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

Gastroschisis and septo-optic-pituitary dysplasia: Is there an association?

AIM

There are several case reports describing patients with both optic nerve hypoplasia/septo-optic-pituitary dysplasia (ONH/SOD) and gastroschisis (GS). Our aim was to investigate whether ONH/SOD is associated with GS.

METHODS

A retrospective population-based study was undertaken using the Population Research Data Repository at the Manitoba Center for Health Policy in Manitoba, Canada to investigate if any patient with ONH/SOD also had GS. In addition, Winnipeg's Surgical Database of Outcomes and Management (WiSDOM), a hospital-based paediatric surgical database, was searched to ascertain if any of the patients with GS also have ONH/SOD.

RESULTS

Cases were 124 patients with ONH/SOD diagnosed during 1990-2019. None had GS. The surgical database had 188 patients from Manitoba with GS during 1991-2019. None had ONH/SOD.

CONCLUSION

There does not appear to be an association between ONH/SOD and GS in our cohorts of patients with these two disorders.

Aberrant gene expression yet undiminished retinal ganglion cell genesis in iPSC-derived models of optic nerve hypoplasia

BACKGROUND

Optic nerve hypoplasia (ONH), the leading congenital cause of permanent blindness, is characterized by a retinal ganglion cell (RGC) deficit at birth. Multifactorial developmental events are hypothesized to underlie ONH and its frequently associated neurologic and endocrine abnormalities; however, environmental influences are unclear and genetic underpinnings are unexplored. This work investigates the genetic contribution to ONH RGC production and gene expression using patient induced pluripotent stem cell (iPSC)-derived retinal organoids (ROs).

MATERIALS AND METHODS

iPSCs produced from ONH patients and controls were differentiated to ROs. RGC genesis was assessed using immunofluorescence and flow cytometry. Flow-sorted BRN3+ cells were collected for RNA extraction for RNA-Sequencing. Differential gene expression was assessed using DESeq2 and edgeR. PANTHER was employed to identify statistically over-represented ontologies among the differentially expressed genes (DEGs). DEGs of high interest to ONH were distinguished by assessing function, mutational constraint, and prior identification in ONH, autism and neurodevelopmental disorder (NDD) studies.

RESULTS

RGC genesis and survival were similar in ONH and control ROs. Differential expression of 70 genes was identified in both DESeq2 and edgeR analyses, representing a ~ 4-fold higher percentage of DEGs than in randomized study participants. DEGs showed trends towards over-representation of validated NDD genes and ONH exome variant genes. Among the DEGs, RAPGEF4 and DMD had the greatest number of disease-relevant features.

CONCLUSIONS

ONH genetic background was not associated with impaired RGC genesis but was associated with DEGs exhibiting disease contribution potential. This constitutes some of the first evidence of a genetic contribution to ONH.

Ophthalmic and Neuroimaging Associations In Optic Nerve Hypoplasia/Septo-Optic-Pituitary Dysplasia

BACKGROUND

Optic nerve hypoplasia (ONH) and septo-optic-pituitary dysplasia (SOD) are neurodevelopmental disorders associated with congenital visual impairment. Our aim was to investigate associations between several ophthalmic and neuroimaging features in patients with ONH/SOD.

METHODS

A retrospective chart and neuroimaging review was performed in patients with ONH/SOD. Ophthalmic signs (e.g., monocular best-corrected visual acuity [BCVA], nystagmus, and strabismus) and neuroimaging data were extracted and their associations were investigated.

RESULTS

There were 128 patients (70 males) with ONH/SOD who had neuroimaging. Their mean age at the end of the study was 13.2 (SD: 7.5) years. Ophthalmic data were available on 102 patients (58 males). BCVA varied from normal to no light perception. There were statistically significant associations between: (A) Reduced optic nerve or chiasm size on neuroimaging and more severely impaired BCVA and (B) laterality of the reduced optic nerve or chiasm size on neuroimaging and laterality of: (1) The eye with reduced BCVA, (2) small optic disc size, and (3) RAPD, if present (p ≤ 0.0002 each). The presence of symmetrically small optic nerves on MRI was significantly more common in patients with nystagmus than when nystagmus was absent (N = 96, 75% vs. 38.6%, p < 0.0001). The presence of neuronal migration disorders, their type and laterality were not associated with BCVA and laterality of the reduced BCVA.

CONCLUSION

The functional and structural associations in ONH are consistent with the impaired visual function that results from the hypoplastic anterior visual pathways. However, these associations were not perfectly concordant making prediction of adult BCVA challenging in these patients.

Risk factors in children with optic nerve hypoplasia and septo-optic dysplasia

AIM

To identify the risk factors for optic nerve hypoplasia (ONH) and septo-optic dysplasia (SOD).

METHOD

A retrospective, population-based study with case-control design was undertaken using the Population Research Data Repository at the Manitoba Center for Health Policy in Manitoba, Canada. Cases were 111 patients (63 males, 48 females; age range 1-35 years [mean 11 years 6 months, SD 7 years 2 months]) with ONH and SOD diagnosed from 1990 to 2019, matched to 555 unrelated population-based controls (315 males, 240 females; age range 1-35 years [mean 11 years 6 months, SD 7 years 2 months]) on year of birth, sex, and area of residence. Additionally, 75 cases (46 males, 29 females; age range 2-35 years [mean 12 years 6 months, SD 7 years 2 months]) with ONH and SOD were matched one-on-one with sibling controls (40 males, 35 females; age range 0-33 years [mean 11 years 7 months, SD 7 years 10 months], the rest did not have siblings). Several antenatal maternal risk factors associated with ONH and SOD were tested for their association with case and control group membership using adjusted odds ratios (ORs) and 95% confidence intervals (CIs) from a multivariate conditional logistic regression model. The outcome was the risk of developing ONH and SOD.

RESULTS

Maternal age at conception (OR = 0.91, 95% CI = 0.86-0.96), primigravida (OR = 3.39, 95% CI = 1.92-6.01), and smoking (OR = 2.86, 95% CI = 1.61-5.05) were independently associated with ONH and SOD in the cohort matched to unrelated controls (p < 0.001). In the sibling cohort, smoking was an important risk factor (OR = 3.65, 95% CI = 1.2-11.1, p = 0.02).

INTERPRETATION

Unmodifiable and modifiable antenatal maternal risk factors are associated with ONH and SOD. Our investigation suggests that several risk factors reported in previous studies may have been due to confounding bias and that maternal smoking during pregnancy is the main modifiable risk factor associated with ONH and SOD.

WHAT THIS PAPER ADDS

Historically, many antenatal risk factors have been associated with optic nerve hypoplasia (ONH) and septo-optic dysplasia (SOD). Population-based data with matched controls for potential confounding bias are lacking. Young maternal age at conception, primigravida, and smoking during pregnancy are the main risk factors for ONH and SOD using a population-based, case-control design.

Visual Acuity Outcomes in Children With Optic Nerve Hypoplasia and Septo-Optic-Pituitary Dysplasia

BACKGROUND

To investigate best-corrected visual acuity (BCVA) outcomes in patients with optic nerve hypoplasia (ONH)/septo-optic-pituitary dysplasia (SOD). Our primary hypothesis was that BCVA in patients with ONH/SOD does not change significantly over time.

METHODS

A chart review was undertaken in patients with a confirmed diagnosis of ONH/SOD. Demographic and clinical ophthalmologic data were extracted. Quantitative BCVA data were investigated across clinic visits after converting acuities to the logarithm of the minimum angle of resolution (logMAR).

RESULTS

There were 102 patients (56 males). Median age at the end of the study was 12.7 years. Median duration of follow-up was 4.5 years. BCVA significantly worsened slightly in the most affected eyes (0.056 average increase in logMAR/year, 95% confidence interval [CI]: 0.037 to 0.075) and significantly improved mildly in the lesser or equally affected eyes (0.014 average decrease in logMAR/year, 95% CI: 0.009 to 0.019) (P < 0.0001).

CONCLUSIONS

Although the overall BCVA data showed a statistically significant change with time, the actual changes were small and are of doubtful meaningful clinical significance (less than one line change on a Snellen chart). Our data suggest that ONH/SOD are nonprogressive neurodevelopmental disorders. The mild worsening of BCVA in the most affected eyes may be caused by amblyopia, whereas the small improvement in the lesser or equally affected eyes may be caused by developmental maturation. In addition, the changes in BCVA may also be due to increasing reliability of visual assessments with increasing age.

Preterm infant retinal OCT markers of perinatal health and retinopathy of prematurity

The increasing survival of preterm infants has led to the importance of improving long-term outcomes associated with preterm birth. Antenatal and perinatal insults not only impact mortality, but also long-term disability. While in the intensive care nursery, preterm infants are also exposed to various stressors that lead to long-term cognitive deficits. It is therefore critical to identify early, low-stress, non-invasive biomarkers for preterm infant health. Optical coherence tomography (OCT) is a powerful imaging modality that has recently been adapted to the infant population and provides noninvasive, high-resolution, cross-sectional imaging of the infant eye at the bedside with low stress relative to conventional examination. In this review we delve into discussing the associations between preterm systemic health factors and OCT-based retinal findings and their potential contribution to the development of non-invasive biomarkers for infant health and for retinopathy of prematurity (ROP).

Neuroimaging Features in Children with Optic Nerve Hypoplasia and Septo-Optic-Pituitary Dysplasia

BACKGROUND

Optic nerve hypoplasia (ONH) and septo-optic-pituitary dysplasia (SOD) are common causes of congenital visual impairment. Our primary aim was to investigate the prevalence of abnormal neuroimaging features in patients with these disorders in Manitoba, Canada, and compare them with published reports.

METHODS

A retrospective neuroimaging review was performed in patients resident in Manitoba with ONH/SOD.

RESULTS

There were 128 patients (M = 70) with ONH/SOD who had neuroimaging. Their mean age (SD) at the end of the study was 13.2 (7.5) years. Males were significantly more likely to have bilateral ONH and a small optic chiasm size, while females were more likely to have a left ONH and a small left optic chiasm size on neuroimaging (p = 0.049). ONH and small optic chiasm size were seen in most patients on neuroimaging. Absent septum pellucidum was noted in 40%, small pituitary gland size in 28%, neuronal migration disorders (NMD) in 20% (>1 type and bilateral in 13 cases), corpus callosum abnormalities were present in 9%, while olfactory bulbs-tracts and olfactory sulci were absent in 8.6% of cases. Unilateral ONH was not significantly associated with other structural brain abnormalities, while NMD were significantly associated with other midline brain abnormalities including a symmetrically small optic chiasm size.

CONCLUSION

The prevalence of structural neuroimaging abnormalities in our cohort with ONH/SOD was generally in the same range reported in other studies with corpus callosum abnormalities being relatively less common in our study. Bilateral NMD were relatively common among patients with NMD. The association between sex and ONH laterality requires further study.

Association of prepregnancy body mass index and gestational weight gain on severity of optic nerve hypoplasia

BACKGROUND

Optic nerve hypoplasia (ONH) is a birth defect of unknown etiology and a leading cause of visual impairment in developed countries. Recent studies suggest that factors of deprivation and exposures of poor nutritional status, such as lower gestational weight gain (GWG), may be associated with increased risk of ONH. The present study describes the prenatal features of mothers of ONH cases, including prepregnancy BMI and GWG, and the associations with clinical features of disease severity.

METHODS

Retrospective study of prenatal records for cases of ONH enrolled in a research registry. Prepregnancy BMI and GWG were compared to maternal characteristics and clinical findings of ONH severity including bilaterality, hypopituitarism, and neuroradiographic abnormalities.

RESULTS

Compared to population-based normative data of births in the United States, mothers of ONH cases (n = 55) were younger (23.3 vs. 25.8 years; p = 0.03), with higher incidence of inadequate GWG (34.0% vs. 20.4%; p = 0.03) predominantly in the first and second trimesters. The presence of major brain malformations was associated with younger maternal age (21.6 [IQR 19.4, 24.7] vs. 24.9 years [IQR 22.1, 28.5] [p = 0.02]), primiparity (44.1% vs. 13.3%; p = 0.05) and decreased prepregnancy BMI (20.9 kg/m2 [19, 22.5] vs. 25.5 kg/m2 [21.3, 28.2]; p < 0.01).

CONCLUSION

Decreased prepregnancy BMI and inadequate GWG correlated with clinical features of ONH severity, specifically bilateral disease and presence of major brain malformations.

Delineating septo-optic dysplasia

BACKGROUND

Septo-optic dysplasia (SOD), once a variable triad of septum pellucidum defects (SPDs), optic nerve hypoplasia (ONH), and hypopituitarism, has had multiple findings added, with uncertain causes, definitions, and limits.

METHOD

Literature review.

RESULTS

SOD is a complex vascular sequence with confounders.

CONCLUSIONS

Proximal anterior cerebral artery trunk disruptions cause overlapping primary effects, giving ONH alone most often, and isolated SPD less. ONH disruptions can spread to pituitary, SPD disruptions to the cerebral cortex, causing schizencephaly and related anomalies. Pituitary defects are rare without ONH, and cortical findings are rare without SPD. Extensions are unidirectional, so isolated pituitary or cortical defects are separate from SOD. Micro- an- ophthalmia, a suggested ONH variant, is not part of SOD. Disruption by-products can affect development, causing cognitive and endocrine issues, and structural anomalies such as corpus callosum thinning, ventriculomegaly, and hippocampal and olfactory findings. Limbic extensions may also contribute to the same structural defects as by-products. Midline CNS developmental anomalies can act as disruptive foci, most likely through vascular variants, but have separate pathogenesis. Relative frequencies of specific pituitary hormone defects change as SOD rates increase. Increasing relative rates of midline CNS developmental defects and cortical anomalies are consistent with rising levels of exogenous exposures sensitizing to midline predispositions.

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.

Use of sweep visual evoked potential in preverbal children with optic nerve hypoplasia

PURPOSE

To evaluate sweep VEP (sVEP) in preverbal children with optic nerve hypoplasia (ONH) and to assess associations between sVEP results, patient clinical characteristics and future recognition visual acuity.

METHODS

The medical records of children with ONH who had sVEP testing and documented recognition visual acuity at the University of Wisconsin from 2005 to 2013 were reviewed retrospectively. Optic nerve size, amblyopia treatment, and neurologic diagnoses were collected.

RESULTS

A total of 57 patients were included: 41 (71%) with bilateral ONH and 27 (47%) with neurologic abnormality. Mean age at initial sVEP was 13.3 months (range, 1-32). Mean duration between initial sVEP and final recognition acuity was 5.5 years (range, 3.5-7). Sweep VEP was associated with ONH severity (P < 0.05). Sweep VEP, and the combination of ONH severity and neurologic status, were significant predictors (P < 0.05) of logMAR optotype acuity, together accounting for 54%-61% of the variance in final recognition acuity.

CONCLUSIONS

Sweep VEP in preverbal children with ONH depends on ONH severity and correlates with final recognition visual acuity. Children with milder degrees of ONH without neurologic abnormalities had better final vision, and patients with severe ONH and neurologic diagnoses had worse vision outcomes.

Birth Weight Is a Significant Predictor of Retinal Nerve Fiber Layer Thickness at 36 Weeks Postmenstrual Age in Preterm Infants

PURPOSE

To assess retinal nerve fiber layer (RNFL) thickness in preterm infants.

DESIGN

Prospective observational study.

METHODS

We imaged 83 awake infants (159 eyes) at 36 ± 1 weeks postmenstrual age (defined as the time elapsed between the first day of the last maternal menstrual period and the time at imaging) using a handheld optical coherence tomography (OCT) system at the bedside. Blinded graders semi-automatically segmented RNFL in the papillomacular bundle (-15 to +15° relative to the fovea-optic nerve axis). We correlated RNFL thickness and 7 characteristics of interest (sex, race, ethnicity, gestational age, birth weight, stage of retinopathy at prematurity, and presence of pre-plus or plus disease) via univariable and multivariable regressions.

RESULTS

RNFL was 3.4 μm thicker in the right eyes than in the left eyes (P < .001). Among 7 characteristics, birth weight was the only independent predictor of RNFL thickness (P < .001). A 250-g increase in birth weight was associated with 5.2 μm (95% confidence interval: 3.3-7.0) increase in RNFL thickness. Compared with very preterm infants, extremely preterm infants had thinner RNFL (58.0 ± 10.7 μm vs 63.4 ± 10.7 μm, P = .03), but the statistical significance disappeared after adjustment for birth weight (P = .25). RNFL thickness was 11.2 μm thinner in extremely low birth weight infants than in very low birth weight infants (55.5 ± 8.3 μm vs. 66.7 ± 10.2 μm; P < .001). The difference remained statistically significant after adjustment for gestational age.

CONCLUSION

Birth weight is a significant independent predictor of RNFL thickness near birth, implying that the retinal ganglion cells reserve is affected by intrauterine processes that affect birth weight.

Whole genome sequencing unveils genetic heterogeneity in optic nerve hypoplasia

Optic nerve hypoplasia (ONH) is a congenital malformation with a reduced number of retinal ganglion cell axons in a thin optic nerve. It is a common cause of visual impairment in children and ONH is associated with neurodevelopmental disorders, pituitary hormone deficiencies, and brain malformations. In most cases, the aetiology is unknown, but both environmental factors and genetic causes have been described. This study aimed to identify genetic variants underlying ONH in a well-characterised cohort of individuals with ONH. We performed array comparative genomic hybridization and whole genome sequencing in 29 individuals with ONH. Rare variants were verified by Sanger sequencing and inheritance was assessed in parental samples. We identified 11 rare single nucleotide variants (SNVs) in ten individuals, including a homozygous variant in KIF7 (previously associated with Joubert syndrome), a heterozygous de novo variant in COL4A1 (previously described in an individual with porencephaly), and a homozygous variant in COL4A2. In addition, one individual harboured a heterozygous variant in OPA1 and a heterozygous variant in COL4A1, both were inherited and assessed as variants of unknown clinical significance. Finally, a heterozygous deletion of 341 kb involving exons 7-18 of SOX5 (associated with Lamb-Schaffer syndrome) was identified in one individual. The overall diagnostic yield of pathogenic or likely pathogenic variants in individuals with ONH using whole genome sequencing was 4/29 (14%). Our results show that there is a genetic heterogeneity in ONH and indicate that genetic causes of ONH are not rare. We conclude that genetic testing is valuable in a substantial proportion of the individuals with ONH, especially in cases with non-isolated ONH.

Strabismus Patterns in Patients with Intrauterine Drug Exposure

Purpose: This retrospective study evaluates the patterns of strabismus, the incidence of amblyopia, and prevalence of anatomical ocular pathology in patients with intrauterine drug exposure (IDE) presenting to a tertiary referral center for an ophthalmic evaluation.Methods: We reviewed charts of patients who presented to our pediatric ophthalmology clinic from 8/2017-10/2018 with reported IDE. The mean age at presentation was 29 months. We documented the type of exposure, birth history, social history, and past medical and surgical history. Visual acuity, motility, fundus exam, and cycloplegic refraction were reviewed.Results: Thirty-eight patients met the criteria. Motility exam showed that 23 patients were exotropic, 10 were esotropic, and 5 were orthophoric. Average angle of the exotropic deviation was 27ΔXT (range X 10 to XT 50). Amblyopia, nystagmus, and anatomical ocular anomalies also occurred frequently.Conclusion: Strabismus and other eye diseases are common in patients with IDE. Exodeviations were the most common finding and occurred in 60.5% of our cohort. Patients with IDE are at a higher risk for treatable conditions such as strabismus and amblyopia. Possible history of IDE should be considered in infants who present with congenital strabismus, particularly exotropia.

Severe Visual Impairments in Infants and Toddlers in the United States

Introduction

This article describes the most prevalent visual conditions and other demographic characteristics of 5,931 young children with severe visual impairments in 28 states in the United States, the largest sample reported to date. The information presented in this article can assist in planning and implementing programs.

Method

The data were collected at the time of entry into specialized early intervention programs for young children with visual impairments through reviews of records, interviews, and direct observations. They were sent to Babies Count: The National Registry for Children with Visual Impairments, Birth to 3 Years at the American Printing House for the Blind. The data were collected and entered between January 2005 and April 2011.

Results

Cortical visual impairment, retinopathy of prematurity (ROP), and optic nerve hypoplasia were the three most prevalent diagnoses. Approximately 60% were identified as being legally blind, and 65% had disabilities in addition to visual impairments. The mean age of the children at the time of diagnosis was 4.9 (SD = 5.7) months, referral to specialized programs was at 10.5 (SD = 7.8) months, and entry into specialized programs was at 11.6 (SD = 8.0) months. There was an average lag of 5.6 months between the diagnosis and referral.

Discussion

Cortical visual impairment, ROP, and optic nerve hypoplasia continue to be the leading causes of severe, uncorrectable visual impairments in children in the United States. ROP appears to be decreasing in prevalence; however, more children with ROP appear to have additional disabilities. The lag of 5.6 months between diagnosis and referral, a longer lag than was previously reported, is of concern.

Implications for practitioners

Information about the characteristics of children with severe uncorrectable visual conditions is valuable for communicating with families, planning and implementing early intervention and educational programs, and collaborating with medical professionals.

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.].

Optic Nerve Hypoplasia Is a Pervasive Subcortical Pathology of Visual System in Neonates

Purpose

Optic nerve hypoplasia (ONH) is the most common cause of childhood congenital blindness in developed nations, yet the fundamental pathobiology of ONH remains unknown. The objective of this study was to employ a ‘face validated' murine model to determine the timing of onset and the pathologic characteristics of ONH.

Methods

Based on the robust linkage between X-linked CASK haploinsufficiency and clinically diagnosed ONH, we hypothesized that heterozygous deletion of CASK (CASK^(+/−)) in rodents will produce an optic nerve pathology closely recapitulating ONH. We quantitatively analyzed the entire subcortical visual system in female CASK^(+/−) mice using immunohistochemistry, anterograde axonal tracing, toluidine blue staining, transmission electron microscopy, and serial block-face scanning electron microscopy.

Results

CASK haploinsuffiency in mice phenocopies human ONH with complete penetrance, thus satisfying the ‘face validity'. We demonstrate that the optic nerve in CASK^(+/−) mice is not only thin, but is comprised of atrophic retinal axons and displays reactive astrogliosis. Myelination of the optic nerve axons remains unchanged. Moreover, we demonstrate a significant decrease in retinal ganglion cell (RGC) numbers and perturbation in retinothalamic connectivity. Finally, we used this mouse model to define the onset and progression of ONH pathology, demonstrating for the first time that optic nerve defects arise at neonatally in CASK^(+/−)mice.

Conclusions

Optic nerve hypoplasia is a complex neuropathology of the subcortical visual system involving RGC loss, axonopathy, and synaptopathy and originates at a developmental stage in mice that corresponds to the late third trimester development in humans.

Neuroimaging and endocrine disorders in paediatric optic nerve hypoplasia

Purpose

Optic nerve hypoplasia (ONH) is one of the leading causes of blindness among children. The purpose of this retrospective study is to determine the risk factors and association between brain MRI findings, pituitary abnormalities and endocrine disorders with the presence of ONH.

Methods

A retrospective review of patients seen at paediatric ophthalmology clinics from January 2006 to December 2016 at Children’s Hospital and Medical Center and the University of Nebraska Medical Center was performed. All patients with a documented diagnosis of ONH or septo-optic dysplasia were identified. MRI and endocrinology results were analysed by masked examiners.

Results

Out of 77 patients, overall incidence of abnormal pituitary on MRI was 35.1% and the incidence of endocrine abnormalities was 37.7%. Of the 57 patients with bilateral ONH, 23 (40.4%) had an abnormal pituitary while 4 of the 20 patients (20.0%) with unilateral ONH had an abnormal pituitary on MRI. The sensitivity and specific of brain MRI as signs of endocrinopathy are 67.9% and 83.3%, respectively.

Conclusion

This study has determined that abnormal MRI findings do not have the sensitivity to predict endocrinopathy, nor does a normal MRI rule out possible endocrine abnormalities. When patients with ONH present with normal neurological examinations, normal endocrine workup and normal developmental milestones, a MRI of the brain may be deferred until new indications arise. Regardless of the MRI status, children with ONH should have a comprehensive endocrine evaluation and continue to have routine endocrine follow-up.

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.

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.

Neuroimaging and clinical features of patients with optic nerve hypoplasia in Taiwan

PURPOSE

To investigate the clinical and neuroradiographic features of Chinese patients with optic nerve hypoplasia (ONH).

METHODS

This was a retrospective case series study. The medical records and magnetic resonance imaging (MRI) studies of patients diagnosed with ONH from September 2001 to December 2013 in the neuro-ophthalmology clinic of Taipei Veterans General Hospital were reviewed.

RESULTS

A total of eight eyes of five patients with ONH were enrolled in this study (1 male, 4 females). The mean age at diagnosis was 14.5 ± 12.0 years (range 0.25-30 years). Ocular examination revealed approximately half of the eyes had tortuous retinal vessels. In MRI studies, all patients had midline brain abnormalities including ectopic posterior pituitary gland (60%), agenesis of septum pellucidum (20%), and Rathke's cleft cyst (20%). Two patients had endocrinopathies-one suffered from hypopituitarism and the other had hyperprolactinemia. Both of them showed ocular findings of tortuous retinal vessels.

CONCLUSION

A high prevalence of midline brain abnormalities was noted in ONH patients of Chinese ethnicity. The presence of tortuous retinal vessels in patients with a midline brain anomaly may indicate the occurrence of endocrinopathy.

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.

Clinical and demographic associations with optic nerve hypoplasia in New Zealand

AIM

To identify the clinical features of optic nerve hypoplasia (ONH) and prevalence within a population of New Zealand children with severe visual impairment.

METHODS

Retrospective review of medical records of children with severe visual impairment registered with Blind and Low Vision Educational Network New Zealand.

RESULTS

Of 1500 children with severe visual impairment, 94 (6.3%) exhibited ONH, and 91 (97%) cases were bilateral. Of these 94 cases, 52 (55%) were males and ethnicities were European Caucasian (52%), Maori (40%), Pasifika (6%) and other (2%). Most children with ONH had poor vision, with 60% having ≤ 6/60 Snellen visual acuity equivalent. The median maternal age was 20.0 years old with 52% ≤ 20 years. There was a statistically significant over-representation of Maori ethnicity (40%) and young maternal age with age less than 20 years old (44%) in our cohort compared to the general population (14.6% and 7.4%, respectively; p<0.0001). Half had hypopituitarism, while neuroimaging abnormalities were detected in 60% cases. Cerebral neuroradiographic abnormalities were found to be associated with higher rate of developmental delay (OR 9.764 95% CI 3.246 to 29.373).

CONCLUSIONS

This is the first major study of visual impairment in New Zealand children, and it demonstrates that ONH is an important cause of severe visual disability; with an over-representation of Maori children and younger maternal age.

Congenital abnormalities of the optic nerve: from gene mutation to clinical expression

Optic nerve malformations are common causes of congenital blindness and are recognized with increasing prevalence. The importance of identifying these malformations lies not only in determining the cause and level of visual impairment, but also in looking for associated treatable or life threatening systemic conditions. A number of genetic mutations have been identified in the development of optic disc anomalies, such as ones in PAX2 or PAX6. Recent advances in genetic testing like array comparative genomic hybridization allow the detection of microdeletions that were previously difficult or impossible to identify.

Absence of age-related optic disk changes in young children with optic nerve hypoplasia

PURPOSE

To determine whether the ratio of optic disk diameter to disk-to-macula distance (DD/DM) in children with optic nerve hypoplasia (ONH) changes over time.

PATIENTS AND METHODS

Fifteen subjects (29 eyes) enrolled in a prospective registry study on ONH had fundus photography performed under the age of 24 months and again at 60 months. Using the ratio of the DD/DM method, the relative size of the optic disk was assessed twice for each photo by one masked expert examiner to determine whether any change in relative disk size occurred over time.

RESULTS

There was no change in relative optic disk size between initial and final fundus photographs. The average (± SD) age at the time of initial and final fundus photography was, respectively, 11.6 ± 5.2 months and 60.6 ± 1.3 months. Strong concordance was noted between the average DD/DM of the initial and the final photographs (ρ=0.939; 95% CI: 0.893, 0.981). There was negligible difference between the individual time point measurements (-0.011 ± 0.03) (95% LOA: -0.07, 0.04).

CONCLUSION

There were no clinically significant changes in relative optic disk size over time in children with ONH; thus, DD/DM measurements need not be adjusted by age beyond 1 year in children with this disorder.

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.

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.

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.

Optic nerve abnormalities in children: a practical approach

Evaluation of children with optic nerve abnormalities is challenging. Fundus photography, ocular coherence tomography, visual field testing, color vision evaluation, neuroimaging, and genetic testing are helpful in the diagnosis and management of these patients. Importantly, many optic nerve problems are not isolated but occur in association with systemic and central nervous system anomalies. The ophthalmologist thus plays a critical role in recognizing patients who warrant systemic and neurologic assessment.