Optic Atrophy and Inner Retinal Thinning in CACNA1F-related Congenital Stationary Night Blindness

Hemizygous pathogenic variants in CACNA1F lead to defective signal transmission from retinal photoreceptors to bipolar cells and cause incomplete congenital stationary night blindness in humans. Although the primary defect is at the terminal end of first-order neurons (photoreceptors), there is limited knowledge of higher-order neuronal changes (inner retinal) in this disorder. This study aimed to investigate inner retinal changes in CACNA1F-retinopathy by analyzing macular ganglion cell layer-inner plexiform layer (GCL-IPL) thickness and optic disc pallor in 22 subjects with molecularly confirmed CACNA1F-retinopathy. Detailed ocular phenotypic data including distance and color vision, refraction and electroretinogram (ERG) were collected. Distance vision was universally reduced (mean: 0.42 LogMAR), six had abnormal color vision and myopia was common (n = 15; mean: −6.32 diopters). Mean GCL-IPL thickness was significantly lower in patients (55.00 µm) compared to age-matched controls (n = 87; 84.57 µm; p << 0.001). The GCL-IPL thickness correlated with scotopic standard (p = 0.04) and bright-flash (p = 0.014) ERG b/a ratios and photopic b-wave amplitudes (p = 0.05). Twenty-one patients had some degree of disc pallor (bilateral in 19). Fifteen putative disease-causing, including five novel variants were identified. This study establishes macular inner retinal thinning and optic atrophy as characteristic features of CACNA1F-retinopathy, which are independent of myopia and could impact potential future treatment strategies.

Long-term follow-up of torsional augmentation surgery in a case of congenital ocular tilt reaction with head tilt

Torsional augmentation surgery was used to correct the anomalous head position (AHP) in a child with congenital ocular tilt reaction (OTR). The underlying neuropathology was hypoplasia involving the right hemicerebellum and contralateral brainstem. Postoperatively there was an acceptable and variable resolution of head tilt sustained over a 25-year follow-up period. These findings suggest that early torsional augmentation surgery can effectively correct stable OTR head tilt in congenital cases over the long term.

Measuring recovery of visual function in children with papilledema using sweep visual evoked potentials

PURPOSE

To assess visual function in children with papilledema using sweep visual evoked potentials (VEP) to determine whether vision function improved following treatment.

METHODS

Contrast sensitivity and grating acuity were prospectively measured by using sweep visual evoked potential testing in children with mild or moderate acute papilledema. A subset of children were tested longitudinally before and after treatment. Subject data was compared with that of age-matched controls using the Wilcoxon-Mann-Whitney test.

RESULTS

A total of 9 subjects (age range, 9-16 years) and 11 controls were included; 5 subjects were studied longitudinally. The control group's logMAR grating acuity (mean, 0.09; range, -0.13 to 0.36) was better than that of the papilledema group (mean, 0.36; range 0.15-0.59). Four patients showed recovery of contrast sensitivity following treatment of their raised intracranial pressure between first and last visit.

CONCLUSIONS

In our study cohort, sweep VEP was able to detect early improvement in contrast sensitivity despite absence of apparent clinical change in disk edema in children undergoing treatment for raised intracranial pressure.

Pediatric orbital cellulitis in the Haemophilus influenzae vaccine era

PURPOSE

To evaluate the microbiology of pediatric orbital cellulitis in blood cultures and abscess drainage cultures following the introduction of the Haemophilus influenzae serotype b (Hib) vaccine.

METHODS

The medical records of all pediatrics patients (aged <18 years) at a tertiary pediatric hospital during the period January 2000 to July 2011 with a computed tomography orbital imaging querying "orbital cellulitis," "periorbital cellulitis," "preseptal cellulitis," or "post-septal cellulitis" were retrospectively reviewed. The records, microbiology, and radiology of these patients were reviewed to assess the rates and complications of H. influenzae orbital cellulitis, including bacteremia and meningitis.

RESULTS

A total of 149 patients were diagnosed with preseptal or orbital cellulitis, of whom 101 (mean age, 7.2 ± 4.0) had true orbital cellulitis. No patients grew H. influenzae from blood cultures. Of the 101 patients, 30 (29.7%) required surgical drainage and had abscess drainage fluid sent for microbiology. Of these, 18 (64.3%) had a positive culture: 4 (13.3%) grew H. influenzae from their abscess drainage fluid samples; 1 grew H. influenzae alone; and 3 had mixed growth that included H. influenzae. The patients positive for H. influenzae were significantly older and had significantly larger abscesses.

CONCLUSIONS

Although there were no cases of H. influenzae bacteremia or meningitis in our cases of orbital cellulitis, abscess drainage fluid microbiology indicated that H. influenzae remains a cause of orbital cellulitis. H. influenzae abscess volume was significantly larger than other bacterial abscesses and was associated with abscesses of mixed bacterial growth in older children.

Functional-structural correlations in the afferent visual pathway in pediatric demyelination

OBJECTIVE

We evaluated the relationship of optical coherence tomography (OCT)-measured ganglion cell layer (GCL) and retinal nerve fiber layer (RNFL) thickness to other functional measures of afferent visual pathway competence including high-contrast visual acuity (HCVA) and low-contrast visual acuity (LCVA), visual field sensitivity, and color vision perception in a pediatric population with demyelinating disorders.

METHODS

This was a cross-sectional evaluation of 37 children, aged 8-18 years, with pediatric demyelinating disorders (n = 74 eyes), and 18 healthy controls (n = 36 eyes), who were recruited from the University of Toronto, Hospital for Sick Children and the University of Calgary, Alberta Children's Hospital, Canada. A standardized visual battery, including spectral-domain OCT, visual fields, LCVA, and HCVA, was performed in all subjects.

RESULTS

Mean RNFL thickness was 26 µm (25.6%) lower in patients with demyelination (76.2 μm [3.7]) compared to controls (102.4 μm [2.1]) (p < 0.0001). Mean GCL thickness was 20% lower in patients as compared to controls (p < 0.0001). Mean GCL and RNFL thickness were strongly correlated (r = 0.89; p < 0.0001), yet in contrast to RNFL thickness, no differences in GCL thickness were noted between optic neuritis (ON) eyes and non-ON eyes of patients. HCVA and LCVA and visual field mean deviation scores decreased linearly with lower RNFL thickness.

CONCLUSION

GCL thickness was decreased in patients regardless of history of ON. The retina may be a site of primary neuronal injury in pediatric demyelination.

The effect of adding orbital computed tomography findings to the Chandler criteria for classifying pediatric orbital cellulitis in predicting which patients will require surgical intervention

PURPOSE

To assess the effect of adding orbital computerized tomography (CT) findings to the Chandler criteria for classifying pediatric orbital cellulitis in predicting which patients will require surgical intervention.

METHODS

The medical records of patients with orbital CT at a tertiary pediatric hospital from January 2000 to March 2011 were reviewed retrospectively. CT images of cases with radiology report of postseptal orbital involvement were further reviewed by a neuroradiologist.

RESULTS

Of 101 cases of orbital cellulitis, 71 (mean age, 7.1 ± 4.0) were successfully managed with systemic antibiotics alone; 30 patients (mean age, 7.2 ± 4.3) required surgical intervention. Bony destruction on CT was significantly associated with surgical intervention (P = 0.02), and the size of the subperiosteal abscess (SPA) was significantly correlated with management outcome. Patients who were managed with systemic antibiotics alone had a mean SPA volume of 2.1 ± 2.4 mL; those who had undergone surgical intervention had a mean SPA volume of 14.3 mL ± 16.8 mL (P < 0.0001). If SPA volume is <3.8 mL, then the probability of surgery is 12%; if SPA is >3.8 mL, the probability of surgery is 71% (P < 0.0001).

CONCLUSIONS

Adding radiological characteristics such as presence of bony destruction on CT and size of SPA to the Chandler orbital cellulitis classification scheme increases the ability to more accurately predict which patients will require surgical intervention.

The optic disc is minimal in children with idiopathic intracranial hypertension

This study sought to characterize the optic disc morphology, particularly the cup-to-disc ratio of the optic nerve head in children with idiopathic intracranial hypertension. The medical charts and digital optic disc photos of children with confirmed diagnosis of idiopathic intracranial hypertension were reviewed retrospectively. The optic disc area, cup area, and cup-to-disc ratio were measured digitally using VISUPAC software, and the mean values of those parameters were compared to the published norms. Of children with idiopathic intracranial hypertension, 83% had absence of the physiological cup of the optic disc, compared to 10% of children in the general population of the same age. The median disc area was 2.2 mm(2), and median cup area was 0.0mm(2), compared to the published norms of 2.69 mm(2) and 0.44 mm(2), respectively. There is very significantly high prevalence of small optic disc cups in children with idiopathic intracranial hypertension, with the cup being absent on majority of cases in our patient cohort. This may signal an underlying systemic predisposition to the development of intracranial hypertension.

Transient visual loss and isolated disk edema in juvenile nasopharyngeal angiofibroma

Juvenile nasopharyngeal angiofibroma is a well-described but rare benign tumor that mainly affects adolescent boys. Although it is capable of extravagant local extension and tissue destruction, the tumor is amenable to effective therapy. Ocular or visual complications have been little noted in the literature. We report a case whose sole symptom was unilateral transient visual impairment and findings were limited to a nonspecific optic disk edema.

Natural history and outcome of optic pathway gliomas in children

BACKGROUND

The optimal management of optic pathway gliomas (OPGs) is complicated by their variable natural history, the association with neurofibromatosis type 1 (NF1) and difficulties in defining progression and response to treatment.

METHODS

This study is a retrospective review of all children presenting to a single institution with an OPG between 1990 and 2004.

RESULTS

Of the 133 children included, 78 (59%) had NF1; 87 (71 NF1) were observed initially, of whom 23 (11 NF1) subsequently required treatment. Forty-six patients received immediate treatment. Initial treatment, without or with an observation period, comprised chemotherapy alone (32, 11 NF1); debulking + chemotherapy (15, 4 NF1); gross total resection (6); radiotherapy (2); debulking + radiotherapy (3); and debulking only (12, 3 NF1). Overall, 16 patients were irradiated during the study period. Four children died (overall survival at 5 and 10 years was 97.6% and 94.6% for those who required treatment). Progression-free survival (PFS) for the 69 patients who needed treatment was 48%. There was no difference in PFS between chemotherapy versus chemotherapy + debulking or debulking alone. PFS for the NF1 patients who required treatment was similar to that of non-NF1 patients. Mean follow-up time was 9.0 (range 0.6-18.0, median 8.6) years.

CONCLUSIONS

The study confirms the complexity of OPGs and that NF1 is a major determinant of the resultant behavior of the tumor.

Ocular manifestations of the Johanson-Blizzard syndrome

Johanson-Blizzard syndrome is a rare autosomal-recessive congenital disorder characterized by hypoplastic nasal alae, midline scalp defects, deafness, microcephaly, hypothyroidism, absent permanent teeth, malabsorption, and failure to thrive. The literature was reviewed to define the reported spectrum of ocular manifestations, which are not well documented. We found that nasolacrimal system malformations are a common feature of Johanson-Blizzard, whereas intraocular malformations are rare. This report describes the ophthalmologic findings and management of 2 affected children.

Reduced grating acuity associated with retinal toxicity in children with infantile spasms on vigabatrin therapy

PURPOSE

To determine whether visual functions are decreased in children with infantile spasms and vigabatrin-attributed retinal toxicity.

METHODS

Contrast sensitivity and grating acuity were measured by using sweep visual evoked potential (VEP) testing in 42 children with infantile spasms (mean age, 29.23 +/- 18.31 months). All children had been exposed to vigabatrin (VGB) for a minimum of 1 month. These children were divided into retinal toxicity and no toxicity groupings based on 30-Hz flicker amplitude reductions on the full-field electroretinogram. A multivariate analysis of variance (MANOVA) compared visual functions between children with and without retinal toxicity.

RESULTS

The MANOVA showed that visual function was significantly affected by VGB retinal toxicity. Further univariate analysis revealed that grating acuity was significantly reduced in children with toxicity. No differences in contrast sensitivity were found between children with toxicity and those without.

CONCLUSIONS

Reduced visual functions from VGB-attributed retinal toxicity can be detected in children with infantile spasms with the sweep VEP.

Dissociated vertical deviation in patients with intermittent exotropia

PURPOSE

To determine whether the age of strabismus onset and the degree of stereopsis are related to the development of dissociated vertical deviation (DVD) in patients with intermittent exotropia and to describe the characteristics of DVD in patients with intermittent exotropia and DVD.

METHODS

Retrospective record review of patients with (1) intermittent exotropia with DVD; (2) infantile esotropia with DVD; and (3) intermittent exotropia without DVD. Age of strabismus onset, stereopsis, strabismus measurements, and the response of DVD to the Bielschowsky head-tilt test were compared among the three groups.

RESULTS

Fifty-two children with intermittent exotropia and DVD were identified. In patients with intermittent exotropia with DVD and intermittent exotropia without DVD group, the mean age of strabismus onset was 12.7 months and 28.9 months, respectively (p = 0.03), and mean stereopsis was 147 arcsec and 65 arcsec (p = 0.02). In patients with intermittent exotropia with DVD and infantile esotropia with DVD, the mean amount of DVD was 9.7(Delta) and 17.2(Delta), respectively (p < 0.01). Bielschowsky head-tilt test showed an increase of DVD on ipsilateral head tilt in 91% and 63.3%, respectively.

CONCLUSIONS

Intermittent exotropia with DVD is characterized by earlier onset of strabismus and worse stereopsis, suggesting that these factors may be related to the development of DVD in patients with intermittent exotropia. Unlike DVD in infantile esotropia, DVD in intermittent exotropia was smaller in amount and demonstrated a more uniform response to the Bielschowsky head-tilt test.

Assessment of chemotherapeutic response in children with proptosis due to optic nerve glioma

INTRODUCTION

Some children with optic pathway gliomas present with proptosis related to intraorbital tumor extension. The radiological assessment of chemotherapeutic response in these patients can be complicated by irregular tumor shape and lack of relation between tumor volume and cosmetic effect.

METHOD

We propose that proptosis measurements and derivation of a proptosis index can be a useful adjunct to the measurement of tumor volume in the radiological assessment of chemotherapeutic response. The proptosis index was derived as the ratio of the difference in proptosis between eyes postchemotherapy to that prechemotherapy. A series of six patients with proptosis and the diagnosis of an optic nerve tumor from an optic pathway glioma registry demonstrate by case example the correlation between the proptosis index and the clinical and radiographic response to chemotherapy.

CONCLUSIONS

We have found that a proptosis index <1 correlates with a chemotherapeutic maintained response and an index >1 correlates with progressive disease.

Obstructive sleep apnea syndrome with bilateral papilledema and vision loss in a 3-year-old child

We describe bilateral papilledema and vision loss in a 3-year-old child with obstructive sleep apnea. Although lumbar puncture initially disclosed a normal opening pressure, cerebrospinal fluid (CSF) pressure monitoring during sleep confirmed intermittent episodes of elevated intracranial pressure corresponding to increased airway resistance. The association of obstructive sleep apnea and raised intracranial pressure is recognized in children with craniosynostosis but has not been reported in its absence.

Evaluation of vertical rectus muscles using ultrasound biomicroscopy

PURPOSE

To evaluate the accuracy of ultrasound biomicroscopy (UBM) in measuring the distance (in mm) from limbus to the insertion of vertical rectus muscles (superior rectus and inferior rectus compared with the "gold standard" surgical caliper at the time of surgery.

METHODS

Prospective, masked, observational study of 31 vertical rectus muscle insertions in which we compared the measurements from the limbus as measured by 50 MHz UBM, either preoperatively or at the time of anesthesia, with that measured by surgical caliper intraoperatively. Measurements (UBM and surgical) were evaluated by two different observers and analyzed using the Bland-Altman method. All UBM measurements were done by the same author. The intraclass correlation coefficient (ICC) and Pearson coefficient with 95% confidence intervals were used to quantify the degree of agreement between the two methods.

RESULTS

Thirty-one vertical muscles were evaluated (13 superior rectus and 18 inferior rectus, of which 7 muscles were reoperations). The average for UBM measurements was 6.63 mm and for surgical caliper was 7.09 mm. The measurements for the two methods were all within +/-2 standard deviations of the mean. Only three measurements showed differences more than 1 mm. The ICC was 0.78 and Pearson coefficient was 0.85, indicating a "very good" correlation between the two methods. The longest distance from the limbus that could be accurately measured with the UBM was 12 mm. In one case a pseudotendon was differentiated from the true insertion of a previously recessed superior rectus muscle.

CONCLUSIONS

The UBM and surgical measurements showed "very good" correlation when allowing for a margin of error of +/-1.0 mm between the two modalities, indicating that the UBM is a good predictor of the position of the vertical rectus muscles.

Contrast sensitivity is reduced in children with infantile spasms

PURPOSE

To investigate whether visual deficits in children with infantile spasm (IS) are the result of seizure activity or of treatment with the anticonvulsant drug vigabatrin (VGB).

METHODS

Vision function was determined in three experiments by determining peak contrast sensitivity (CS) and grating acuity (GA) with the sweep visual evoked potential. Cross-sectional study A: 34 children, including 11 patients with childhood epilepsy with exposure to VGB for at least 6 months, 10 with childhood epilepsy exposed to antiepileptic drugs other than VGB, and 13 normally developing children. Cross-sectional study B: 32 children, including 16 with IS naïve to VGB and 16 normally developing children. Longitudinal study: seven children with IS naïve to VGB, with subsequent follow-up 5 to 10 months after starting VGB.

RESULTS

In cross-sectional study A, the median CS was reduced by 0.5 log units (P = 0.025) in children with epilepsy exposed to VGB compared with those exposed to other antiepileptic drugs and normally developing children. In cross-sectional study B, the median CS was reduced by 0.25 log units (P = 0.0015) in children with IS (VGB naïve) compared with normally developing children. Longitudinal assessment showed no decrease in CS in children with IS who were followed up 5 to 10 months after starting VGB. There was no difference in GA among groups in any of the experiments.

CONCLUSIONS

Patients with IS have CS deficits, but a sparing of GA. This deficit is present before VGB treatment and does not worsen with treatment onset. Results suggest that visual dysfunction is largely the result of the seizures themselves.

Screening and Diagnosis of Optic Pathway Gliomas in Children with Neurofibromatosis Type 1 by Using Sweep Visual Evoked Potentials

PURPOSE

Neurofibromatosis type 1 (NF-1) is an autosomal dominant phakomatosis with a prevalence of 1 in 2000 to 1 in 5000. Up to 24% of these patients have optic pathway gliomas (OPGs). In the present study, the use of sweep visual evoked potentials (SVEPs) was investigated as a screening tool for identifying patients with NF-1 who had OPGs by comparing them to those patients with no OPGs and to normally developing children.

METHODS

Contrast sensitivity and grating acuity were measured with the SVEP. Sixteen children with OPGs (OPG group), 14 children with NF-1 without OPGs (nOPG), and 16 aged-matched control subjects were recruited. All participants had best-corrected visual acuity of 6/9 or better. All were tested monocularly.

RESULTS

Comparisons between groups by using the Tukey B test showed a significant reduction of mean log contrast sensitivity in the OPG group (1.55) compared with the nOPG (1.9, P = 0.006) and control (2.10, P < 0.001) group. There was no significant difference between the nOPG and control groups (P = 0.195). Grating acuity was comparable between groups, and no statistically significant differences were found. Log contrast sensitivity was moderately sensitive in identifying patients with OPG and was highly specific in screening out patients with no OPG.

CONCLUSIONS

Children with OPGs have reduced contrast sensitivity when assessed using the SVEP. Children with no OPGs display no differences in visual functioning compared with control subjects. The findings suggest that the SVEP can be a useful and noninvasive screening tool for early detection of visual pathway gliomas in children with NF-1 and normal visual acuity.

Assessment of change of optic nerve head cupping in pediatric glaucoma using the RetCam 120

PURPOSE

To ascertain the interobserver agreement among various specialists when analyzing images of the optic nerve head taken with the RetCam 120 (Clarity Medical Systems, Inc., Pleasanton, CA) for assessing the progression of optic disk cupping in pediatric glaucoma.

METHODS

Five observers compared pairs of RetCam 120 two-dimensional photographs from 64 eyes to identify whether or not changes in the optic disk had occurred. Observers included a pediatric glaucoma specialist, pediatric neurophthalmologist, strabismologist, pediatric ophthalmic imaging specialist, and pediatric ophthalmology fellow. Each was masked to the patient identity and clinical course. For each patient, the observers reviewed the photographs taken prior to therapy and at a minimum of 6 months following initiation of therapy. Interobserver variability was calculated and analysis conducted to identify influential variables.

RESULTS

Poor agreement was noted between the observers. No significant association was obtained between agreement level and variables affecting photographic quality: variability of contrast and illumination, exposure and magnification, image clarity, presence of fluorescein on the cornea, and pixelation of the image with poor resolution. Raters noted problems with these image variables in 75.6% of the observations. The Kappa statistic obtained was kappa = 0.29 with overall proportion of agreement of p = 0.69, suggesting a fair agreement but not a moderate agreement.

CONCLUSIONS

Comparison of RetCam 120 pediatric optic nerve head photographs, when performed subjectively by observers with different perspectives, and in isolation from clinical information, may not be a reliable indicator of cupping change. In addition, variations in image contrast, luminance, color, and pixelation pose significant challenges to agreement between observers. Comparison of RetCam 120 images should not be considered the sole criterion for monitoring pediatric glaucoma.

The clinical features, MRI findings, and outcome of optic neuritis in children

BACKGROUND

Optic neuritis (ON) in childhood is thought to be more likely bilateral and less likely to lead to multiple sclerosis (MS) vs ON in adults.

METHODS

The authors evaluated clinical features, maximal visual deficit and recovery, visual evoked potentials (VEPs), neuroimaging, and outcome in a cohort of children with ON.

RESULTS

Records of 36 children (female/male ratio 1.6), ages 2.2 to 17.8 (mean 12.2) years, were reviewed. ON was unilateral in 58% and bilateral in 42%. Maximal visual deficit was severe in 69%, but full recovery occurred in 39 of 47 affected eyes (83%). VEPs were abnormal in 88%. Neurologic abnormalities in addition to those associated with ON were documented in 13 children. Neuroimaging studies of the optic nerve were abnormal in 55%. Brain MRI in 35 children demonstrated white matter lesions separate from the optic nerves in 54%. Follow-up is 2.4 years (0.3 to 8.3 years). To date, 13 children (36%) have been diagnosed with MS and 1 has Devic disease. Bilateral ON was more likely to be associated with MS outcome (p = 0.03). All 13 children with MS had white matter lesions on brain MRI. None of the children with a normal brain MRI have developed MS to date.

CONCLUSIONS

Contrary to expectations, optic neuritis (ON) in childhood was more likely to be unilateral, multiple sclerosis (MS) risk was high (36% at 2 years), and bilateral rather than unilateral ON was associated with a greater likelihood of MS. Clinical findings extrinsic to the visual system on baseline examination (p < 0.0001) and MRI evidence of white matter lesions outside the optic nerves (p < 0.0001) were strongly correlated with MS outcome.

The clinical features, MRI findings, and outcome of optic neuritis in children

BACKGROUND

Optic neuritis (ON) in childhood is thought to be more likely bilateral and less likely to lead to multiple sclerosis (MS) vs ON in adults.

METHODS

The authors evaluated clinical features, maximal visual deficit and recovery, visual evoked potentials (VEPs), neuroimaging, and outcome in a cohort of children with ON.

RESULTS

Records of 36 children (female/male ratio 1.6), ages 2.2 to 17.8 (mean 12.2) years, were reviewed. ON was unilateral in 58% and bilateral in 42%. Maximal visual deficit was severe in 69%, but full recovery occurred in 39 of 47 affected eyes (83%). VEPs were abnormal in 88%. Neurologic abnormalities in addition to those associated with ON were documented in 13 children. Neuroimaging studies of the optic nerve were abnormal in 55%. Brain MRI in 35 children demonstrated white matter lesions separate from the optic nerves in 54%. Follow-up is 2.4 years (0.3 to 8.3 years). To date, 13 children (36%) have been diagnosed with MS and 1 has Devic disease. Bilateral ON was more likely to be associated with MS outcome (p = 0.03). All 13 children with MS had white matter lesions on brain MRI. None of the children with a normal brain MRI have developed MS to date.

CONCLUSIONS

Contrary to expectations, optic neuritis (ON) in childhood was more likely to be unilateral, multiple sclerosis (MS) risk was high (36% at 2 years), and bilateral rather than unilateral ON was associated with a greater likelihood of MS. Clinical findings extrinsic to the visual system on baseline examination (p < 0.0001) and MRI evidence of white matter lesions outside the optic nerves (p < 0.0001) were strongly correlated with MS outcome.

Ultrasound biomicroscopy in strabismus reoperations

PURPOSE

To evaluate the accuracy of ultrasound biomicroscopy (UBM) for measuring the insertional distance from the limbus of horizontal extraocular muscles (EOM) that had previous surgery.

METHODS

This prospective, masked, observational study compared the distance of the horizontal EOM insertion from the limbus as measured by 50-MHz UBM, either preoperatively or at the time of the anesthesia, with that measured by surgical caliper intraoperatively.

RESULTS

Forty-three horizontal rectus muscles in 23 subjects were measured using the UBM. Of these 43 muscles, 41 (22 medial rectus and 19 lateral rectus muscles) were successfully imaged by UBM and also received intraoperative surgical measurements. Two medial rectus muscles of one patient were inserted too far from the limbus (beyond 12 mm) to be detected by UBM. The mean measured distances of the horizontal muscle insertions from the limbus were 9.0 mm with UBM and 9.3 mm at surgery (P = 0.0001, showing no significant difference). For 33 (80.5%) of the muscles, the 2 methods agreed within 1 mm (P < 0.0001). There was no difference in accuracy for lateral rectus compared with medial rectus muscles or when comparing the muscles imaged by UBM under topical versus general anesthesia.

CONCLUSION

The 50-MHz UBM can accurately measure the horizontal EOM insertion distances from the limbus for muscles in patients that had previous surgery. The limit of detection was 12 mm from the limbus for the MR and 14 mm for the LR. Depending on the patient's age and level of cooperation, the UBM study can be done under either general anesthesia or topical anesthesia.

A case of Horner syndrome with intermittent mydriasis in a patient with hypoplasia of the internal carotid artery

We report a rare case of hypoplasia of the right internal carotid artery (ICA) with ipsilateral congenital Horner syndrome. The etiology and pathogenesis of hypoplasia of the ICA is not well understood. Multiple types of collateral flow have been reported to develop to maintain blood supply to the ipsilateral cerebral hemisphere. Although collateral flow may allow these patients to remain asymptomatic, we postulate that the enlarged posterior communicating artery (PcomA) in our patient caused mass effect on the cisternal segment of cranial nerve III causing intermittent mydriasis apart from Horner syndrome.

Anterior Ischemic Optic Neuropathy Complicating Cranial Vault Reconstruction for Sagittal Synostosis in a Child

The authors report a case of postoperative visual loss in a pediatric patient who underwent an uneventful cranial vault reconstruction. A 5-year-old boy underwent total cranial vault reconstruction for nonsyndromic sagittal synostosis. He was positioned prone for 6 hours and then supine for the final 2 hours of surgery. Controlled hypotension was used to maintain the systolic arterial pressure at 80 mmHg to 90 mmHg. The intraoperative hematocrit was 23% to 31%. In the immediate postoperative period, both pupils were noted to be reactive to light. After an uneventful night in the intensive care unit, he was transferred to the ward. The eyelids were edematous on postoperative day 1, and visual examination was no longer possible. He was discharged home on postoperative day 4, and readmitted 2 days later with bilateral blindness. The pupils were nonreactive, and the optic discs were pale and edematous. Computed tomography and magnetic resonance imaging of the head revealed no abnormality. Intravenous steroid therapy was initiated, and the patient was taken to the operating room for re-exploration; the intracranial pressure was found to be normal. The presumed diagnosis was bilateral infarctions of the anterior optic nerves. Visual acuity 14 months after surgery was less than 3/200 in the right eye and 20/20-2 in the left, indicating significant recovery. Pediatric patients undergoing cranial vault reconstruction are at risk for postoperative visual loss because of ischemic optic nerve injury. Prolonged duration in the prone position and significant blood loss may be risk factors.

Reduced visual function associated with infantile spasms in children on vigabatrin therapy

PURPOSE

To use visual evoked potential (VEP) testing to determine whether visual deficits are present in children with a history of vigabatrin use.

METHODS

Contrast sensitivity and visual acuity were assessed by visual evoked potential testing and compared between 28 children (mean age, 4.90 +/- 4.92 years) with seizure disorders who had taken vigabatrin and 14 typically developing children (mean age, 3.14 +/- 1.70 years). Exclusion criteria were heritable eye disease, suspected cortical visual impairment, nystagmus, and prematurity >2 weeks. The effects of the following factors on contrast sensitivity and visual acuity were examined: type of seizure (infantile spasms versus other), ERG result, duration of vigabatrin therapy, cumulative dosage of vigabatrin, and other seizure medications (other versus no other medication).

RESULTS

Contrast sensitivity and visual acuity were reduced in vigabatrin-treated children with infantile spasms compared with vigabatrin-treated children with other seizure disorders and typically developing control subjects. The other factors examined had no significant effect on contrast sensitivity or visual acuity, with adjustment for seizure type.

CONCLUSIONS

Children with infantile spasms on vigabatrin may have compromised visual function, even in the absence of suspected cortical visual impairment. The children tested in the present study have reduced vision, probably associated with infantile spasms rather than vigabatrin.

Characteristic retinal atrophy with secondary "inverse" optic atrophy identifies vigabatrin toxicity in children

OBJECTIVE

To describe the clinical pattern of retinal atrophy in children caused by the anticonvulsant vigabatrin.

DESIGN

An interventional case series report.

PARTICIPANTS

One hundred thirty-eight patients, mainly infants, were evaluated regularly for evidence of possible vigabatrin toxicity in the Eye and Neurology clinics at the Hospital for Sick Children, Toronto.

METHOD

Sequential clinical and electroretinographic (International Society for Clinical Electrophysiology of Vision standards) evaluations every 6 months.

MAIN OUTCOME MEASURES

Presence of recognizable retinal and optic atrophy in the presence of abnormal electroretinogram (ERG) and other clinical findings.

RESULTS

Three children being treated for seizures with vigabatrin showed definite clinical findings of peripheral retinal nerve fiber layer atrophy, with relative sparing of the central or macular portion of the retina and relative nasal optic nerve atrophic changes. Some macular wrinkling was evident in 1 case. Progressive ERG changes showing decreased responses, especially the 30-Hz flicker response, supported the presence of decreased retinal function.

CONCLUSIONS

A recognizable and characteristic form of peripheral retinal atrophy and nasal or "inverse" optic disc atrophy can occur in a small number of children being treated with vigabatrin. The changes in superficial light reflexes of the retina in children facilitate the clinical recognition of nerve fiber layer atrophy. The macula is relatively spared, although superficial retinal light reflexes indicating wrinkling of the innermost retina suggest early macular toxicity as well. Because these changes are accompanied by electrophysiologic evidence of retinal dysfunction, discontinuation of vigabatrin should be strongly considered.

Orbital involvement by nasopharyngeal angiofibroma

This article describes a rare cause of orbital apex syndrome in a child--juvenile nasopharyngeal angiofibroma. A high level of suspicion while treating an adolescent male with chronic nasal obstruction, epistaxis, and a nasal mass will promote early diagnosis. Multidisciplinary care is advisable, especially for advanced disease.

Changes in the electroretinogram resulting from discontinuation of vigabatrin in children

Electroretinograms (ERGs) have been recorded longitudinally in children before and during treatment with the antiepileptic drug vigabatrin for the past 3.5 years. Vigabatrin induced changes in ERG responses occur in children; the most dramatic changes occur in the oscillatory potentials. The purpose of this study was to identify changes in ERG responses associated with discontinuation of vigabatrin treatment. If vigabatrin-induced changes reverse after discontinuation of the drug we infer that the original change is not an indicator of toxicity. ERG data were analyzed from 17 children who discontinued vigabatrin therapy. The duration of treatment ranged from 5 to 52 months, the age for the first ERG ranged from 6 to 38 months (median 10 months). ERGs were tested using the standard protocol established by the International Society for Clinical Electrophysiology of Vision, with Burian-Allen bipolar contact-lens electrodes. In addition to standard responses we recorded photopic oscillatory potentials (OPs). During vigabatrin treatment OPs show a greater change than other ERG responses, with the early occurring wavelets from the photopic OPs showing the greatest change. With discontinuation of vigabatrin the amplitude of the early wavelets of the photopic OPs increased dramatically compared with amplitudes while taking the drug (paired t-test, p = 0.000075). The scotopic oscillatory potentials also show some recovery. Although changes in oscillatory potentials may occur with vigabatrin toxicity, a large change likely occurs with a non-toxic pharmacological effect of vigabatrin on GABAergic amacrine cells in the inner plexiform layer. Reduction of OPs in children on vigabatrin may not be related to toxicity.

Longitudinal changes in photopic OPs occurring with vigabatrin treatment

PURPOSE

Vigabatrin (gamma-vinyl-GABA) is an antiepileptic drug successful in the management of infantile spasms. Photopic ERGs were tested in children followed longitudinally before and during vigabatrin treatment.

METHODS

Subjects were 26 infants (age range 1.5-24 months, median 7.6 months) on vigabatrin treatment who had been tested on multiple visits (two to four visits; mean, three visits). Eighteen of these were assessed initially before starting vigabatrin therapy and eight were assessed within 1 week of initiation of the drug. ERGs were recorded at 6-month intervals. Standard ISCEV protocol with Burian-Allen bipolar contact-lens electrodes (standard flash 2.0 cd.s/m2) was used. Although ISCEV standards were followed, a higher flash intensity (set at 3.6 cd.s/m2) was chosen for single-flash cone assessment to provide a better definition of OPs. Photopic OPs were divided into categories of early OPs and late OP (OP4). Responses were compared with age corrected limits extrapolated from our lab control database.

RESULTS

Results showed differential effects of vigabatrin on the summed early OP amplitudes versus the late OP (OP4) and cone b-wave amplitude. The early OPs showed significant decrease (p = 0.0005, repeated measures analysis of variance) after 6 months and remained decreased for the duration of treatment. There was no significant change seen in the late OP. The cone b-wave amplitude showed initial increase (p = 0.04) after 6 months, followed by a decrease after 18 months; a trend similar to that of the late OP.

CONCLUSION

Early photopic OPs were disrupted more than the late OP, suggesting relative deficit in the ON (depolarizing) retinal pathways.

Ophthalmic assessment of children before renal transplantation

OBJECTIVE

To evaluate the usefulness of routine ophthalmic examination before renal transplantation in children.

METHODS

We reviewed the records of ophthalmic assessments of renal transplant recipients at The Hospital for Sick Children, Toronto, Ont., from January 1989 to June 1996. If abnormalities had been found, we determined whether they had previously been documented, were related to the renal disease or other systemic disease, had required intervention or had affected visual function. We calculated the maximum statistical chance of detecting a meaningful eye problem at the pretransplantation assessment. We also estimated the direct cost of the ophthalmic assessment and the effect, if any, of the findings on the patient's medical management.

RESULTS

We included 107 charts. Before the ophthalmic assessment, 32 patients (30%) had known eye problems. The ocular examination detected abnormalities in 46 patients (43%); the abnormalities had not been detected previously in 14 (13%). New, potentially vision-threatening eye disorders were found in 6 (6%) of the patients. No finding affected the short- or long-term management of any patient.

CONCLUSION

Children with chronic renal failure had a high prevalence of ocular abnormalities, but most of the abnormalities did not affect visual function. Although ophthalmic assessment before transplantation did not alter the medical management of the renal transplant patients, consultation may be helpful in selected patients, particularly those who are not already under the care of an optometrist or ophthalmologist and those who have a visual complaint.

Ocular findings in lissencephaly

PURPOSE

To report our retrospective study of 20 cases with lissencephaly and describe ocular and visual abnormalities associated with this disorder.

METHODS

Patients with lissencephaly were identified and classified into classic (type I) or cobblestone (type 2) lissencephaly on the basis of a review of clinical records and neuroimaging studies. Only patients examined by an ophthalmologist were included in the study.

RESULTS

Only 1 patient had a normal ocular examination. Ocular abnormalities included optic nerve hypoplasia and atrophy, retinal dysplasia, retinal nonattachment, macular hypoplasia, anterior segment malformation, and strabismus.

CONCLUSIONS

Ocular abnormalities in classic (type 1) lissencephaly are less severe. Central, steady, and maintained fixation may be present despite the presence of optic nerve hypoplasia, optic atrophy, macular hypoplasia, strabismus, or refractive errors. Retinal and anterior segment abnormalities were observed only in cobblestone (type 2) lissencephaly. These patients often have severe visual impairment because of retinal or cortical disease.

Pontocerebellar hypoplasia type 1: new leads for an earlier diagnosis

Pontocerebellar hypoplasia type 1 is a rare disease characterized by pontocerebellar hypoplasia and anterior horn cell degeneration. The oldest reported child died at the age of 26 months. Two siblings were diagnosed with pontocerebellar hypoplasia type 1 after the death of the second sibling at 40 months of age from respiratory failure and the unexpected finding of anterior horn cell degeneration on her autopsy. The older sibling was a boy who was labeled as having cerebral palsy. He died at 14 months of age from pneumonia following a clinical course similar to his sister's, who was born 5 years after his death. Both siblings had significant global developmental delay with axial and peripheral hypotonia initially. Peripheral hypertonia with brisk reflexes developed later but were absent prior to death. Extensive investigations in the second sibling ruled out known metabolic (including congenital disorders of glycosylation) and mitochondrial diseases using skin fibroblast cultures and enzyme analysis. Genetic testing for Friedreich's ataxia; neuropathy, ataxia, and retinitis pigmentosa (NARP); spinal muscular atrophy; and spinocerebellar ataxia type 1, 2, 3, 6, 7, and 8 gene abnormalities was negative. The elecroretinogram showed a previously unreported finding of abnormal and progressive rod/cone response. Our cases provide clinical and previously unreported electroretinographic evidence for neurodegeneration in pontocerebellar hypoplasia type 1 and call for the expansion of the disease phenotype.

Nasal endoscopy in the treatment of congenital lacrimal sac mucoceles

PURPOSE

To determine the incidence of intranasal cysts associated with lacrimal sac mucoceles and the cure rate with nasal endoscopic cyst marsupialization.

DESIGN

Interventional case series.

SETTING

University-affiliated teaching hospital.

PATIENT POPULATION

Twenty-five infants with non infected or infected lacrimal sac mucoceles or dacrocystitis without obvious mucocele were consecutively enrolled. INTERVENTION PROCEDURES: Management included local lacrimal massage, parenteral antibiotics, and when still symptomatic, nasolacrimal duct probing with concomitant nasal endoscopy. Intranasal cysts identified were marsupialized until the distal end of the nasolacrimal duct probe was visualized.

MAIN OUTCOME MEASURES

Presence of intranasal cyst identification and cure rate.

RESULTS

Infants were 4 days to 10 weeks old (mean 19 days). Forty-eight percent had a bluish cutaneous mass inferior and lateral to the lacrimal sac. Twenty percent were bilateral. At presentation, 76 percent had dacrocystitis. Fourteen percent had respiratory distress. Only one child responded to medical management. At endoscopy, 23 of 24 infants had ipsilateral intranasal cysts. The one child without nasal cyst had recurrent dacrocystitis and no mucocele. All children with mucocele were cured except one child with residual nasolacrimal duct obstruction.

CONCLUSIONS

Lacrimal sac mucoceles were almost always associated with intranasal cysts. Nasal endoscopy is a valuable addition to the treatment plan for lacrimal sac mucoceles not responding to a brief trial of massage or infantile dacrocystitis. To avoid potential complications, we recommend against waiting until infection occurs before proceeding with surgery.

Assessment of extraocular muscles position and anatomy by 3-dimensional ultrasonography: a trial in craniosynostosis patients

PURPOSE

To determine whether 3-dimensional ultrasonography (3D US) provides information about anatomy and position of extraocular muscles to better guide surgeons approaching strabismus in patients with craniosynostosis who often have anomalous or absent eye muscles.

METHODS

The 4 rectus eye muscles were imaged using 3D US for 7 children with craniosynostosis before or after strabismus surgery. Reconstructed 3D images were interpreted as having normal or abnormal anatomy and position, based on comparison with images acquired from 6 normal eyes. Interpretation was validated against the intraoperative findings from strabismus surgery.

RESULTS

A total of 34 scans from the study group were used for comparison and validation purposes. Accuracy of anatomical assessments was 85% +/- 12% (percentage +/- confidence interval) and of positional assessments was 62% +/- 16%. Sensitivity and specificity of anatomical assessments was 80% +/- 14% and 88% +/- 10%, respectively. Anatomic anomalies detected by 3D US included excessively thick, thin, scarred and fibrotic, and absent muscles. Sensitivity and specificity of positional assessments was 48% +/- 17% and 85% +/- 12%, respectively. Positional anomalies such as muscle displacement off the normal clock hour axis or posteriorly displaced insertion were also detected.

CONCLUSIONS

The 3D US may have an adjunctive role in determining anatomy and position of rectus muscles in patients with craniosynostosis, although it was more accurate in assessing anatomic features rather than positional features of rectus muscles.

Childhood Miller Fisher syndrome: case report and review of the literature

Three years ago Ray Buncic and I were having a break from the lectures at an ophthalmology meeting. Ray told me of his earnest desire to provide Canadian ophthalmologists with a series of updates in pediatric ophthalmology. After a few days we were both back to the "busi-ness" of medicine, with little time to devote to such a project. Then, along came the COS Council on Continuing Professional Development (CPD) and the MaintCert program--a bold initiative to draw talent of Canadian ophthalmology into a program of continuing medical education (CME). One initiative was to use the Canadian Journal of Ophthalmology as a CME tool. This article by Eedy Mezer and Ray Buncic is highlighted as a Section 3 learning activity (self-assessment). I am delighted to have seen Ray bring forward his idea in this manner. The Canadian Journal of Ophthalmology has initiated this project in conjunction with the Council on CPD. There are a number of questions that relate to this article that can be answered on the COS Web site (http://www.eyesite.ca). Participants will be provided with an aggregate score and a certificate that can be printed to allow them to record this activity for Section 3 credits with the Royal College of Physicians and Surgeons of Canada.

Retinal findings in children with intracranial hemorrhage

PURPOSE

To identify the incidence of Terson's syndrome in children.

DESIGN

Prospective, observational case series.

PARTICIPANTS

Fifty-seven consecutive children with known intracranial hemorrhage from nonabuse causes.

METHODS

Dilated fundus examination to detect intraretinal hemorrhages or other abnormalities.

MAIN OUTCOME MEASURES

Presence or absence of intraretinal hemorrhages or other abnormalities.

RESULTS

Fifty-five patients (96%) had no evidence of intraretinal or vitreous hemorrhage. Two patients had abnormal retinal examinations. One patient had a single dot hemorrhage associated with presumed infectious white retinal lesions. The second patient had three flame and two deeper dot intraretinal hemorrhages after a motor vehicle accident (1.5% incidence of retinal hemorrhage).

CONCLUSIONS

Retinal hemorrhage is uncommon in children with intracranial hemorrhage not resulting from shaken baby syndrome. The maximal incidence of intraretinal hemorrhage in children with nonabuse intracranial hemorrhage is 8%.

Evaluation of the ultrasound biomicroscope in strabismus surgery

PURPOSE

This study was done to determine the ability of the ultrasound biomicroscope (UBM) to define the distance of the horizontal extraocular muscle insertions from the limbus in children undergoing strabismus surgery.

METHODS

A total of 51 children undergoing primary surgery on their horizontal muscles were recruited for this study. The 50 MHz UBM was used before surgery on the muscle(s) requiring an operation to define the distance of the insertion of the horizontal rectus muscle(s) from the limbus. These data were stored on a computer and masked from the surgeon who measured the actual insertion from the limbus with calipers intraoperatively. An intraclass correlation coefficient was calculated to determine the correlation of the UBM measurement with that performed during surgery.

RESULTS

Measurement of the distance of the insertions from the limbus were taken on 79 muscles of the 51 patients: 44 medial rectus (MR) and 35 lateral rectus (LR). Mean age of the patients was 6.4 +/- 3.7 years (range, 1-15). A total of 29 children (56.9%) were female. The mean distance of MR from the limbus measured surgically was 5.2 +/- 0.6 mm (range, 4-6 mm; median, 5 mm) and measured with the UBM was 5.2 +/- 0.9 mm (range, 4-7.6 mm; median, 5.3 mm). Comparable results for the LR muscles were 6.4 +/- 0.6 mm (range, 5.5-7.5 mm; median, 6.5 mm) and 6.9 +/- 0.7 mm (range, 5.9-8.4 mm; median, 6.9 mm), respectively. An intraclass correlation coefficient of 0.71 signified good agreement between the surgical and UBM measurements of the distance from the limbus of the horizontal rectus muscle insertions.

CONCLUSION

The UBM could be used reliably as a tool before surgery to estimate the distance of the horizontal rectus muscles from the limbus in children with strabismus.

The Hospital for Sick Children, Toronto, Longitudinal ERG study of children on vigabatrin

The purpose of this longitudinal study was to identify changes in ERG responses associated with vigabatrin treatment. We accomplished this by recording longitudinally ERGs in children before and during vigabatrin treatment and comparing results between children on vigabatrin monotherapy and those taking additional anticonvulsive medications. Thirty-three children on vigabatrin therapy were tested; the duration between visits was approximately 6 months. Thirteen children were assessed initially before starting vigabatrin therapy and seven were assessed soon after (age range 1.5-126 months, median 6 months). The remaining 13 patients were already on vigabatrin at the time of initial visit (age range 6.5-180 months, median 16 months). ERGs were tested using the standard protocol established by the International Society for Clinical Electrophysiology of Vision, with Burian-Allen bipolar contact-lens electrodes. In addition to standard responses we recorded photopic oscillatory potentials (OPs). All 33 patients were tested longitudinally on at least two occasions and 11 were tested on three occasions. For children whose only anticonvulsive drug was vigabatrin there was a significant curvature (quadratic function, p < 0.05) of the predicted cone b-wave amplitude with time; exhibited as increase in b-wave amplitude followed by subsequent decrease. Descriptive data demonstrated the same pattern in the group taking anticonvulsive medications in addition to vigabatrin. In most children the flicker amplitude declined between 6 months and 1 year of vigabatrin treatment. Our data demonstrated that rod responses, which may be abnormal before initiation of vigabatrin, did not change substantially with vigabatrin treatment.

Which ocular and neurologic conditions cause disparate results in visual acuity scores recorded with visually evoked potential and teller acuity cards?

PURPOSE

We investigated whether disparity between visually evoked potential (VEP) acuity scores and Teller Acuity Card (TAC) scores varied according to presence of ocular or neurologic conditions.

METHODS

Charts from 175 children (mean age, 34.8 months; range, 3 to 158 months) referred for visual acuity testing were examined. All children had been tested with pattern-alternation VEP and TAC and had undergone a complete eye examination. VEP and TAC acuity scores were relative to age-expected acuity scores for each acuity test. The absence and degree of macular abnormality, retinal abnormality, optic nerve hypoplasia, optic nerve atrophy, cortical visual impairment, developmental delay, cerebral palsy, seizures, and nystagmus were noted. Analysis of variance models were used to determine whether differences between VEP and TAC scores varied according to the presence of specific deficits. Logistic regression analysis determined whether degree of specific deficits was associated with a greater chance of inconsistency between VEP and TAC scores (>0.3 log unit difference).

RESULTS

Inconsistent scores were found in 48% of children. Developmental delay was associated with relatively poorer TAC than VEP score, and the chance of inconsistency increased with severity of developmental delay.

CONCLUSIONS

Diagnosis-dependent variability exists between TAC and VEP scores. Therefore knowledge of the clinical picture is necessary in interpretation of VEP and TAC scores. It is not clear which test is more useful when a disparity exists, either from this or previous studies. When visual acuity is assessed longitudinally in a given child, then consistency in method for acuity assessment is important.

The natural history and ophthalmic involvement in childhood myasthenia gravis at the hospital for sick children

OBJECTIVE

To characterize signs, symptoms, and the natural history of myasthenic syndromes in pediatric patients.

DESIGN

Retrospective noncomparative case series.

PARTICIPANTS

Thirty-four patients with a diagnosis of myasthenia were identified from either the hospital's or treating physician's database.

METHODS

Retrospective chart review, clinical examination, and telephone interview.

MAIN OUTCOME MEASURES

Information pertaining to the ophthalmologic and neurologic examination, diagnostic interventions, and treatment was noted. Patients with active disease, attending during the study period, were examined at their outpatient visits. Those who no longer attended the hospital were contacted by means of a telephone interview to complete their follow-up.

RESULTS

Thirty-four children were found to have myasthenia. Two had transient neonatal myasthenia, which resolved quickly. Seven (20.6%) patients had congenital myasthenic syndromes (CMS) and 25 (73.5%, 19 females) were affected with autoimmune myasthenia gravis (AMG). In those patients with severe CMS, three showed signs of generalized weakness, including failure to thrive, frequent apneas, and aspirations. In four patients with mild CMS, eye signs were relatively more prominent. In all patients with CMS, strabismus, ophthalmoplegia, and ptosis were the main ophthalmologic signs and remained relatively constant. Fourteen (56%) patients with AMG had ocular signs and symptoms, and five of them progressed to systemic involvement in 7.8 months on average (range, 1-23). The remaining nine patients with ocular AMG had either strabismus or ptosis and were treated with pyridostigmine (nine patients) and prednisone (two patients). Patients with ocular AMG were seen at 78 months on average, those with systemic AMG at 85.6 months. Systemic AMG was seen in 16 patients. No thymomas were found in 14 patients who underwent thymectomy. Of the 25 patients with AMG, 8 are still being treated, 8 are in remission for an average of 65.2 months and are asymptomatic, 4 patients are receiving long-term immunosuppressants (1 has likely sustained permanent damage to her extraocular muscles with complete ophthalmoplegia and ptosis), and 4 have been lost to follow-up. Finally, one patient died after aspiration because of bulbar weakness.

CONCLUSIONS

Patients with CMS varied in the degree of severity. Apneic attacks, aspiration, and failure to thrive may obscure the diagnosis. Compared with AMG, their ophthalmologic signs and symptoms were usually permanent. Visual signs and symptoms were usually prominent in those patients with active AMG, but those in remission were asymptomatic. More than half of the patients with juvenile AMG had ocular symptoms. Generalization occurred in a minority in an average of 7.8 months. Patients entered remission after approximately 2 years of treatment and were visually asymptomatic. This study suggests that long-term permanent damage to the extraocular muscles as a result of juvenile AMG is rare. Myasthenia gravis is a life-threatening disease as evidenced by the death of one of our patients. Many of these patients are first seen by the ophthalmologist who can aid the diagnosis, screen for amblyopia, and monitor the patient's response to therapy.

Pediatric tetracycline-induced pseudotumor cerbri

BACKGROUND

Tetracyclines have long been recognized as a cause of pseudotumor cerebri in adults, but the role of tetracyclines in the pediatric age group has not been well characterized in the literature and there have been few reported cases. We present 6 cases to better delineate the problem, the patient profile, the response to treatment, and the sequelae.

METHODS

We retrospectively analyzed the records of all patients admitted with a diagnosis of pseudotumor cerebri who had documented usage of a tetracycline-class drug immediately before presentation at the Hospital For Sick Children in Toronto, Canada, from January 1, 1986, to March 1, 1996.

RESULTS

Six patients (5 female, 1 male) who met all inclusion and exclusion criteria were identified; their ages ranged from 12 to 17 years. All were being treated for acne vulgaris. Duration of use before diagnosis was as short as 2 weeks and as long as 10 months, with a mean of 4.4 months. Duration of symptoms ranged from 0.57 to 4 weeks. Symptoms included headache (6 of 6), nausea (5 of 6), and diplopia (4 of 6). All for whom height and weight data were known (5 of 6) were in the upper quartile for body mass index. Visual acuity was 6/6 in all but 1 eye of one patient (6/9) at diagnosis, and final visual acuity was 6/6 in all patients. All had normal color vision, where this was recorded (5 of 6). The only recorded field defect was enlargement of the blind spot (4 of 6). All patients responded to treatment, with loss of symptoms in 1 day to 4 weeks.

CONCLUSIONS

Pseudotumor cerebri as a result of tetracycline-class drugs does occur in the pediatric population. With prompt and appropriate medical treatment, long-term sequelae can almost always be avoided. Physicians who treat patients with tetracyclines need to be aware of the potential complications in children.

Pediatric Horner syndrome

INTRODUCTION

The purpose of this study was to define the etiologies of Horner syndrome in the pediatric population.

METHODS

A retrospective review was performed of the medical records of all pediatric Horner syndrome patients (< 18 years old) examined by the pediatric ophthalmology services at two large referral centers.

RESULTS

Seventy-three pediatric Horner syndrome patients were identified. Of these, 31 (42%) were congenital, 11 (15%) were acquired without surgical intervention, and 31 (42%) were acquired after a surgical procedure of the thorax, neck, or central nervous system. Of the congenital Horner syndrome patients, a history of delivery with the use of forceps, vacuum extraction, shoulder dystocia, fetal rotation, or postterm delivery was elicited in 16 patients (53%). Concomitant brachial plexus injury was identified in only 3 patients. Two patients had congenital varicella syndrome and 1 patient was diagnosed with neuroblastoma. This patient had a palpable supraclavicular mass and stridor. Diagnosis of the patients with acquired Horner syndrome included neuroblastoma (2), trauma (1), rhabdomyosarcoma (1), brainstem vascular malformation (1), disseminated sclerosis (1), and not determined (5).

CONCLUSION

In children with congenital Horner syndrome, a history of forceful manipulation of the infant during birth may reduce the need for extensive systemic evaluation. Without such history, a decision to proceed with further evaluation is made with consideration of the relative incidence of neuroblastoma by age and the physical findings. All acquired pediatric Horner syndrome patients without a known etiology require thorough evaluation because of the frequent association of serious underlying disease.