Neuro-ophthalmological findings in relation to CNS lesions in patients with myelomeningocele

Advances in the diagnosis and treatment of acute acquired comitant esotropia

Acute acquired comitant esotropia (AACE) is mainly characterized by sudden onset, accompanied by diplopia, without extraocular muscles paralysis or ocular motility disorders. In recent years, the incidence of AACE has been increasing, researchers have found that this phenomenon may be related to the widespread use of electronic devices and the increase in the number of people working from home during the COVID-19 pandemic. However, its neural mechanisms have not been fully elucidated. This article primarily reviews the latest developments in the diagnosis and treatment of AACE from the perspectives of etiology and treatment methods, aiming to provide direction for future in-depth exploration of the pathogenesis and treatment approaches of this disease.

Neurological pathologies in acute acquired comitant esotropia

BACKGROUND

Acute acquired comitant esotropia (AACE) is an uncommon subtype of esotropia characterized by sudden and usually late onset of a relatively large angle of comitant esotropia with diplopia in older children and adults.

METHODS

A literature survey regarding neurological pathologies in AACE was conducted using databases (PubMed, MEDLINE, EMBASE, BioMed Central, the Cochrane Library, and Web of Science) in order to collect data for a narrative review of published reports and available literature.

RESULTS

The results of the literature survey were analyzed to provide an overview of the current knowledge of neurological pathologies in AACE. The results revealed that AACE with unclear etiologies can occur in many cases in both children and adults. Functional etiological factors for AACE were found to be due to many reasons, such as functional accommodative spasm, the excessive near work use of mobile phones/smartphones, and other digital screens. In addition, AACE was found to be associated with neurological disorders, such as astrocytoma of the corpus callosum, medulloblastoma, tumors of the brain stem or cerebellum, Arnold-Chiari malformation, cerebellar astrocytoma, Chiari 1 malformation, idiopathic intracranial hypertension, pontine glioma, cerebellar ataxia, thalamic lesions, myasthenia gravis, certain types of seizures, and hydrocephalus.

CONCLUSIONS

Previously reported cases of AACE with unknown etiologies have been reported in both children and adults. However, AACE can be associated with neurological disorders that require neuroimaging probes. The author recommends that clinicians should perform comprehensive neurological assessments to rule out neurological pathologies in AACE, especially in the presence of nystagmus or abnormal ocular and neurological indications (e.g., headache, cerebellar imbalance, weakness, nystagmus, papilloedema, clumsiness, and poor motor coordination).

Clinical profile and management of sixth nerve palsy in pediatric patients (0-15 years) in Southern India - A hospital-based study

PURPOSE

This study was done to evaluate the clinical profile in pediatric patients (0-16 years) presenting with acute onset esotropia due to sixth nerve palsy and its management options in a tertiary care set up of Southern India.

METHODS

A total of 12 patients presenting to our OPD with acute onset esotropia due to sixth nerve palsies were included in this retrospective study. All patients were observed for 6 months and managed with prism and/or patching while waiting for spontaneous resolution and later managed surgically. Neuroimaging was done in all cases.

RESULTS

The mean deviation of esotropia at presentation was 30.17 ± 5.7 Prism Diopter (range 12-50 Prism Diopter 95% CI, SD 10.11). Mean age of the patients during presentation was 8.6 ± 2.4 years (range: 1-15 years, SD 4.27). Among the common causes of sixth nerve palsy in our study population were trauma and idiopathic intracranial hypertension followed by tumor and miscellaneous causes. Only three patients underwent surgical correction of residual deviation after a waiting period of 6 months for self-resolution. Spontaneous resolution was observed in 41.6% patients, and surgical correction (unilateral resection-recession) was done in 25% of the patients with good surgical outcome.

CONCLUSION

At 1-year follow up, the motor outcome was satisfactory except for one patient who had diffuse pontine glioma and had worsening neurological symptoms on follow-up.

Pattern of oculomotor and visual function in children with hydrocephalus

PURPOSE

To investigate the ocular motility disturbances, optic nerve changes, and refractive errors in children with or without surgically treated hydrocephalus.

METHODS

This retrospective study included 63 subjects diagnosed with hydrocephalus between 2007 and 2019 at the Baskent University Hospital. Full orthoptic and ophthalmic examination and brain magnetic resonance imaging were performed in all subjects.

RESULTS

The mean age of patients was 68.4±27.6 months, and the mean follow-up time was 21.3±5.2 months. Twenty-one (51.2%) patients had esotropia (ET), and 14 (34.1%) had exotropia (XT). Of the patients with ET, 9 (14.2%) had a sixth nerve palsy. Four patients (6.3%) had a fourth nerve palsy, and 1 had a superior rectus palsy. Eleven patients had manifest, and 2 latent, nystagmus. Thirteen (20.6%) patients had optic disc abnormalities. The mean BCVA was 0.4±0.2 (0.05-1.0) in the right eye and 0.5±0.2 (0.1-1.0) in the left eye. Of the 19 (30.1%) patients who had a significant refractive error, 9 (47.3%) had hyperopia. Thirty-six (57.1%) patients had ventriculoperitoneal shunt surgery, and 11 (30.5%) of them had shunt revision due to occlusion. Ocular motility disorders were found to be significantly more common in patients who underwent single shunt surgery and shunt revision than those who had no surgical procedure (P=0.041and P=0.032, respectively).

CONCLUSION

The evaluation of ocular motility disorders and visual dysfunction in hydrocephalic children can be a source of valuable information when diagnosing and following the disease.

Cerebellar motor function in spina bifida meningomyelocele

Spina bifida meningomyelocele (SBM), a congenital neurodevelopmental disorder, involves dysmorphology of the cerebellum, and its most obvious manifestations are motor deficits. This paper reviews cerebellar neuropathology and motor function across several motor systems well studied in SBM in relation to current models of cerebellar motor and timing function. Children and adults with SBM have widespread motor deficits in trunk, upper limbs, eyes, and speech articulators that are broadly congruent with those observed in adults with cerebellar lesions. The structure and function of the cerebellum are correlated with a range of motor functions. While motor learning is generally preserved in SBM, those motor functions requiring predictive signals and precise calibration of the temporal features of movement are impaired, resulting in deficits in smooth movement coordination as well as in the classical cerebellar triad of dysmetria, ataxia, and dysarthria. That motor function in individuals with SBM is disordered in a manner phenotypically similar to that in adult cerebellar lesions, and appears to involve similar deficits in predictive cerebellar motor control, suggests that age-based cerebellar motor plasticity is limited in individuals with this neurodevelopmental disorder.

The cerebellar dysplasia of Chiari II malformation as revealed by eye movements

INTRODUCTION

Chiari type II malformation (CII) is a developmental deformity of the hindbrain. We have previously reported that many patients with CII have impaired smooth pursuit, while few make inaccurate saccades or have an abnormal vestibuloocular reflex. In contrast, saccadic adaptation and visual fixation are normal. In this report, we correlate results from several eye movement studies with neuroimaging in CII. We present a model for structural changes within the cerebellum in CII.

METHODS

Saccades, smooth pursuit, the vestibulo-ocular reflex, and visual fixation were recorded in 21 patients with CII, aged 8-19 years and 39 age-matched controls, using an infrared eye tracker. Qualitative and quantitative MRI data were correlated with eye movements in 19 CII patients and 28 controls.

RESULTS

Nine patients with CII had abnormal eye movements. Smooth pursuit gain was subnormal in eight, saccadic accuracy abnormal in four, and vestibulo-ocular reflex gain abnormal in three. None had fixation instability. Patients with CII had a significantly smaller cerebellar volume than controls, and those with normal eye motion had an expanded midsagittal vermis compared to controls. However, patients with abnormal eye movements had a smaller (non-expanded) midsagittal vermis area, posterior fossa area and medial cerebellar volumes than CII patients with normal eye movements.

CONCLUSIONS

The deformity of CII affects the structure and function of the cerebellum selectively and differently in those with abnormal eye movements. We propose that the vermis can expand when compressed within a small posterior fossa in some CII patients, thus sparing its ocular motor functions.

Nonsurgical treatment for esotropia secondary to Arnold-Chiari I malformation: A case report

A 14-year-old girl with diplopia and esotropia secondary to Arnold-Chiari I malformation was surgically treated with Arnold-Chiari I malformation decompression (suboccipital craniectomy), C1 and partial C2 laminectomy, and duraplasty. The residual esotropia was treated with compensatory prisms and vision therapy more than 1 year after Arnold-Chiari malformation surgery. The esotropia was resolved after approximately 3.5 months of treatment. Five years later, the patient continued to maintain fusion without compensatory prism.

Strabismus, Binocular Functions and Ocular Motility in Children with Hydrocephalus

PURPOSE

To investigate heterotropia, heterophoria, head posture, nystagmus, stereo acuity, ocular motility and near point of convergence (NPC) in children with hydrocephalus treated surgically before 1 year of age. In addition, the effects of being born with hydrocephalus, the effect of the etiology of hydrocephalus, number of shunt revisions and the size of the ventricles on these variables were studied.

METHODS

A population-based study was performed in 75 children and the results were compared with the results of an age- and sex-matched group (comp group) (n = 140).

RESULTS

Heterotropia 68.9% (comp group 3.6%; p < 0.001), abnormal head posture 41.3% (comp group 0; p < 0.001), nystagmus 44.0% (comp group 0; p < 0.001), stereo acuity < or =60'' 33.8% (comp group 97.1%; p < 0.001) and ocular motility defects 69.7% (comp group 0.7%; p < 0.001) were more common among children with hydrocephalus than in the comparison group. Children with overt hydrocephalus at birth had significantly more heterotropia (p = 0.0006), esotropia (p = 0.002), abnormal head posture (p = 0.02) and motility defects (p = 0.003) compared to those with hydrocephalus developing during the first year of life. The etiology, number of shunt revisions and the size of the ventricles had no significant effect on any of the investigated variables.

CONCLUSIONS

Children with hydrocephalus surgically treated before the age of one year commonly present orthoptic abnormalities. The etiology of hydrocephalus, number of shunt revisions and ventricle size seem to be of minor importance compared with the age of onset of hydrocephalus with regard to the risk for orthoptic abnormalities.

Visuospatial skills, ocular alignment, and magnetic resonance imaging findings in very low birth weight adolescents

PURPOSE

To describe ocular alignment and stereoacuity in adolescents with very low birth weight (VLBW) in comparison with a matched control group and to investigate associations with white matter damage of immaturity (WMDI) and visuospatial skills in the VLBW group.

METHODS

Fifty-nine 15-year-old VLBW subjects and 55 age- and sex-matched controls with normal birth weight underwent examination, including measurement of ocular alignment using cover test and Maddox rod and cycloplegic refraction. Stereoacuity was assessed with the TNO test, best-corrected visual acuity with a Konstantin Moutakis letter chart, and visuospatial skills with the performance tests, defined as performance intelligence quotient (IQ), in the Wechsler Intelligence Scale for Children (WISC-III). All VLBW subjects underwent magnetic resonance imaging of the brain.

RESULTS

Ocular misalignment was significantly more common in the VLBW group than in the control group (22% compared with 4%; p = 0.004). Exophoria, subnormal stereoacuity, and subnormal performance IQ were significantly more common in the VLBW group than in the control group (p = 0.006, p = 0.011, and p = 0.015, respectively). Ocular misalignment was associated with WMDI (p = 0.035) and subnormal performance IQ (p = 0.020). Of the VLBW subjects with ocular misalignment, 69% had WMDI and/or subnormal performance IQ.

CONCLUSIONS

The VLBW adolescents had more visuospatial problems, lower stereoacuity, and more ocular misalignment than the control subjects. Ocular misalignment was associated with visuospatial deficiencies and/or WMDI in the VLBW group and was a better predictor for visuospatial deficits than WMDI.

Sustained attention in children with two etiologies of early hydrocephalus

Several studies have shown that children with spina bifida meningomyelocele (SBM) and hydrocephalus have attention problems on parent ratings and difficulties in stimulus orienting associated with a posterior brain attention system. Less is known about response control and inhibition associated with an anterior brain attention system. Using the Gordon Vigilance Task (Gordon, 1983), we studied error rate, reaction time, and performance over time for sustained attention, a key anterior attention function, in 101 children with SBM, 17 with aqueductal stenosis (AS; another condition involving congenital hydrocephalus), and 40 typically developing controls (NC). In SBM, we investigated the relation between cognitive attention and parent ratings of inattention and hyperactivity and explored the impact of medical variables. Children with SBM did not differ from AS or NC groups on measures of sustained attention, but they committed more errors and responded more slowly. Approximately one-third of the SBM group had attention symptoms, although parent attention ratings were not associated with task performance. Hydrocephalus does not account for the attention profile of children with SBM, which also reflects the distinctive brain dysmorphologies associated with this condition.

Longterm oculomotor and visual function in spina bifida cystica: a population-based study

PURPOSE

To document and describe the development from birth of visual and oculomotor functions in a group of children with spina bifida cystica (myelomeningocele and myeloschisis [MMC]). The emphasis in this study is on findings at 12-14 year follow-up.

METHODS

Twenty children aged 12-14 years with myelomeningocele and Chiari-related malformations were examined by an orthoptist and a paediatric ophthalmologist. A further child who did not wish to participate actively in the study is also reported. Visual acuity for near and distance, refractometer readings in cycloplegia, the presence of ocular motility disorders and nystagmus were recorded. Accommodation, convergence, colour vision and stereo acuity were assessed and the fundus and media were examined.

RESULTS

Six children (29%) in the study group had subnormal vision, although no child was visually impaired. Eleven (52%) showed manifest strabismus and 17 (81%) had a significant refractive error. Near visual acuity was normal in nearly all the children, but accommodation was defective in 10. Nine children had nystagmus and two had optic atrophy. No visual field defects were found.

CONCLUSIONS

The high incidence of ocular disturbances in children with spina bifida highlights the importance of regular ophthalmological investigation and follow-up.

Smooth ocular pursuit in Chiari type II malformation

Chiari type II malformation (CII) is a congenital anomaly of the cerebellum and brainstem, both important structures for processing smooth ocular pursuit. CII is associated with myelomeningocele and hydrocephalus. We investigated the effects of CII on smooth pursuit (SP) eye movements, and determined the effects of spinal lesion level, number of shunt revisions, nystagmus, and brain dysmorphology on SP. SP was recorded using an infrared eye tracker in 21 participants with CII (11 males, 10 females; age range 8-19y, mean 14y 3mo [SD 3y 2mo]). Thirty-eight healthy children (21 males, 17 females) constituted the comparison group. Participants followed a visual target moving sinusoidally at +/- 10 degrees amplitude, horizontally and vertically at 0.25 or 0.5Hz. SP gains, the ratio of eye to target velocities, were abnormal in the CII group with nystagmus (n= 8). The number of shunt revisions (range 0-10), brain dysmorphology, or spinal lesion level (n= 15 for lower and n= 6 for upper spinal lesion level) did not correlate with SP gains. SP is impaired in children with CII and nystagmus. Abnormal pursuit might be related to the CII dysgenesis or to effects of hydrocephalus. The lack of effect of shunt revisions and abnormal tracking in participants with nystagmus provide evidence that it is related primarily to the cerebellar and brainstem malformation.

Risk of strabismus and ambylopia in children with hydrocephalus

OBJECTIVES

The present study was undertaken to determine the risk of strabismus and ambylopia in children who underwent operation for hydrocephalus and to compare our results with those in previous studies.

METHODS

Full orthoptic and ophthalmological examinations, including cycloplegic refraction, were performed in all subjects.

RESULTS

Ten of 25 patients (40%) were found to have manifest squint. Four of these had esotropia and six had exotropia. No paretic squint or alphabetic pattern strabismus was determined. Refraction measurements revealed amblyogenic refractive errors (significant refractive errors that cause amblyopia) in five of the 25 (20%) patients in this study. Strabismus and the risk of amblyopia were found to be significantly higher in patients who experienced shunt revision than those who had not (P<0.05).

CONCLUSION

Amblyopia, strabismus, and other acquired defects in the visual system related to hydrocephalus should be closely monitored and treated when indicated. Regular ophthalmic supervision will provide and help to maintain the best possible standard of vision in children with hydrocephalus.

Degree of tectal beaking correlates to the presence of nystagmus in children with Chiari II malformation

INTRODUCTION

Tectal beaking is a common finding in children born with a myelomeningocele. Quantitation of the presence or absence of this finding correlated with normal or abnormal eye movements is lacking in the medical literature.

MATERIALS AND METHODS

We prospectively evaluated 50 children in our multidisciplinary spina bifida clinic. Each child was observed for the presence or absence of nystagmus at rest or with extraocular movement. Grades of nystagmus and severity of tectal beaking (Types I-III) on MRI were then correlated.

RESULTS

Overwhelmingly, children with greater dysmorphology of the mesencephalic tectum were most likely to have nystagmus. Higher grades of nystagmus were associated with Type III tectal beaking.

CONCLUSIONS

We have demonstrated that there is a correlation between the presence and severity of nystagmus and the severity of tectal beaking and have quantified this association in patients with the Chiari II malformation. This information may act as a guide in predicting which children with the Chiari II malformation will have significant nystagmus. These data may aid the clinician in the interpretation of oculomotor abnormalities in this cohort of patients.

Is tooth agenesis related to brainstem anomalies in myelomeningocele patients with Chiari II malformations?

Defects in the prenatal development of the brainstem can result in cranial nerve deficiencies. As the development of tooth germ is dependent on n. trigeminus, which originates from the brainstem, the hypothesis underlying this study was that anomalies of the brainstem would lead to an increased prevalence of tooth agenesis. Twenty-three patients (13 F and 10 M, age range 6-37 years) were studied, all with myclomeningocele and brainstem anomalies (Chiari II). They were examined retrospectively from the data in journals and dental radiographs and compared to available data on the prevalence of tooth agenesis in the Swedish population. Our hypothesis was rejected, since there was insignificant difference in the frequency of agenesis in our material (8.7%) compared with that of the Swedish population (7.4%).

Oculographic and clinical characterization of thirty-seven children with anomalous head postures, nystagmus, and strabismus: the basis of a clinical algorithm

BACKGROUND AND PURPOSE

We studied children with nystagmus who also had anomalous head postures and strabismus to determine the etiology of the conditions and present a diagnostic clinical algorithm.

METHODS

The patients for this study were among the 560 patients evaluated in the ocular motor neurophysiology laboratory between the years 1991 and 1997. Clinical characteristics, infrared oculography data, and medical and surgical treatments were entered into a database for analysis. Oculography was performed on all patients according to a standard protocol, and data were stored and analyzed off-line. Etiology of anomalous head posture was determined with both clinical and oculography information.

RESULTS

Thirty-seven children are the subjects of this report. The etiology of anomalous head posture was a "gaze null" due to congenital nystagmus in 23 (62%) patients, an "adduction null" due to manifest latent nystagmus in 12 (32%) patients, spasmus nutans in 1 (3%) patient, and strabismus in 1 (3%) patient. The patients' ages ranged from 9 months to 12 years and averaged 4.4 years. Sixty-nine percent were male patients. Nineteen (63%) of 30 patients had abnormal recognition (linear optotype) acuity in at least 1 eye on monocular cover; the recognition remained abnormal in 5 (17%) of 30 patients under binocular conditions. Thirty percent of patients had amblyopia, 16% had some structural disease of the eyes, 22% had some systemic syndrome or abnormality, 57% had a significant refractive error, and 27% had some ability to fuse.

CONCLUSIONS

The major etiology for anomalous head posture in these patients was to adopt a gaze null due to congenital nystagmus (62% of patients) regardless of the direction of their anomalous head posture or type of strabismus. Moving the fixing eye as the first step for the anomalous head posture, combined with moving the nonfixing eye for the resulting strabismus may help treat these patients.

Acute acquired comitant esotropia: a prospective study

PURPOSE

To define the clinical characteristics of patients presenting with acute onset esotropia and features suggestive of possible underlying central nervous system pathology. To assess the prognosis for the return of binocular function and to consider the most appropriate management.

METHODS

A prospective clinical study was carried out of all patients presenting to the department of paediatric ophthalmology at a university teaching hospital over the period January 1994 to April 1997. Each patient underwent a full ophthalmological examination (including assessment of sensory status). All patients were referred to a paediatric neurologist for examination and CT and/or MRI scan.

RESULTS

Ten patients presented during the study period. Uncorrected hypermetropia and/or decompensated monofixation syndrome were the commonest aetiological factors. One patient was found to have a cerebellar tumour. In 5 patients prescription of the full hypermetropic correction alone was sufficient to restore binocularity. Five patients required bilateral medial rectus recession. Binocular function was restored in all cases--in 5 cases with bifoveal fusion.

CONCLUSION

Decompensation of a pre-existing phoria or monofixation syndrome appears the commonest aetiology. Prescription of the full hypermetropic correction found at cycloplegic refraction forms an essential part of initial management. No single clinical sign can reliably indicate the rare patient harbouring a tumour. A high index of suspicion should be maintained and neuro-imaging considered in the absence of expected findings such as hypermetropia or fusion potential or in the presence of atypical features or neurological signs.

Intact binocular function and absent ocular torsion in children with alternating skew on lateral gaze

BACKGROUND

A form of skew deviation, called alternating skew on lateral gaze, resembles bilateral superior oblique overaction. Oblique muscle overaction has been recently speculated to result from loss of fusion with subsequent "free-wheeling" of the torsional control mechanisms of the eyes, causing sensory intorsion or extorsion with attendant superior or inferior oblique muscle overaction, respectively. We wanted to investigate whether loss of fusion plays a role in the pathogenesis of alternating skew on lateral gaze.

SUBJECTS AND METHODS

We examined seven consecutive patients with posterior fossa tumors, enrolled in a multi-disciplinary pediatric neuro-oncology program, who displayed alternating skew on lateral gaze. All patients underwent a thorough ophthalmologic evaluation.

RESULTS

Visual acuities in the study patients ranged from 20/20 to 20/40. Five of the seven patients were orthotropic, and showed 40 sec of arc stereopsis. Three patients showed associated downbeat nystagmus. No ocular torsion was found in any of the five patients who showed normal stereopsis upon inspection of fundus landmarks on indirect ophthalmoscopy.

CONCLUSION

Patients with alternating skew on lateral gaze often have normal binocular vision and stereopsis, and lack ocular intorsion so typical of superior oblique overaction. Alternating skew on lateral gaze is neurologically mediated, with no role for defective fusion in its pathogenesis.

Neurological dysfunction above cele level in children with spina bifida cystica: a prospective study to three years

The aim of this study was to characterize the neurological dysfunction above the cele level in children with spina bifida cystica. 22 neonates were investigated prospectively to a median age of three years. Before primary closure of the spinal malformation and at three and 18 months of age, MRI and inspection of vocal cord function were performed. The children were also assessed by a physical therapist at 12 and 24 months, 19 children had a Chiari malformation, 18 children developed neurological dysfunction above the cele level. Children with signs of isolated motor impairment stabilized or improved during the second year. Six children developed severe functional impairment of respiration, feeding and motor performance within the first three months of life. Severe neurological signs/symptoms were associated with myeloschisis, clinical signs of a tethered cord and recurrent periods of shunt dysfunction.

The prevalence of neurologic dysfunction in children with strabismus who have superior oblique overaction

BACKGROUND

Children with certain neurologic diseases (hydrocephalus, meningomyelocele, or cerebral palsy) have been reported to manifest a high frequency of A-pattern strabismus and superior oblique overaction. However, it is not generally recognized whether children with strabismus who have superior oblique overaction are more likely to have concurrent neurologic diseases than those without superior oblique overaction. In this study, the authors examine this issue.

METHODS

The authors retrospectively reviewed the medical records of all patients (n = 168) with overdepression of the downturned eye in adduction, who were examined between October 1989 and March 1992. A randomly selected population of children with strabismus who did not have overdepression of the eye on infraduction and adduction served as controls (n = 98). Patients with simulating or confounding conditions such as pseudo-superior oblique overaction, inferior rectus skew deviation (alternating skew on lateral gaze), and restrictive or paralytic strabismus, and who were older than 20 years of age, were excluded.

RESULTS

One hundred twelve patients with true superior oblique overaction were analyzed. Of these 112 patients, 45 (40.2%) had concurrent neurologic abnormalities, compared with less than one fifth (17.3%) of control subjects (17 of 98) (P < or = 0.001).

CONCLUSIONS

Children with strabismus who have superior oblique overaction were found to have higher prevalence of concurrent neurologic diseases than control subjects. Superior oblique overaction may represent a clinical marker for an associated neurologic dysfunction, possibly representing a form of skew deviation in some cases.

Ophthalmic assessment of physically disabled children attending a rehabilitation centre

A retrospective analysis was conducted of 397 children, ranging in age from 2 to 19 years, attending the Regency Park Centre for Young Disabled in Adelaide. The disorders represented included cerebral palsy, head injury, spina bifida, severe speech and/or language disorders, muscular dystrophy and a number of less common conditions. The incidence of significant ophthalmic abnormalities in this population was 51%, with the highest incidence being 69 and 62% among children with head injury and cerebral palsy, respectively. Children with severe speech and language disorders had an incidence of 24%. Overall, routine examinations revealed previously unsuspected significant eye abnormalities in 31% of the children. A complete ophthalmic examination should be part of the evaluation of all physically disabled children to ensure early identification and treatment of abnormalities, and to optimize rehabilitation.

Alternating skew on lateral gaze. Neuroanatomic pathway and relationship to superior oblique overaction

BACKGROUND

Previous studies of patients with heterogeneous, often diffuse neurologic disorders concluded that the neurologic substrate for alternating skew on lateral gaze may be localized at the level of the brain stem tegmentum or the cervico-medullary junction, or both. The localized nature of brain tumors offers an opportunity to further investigate the anatomic localization for this as well as other conditions.

METHODS

To test the hypothesis that cervico-medullary and cerebellar lesions are responsible for alternating skew on lateral gaze, the authors investigated a series of 50 children with brain tumors, 39 of whom showed neuro-ophthalmologic abnormalities on clinical testing. Seven children had alternating skew on lateral gaze.

RESULTS

All seven children with alternating skew on lateral gaze showed neoplastic involvement at the level of the cervico-medullary junction and/or the cerebellum on critical analysis of neuro-imaging studies.

CONCLUSION

The authors conclude that the neuroanatomic substrate for alternating skew on lateral gaze is localized at the level of the cervico-medullary junction and/or the cerebellum. Knowing that (1) alternating skew on lateral gaze closely mimics superior oblique overaction clinically, (2) superior oblique overaction is frequently found in patients with myelomeningocele, and (3) myelomeningocele is uniformly associated with Arnold-Chiari type II which includes cerebellar and cervico-medullary region abnormalities, the authors propose that alternating skew on lateral gaze and superior oblique overaction associated with myelomeningocele have similar neuroanatomic pathways.

Neuro-ophthalmological evaluation of patients with myelomeningocele and Chiari malformations

Twenty-eight patients (14 females and 14 males aged between four and 34 years) with myelomeningocele and Chiari malformations were examined neuro-ophthalmologically. All patients had been under proper neurosurgical care and no reduction of visual function was found that could be related to optic atrophy or other changes in the visual pathways. However, ocular motility disorders, including strabismus, were common, although no case of down-beat nystagmus was observed. Manifest strabismus was found in 11 patients. Esotropia with or without A-pattern was seen in nine patients. Spontaneous or gaze-related nystagmus and abnormal optokinetic nystagmus represented the most common disturbances of ocular motility. Abnormalities of horizontal eye-movements were more common than those of vertical eye-movements. Strabismus of the manifest type was combined with other ocular motility disturbances in most cases.