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

Prevalence of neurological involvement and malformative/systemic syndromes in A- and V-pattern strabismus

PURPOSE

To evaluate the prevalence of neurological involvement and malformative/systemic syndromes in A- and V-patterns with respect to other kinds of infantile concomitant strabismus.

METHODS

A retrospective comparative study of 14,006 consecutive patients examined in the Pediatric Ophthalmology and Strabismus Unit at the Catholic University of Rome between January 2002 and February 2010 was carried out. A total of 2.72% (385) of patients presented with concomitant constant infantile strabismus associated with A- and V- patterns (study group; mean age 8 years; range: 8 months - 37 years; male 211, female 174). Another 377 consecutive patients affected by infantile concomitant strabismus without A- or V- patterns were used as controls (control group; mean age 9 years, range: 1-34 years; male 194, female 183). All patients underwent a complete ophthalmologic and orthoptic examination with ocular motility evaluation and prism cover test or the Hirschberg test in primary, up and down gaze positions, as well as cycloplegic retinoscopy. The angle of deviation was evaluated at near (33 cm) and distance fixation (6 m) with full correction of refraction.

RESULTS

Neurological involvement and malformative/systemic syndromes were observed in 30.4% of the study group and in 19.8% of patients in the control group (P < 0.001). Patients with A-pattern showed a greater prevalence of neurological impairment, hydrocephalus and meningomyelocele, while those affected by V-pattern exhibited a greater prevalence of craniosynostosis and malformative syndromes.

CONCLUSIONS

Neurological involvement and malformative/systemic syndromes seem to be more evident in patients presenting with A- and V-pattern strabismus.

A-pattern strabismus with overdepression in adduction: a special type of bilateral skew deviation?

BACKGROUND

Skew deviation is an acquired vertical ocular misalignment caused by damage to the prenuclear vestibular inputs to the ocular motor nuclei. A-pattern strabismus often has bilaterally symmetric vertical incomitance and overdepression in adduction (superior oblique overaction) and can be associated with developmental delay, cerebral palsy, hydrocephalus, spina bifida, or posterior fossa or other brainstem disease. The purpose of this study is to describe the ocular motility and torsion findings in patients with A-pattern strabismus and bilateral overdepression in adduction (superior oblique muscle overaction) and to propose a possible brainstem mechanism underlying these observations.

RESULTS

Most of the 13 patients identified had other neurologic abnormalities, including spina bifida, hydrocephalus, perinatal stroke, or global delay. Only 2 patients had vertical ocular misalignment in primary gaze. Of the 13, 7 had incomitant vertical tropias during lateral gaze, and 12 had bilateral incyclotorsion documented on fundus examination. Despite having bilateral overdepression in adduction (superior oblique overaction), 11 of the 13 had no difference in vertical ocular misalignment with alternating head tilt rather than reversing hypotropias as would be expected from primary oblique dysfunction. The findings are consistent with damage to the utricular pathways corresponding to the anterior semicircular canal and a resulting posterior canal predominance to the extraocular muscle subnuclei that creates increased tonus to the depressors, bilaterally.

CONCLUSIONS

A-pattern strabismus may, in some cases, represent a special form of skew deviation. The ocular motility and clinical findings are consistent with bilateral damage to the utricular pathways corresponding to the anterior semicircular canals rather than bilateral primary superior oblique muscle overaction.

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.

Neuro-ophthalmologic findings in patients with rhombencephalosynapsis

Rhombencephalosynapsis is a rare, sporadic, posterior fossa malformation characterized by agenesis of the cerebellar vermis, dorsal fusion of the cerebellar hemispheres, and fusion of the dentate nuclei and superior cerebellar peduncles. Ophthalmologic findings in patients with rhombencephalosynapsis have not been described in detail. Optic nerve and chiasmal hypoplasia were reported in two patients. Strabismus has been noted in several patients; however, specific details were not provided. We describe the association of A-pattern strabismus and superior oblique overaction with rhombencephalosynapsis.

Treatment of acute comitant esotropia in Chiari I malformation

PURPOSE

To explore the appropriate treatment of acute comitant esotropia in patients with Chiari I malformation.

DESIGN

Interventional case reports and literature review.

PARTICIPANTS

Two patients with Chiari I malformation presenting with acute comitant esotropia are described.

INTERVENTION

Strabismus surgery, then neurosurgical decompression of the Chiari I malformation was performed.

MAIN OUTCOME MEASURE

Both patients were evaluated for resolution of esotropia and other ocular motility problems.

RESULTS

After initially successful strabismus surgery, both patients developed recurrent esotropia with diplopia, which resolved on suboccipital decompression.

CONCLUSION

Comitant esotropia may recur and other eye movement disorders may develop after initially successful strabismus surgery in patients with Chiari I malformation. The data suggest that the appropriate sequence of treatment should first be suboccipital decompression, then strabismus surgery if spontaneous realignment does not occur, but further studies are needed to confirm this impression.

Strabismus in children with cerebral palsy

In 48 children with cerebral palsy the characteristics of the squint and amblyopia were analyzed, also with respect to the features of cerebral palsy and to birth weight. Strabismus of congenital esotropia type was found to be common, as was also exotropia of early onset. Spontaneous alternation or an accommodative component of the squint was present only in a few cases. There was no evidence of an accumulation of any strabismus type in the different subgroups of cerebral palsy, whereas amblyopia or an obvious risk for amblyopia was found in the great majority of the cases. Some kind of amblyopia treatment was given to 34. Most of them showed improvement of the visual capacity which encourages treatment of amblyopia, even in children with cerebral palsy.

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.

On infantile esotropia with nystagmus in abduction

Infantile esotropia with nystagmus in abduction is characterized by early onset, jerk nystagmus in abduction, and dissociated vertical deviation, among other features. Electro-oculographic tracings present easily recognizable patterns both in saccadic and pursuit movements. Visual evoked responses are asymmetric in most cases and optokinetic nystagmus is invariably asymmetric. Visual cortex maldevelopment seems to play a major pathogenic role. Recent findings in myelomeningocele and in patients with posterior fossa tumors suggest that pathological alterations in this area may tend to induce similar anomalies in electro-oculographic and optokinetic nystagmus recordings. Posterior fossa damage or impairment is therefore suspected to be a possible causative factor in the development of infantile esotropia with nystagmus in abduction.