Pediatric abusive head trauma: visual outcomes, evoked potentials, diffusion tensor imaging, and relationships to retinal hemorrhages.

PURPOSE: Function and anatomy of the visual system were evaluated in children with abusive head trauma (AHT). The relationships between retinal hemorrhages at presentation were examined with outcome measures. METHODS: Retrospective review of data in children with AHT for 1) visual acuity at last follow-up, 2) visual evoked potentials (VEP) after recovery, 3) diffusion metrics of white matter tracts and grey matter within the occipital lobe on diffusion tensor imaging (DTI), and 4) patterns of retinal hemorrhages at presentation. Visual acuity was converted into logarithm of minimum angle of resolution (logMAR) after correction for age. VEPs were also scored by objective signal-to-noise ratio (SNR). RESULTS: Of 202 AHT victims reviewed, 45 met inclusion criteria. Median logMAR was reduced to 0.8 (approximately 20/125 Snellen equivalent), with 27% having no measurable vision. Thirty-two percent of subjects had no detectable VEP signal. VEPs were significantly reduced in subjects initially presenting with traumatic retinoschisis or hemorrhages involving the macula (p < 0.01). DTI tract volumes were decreased in AHT subjects compared to controls (p < 0.001). DTI metrics were most affected in AHT victims showing macular abnormalities on follow-up ocular examination. However, DTI metrics were not correlated with visual acuity or VEPS. There was large inter-subject variability within each grouping. DISCUSSION: Mechanisms causing traumatic retinoschisis, or traumatic abnormalities of the macula, are associated with significant long-term visual pathway dysfunction. AHT associated abnormalities of the macula, and visual cortical pathways were more fully captured by VEPs than visual acuity or DTI metrics.

Two Missense CACNA1A Variants in a Single Family with Variable Neurobehavioral, Cerebellar, Epileptic, and Oculomotor Features.

We describe two novel missense variants in CACNA1A segregating in a family with variable severity of ataxia/oculomotor dysfunction, neurobehavioral impairments, and epilepsy. The most severe outcome occurred in a compound heterozygous proband, which could represent variable expression of the paternal allele or biallelic modulation of calcium channel function. Acetazolamide and lamotrigine were effective for seizure control.

Retinal and visual function in infants with non-accidental trauma and retinal hemorrhages.

PURPOSE: To investigate retinal function and visual outcomes in infants with retinal hemorrhages due to non-accidental trauma (NAT). METHODS: This is a retrospective review of full-field or multifocal electroretinogram (ERG) recordings, visual acuity in log minimum angle of resolution (logMAR), clinical status, and neuroimaging. Multifocal ERGs from the central 40° were compared to corresponding fundus imaging. Visual acuity was measured by Teller cards at follow-up. ERGs were compared to controls recorded under anesthesia. RESULTS: Sixteen children met inclusion criteria (14 recorded during the acute phase and 2 during long-term follow-up). During the acute phase, ERGs (n = 4 full field; n = 10 multifocal ERG) showed abnormal amplitude, latency, or both in at least one eye. Ten subjects had significantly reduced responses in both eyes, 3 of which had an ERG dominated by a negative waveform (absent b-wave or P1). The remaining six subjects had responses in one eye that were near normal (≥ 50% of controls). ERGs were sometimes abnormal in local areas without hemorrhage. ERGs could be preserved in local areas adjacent to traumatic retinoschisis. Two subjects with reduced visual acuity had belated ERGs: One had an abnormal macular ERG and the other had a normal macular ERG implying cortical visual impairment. At follow-up, 10 of 14 subjects had significant visual acuity loss (≥ 0.7 age-corrected logMAR); four subjects had mild vision loss (≤ 0.5 age-corrected logMAR). Visual acuity outcome was not reliably associated with the fundus appearance in the acute phase. All subjects with a negative ERG waveform had severe vision loss on follow-up. CONCLUSIONS: Retinal dysfunction was common during the acute phase of NAT. A near normal appearing fundus did not imply normal retinal function, and ERG abnormality did not always predict a poor visual acuity outcome. However, a negative ERG waveform was associated severe visual acuity loss. Potential artifacts of retinal hemorrhages and anesthesia could not fully account for multifocal ERG abnormalities. Retinal function can be preserved in areas adjacent to traumatic retinoschisis.

Bi-allelic mutations of CCDC88C are a rare cause of severe congenital hydrocephalus.

Congenital or infantile hydrocephalus is caused by genetic and non-genetic factors and is highly heterogeneous in etiology. In recent studies, a limited number of genetic causes of hydrocephalus have been identified. To date, recessive mutations in the CCDC88C gene have been identified as a cause of non-syndromic congenital hydrocephalus in three reported families. Here, we report the fourth known family with two affected individuals with congenital hydrocephalus due to a homozygous mutation in the CCDC88C gene identified by whole exome sequencing. Our two newly described children, as well as the previously published ones, all shared several features including severe infantile-onset hydrocephalus, mild to severe intellectual delay, varying degrees of motor delay, and infantile onset seizures. All identified homozygous mutations in CCDC88C abolish the PDZ binding site necessary for proper CCDC88C protein function in the Wnt signaling pathway. Our report further establishes CCDC88C as one of the few known recessive causes of severe prenatal-onset hydrocephalus. Recognition of this syndrome has important diagnostic and genetic implications for families identified in the future.

Optical Coherence Tomography in Optic Nerve Hypoplasia: Correlation With Optic Disc Diameter, Nerve Fiber Layer Thickness, and Visual Function.

BACKGROUND: The correlation between optic disc diameters (DDs) with average retinal nerve fiber layer thickness (RNFLT) and visual function in children with optic nerve hypoplasia (ONH) having nystagmus is unknown. METHODS: Data were obtained from a retrospective review of 28 children (mean age: 9.4 years; ±5.1). Optic DD was defined as the maximal horizontal opening of Bruch membrane with spectral optical coherence tomography combined with a confocal laser ophthalmoscope. Average RNFLT was obtained from circumpapillary b-scans. RNFLT was also remeasured at eccentricities that were proportionate with DD to rule out potential sampling artifacts. Visual function was assessed by visual acuity at last follow-up and by visual evoked potentials (VEP) in 11 patients. The eye with the larger DD, which had better visual acuity, was analyzed to exclude potential effects of amblyopia. RESULTS: DD was correlated with average RNFLT (r = 0.61), visual acuity (r = 0.32), and VEPs (r = 0.66). The relationship between RNFLT and DD was as follows: average RNFLT (µm) = 0.074 * DD (µm) - 18.8. RNFLT also correlated with the ratio of horizontal optic DD to macula-disc-margin distance (DD:DM; r = 0.59). RNFLT measured at eccentricities proportionate with DD showed progressive decrease in thickness only for DDs <1,100 µm. All patients with DD <1,000 µm had subnormal visual acuity, whereas those with DD <1,200 µm had subnormal VEPs. CONCLUSIONS: DD correlates with average RNFLT and with visual function in children with ONH. Using OCT imaging, DD can be obtained in children with nystagmus and provides objective information.

Clinical Outcomes in Children With Orbital Cellulitis and Radiographic Globe Tenting.

PURPOSE: Axial displacement of the globe with tenting centered on the optic nerve-globe junction is a predictor of visual loss in adults. The purpose of this study was to determine the visual outcomes of children with orbital cellulitis and globe tenting. METHODS: The records of 46 consecutive children with orbital cellulitis at a single tertiary children's hospital were reviewed retrospectively. Initial and final visual acuities were available for 34 of 46 patients (74%). Globe tenting was defined by an angle of 130° or less at the optic nerve-globe junction as derived from sagittal CT or MRI. Visual acuities of 4 children with globe tenting (mean age, 10.3 ± 3.3 years) were compared with those of 30 children without globe tenting (mean age, 10.8 ± 3.5 years). Final logarithm of the minimum angle of resolution visual acuities were analyzed. RESULTS: The mean posterior globe angle was 124.5° ± 8.0° in patients with globe tenting, compared with 145.6° ± 7.4° in the affected eye of the patients without globe tenting (p = 0.002). Final visual acuity was logarithm of the minimum angle of resolution = 0 following treatment in patients with globe tenting and logarithm of the minimum angle of resolution = 0.02 in patients without tenting (p = 0.70). DISCUSSION: We propose that the increased elastic compliance of the optic nerve sheath and sclera in children may contribute to better visual outcomes. CONCLUSIONS: Pediatric orbital cellulitis with globe tenting may not lead to devastating vision loss as previously seen in adults.

The relationship of nystagmus waveform on the VEP response in infantile nystagmus syndrome: a small case series.

PURPOSE: The relationship between eye movements and the visual evoked potential (VEP) response was examined in two subjects with infantile nystagmus syndrome (INS). Changes in VEP amplitude were compared between periods of foveation versus periods of high-frequency nystagmus. An analysis is proposed that improves extraction of the checkerboard reversal VEP signal from subjects with INS. METHODS: INS subjects were 2 healthy children (12-13 years old) with 20/40 or better corrected acuity. Optical coherence tomography confirmed the optic nerves, retina, and fovea were within normal variation. VEPs were recorded to checkerboard reversal and to onset/offset of horizontal gratings while simultaneously recording the electrooculogram (EOG). VEP epochs underwent Fourier analysis, and epochs were examined for phase consistency with the mean. Foveation periods were compared to video-oculography recordings from a separate session. RESULTS: Optic nerve misrouting, such as crossed VEP asymmetry seen in albinism, or ipsilateral VEP asymmetry seen in achiasma, was not detected in either subject. By averaging only epochs in which EOG epochs showed foveation, VEP amplitude could be increased ≥59%. Averaging the VEP only on epochs with consistent phase at Oz increased VEP amplitude by ≥twofold; subsequent EOG epochs after this analysis mostly contained foveation periods or minimal EOG activity. Latency varied <14 ms across all analyses. CONCLUSIONS: The checkerboard reversal VEP signal is dependent on foveation periods in subjects with INS despite good visual acuity. Reduction in VEP amplitude due to retinal image motion induces noise and/or lack of phase locking in the VEP epochs. Selective averaging of epochs based on phase consistency improves the extraction of a VEP signal, likely when retinal image motion is minimized.

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.

Congenital eyelid ptosis: onset and prevalence of amblyopia, associations with systemic disorders, and treatment outcomes.

OBJECTIVES: To determine the age at onset of amblyopia, the response to occlusion therapy, and the association with systemic disorders in children with congenital eyelid ptosis. STUDY DESIGN: Retrospective chart review of children seen at Seattle Children's Hospital with moderate or severe congenital ptosis. Assessments were longitudinal visual acuity development using objective methods, definition of ptosis severity by eyelid margin to pupillary light reflex distance (margin reflex distance [MRD]), age at amblyopia diagnosis, correlation between amblyopia and MRD, and associated systemic disorders. RESULTS: Eighty-four children with moderate-to-severe congenital ptosis met inclusion criteria; the mean longitudinal follow-up was 49.1 months. Fifteen (18%) of these children had amblyopia, of which 9 had deprivation amblyopia (mean age 17.3 months ± 11.2) and 6 had anisometropic or strabismic amblyopia (mean age 60 months ± 11.8). Eleven (73%) of the children with amblyopia were successfully treated with occlusion therapy. Amblyopia was not correlated with MRD. A systemic disorder was identified in 29 (35%) of the children, the most common being genetic, chromosomal, or neurologic conditions. Patients with systemic disorders and developmental delay have significantly lower visual acuity bilaterally compared with patients without systemic disorders (P ≤ .003). CONCLUSIONS: Using longitudinal and objective visual acuity assessments, the incidence of amblyopia was 18% in children with moderate to severe congenital ptosis. Visual deprivation was the predominant risk factor that was reliably distinguished by its earlier onset in young children. The best indicator of amblyopia in children is visual acuity rather than MRD measurements. Systemic disorders are frequent in children with moderate to severe congenital ptosis.

Waveform variance and latency jitter of the visual evoked potential in childhood.

PURPOSE: Recording the visual evoked potential (VEP) in young children is challenging due to movement artifacts with variable fixation or attention. This study examined the effects of latency jitter, noise, and waveform consistency on the averaging of the VEP across childhood age. METHODS: Stimuli were contrast-reversing (1.4 Hz) checkerboards of 163 arc minutes and pattern-onset-offset of 0.5 cycle/degree horizontal sine-wave gratings. Subjects were 79 normal children (0.3-16 years age; mean 6.9). Results were compared to recordings of EEG noise only (noise controls). Epochs underwent four averaging methods: (1) latency jitter correction using cross-correlation, (2) correction of phase shifts across a limited bandwidth in the Fourier domain, (3) selection of epochs based on consistency in the time domain, and (4) selection of epochs based on phase consistency in the Fourier domain. Signal-to-noise ratios (SNR) were estimated in both the time and Fourier domains. RESULTS: Compared to standard averaging, all methods improved the amplitude of the primary peak (P100) while generating mild changes in latency. All methods also increased amplitudes of residual peaks in noise controls. In VEPs with an adequate SNR, selective averaging in the Fourier domain provided the greatest improvement in amplitude (61 % increase; p < 0.0001) without prolongation in latency. Correction of latency jitter did not consistently improve amplitude but caused latency prolongation in 24 % of subjects. There was no age-related effect of any averaging method for either stimulus. CONCLUSIONS: Since latency jitter correction does not improve VEP amplitude more than selective averaging, recording artifacts in children are dominated by random phase components rather than inducing latency jitter.

Anatomic features and function of the macula and outcome of surgical tenotomy and reattachment in achiasma.

OBJECTIVE: To examine the anatomic features and function of the macula in achiasma and to compare visual acuity, eye movements, foveation, and eye velocity before and after tenotomy and reattachment (T&R) surgery. DESIGN: Case series. PARTICIPANTS: Two children with isolated achiasma. METHODS: Ophthalmologic examinations, brain magnetic resonance imaging, full-field and multifocal electroretinography (ERG), visual evoked potentials (VEPs), spectral-domain optical coherence tomography (OCT), eye-movement recordings, and unilateral T&R in 1 patient. MAIN OUTCOME MEASURES: Visual acuity before and after surgery, macular anatomic features and function, and eye velocity before and after T&R surgery in 1 patient. RESULTS: Magnetic resonance imaging and VEP confirmed absence of decussation of retinofugal fibers in both patients. Visual acuity was 20/100 and 20/200. The anatomic features and function of the fovea and macula were normal by OCT and multifocal ERG. After T&R, there was a marked reduction in horizontal eye velocity and monocular visual acuity improved to 20/80. CONCLUSIONS: The finding that the macula is normal in achiasma suggests that reduced acuity is the result of retinal image motion from nystagmus. Two-muscle T&R reduces horizontal retinal image motion and can improve visual acuity in achiasma or patients with infantile nystagmus.

Persistent figure-eight and side-to-side head shaking is a marker for rhombencephalosynapsis.

BACKGROUND: Head-shaking stereotypies have been described in patients with neurological impairment. We noted an unusual preponderance of head shaking in patients with rhombencephalosynapsis (RES). We sought to delineate the movements further and determine whether oculomotor and vestibular testing could reveal their cause. METHODS: Information was collected from direct observation, video review and parental questionnaire from 59 patients with RES. Oculomotor and vestibular testing was performed in 4 children. RESULTS: Of 59 patients, 50 had persistent head shaking that was often observed years before RES was recognized. Three affected children demonstrated abnormal central vestibular processing. CONCLUSIONS: Head-shaking is common in RES. These characteristic movements may provide input to a defective vestibular system or may represent a motor pattern that is usually suppressed by vestibular feedback. Persistent head shaking should alert clinicians to the possible presence of a congenital hindbrain abnormality that affects the vestibulocerebellum, particularly RES.

Longitudinal measures of visual function, tumor volume, and prediction of visual outcomes after treatment of optic pathway gliomas.

PURPOSE: To examine longitudinal changes in visual acuity, tumor volume, and visual evoked potentials (VEP) before and after treatment in children with optic pathway gliomas. DESIGN: Retrospective cohort study. PARTICIPANTS: Twenty-one patients (0.7-9 years of age). METHODS: Patients initially were treated either by chemotherapy (n = 18) or radiotherapy (n = 3). Patients were followed up with serial magnetic resonance imaging, age-corrected visual acuity measurements in logarithm of the minimum angle of resolution (logMAR) units, and pattern VEP. Longitudinal visual outcome data were obtained on average for 9 years (range, 4-16 years). Tumor volumes before and after treatment were estimated in 15 patients. Multivariate regression was used to predict visual outcomes. MAIN OUTCOME MEASURES: Visual acuity, relative tumor volumes, and VEP. RESULTS: Before treatment, 81% of patients had reduced visual acuity and 81% had optic nerve pallor, whereas all had a reduced VEP in 1 or both eyes. After initial treatment, tumor volume decreased in 53%, stabilized in 27%, and progressively increased in 20%. Treatment arrested the rapid decline in visual acuity loss and stabilized visual acuity for 4 to 5 years. The rate of visual acuity decline was not correlated with tumor shrinkage. Sixty-two percent of patients required additional treatment with either chemotherapy or radiation because of tumor growth or progressive loss of visual function. Visual acuity at last examination was stable or improved in 33% of patients, but on average declined 0.4 logMAR units. Visual acuity was 20/200 or better in 1 eye of 62% of patients. The rate of visual acuity decline was predicted weakly by tumor volume at presentation (R(2) = 0.19; P<0.009). Visual acuity at last examination was predicted best by visual acuity and tumor volume at presentation (R(2) = 0.66; P<0.001). CONCLUSIONS: Systemic chemotherapy arrested the decline in visual acuity and stabilized vision on average for 5 years. At presentation, VEPs were a more sensitive indicator of optic pathway damage than visual acuity or optic nerve appearance. Although tumor reduction or stabilization was achieved in 80% of patients, pre-existing visual damage, indexed by objective measures of tumor volume and visual function, limited visual outcomes. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Optical Coherence Tomography and Visual Outcomes in Pediatric Abusive Head Trauma.

PURPOSE: Compare follow-up optical coherence tomography (OCT) with visual function in children with abusive head trauma (shaken baby syndrome). METHODS: Retrospective follow-up studies of 3 children who were victims of abusive head trauma (AHT) within the first year of life. RESULTS: OCTs showed disrupted retinal layering, thick detached internal limiting membrane, focal posterior vitreous separation, and multilayered tractional retinoschisis. Significant vision loss occurred in 3 out of 4 eyes with a history of traumatic retinoschisis. Normal visual acuity and low-normal visual evoked potentials were measured in a child with foveal distortion, reduced global nerve fiber layer thickness, detached internal limiting membrane, and history of vitreous hemorrhage. DISCUSSION: Significant abnormalities of retinal anatomy can be detected on OCT years after AHT. OCTs and assessment of visual pathways help to elucidate causes of visual dysfunction in children with AHT.

A reduced visual pathway response in infantile nystagmus syndrome.

PURPOSE: To investigate visual cortical responses in children with infantile nystagmus syndrome (INS) and the potential contribution of foveation periods. METHODS: The medical records of children with INS who had visual evoked potential (VEP) recordings to reversing checkerboards and onset of horizontal gratings were reviewed retrospectively. VEP recordings underwent objective selective averaging for extraction of brief periods having consistent amplitude and timing with the stimulus presentation. VEP amplitude, latency, and signal-to-noise ratios (SNR) were compared to results from published age-matched controls under the same conditions. Relative foveation in INS subjects was determined from the proportion of time a video-oculography recording met eye position and velocity criteria. RESULTS: A total of 26 children met inclusion criteria. Selective averaging increased VEP amplitude and SNR in INS by 270%-420% compared to standard averaging (P < 0.0001). The INS change in VEP response was greater for reversing checkerboard stimulation than horizontal-grating onset and was significantly greater than that in controls (P < 0.001). Latency was not changed by selective averaging. Relative foveation was correlated with increasing VEP amplitude (P = 0.02) and number of trials chosen for selective averaging (P < 0.01). After selective averaging, relative foveation correlated with VEP amplitude to reversing checkerboards only (P = 0.007). CONCLUSIONS: Nystagmus likely causes a reduced visual cortical response in children with INS. A significantly larger response can be extracted from brief periods during nystagmus eye movements, supporting the hypothesis that the INS visual system generates a larger cortical signal during brief foveation periods.

Cerebral Visual Impairment Characterized by Abnormal Visual Orienting Behavior With Preserved Visual Cortical Activation.

Purpose: Children with cerebral visual impairment (CVI) often have abnormal visual orienting behaviors due to impaired or damaged visual cortex. Alternatively, visual-cortical function is intact but visual information is not transformed downstream into an appropriate oculomotor output (visuomotor dysfunction). We examined visual, anatomic, and oculomotor assessments to distinguish visuomotor dysfunction from CVI associated with severely reduced visual-cortical response. Methods: We reviewed the medical records from children with CVI having abnormal visual orienting behaviors, normal ocular examinations, and born near term. Relevant data were visual evoked potentials (VEPs), Teller card acuity, eye movements recorded by video-oculography (VOG), and neuroimaging (magnetic resonance imaging [MRI]) including diffusion tensor imaging (DTI) tractography. Results: Thirty subjects had visuomotor dysfunction based on a normal VEP; of these 33% had a normal MRI and 67% had white matter abnormalities associated with metabolic disease and/or decreased volume of brain parenchyma. VOG recordings showed smooth pursuit gains were uniformly reduced and saccades were dysmetric but followed the main sequence. Ten subjects had severe CVI based on VEPs at noise levels; visual acuities and MRI findings overlapped those of the visuomotor dysfunction group. Developmental delay, seizures, microcephaly, and hypotonia were common across all groups. All subjects with an abnormal conventional MRI had abnormal metrics on DTI tractography from the occipital lobe. Conclusions: A subset of patients with CVI have abnormal visual orienting behaviors despite a normal VEP (visuomotor dysfunction). A majority have abnormal white matter metrics on tractography suggesting a downstream defect in sensorimotor transformation. Clinically, visuomotor dysfunction is indistinguishable from severe CVI.

Developmental anatomy of the nasolacrimal duct: implications for congenital obstruction.

OBJECTIVE: To measure the height, anteroposterior, and transverse diameters of the nasolacrimal duct (NLD) in normal children between 2 weeks and 34 months of age and to compare the development of the NLD with the maxilla. DESIGN: Retrospective case series. PARTICIPANTS: Thirty-eight children with no history of NLD abnormalities who underwent prior axial computed tomography (CT) facial scans of 0.50 to 0.625 mm resolution. METHODS: Consecutive cases of CT facial series over a 16-month period at a single institution were studied. MAIN OUTCOME MEASURES: Height, anteroposterior and transverse diameters, and volume of the NLD; height of the maxillary sinus. RESULTS: The height of the bony NLD increases 1.8-fold, the average diameter increases 1.4-fold, and the volume increases 4.6-fold between 2 weeks and 34 months of age. The dimensional increases of the NLD are nonlinear, with most of the increase occurring in the first 6 months of life. The increase in height of the NLD is highly correlated with postnatal growth of the maxilla. CONCLUSIONS: Spontaneous resolution of NLD obstruction in normal infants is coincident with elongation, limited radial extension, and the resulting volume expansion of the NLD. We propose that increases in hydrostatic pressure within the fluid column of the NLD combined with central cavitation of the epithelial core can account for the patency of the NLD in normal infants. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Matching Misaligned Spectralis OCTs to a Reference Scan in Pediatric Glaucoma with Poor Fixation and Nystagmus.

Purpose: Poor fixation or nystagmus in children causes misalignment errors when measuring circumpapillary retinal nerve fiber layer (cpRNFL) thickness by simultaneous scanning laser ophthalmoscope imaging/optical coherence tomography (SLO/OCT). We investigated a method to assess cpRNFL from misaligned SLO/OCT scans. Methods: Heidelberg Spectralis SLO/OCT scans from a single clinical examination were retrospectively analyzed when automated eye tracking was unreliable. Retinal layer thickness was measured at overlapping match locations between a reference and misaligned scans based on the position data from simultaneously acquired SLO images. Three layers were segmented: cpRNFL, internal limiting membrane to outer nuclear layer (ILM-ONL), and total retinal thickness (TR). Accuracy was defined as the difference in thickness between the reference and misaligned scans at their match locations after correction for scan angle. Results: Thirty-five subjects, evaluated for glaucomatous nerve loss, met inclusion criteria. Group-averaged accuracy was -2.7, 1.4, and 0.3 µm for cpRNFL, ILM-ONL, and TR thickness, respectively. Across all layers, interobserver intraclass correlation coefficients ranged from 0.97 to 0.63 and the maximum Bland-Altman 95% limits of agreement were -21.6 to 20.7 µm. Variability was greatest for cpRNFL thickness and least for TR thickness. Increased variability was associated with lower signal-to-noise ratio but not with image-motion indices of shear, rotation, and scale. Conclusions: Retinal layer thickness can be compared to a reference cpRNFL OCT scan when poor fixation and nystagmus causes misalignment errors. The analysis can be performed post hoc using multiple misaligned scans from standard SLO/OCT protocols. Translational Relevance: Our method allows for assessment of cpRNFL in children who fail eye tracking.

Optical coherence tomography findings in Cohen syndrome.

Cohen syndrome is a rare disease that causes myopia and retinal degeneration in the setting of developmental delay and characteristic craniofacial features. We report optical coherence tomography (OCT) abnormalities in 4 patients with Cohen syndrome, 2 of whom have longitudinal follow-up. All subjects had schisis-like changes, with cystoid spaces in the inner retina as well as diffuse outer retinal atrophy sparing the subfoveal region. Ophthalmologic findings in 1 patient led to the work-up that resulted in a diagnosis of Cohen syndrome, suggesting that characteristic retinal abnormalities visualized by fundus examination and OCT may represent distinguishing features of this syndrome.

Visual Function, Brain Imaging, and Physiological Factors in Children With Asymmetric Nystagmus due to Chiasmal Gliomas.

PURPOSE: Asymmetric nystagmus can be an important presenting sign of optic pathway gliomas in young children. We investigated the causes of asymmetric nystagmus in children with chiasmal or suprasellar optic pathway gliomas compared with children with similar optic pathway gliomas and stable gaze. METHODS: Longitudinal magnetic resonance imaging before and after treatment, age-corrected visual acuity, ocular examinations, video-oculography, visual evoked potentials, and retinal nerve fiber layer thickness were retrospectively reviewed. RESULTS: Twenty-two children were included (eight with asymmetric nystagmus and 14 with stable gaze). Subjects with asymmetric nystagmus presented at a younger age than those with stable gaze (2.0 vs 5.6 years; P < 0.001). None had neurofibromatosis type 1. Visual acuity, visual evoked potentials, nerve fiber layer, severity of optic atrophy, hydrocephalus, tumor volume, and tumor locations did not differ between those with asymmetric nystagmus and stable gaze. Asymmetric nystagmus resolved shortly after treatment, even though the average visual acuity did not improve. Changes in visual acuity or tumor volume were not different between those with asymmetric nystagmus and stable gaze after treatment. Eye movement recording from two subjects with asymmetric nystagmus revealed an asymmetric pendular-oscillation with vertical components. One subject with stable gaze developed asymmetric nystagmus with tumor growth into the rostral midbrain and associated unilateral vision loss. Another subject with tumor growth into the rostral midbrain acquired vertical saccade dysmetria. CONCLUSION: We hypothesize that asymmetric nystagmus associated with optic pathway gliomas is caused by subclinical abnormalities to retinal axons that connect to gaze holding centers in the rostral midbrain. Direct compression of the rostral midbrain was a possible factor to asymmetric nystagmus in some subjects. However, many subjects with stable gaze also show midbrain compression.