual acuity, 8 (42%) had strabismus, and 5 (26%) had nystagmus. Systemic conditions included developmental delay in 12 (63%), neurologic deficits in 10 (53%), and endocrine dysfunction in 5 (26%).

CONCLUSIONS AND RELEVANCE

This population-based study demonstrated an incidence of ONH of 1 in 2287 live births. More than half of the patients had developmental and neurologic deficits, and one-fourth had a diagnosis of endocrine dysfunction.

Optic nerve hypoplasia syndrome: a review of the epidemiology and clinical associations

OPINION STATEMENT

BACKGROUND

Optic nerve hypoplasia (ONH) has developed into a leading cause of congenital blindness. The frequently associated features of hypopituitarism and absent septum pellucidum were felt to have embryonic linkage as "septo-optic dysplasia" or "de Morsier's syndrome." More recent studies have suggested these associations are independent of one another. This review provides an assessment of the historical and recent evidence linking neuroradiologic, endocrinologic and developmental morbidity in patients with ONH. The prenatal risk factors, heritability, and genetic mutations associated with ONH are described.

RESULTS

Recognition of the critical association of ONH with hypopituitarism should be attributed to William Hoyt, not Georges de Morsier. De Morsier never described a case of ONH or recognized its association with hypopituitarism or missing septum pellucidum. Hypopituitarism is caused by hypothalamic dysfunction. This, and other more recently identified associations with ONH, such as developmental delay and autism, are independent of septum pellucidum development. Other common neuroradiographic associations such as corpus callosum hypoplasia, gyrus dysplasia, and cortical heterotopia may have prognostic significance. The predominant prenatal risk factors for ONH are primiparity and young maternal age. Presumed risk factors such as prenatal exposure to drugs and alcohol are not supported by scrutiny of the literature. Heritability and identified gene mutations in cases of ONH are rare.

CONCLUSION

Children with ONH require monitoring for many systemic, developmental, and even life-threatening problems independent of the severity of ONH and presence of brain malformations including abnormalities of the septum pellucidum. "Septo-optic dysplasia" and "de Morsier's syndrome" are historically inaccurate and clinically misleading terms.

Peripheral nonperfusion and tractional retinal detachment associated with congenital optic nerve anomalies

PURPOSE

To report an association of congenital optic nerve anomalies with peripheral retina nonperfusion and to describe the clinical manifestations and treatment.

DESIGN

Retrospective, observational case series.

PARTICIPANTS

Fifteen patients with congenital optic nerve anomalies referred for pediatric retina consultation were studied. Sixteen eyes of 9 patients with optic nerve hypoplasia and 8 eyes of 6 patients with other congenital optic nerve anomalies, including optic nerve coloboma, morning glory disc, and peripapillary staphyloma, were included.

METHODS

All patients underwent examinations under anesthesia. Wide-angle retina photographs and fluorescein angiograms were reviewed. The severity of nonperfusion was graded. The presence of fibrovascular proliferation (FP), vitreous hemorrhage (VH), and tractional retinal detachment (TRD) were documented. Anatomic outcome after treatment was recorded.

MAIN OUTCOME MEASURES

Severity of nonperfusion, occurrence of secondary complications, and the anatomic outcome of patients who underwent laser treatment.

RESULTS

In patients with optic nerve hypoplasia, 12 of 16 eyes (75%) had severe peripheral nonperfusion, 12 of 16 eyes (75%) had FP, 3 of 16 eyes (19%) had VH, and 10 of 16 eyes (63%) had TRD. Six of these eyes with severe nonperfusion received laser photocoagulation to the nonperfused retina; laser-treated retinas remained attached in all 6 eyes. In patients with the other optic nerve anomalies, 7 of 8 eyes (88%) had mild to moderate nonperfusion, 2 of 8 eyes (25%) had FP, 1 of 8 eyes (12%) had VH, and 2 of 8 eyes (25%) had TRD. Six of 9 patients (67%) with optic nerve hypoplasia and 1 of 6 patients (17%) with other anomalies had a coexisting congenital brain disease.

CONCLUSIONS

Congenital optic nerve anomalies may be associated with peripheral retina nonperfusion and the secondary complications of FP, VH, and TRD. In this select group of patients, the nonperfusion associated with optic nerve hypoplasia seemed to be more severe and associated more frequently with secondary complications. Peripheral retina examination in eyes with optic nerve anomalies may identify nonperfusion or FP. Laser treatment of the avascular retina may have helped prevent complications from proliferative retinopathy in eyes clinically observed to have progressed or considered at risk for progression to proliferative retinopathy.

Reappraisal of the optic nerve hypoplasia syndrome

BACKGROUND

Optic nerve hypoplasia (ONH) has been described as an increasingly prevalent cause of congenital blindness. Its association with hypopituitarism and absent septum pellucidum has been recognized for more than 40 years as "septo-optic dysplasia" or "de Morsier syndrome." More recent studies have suggested that these associations are independent of one another. This review was designed to assess the historical and recent evidence for associations of neuroradiologic, endocrinologic, and developmental problems in patients with ONH.

EVIDENCE ACQUISITION

Historical and contemporary literature review.

RESULTS

The medical literature does not support the notion that Georges de Morsier ever described a case of ONH or recognized its association with hypopituitarism or missing septum pellucidum. Recognition of the critical association of ONH with hypopituitarism should be attributed to William Hoyt. Hypopituitarism and other more recently identified associations with ONH, such as developmental delay, hypothalamic dysfunction, and autism, are independent of septum pellucidum development. Other common neuroradiographic associations, such as corpus callosum hypoplasia, gyrus dysplasia, and cortical heterotopia, may have prognostic significance.

CONCLUSIONS

Children with ONH need to be monitored for many systemic, developmental, and even life-threatening problems independent of the status of the septum pellucidum. "Septo-optic dysplasia" and "de Morsier syndrome" are historically inaccurate and clinically misleading terms that should be abandoned.

The optic nerve head in congenital fibrosis of the extraocular muscles

OBJECTIVE

Optic nerve head abnormalities have been reported in some patients with congenital fibrosis of the extraocular muscles (CFEOM). This study prospectively assesses optic nerve head appearance in a consecutive CFEOM cohort.

METHODS

All patients with CFEOM referred between 2006 and 2010 and who were mature enough to cooperate with fundus photography were included. Fundus photographs were reviewed with attention to optic nerve head features (eg, cupping >0.6, asymmetric cupping >0.3, optic nerve hypoplasia). Interested participants had CFEOM candidate gene analysis (KIF21A, TUBB3, PHOX2A) for genetic counseling purposes.

RESULTS

Ten CFEOM patients (five CFEOM1, five CFEOM3, age range 5-23 years) from eight families (all consanguineous but one) participated. All 10 patients had notable disc excavation (5) or optic nerve hypoplasia (5). CFEOM candidate gene analysis was performed in all patients and revealed a heterozygous p.R954W KIF21A mutation only in the patient who was not from a consanguineous family.

CONCLUSIONS

Our observations suggest the optic nerve head can be affected by the orbital dysinnervation that occurs in CFEOM. Because careful clinical optic nerve head assessment is difficult in young patients with CFEOM and associated large angle incomitant strabismus, optic nerve head abnormalities may be under-diagnosed. The absence of mutations in known CFEOM genes in our cohort of consanguineous families suggests further genetic heterogeneity of this group of conditions.

Optic nerve hypoplasia in North America: a re-appraisal of perinatal risk factors

PURPOSE

The purpose of this study is to describe and clarify the birth and prenatal characteristics of a large cohort of children with optic nerve hypoplasia.

METHODS

This is a descriptive report of 204 patients aged

RESULTS

Birth characteristics were unremarkable for birthweight and gestation, but significant for increased frequency of caesarean delivery and fetal and neonatal complications. Young maternal age and primaparity were dominating maternal features. Preterm labour, gestational vaginal bleeding, low maternal weight gain and weight loss during pregnancy were prevalent.

CONCLUSIONS

These findings confirm young maternal age and primaparity as associated risk factors, challenge many other suggested factors such as alcohol and drug abuse, and introduce potentially significant prenatal characteristics such as maternal weight loss and early gestational vaginal bleeding as aetiological correlates.

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Key Words

• aetiology
• de morsier syndrome
• optic nerve hypoplasia
• perinatal
• prenatal
• septo-optic dysplasia

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MESH Headings

• Birth Weight
• Child, Preschool
• Eye Abnormalities/epidemiology
• Female
• Gestational Age
• Humans
• Infant
• Infant, Newborn
• Infant, Premature
• Male
• Maternal Age
• North America/epidemiology
• Optic Nerve/abnormalities
• Parity
• Pregnancy
• Prospective Studies
• Registries/statistics & numerical data
• Risk Factors
• Sweden/epidemiology

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Grants

• M01 RR000043-44 NCRR NIH HHS
• UL1 RR031986 NCRR NIH HHS
• M01 RR00043 NCRR NIH HHS
• UL1 RR031986-01 NCRR NIH HHS
• M01 RR000043 NCRR NIH HHS

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Affiliation(s)

Pamela Garcia-Filion The Vision Center at Childrens Hospital Los Angeles, and Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, California 90027, USA.
Cassandra Fink
Mitchell E Geffner
Mark Borchert

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Optic nerve heads in pediatric African Americans using retinal tomography

PURPOSE

To characterize optic nerve head (ONH) parameters including symmetry between the eyes in healthy African American children using the Heidelberg retinal tomograph II, and to determine if there are associations between these parameters and age, refractive error, or gender.

METHODS

The ONHs of 146 African American children aged 6 to 17 years without ocular disease were imaged with the Heidelberg retinal tomograph II. Mean values for 11 ONH parameters were determined as was their relationship to age, gender, and refractive error. Interocular symmetry of the parameters was determined.

RESULTS

The mean (+/-standard deviation) disc area, rim area, and cup area were 2.18 +/- 0.57 mm2, 1.63 +/- 0.40 mm2, and 0.52 +/- 0.37 mm2, respectively. The mean linear cup-to-disc (C/D) ratio was 0.45 +/- 0.15, and mean cup depth was 0.22 +/- 0.10 mm. The mean retinal nerve fiber layer thickness was 0.26 +/- 0.07 mm. The ONH parameters were not related to age or refractive error. With the exception of the C/D area ratio and linear C/D ratio, which were greater in boys than in girls, ONH parameters were not related to gender. Most parameters were strongly correlated between the right and left eyes. The average interocular differences in disc area, cup area, rim area, linear C/D ratio, and mean retinal nerve fiber layer thickness were 0.09 +/- 0.31 mm2, 0.04 +/- 0.22 mm2, 0.06 +/- 0.40 mm2, 0.02 +/- 0.11, and 0.00 +/- 0.06 mm2, respectively.

CONCLUSIONS

ONH parameters were not related to age and refractive error, and only C/D area ratio and linear C/D ratio were greater in boys than girls in a clinical sample of African American children. These measures of normative ONH parameters and range of interocular differences may be helpful in clinical pediatric eye care to facilitate identification of African American children with abnormal optic discs.

Ophthalmic features in a dysmorphic boy with chromosome 4q deletion and duplication

The 4q deletion syndrome shows varying phenotype, ranging from severe and complex malformations, unconformable with life, to more specific findings, as genitourinary, gastrointestinal and cardiac malformations, cleft palate,microcephaly, hypertelorism and abnormal ears and limbs. Strabismus, nystagmus, ophthalmoplegia, and optic nerve anomalies have been rarely described in literature. We report an original case of simultaneous deletion and duplication of chromosome 4q, confirmed by SNPs-array analysis of DNA, and characterized by a previously unreported association between optic nerve hypoplasia and progressive external ophthalmoplegia.

Superior segmental optic nerve hypoplasia: The topless disc syndrome

BACKGROUND

Optic nerve hypoplasia is a well-known congenital maldevelopment presenting with an abnormally small optic nerve head occupying the central aspect of a normally sized chorioscleral canal. Characteristically, the optic nerve head is surrounded by scleral anlage with a "double ring sign." Less commonly appreciated, however, is the fact that optic nerve hypoplasia may be sectorial rather than total and involving only the superior aspect of the optic disc with corresponding inferior visual field loss.

CASE REPORT

A 51-year-old woman presented with a previous diagnosis of idiopathic optic atrophy superiorly in the left eye. Detailed observation revealed that the disc was not atrophic superiorly but actually hypoplastic, and the patient received a conclusive diagnosis of superior segmental optic nerve hypoplasia.

CONCLUSIONS

It must be appreciated that optic nerve hypoplasia can also affect solely the superior aspect of the disc with subsequent functional deficits. It is important to differentiate this syndrome from true optic atrophy to ensure proper management.

Eye malformations in children with heavy alcohol exposure in utero

OBJECTIVE

To determine whether children who do not develop fetal alcohol syndrome (FAS) despite heavy alcohol exposure are at risk for eye abnormalities.

STUDY DESIGN

We screened 9628 pregnant women and identified 101 women who were drinking >/= 2 oz of absolute alcohol per day and 101 nondrinking control women. We followed 43 exposed and 55 control offspring between age 4 and 9 years, performing masked standardized ophthalomologic examinations.

RESULTS

The groups did not differ in their rates of impaired visual acuity, refractory errors, ptosis, epicanthal folds, or short palpebral fissures. Biomicroscopy examination was normal in all exposed subjects; cataracts were detected in 2 control subjects (4%) but in no exposed subjects. Arterial tortuosity was seen in 7 exposed subjects (16%) and in 8 control subjects (15%). Optic nerve hypoplasia was not detected in any subject.

CONCLUSIONS

Previous research has found that children with FAS have a high incidence of serious ophthalmologic defects; our data indicate that the risk is limited to children with FAS and does not extend to children exposed to high levels of alcohol prenatally who do not develop FAS. Eye examinations are unlikely to clarify the diagnosis in children suspected of having alcohol-related damage.

Value of the Heidelberg Retinal Tomograph in optic nerve hypoplasia

PURPOSE

A case of optic nerve hypoplasia (ONH) is reported to demonstrate the value of the Heidelberg Retinal Tomograph II (HRT) in assisting with the diagnosis.

CASE REPORT

An 8-year-old black male was referred to our clinic for evaluation of right esotropia and presumed amblyopia. Best-corrected visual acuities were 20/60 OD (right eye) and 20/25 OS (left eye). Cover test showed constant right esotropia, measuring 10 at distance and 16 at near. A smaller optic nerve head was detected OD with absence of the double ring sign. The findings of HRT were consistent with a diagnosis of unilateral ONH, with a disc area of 1.545 mm OD vs. 2.527 mm OS.

DISCUSSION

The clinical features, management, and associations of ONH are discussed.

CONCLUSION

HRT is a useful tool to assist in diagnosis of ONH by physically measuring the optic nerve.

Neuroradiographic, endocrinologic, and ophthalmic correlates of adverse developmental outcomes in children with optic nerve hypoplasia: a prospective study

BACKGROUND

Developmental delay has been reported to occur with optic nerve hypoplasia, a leading cause of pediatric blindness, but has not been systematically examined for its prevalence and correlation with associated pathologies of optic nerve hypoplasia.

OBJECTIVE

The purpose of this study was to determine the developmental outcomes of children with optic nerve hypoplasia and the correlation of development with neuroradiographic, endocrinologic, and ophthalmic findings.

METHODS

We conducted a prospective analysis of 73 subjects diagnosed with optic nerve hypoplasia at <36 months of age for developmental outcomes at 5 years of age. Subjects underwent neuroradiographic imaging, endocrinologic testing and examination, and ophthalmologic examination; developmental outcomes were assessed by using the Battelle Developmental Inventory.

RESULTS

At 5 years of age, developmental delay was present in 71% of subjects with optic nerve hypoplasia. Of patients with unilateral (18%) and bilateral optic nerve hypoplasia, 39% and 78%, respectively, experienced developmental delay. Corpus callosum hypoplasia and hypothyroidism were significantly associated with poor outcome in all of the developmental domains and an increased risk of delay. Absence of the septum pellucidum was not associated with adverse development. Six subjects had neither a neuroradiographic nor an endocrinologic abnormality, and of those, 4 were developmentally delayed.

CONCLUSIONS

These prospective data confirm the significant association of developmental delay with optic nerve hypoplasia and identify corpus callosum hypoplasia and hypothyroidism as strong correlates. A diagnosis of optic nerve hypoplasia warrants neuroradiographic and endocrinologic testing for risk factors of delay and developmental assessments for early intervention planning.

Septo-optic dysplasia associated with abnormal foveal development

PURPOSE

To report a case of abnormal foveal development in a patient with septo-optic dysplasia.

METHODS

Observational case report, consisting of clinical examination, fluorescein angiography, and optical coherence tomographic (OCT) evaluation of a patient who presented with septo-optic dysplasia.

RESULTS

A 3-month-old girl with septo-optic dysplasia was found to have bilateral foveal schisis by OCT and absence of foveal avascular zone by fluorescein angiography.

CONCLUSIONS

Abnormal foveal development can be seen in patients with septo-optic dysplasia. Both foveal schisis and absence of foveal avascular zone may contribute to visual outcome. Detailed macular evaluation is recommended in patients who present with optic nerve hypoplasia.

Developmental abnormalities of the optic nerve and chiasm

Developmental anomalies of the optic nerve are an important and growing cause of lifelong visual handicap and they are often associated with systemic abnormalities. This review focuses on the ocular and systemic aspects of developmental anomalies arising from defects of fetal fissure closure and retinal ganglion cell development, and covers some other optic-disc anomalies that have systemic significance.

VEP asymmetry with ophthalmological and MRI findings in two achiasmatic children

Achiasmia is a rarely diagnosed visual pathway maldevelopment where all or the majority of nasal retinal fibres fail to decussate at the optic chiasm. It has been identified by neuroimaging and also by visual evoked potential (VEP) asymmetry. VEP asymmetry has not been defined consistently in previous studies. The aim was to study VEP asymmetry to flash stimulation in two children with maldevelopment of the optic chiasm in comparison to control children. Both children had congenital nystagmus, optic nerve hypoplasia with a bilateral small double ring, bitemporal visual field defect and normal colour vision. In child 1 visual acuity in both eyes was 0.1, in child 2 it was 0.2. MRI showed reduced chiasmal size in child 1, while in child 2 it was combined with other midline abnormalities. VEP to monocular flash stimulation showed in both children distinctive occipital distribution, which was not observed in control children. The N2 wave was distributed asymmetrically over the ipsilateral hemisphere to the stimulated eye, while the P2 wave was distributed over both hemispheres. The P2 wave was however better defined over the ipsilateral hemisphere. Flash VEP occipital distribution remained similar in child 1, who was followed from 10 months to 9 years. These cases of achiasmia demonstrate a distinctive VEP asymmetry in the distribution of the flash VEP N2 wave, as well as the expected structural defect determined by neuroimaging.

Systemic and ocular findings in 100 patients with optic nerve hypoplasia

To describe associated ocular, neurologic, and systemic findings in a population of children with optic nerve hypoplasia, a retrospective chart review of 100 patients with optic nerve hypoplasia for the presence of neurologic, radiologic, and endocrine abnormalities was performed. Neuroimaging and endocrine studies were obtained in 65 cases. Visual acuity and associated ocular, neurologic, endocrine, systemic, and structural brain abnormalities were recorded. Seventy-five percent had bilateral optic nerve hypoplasia. Conditions previously associated with optic nerve hypoplasia and present in our patients include premature birth in 21%, fetal alcohol syndrome in 9%, maternal diabetes in 6%, and endocrine abnormalities in 6%. Developmental delay was present in 32%, cerebral palsy in 13%, and seizures in 12%. Of those imaged, 60% had an abnormal study. Neuroimaging showed abnormalities in ventricles or white- or gray-matter development in 29 patients, septo-optic dysplasia in 10, hydrocephalus in 10, and corpus callosum abnormalities in 8. There was an associated clinical neurologic abnormality in 57% of patients with bilateral optic nerve hypoplasia and in 32% of patients with unilateral optic nerve hypoplasia. Patients with unilateral and bilateral optic nerve hypoplasia frequently have a wide range and common occurrence of concomitant neurologic, endocrine, and systemic abnormalities.

Clinical Feature Analysis of Congenital Optic Nerve Abnormalities

PURPOSE

We investigated the clinical characteristics and associated ocular and systemic anomalies in young children with congenital optic nerve abnormalities, and evaluated the therapeutic results of treatment for strabismus and amblyopia.

METHODS

A retrospective study was conducted using the medical records of patients who were diagnosed with congenital optic nerve abnormalities in our hospital between 1995 and 2004.

RESULTS

This study involved 72 eyes of 51 young children (M : F = 25 : 26); 21 of these patients (41.2%) had bilateral abnormalities. The types and percentages of each abnormality were as follows: optic nerve hypoplasia, 47%; optic disc coloboma, 31.4%; morning glory syndrome, 11.8%; and myelinated nerve fiber, 9.8%. The first clinical manifestations noticed by parents were strabismus and decreased visual acuity. Occlusion therapy was carried out in 16 patients, and the visual acuities of two patients were improved by more than two lines of the Early Treatment Diabetic Retinopathy Study visual acuity chart. Accompanying strabismus was found in 70.6% of the patients; 14 patients underwent strabismic surgery, and 10 of these patients (41.2%) maintained a stable angle.

CONCLUSIONS

The most common congenital optic nerve abnormality was optic nerve hypoplasia, and the associated systemic abnormalities found were optic nerve hypoplasia and disc coloboma. Patients with congenital optic nerve abnormalities usually have a generally poor visual prognosis, but we emphasize the importance of treatment for associated strabismus and amblyopia.

Optic nerve axons: life and death before birth

In the 2004 Bowman Lecture, I give a panegyric for Sir William Bowman, an estimate of the importance and the epidemiology of anterior visual pathway developmental disorders, followed by a history of the anterior visual system. I review the normal development of the optic nerve and chiasm and the main developmental disorders: Optic Nerve Aplasia, Optic Nerve Hypoplasia and Achiasmia.

Endocrine status in patients with optic nerve hypoplasia: relationship to midline central nervous system abnormalities and appearance of the hypothalamic-pituitary axis on magnetic resonance imaging

We here: 1) describe the phenotypic spectrum, including magnetic resonance imaging (MRI) appearances of the pituitary stalk and anterior and posterior pituitary [H-P (hypothalamic-pituitary) axis], in children with optic nerve hypoplasia (ONH) with or without an abnormal septum pellucidum (SP); and 2) define endocrine dysfunction according to the MRI findings. Medical records of 55 children with ONH who had been assessed by ophthalmology and endocrine services were reviewed. All had MRI of the brain and H-P axis. Forty-nine percent of the ONH patients had an abnormal SP on MRI, and 64% had a H-P axis abnormality. Twenty-seven patients (49%) had endocrine dysfunction, and 23 of these had H-P axis abnormality. The frequency of endocrinopathy was higher in patients with an abnormal SP (56%) than a normal SP (39%). Patients were divided into four groups based on SP and H-P axis appearance: 1) both normal; 2) abnormal SP and normal H-P axis; 3) normal SP and abnormal H-P axis; and 4) both abnormal. The frequency of multiple pituitary hormone deficiency was highest (56%) in group 4, lower (35%) in group 3, and even lower (22%) in group 2. Precocious puberty was most common in group 2. None of the patients in group 1 had endocrine dysfunction. Thus, SP and H-P axis appearances on MRI can be used to predict the likely spectrum of endocrinopathy.

A selective loss of small-diameter myelinated optic nerve axons in rats prenatally exposed to ethanol

Pregnant rats were fed an ethanol-containing liquid diet between gestational days 10 and 21. The optic nerves of their litters at 49 days of age were examined using quantitative stereological procedures. Cross-sectional areas of the optic nerve in ethanol-exposed rats were significantly smaller than those in controls. This was reflected in the reduced number of myelinated fibers, but not of non-myelinated fibers. The size distribution histogram indicated a decreased number of small axonal-diameter myelinated fibers in ethanol-exposed rats. The results suggested optic nerve hypoplasia in ethanol-exposed rats characterized by a selective loss of small-diameter myelinated fibers.

Molecular characterization and mapping of ATOH7, a human atonal homolog with a predicted role in retinal ganglion cell development

The human ATOH7 gene encodes a basic helix-loop-helix (bHLH) transcription factor that is highly similar to Drosophila Atonal within the conserved bHLH domain. The ATOH7 coding region is contained within a single exon. We mapped ATOH7 to Chromosome (Chr) 10q21.3-22.1, a region syntenic to the segment of mouse Chr 10 where Atoh7 (formerly Math5) is located. The evolutionary relationship between ATOH7 and other atonal homologs was investigated using parsimony analysis. A direct comparison of ATH5/7 and ATH1 protein subgroups to Atonal also revealed a nonrandom distribution of amino acid changes across the bHLH domain, which may be related to their separate visual and proprioceptive sensory functions. Among bHLH genes, ATOH7 is most closely related to Atoh7. This sequence conservation extends significantly beyond the coding region. We define blocks of strong homology in flanking human and mouse genomic DNA, which are likely to include cis regulatory elements. Because targeted deletion of Atoh7 causes optic nerve agenesis in mice, we propose ATOH7 as a candidate for human optic nerve aplasia and related clinical syndromes.

Optic nerve hypoplasia and small eyes in presumed amblyopia

PURPOSE

To assess the anatomy of eyes presumed to be amblyopic and their fellow eyes.

PARTICIPANTS

Two hundred seventy-five patients diagnosed with amblyopia and 88 healthy or glaucomatous subjects.

METHODS

All subjects underwent complete examinations, including cycloplegic refraction, slit lamp examination, ophthalmoscopy, and retinal imaging. Axial lengths were determined on 263 amblyopic and 88 healthy and glaucomatous subjects by ultrasonic biometry.

MAIN OUTCOME MEASURES

Optic disc areas were determined by magnification correction of disc images performed with formulas. Dysversion of the optic disc was determined by simultaneous viewing of disc photographs, digitized images of both eyes, or both.

RESULTS

The mean disc area of eyes presumed to be amblyopic was 1.72 mm(2) +/- 0. 73 SD and 1.95 mm(2) +/- 0.69 SD for nonamblyopic eyes (P =.0017). The mean disc area for 176 optic discs of glaucomatous and healthy eyes was 2.61 mm(2) +/- 0.95 SD. The mean axial length for eyes in the general population is 23.65 mm +/- 1.35 SD. The healthy and glaucomatous group in this study had a mean axial length of 23.89 mm +/- 1.29 SD. The eyes with poorer vision that were assumed to be amblyopic averaged 22.42 mm +/- 2.01 SD in length, whereas their nonamblyopic fellow eyes averaged 22.83 mm +/- 1.89 SD (P =.022). The differences between eyes in the healthy population and eyes that are presumably amblyopic, as well as the healthy and fellow eyes, are highly significant (P <.0001)(7.0 x 10(-16)).

CONCLUSION

Vision impairment in presumed amblyopia is associated with optic nerve hypoplasia with relative microphthalmos, which is more notable in those eyes with poorer vision.