Pearls & Oy-sters: Ocular Myasthenia Gravis: Central Ocular Motor Signs and Unilateral Visual Loss Caused by the Great Neuro-Ophthalmologic Impersonator

Myasthenia gravis (MG) has been described as a great mimicker of other neurologic and ocular motility disorders, including centrally mediated ophthalmoplegia. For example, ocular myasthenia gravis (ocular MG) may cause impaired binocular visual acuity for near vision due to reduced accommodation or for distance vision due to accommodative excess. Notably, accommodative excess due to ocular MG is rare, but may occur with exotropia, with or without diplopia. We report 2 cases of ocular MG: First, a 32-year-old man with exotropia, bilateral hypometric and slowed adducting saccades with dissociated abducting nystagmus, miosis, and decreased distance vision in his right eye; second, a 45-year-old man with similar ocular motor deficits, miosis, and myopia. Both patients showed ocular motor deficits which appeared to localize to the pons but were instead due to ocular MG. Ocular MG should be considered in patients who present with reduced visual acuities due to any disruption in accommodation. Any ocular motor deficit, even if appearing to be centrally mediated or occurring without ptosis, may be caused by ocular MG.

The causal effect of obesity on concomitant exotropia: A lifecourse Mendelian randomization study

Obesity is now a significant global public health issue. Limited understanding exists regarding the association between obesity and concomitant exotropia. Our objective was to identify the causal relationship between lifecourse obesity, including birth weight, childhood body mass index (BMI), and adult BMI, and the risk of concomitant exotropia. We used a two-sample Mendelian randomization (MR) strategy to examine the causal relationship with inverse-variance weighted method as the primary MR analysis. We carried out sensitivity analyses to evaluate the accuracy and robustness of our findings. Also, we performed reverse-direction MR analysis to eliminate the possibility of reverse causality. Childhood BMI, as opposed to birth weight or adult BMI, had a significant impact on the risk of concomitant exotropia (odds ratio = 1.40, 95% confidence interval (CI): 1.08-1.81, P = .01). This significance persisted even after accounting for birth weight and adult BMI using multivariable MR analysis (odds ratio = 1.35, 95% CI: 1.04-1.75, P = .02). There was no significant heterogeneity or pleiotropy observed in sensitivity analyses (P > .05). Multivariable MR analysis further confirmed the absence of pleiotropic effects of some risk factors including prematurity, maternal smoking around birth and refractive error. Reverse causality did not affect the causal relationship (beta = -0.0244, 95% CI: -0.0545 to 0.0056, P = .11). Genetic predisposition to higher childhood BMI was found to be causally linked to an increased risk of concomitant exotropia.

Ocular Torsional Instability-A Neurodiagnostic Sign of Prenuclear Disease

BACKGROUND

Accurate diagnosis of efferent visual system disease in neuro-ophthalmology involves the classification of clinical signs as prenuclear, nuclear, or infranuclear in origin. Over many years, I have come to recognize ocular torsional instability as a clinical sign of prenuclear disease.

METHODS

Retrospective chart review of patients in whom ocular torsional instability was diagnosed using indirect ophthalmoscopy.

RESULTS

Twenty patients were diagnosed as having ocular torsional instability (OTI). Eight had neuro-ophthalmologic disease caused by structural injury to prenuclear ocular motor areas. Six of these had structural lesions primarily involving the cerebellum, one had a midbrain glioma, and one had traumatic encephalomalacia. Eight additional patients had infantile strabismus (esotropia in 7, exotropia in 1) associated with various combinations of monocular nasotemporal optokinetic asymmetry, latent nystagmus, and dissociated vertical divergence (DVD), indicating prenuclear involvement of subcortical visuovestibular pathways within the brain. Three additional patients presented with intermittent exotropia with DVD signifying early onset, while 2 had acquired esotropia that was noninfantile in origin. One had partially accommodative esotropia with bilateral inferior oblique overaction, and one presented with acquired esotropia followed by spontaneous secondary exotropia.

CONCLUSIONS

OTI provides a useful clinical sign of prenuclear ocular motor dysfunction. When detected in patients without any signs of infantile or early-onset strabismus, OTI signifies the need for neuroimaging to rule out neurovestibular or cerebellar causes of prenuclear disease.

Rescue of exotropia subsequent to pulled-in-two syndrome of the medial rectus muscle occurring during surgery for high myopic strabismus fixus: A case report

RATIONALE

Pulled-in-two syndrome is one of the significant complications of strabismus surgery. This study aimed to report a case of pulled-in-two syndrome of the contractured medial rectus muscle (MR) that occurred during strabismus surgery for strabismus fixus due to high myopia, and to describe a rescue of this complication.

PATIENT CONCERNS

A woman in her 60s presented to our Ophthalmology Department with the main complaint of unilateral high myopia and severe myopic strabismus fixus. Esotropia exceeded 45° and hypotropia exceeded 15° in her right eye in the Hirschberg test. Right eye duction was markedly limited in every gaze direction. Orbital magnetic resonance images showed rupture of the superior rectus to lateral rectus band ligament and lengthening of the distance between the SR and LR muscles in the right eye.

DIAGNOSIS

Due to the patient's ophthalmic examination and imaging results, she was diagnosed with high myopic strabismus fixus.

INTERVENTIONS

We performed MR recession and Yokoyama surgery to correct right eye hypoesotropia. In the MR recession procedure, pulled-in-two syndrome (MR muscle tear) occurred. Thus, no additional procedure was performed on the MR. After the surgery, she presented 45 prism diopter exotropia and 18 prism diopter residual right hypotropia in a Krimsky test. We performed a second surgery, combining MR muscle advancement and inferior rectus (IR) muscle recession, 3 months after the first surgery.

OUTCOMES

One and a half years after the second surgery, she presented exotropia of 14 prism diopters without hypotropia in the Krimsky test and was satisfied with her ocular position and improved motility.

LESSONS

We experienced pulled-in-two syndrome in a case with severe myopic strabismus fixus and achieved a good outcome by performing additional surgery 3 months later, in which the lost MR muscle was advanced. This case underscores that, if the lost muscle cannot be found during surgery, one should maintain composure and perform a reoperation a few months after the initial surgery, if necessary. This case report can aid in making rescue treatment decisions when pulled-in-two syndrome occurs.

Ocular findings and strabismus surgery outcomes in Chinese children with Angelman syndrome: Three case reports

RATIONALE

Angelman syndrome (AS) is an uncommon genetic disease characterized as serious retarded mental development and ocular abnormality.

PATIENT CONCERNS

This report aims to present the ophthalmological features, and identify the diagnosis and outcomes of strabismus surgery in AS patients.

DIAGNOSIS

Three children with exotropia were diagnosed with AS based on their typical clinical features.

INTERVENTIONS

All patients underwent multiplex ligation-dependent probe amplification (MLPA) analysis and accepted lateral rectus recession surgery with the assistance of intravenous combined inhalation anesthesia.

OUTCOMES

The maternal heritage deletion of chromosome 15q11.2-q13 was verified in all patients by MLPA. All patients with strabismus could not cooperate during the vision test, and had astigmatism. The strabismus type of AS patients was horizontal exotropia, and no vertical strabismus was found. One of these patients was combined with high myopia. The hypopigmentation on the hair and iris was ubiquitous. However, retina pigmentation was normal. After different degrees of lateral rectus recession, the exotropia was significantly relieved, and the surgical effects were stable postoperatively.

LESSONS

Horizontal exotropia is the major strabismus type. Severe intellectual disability, hyperactivity, and speech impairment are the common characteristics of AS children. Its examination and operation design remains challenging. Thus, repeated examinations and intelligence rehabilitation are essential.

Effect of strabismus surgery on ocular axial length, anterior chamber depth, and intraocular pressure

We evaluated changes in ocular axial length (AL), anterior chamber depth (ACD), and intraocular pressure (IOP) after strabismus surgery by comparing the operated and fellow eyes in patients undergoing unilateral strabismus surgery.This was a prospective study including patients who underwent unilateral strabismus surgery for exotropia alone or exotropia with unilateral superior oblique palsy. The AL and ACD using IOLMaster biometer and the IOP using non-contact tonometry were measured 1 day prior to surgery and 1 week, 1 month, and 3 months postoperatively.Fourteen female and 22 male patients (mean age: 8.2 years) were included in the study. In the operated eye, the mean AL increased significantly from 23.99 mm preoperatively to 24.08 mm 1 week postoperatively (P < .001), and although the mean ACD decreased in this time, the decrease was not statistically significant. The mean IOP of the operated eye increased from 17.08 mmHg preoperatively to 20.31 mmHg at 1 week postoperatively (P = .01), as did the IOP of the fellow eye (P = .03). However, the AL and IOP of the operated eyes decreased by 1 month postoperatively. There were no significant differences in the AL, ACD, and IOP between operated and fellow eyes by 3 months postoperatively.Strabismus surgery caused significant AL elongation in the operated eye and IOP elevation in both the operated and fellow eyes immediately after surgery. However, both ocular changes were transient. The AL, ACD, and IOP did not exhibit any significant differences between operated and fellow eyes 3 months postoperatively.

Prognostic Factors Predicting the Surgical Outcomes of Bilateral Lateral Rectus Recession for Patients with Concomitant Exotropia in Chiang Mai University Hospital

OBJECTIVE

To determine the preoperative variables affecting early and late favorable outcomes of bilateral lateral rectus recession surgery for concomitant exotropia.

MATERIAL AND METHOD

A retrospective study of 65 patients with concomitant exotropia (constant and intermittent) who had bilateral lateral rectus recession was conducted. The follow-up period was more than 1 year in all patients. Preoperative parameters were obtained and evaluated using univariate analysis.

RESULTS

Sixty-five patients with concomitant exotropia who underwent bilateral lateral rectus recession were included. In the early and late postoperative outcome, 78% and 82% of the patients were in the success group, respectively. Meanwhile, 22% and 18% were in the failure group, respectively. There was no association between postoperative outcome and preoperative variables i.e. age at onset (p = 0.841, 0.591), age at surgery (p = 0.564, 0.634), interval between onset and surgery (p = 0.506, 0.753), preoperative deviation (p = 0.278, 0.211), refractive error (p = 0.217, 0.136), anisometropia (p = 0.946, 0.946), phase of exotropia (p = 0.741, 0.013), A-V pattern (p = 1.000, 1.000), stereopsis (p = 0.841, 0.268) and amblyopia (p = 0.569, 0.567).

CONCLUSION

Preoperative variables could not be used to predict the early and late postoperative outcome.

[Clinical analysis of thyroid associated ophthalmopathy with myasthenia Graves in 12 patients]

OBJECTIVE

To summarized the clinical features of thyroid associated ophthalmopathy patients with myasthenia gravis.

METHODS

This is a retrospective case series study. The clinical data of 12 thyroid associated ophthalmopathy patients with myasthenia gravis were collected in the 416 Hospital of Nuclear Industry from Oct. 2012 to Feb. 2014. All patients had a detailed medical history including symptoms of onset, the best corrected visual acuity, anterior and posterior segment examination, the exophthalmos, eyelid position, eye movement, diplopia, strabismus, systemic symptoms, concurrent fatigue test, neostigmine test, thyroid function and orbital CT scan. One patient underwent CT examination of thymus.

RESULTS

In all 12 patients, there were 8 females and 4 males with age from 13.0 to 44.0 years (the median age of 26.5 years), 11 cases had difficulties to open their eyes which was least severe in the morning and worsened in the evening. All of cases did not have general symptoms. Ptosis was observed in 9 cases, 3 cases were bilateral, and 6 cases were unilateral. Abnormal extra ocular muscle function was observed in 8 cases, all of them were bilateral. In these 16 eyes, the limitation of downward gaze were observed in 15 eyes, the limitation of upward, outward and inward gaze were observed in 14 eyes, eye fixation occurred in 4 eyes. Four cases had diplopia, 3 cases had strabismus, and 2 of them were exotropia. Orbital CT demonstrated extraocular muscle thickening in 6 cases. Thickening of inferior rectus were observed in all 12 eyes, superior rectus and medial rectus were found thickened in 6 eyes, and thickening of lateral rectus muscle was found in 3 eyes.

CONCLUSIONS

The clinical features of thyroid associated ophthalmopathy patients with myasthenia gravis were complex. When ptosis and eye movement disorders were not consistent with TAO severity, associating with exotropia and systemic muscle paralysis, myasthenia gravis should be considered.

Association between childhood strabismus and refractive error in Chinese preschool children

PURPOSE

To investigate the association between concomitant esotropia or concomitant exotropia and refractive error in preschool children.

METHODS

A population-based sample of 5831 children aged 3 to 6 years was selected from all kindergartens in a representative county (Yuhuatai District, Nanjing, Jiangsu Province) of Nanjing, China. Clinical examinations including ocular alignment, ocular motility, visual acuity, optometry, stereopsis screening, slit lamp examination and fundus examination were performed by trained ophthalmologists and optometrists. Odd ratios (OR) and 95% confidence intervals (95% CI) were calculated to evaluate the association of refractive error with concomitant esotropia and concomitant exotropia.

RESULTS

In multivariate logistic regression analysis, concomitant esotropia was associated independently with spherical equivalent anisometropia (OR, 3.15 for 0.50 to <1.00 diopter (D) of anisometropia, and 7.41 for > = 1.00 D of anisometropia) and hyperopia. There was a severity-dependent association of hyperopia with the development of concomitant esotropia, with ORs increasing from 9.3 for 2.00 to <3.00 D of hyperopia, to 180.82 for > = 5.00 D of hyperopia. Concomitant exotropia was associated with astigmatism (OR, 3.56 for 0.50 to 1.00 D of astigmatism, and 1.9 for <0.00 D of astigmatism), myopia (OR, 40.54 for -1.00 to <0.00 D of myopia, and 18.93 for <-1.00 D of myopia), and hyperopia (OR, 67.78 for 1.00 to <2.00 D of hyperopia, 23.13 for 2.00 to <3.00 D of hyperopia, 25.57 for 3.00 to <4.00 D of hyperopia, and 8.36 for 4.00 to <5.00 D of hyperopia).

CONCLUSIONS

This study highlights the close associations between refractive error and the prevalence of concomitant esotropia and concomitant exotropia, which should be considered when managing childhood refractive error.

[Ocular deviation as the cause of "psychiatric" problems]

We describe two cases with complaints of atypical headache who were initially diagnosed as having psychiatric problems, but who, after careful evaluation, were found to have an underlying eye disorder. Both patients were known to have an ophthalmic history. Patient A, a 21-year-old female, presented with severe headache, which was so disabling that she was declared unfit for work. A diagnosis of tension headache was made and she received psychological treatment with neurofeedback, homeopathy and acupuncture, which had no effect. Patient B, a 26-year-old male, complained of extreme photophobia, nausea and dizziness. The patient was diagnosed as having a conversion disorder and was admitted to a psychiatric clinic and given psychotropic treatment. Careful ophthalmological examination revealed that an ocular deviation was causing the symptoms in both patients and could be treated appropriately with strabismus surgery. These cases emphasise the importance of a thorough general medical and ophthalmic history and proper examination at all times without putting a psychiatric stigma on the patient.

[Clinical investigation on AC/A ratio in intermittent exotropia coexisting with ametropia]

OBJECTIVE

To investigate AC/A ratio and coexisting ametropia in intermittent exotropia. To discuss the relation between AC/A ratio and the development of intermittent exotropia.

METHODS

The medical records of 135 patients who had an exotropia were retrospectively reviewed. Patients were divided into 3 groups based on the type of ametropia: exotropia without ametropia (-0.50-+3.00 D between the age of 3-6 years old, -0.50-+2.00 D between the age of 7-40 years old) , exotropia coexisting with myopia (-0.50-7.75 D) and exotropia coexisting with hypermetropia ( ≥ + 3.00 D of 3-6 years old , ≥ + 2.00 D of 7 ∼ 40 years old). AC/A ratios of all patients were assessed using synoptophore method. Distance and near deviations were assessed using prism cover test. AC/A ratios and deviation angles of 3 groups were compared. The relationship between AC/A ratios and ametropia/age were investigated.

RESULTS

There were obvious differences in AC/A ratios(2.686 ± 1.372, 1.773 ± 1.110, 4.581 ± 1.552, F = 36.323, P < 0.001) and in near deviation angles (44.473(Δ) ± 19.008(Δ), 53.621(Δ) ± 20.749(Δ), 34.455(Δ) ± 13.292(Δ), F = 8.762, P = < 0.001) between 3 groups of patients, no obvious differences were seen in distance deviation angles (40.333(Δ) ± 19.474(Δ), 44.052(Δ) ± 23.722(Δ), 35.590(Δ) ± 11.143(Δ), F = 1.444, P = 0.24). AC/A ratios were negative linear correlated with refractive powers for patients of intermittent extropia coexisting with myopia or with hypermetropia (r = 0.320, P = -0.469 and r = -0.046, P = 0.036, respectively) . A trend of decline with age was found for AC/A ratios only in patients of intermittent extropia without ametropia (r = -0.320, P = 0.019; r = -0.023, P = 0.865; r = 0.246, P = 0.296 for the other 2 groups, respectively).

CONCLUSIONS

Myopia and hypermetropia, when coexisting with abnormally low or high AC/A ratio, can destroy the balance between extraocular muscles and induce exophoria to be manifest.

Sensory exotropia associated with keratoconus and review of literature: strabismus and keratoconus

PURPOSE

To present a case of sensory strabismus due to keratoconus with an ipsilateral nodular lesion of the bulbar con-junctiva.

CASE PRESENTATION

The patient is a 17 year-old-boy. The fixing eye was the right eye and keratoconus in this eye was late onset. Vision in the left eye was poor and keratoconus was advanced in this eye. Due to longstanding of keratoconus and occurrence in the sensitive period, sensory exotropia had developed in the left eye. A nodular lesion of the bulbar conjunctiva was also present in the ipsilateral eye.

CONCLUSION

Sensory exotropia is not unusual but to be due to longstanding keratoconus is not a usual strabismus. If keratoconus develops before 7 years of age, sensory strabismus can develop. We reported and reviewed literature that keratoconus seldom begins in the sensitive period where abnormal visual experience affects visual development and may induce sensory exotropia.

Exotropia in children with high hyperopia

PURPOSE

To describe the clinical characteristics, treatment, and subsequent clinical course of children with exotropia and high hyperopia.

METHODS

The medical records of 26 patients seen between 1990 and 2009 who had an exotropia and ≥4.00 D of hyperopia were retrospectively reviewed. We analyzed the clinical characteristics, treatments, and subsequent alignment outcomes.

RESULTS

A total of 26 patients between the ages of 2.5 months and 9 years were included. Of these, 15 had associated medical conditions or developmental delay. Of 22 patients with measured visual acuities, 19 had amblyopia (10 unilateral, 9 bilateral). None of the patients demonstrated fine stereoacuity. Twenty-three exotropic children were treated with spectacles: 15 were fully corrected, 10 of whose exotropia improved; 8 received partial correction of their hyperopia, 3 of whose exotropia improved. Six patients who presented with large, poorly controlled exotropia and did not improve with spectacle correction required strabismus surgery.

CONCLUSIONS

Children with high hyperopia and exotropia are likely to have developmental delay or other systemic diseases, amblyopia, and poor stereopsis. Treatment of high hyperopia in exotropic children with their full cycloplegic refraction can result in excellent alignment.

[Intermittent exotropia: bilateral lateral rectus recession treatment and long term results]

PURPOSE

To describe the long-term surgical outcomes of bilateral lateral rectus recession in patients with intermittent exotropia.

METHODS

Retrospective review of 18 patients diagnosed with intermittent exotropia between 1995 and 2005 who underwent surgical treatment in the Ramon y Cajal Hospital.

RESULTS

Of the 18 patients with intermittent exotropia, 50% were basic subtype. All of them underwent bilateral lateral rectus recession, associated with a previous failed botulinum toxin injection in 8 of them. Satisfactory results (less than 10 PD orthophoria) were obtained in 68.2% of the patients after a 4.5-year follow-up period.

CONCLUSIONS

Bilateral lateral rectus recession is an effective and stable surgical procedure in the long-term motor control of intermittent exotropia, especially in basic subtype. Previous injection of botulinum toxin did not affect the results.

Correction of hyperopia in intermittent exotropia

Therapeutic options for the management of the early phase of intermittent exotropia are limited. The correction of seemingly insignificant refractive errors might result in better control of the deviation. Patients with hyperopia present an interesting dilemma. Accommodative convergence may be used in uncorrected hyperopia to control exotropia, so it might be anticipated that correction of hyperopia will increase both the frequency and the size of the deviation. This is not always the case. We have all experienced patients with high hyperopia and intermittent exotropia that improved following optical correction. It is postulated that the improvement in visual acuity and, in some cases, the normalization of accommodation might lead to this result.

[Value of complex ultrasonography in children with concomitant strabismus]

28 children with concomitant strabismus were examined using complex ultrasonography. Thickness of horizontal recti muscles was estimated in convergent and divergent strabismus. The blood flow in central retinal artery was estimated in patients with concomitant strabismus.

Surgical management of clinically significant hypertropia associated with exotropia

PURPOSE

To report the surgical treatment of hypertropia coexisting with exotropia, with either vertical offset surgery or additional vertical muscle surgery simultaneous to correction of the exotropia.

METHODS

A total of 35 patients with exotropia and hypertropia who underwent a horizontal muscle surgery for exotropia were included. To determine efficacy in resolving a vertical deviation in patients with exotropia, 28 patients were compared in 2 groups: those who underwent horizontal muscle surgery with vertical offset and those who underwent horizontal muscle surgery with additional vertical muscle surgery. An additional 7 patients who had exotropia and hypertropia but did not undergo vertically corrective surgery were included for comparison.

RESULTS

Vertical offset of horizontal rectus muscles (4 mm) resulted in 8(Delta) correction of the distance hypertropia. Vertical rectus muscle recession used in the treatment of larger hypertropic deviations with exotropia had a 3(Delta) correction per 1 mm of recession. Success rates for hypertropia correction were similar between groups, 63% vertical offset and 71% vertical muscle groups; overcorrections occurred in 29% of the vertical muscle group. The vertical correction in both groups was stable in 88% over 6 months postoperatively.

CONCLUSIONS

Vertical offset of the horizontal muscles simultaneous with exotropia correction has a beneficial effect in small-angle hypertropia (<14(Delta)). Vertical rectus muscle surgery in patients with hypertropia greater than 10(Delta) had equivalent success; however, in intermittent exotropia the hypertropia was prone to overcorrection.

Outpatient assessment of neurovisual functions in children with Cerebral Palsy

This study examined the feasibility of the Atkinson Battery for Child Development for Examining Functional Vision (Atkinson, Anker, Rae, et al., 2002) to evaluate neurovisual functions of children with neurodevelopmental disorders in outpatient setting. A total of 90 patients underwent a comprehensive evaluation. Among these, a group of 33 children with Cerebral Palsy (CP), mean age 6 years, with different types of CP (26% diplegic, 37% hemiplegic and 37% tetraplegic) were selected to constitute the cohort of the study. Visual sensory measures as well as higher level visual functions were considered. Overall, 73% patients had impairments at the assessment protocol, the majority of which presenting difficulties on both visuoperceptual and visuospatial tasks (79%). Subgroups of participants presented similar profiles of impairments with spared basic visuocognitive abilities and limitations in visuoperceptual and visuospatial domains. The Atkinson's battery proved to be valuable for evaluation in outpatient setting and follow-up testing. Some limitations emerged. For the definition of personalized and detailed rehabilitation programs a breakdown of the different components of vision and subsequent in-depth evaluation are needed.

Exodeviation compensated for by dragged macula: pseudo-exodeviation

Dragged macula is a manifestation of several ophthalmic conditions. We present a 25-years-old male with dragged macula in the right eye, good vision in both eyes, and pseudo-exodeviation of 45 prism diopter without diplopia. We tried to correlate between the degree of pseudo-deviation and the distant of the fovea from its expected original position.

Double vision in a patient with thyroid disease: what's the big deal?

A 70-year-old woman with a 46-year history of Graves disease had significant thyroid related orbitopathy (TRO) requiring previous bilateral orbital decompressions and one previous strabismus procedure for an exotropia of 60 PD. At the initial neuro-ophthalmology assessment, she had an exotropia of 20 PD and was scheduled for further surgery, but at the time of a second assessment a few weeks later, her strabismus had markedly changed. Accordingly, the patient underwent a neostigmine bromide test that demonstrated evidence of co-existing myasthenia gravis.

Aicardi syndrome associated with anterior cephalocele in a female infant

Aicardi syndrome is a triad of abnormalities that includes total or partial agenesis of the corpus callosum, chorioretinal lacunae, and infantile spasms. This syndrome was first described in 1965. A female infant with Aicardi syndrome associated with a nasoethmoidal cephalocele is described in this report. She presented with a history of unilateral nasal discharge since birth and seizures since age 1 week. She was microcephalic and there was visual impairment. A fleshy mass of the left nostril was noted. Ophthalmological evaluation revealed left exotropia, dysplastic optic discs and retina, 'morning glory' appearance of the left optic disc, and bilateral chorioretinal lacunae. Magnetic resonance imaging of the brain showed absence of the corpus callosum, dysmorphic changes of the lateral ventricles, a superiorly located third ventricle, heterotopic grey matter of the frontal lobes, a left nasoethmoidal cephalocele, and closed lip schizencephaly of the left frontal lobe. This female infant developed asymmetric infantile spasms at age 8 weeks. Surgical correction of the cephalocele was declined. She developed recurrent pneumonias secondary to aspiration of feeds and died at age 8 months during one of these events.

Comitant horizontal strabismus: an Asian perspective

AIM

Recent studies suggest that Asian strabismus patterns are different from those in the West. This study aims to determine the profile of children with comitant horizontal strabismus in Singapore.

METHOD

682 children aged <or=16 years presenting with strabismus for the first time between 2000 and 2002 were included in this study. The type and size of the squint, visual acuity, refractive error and stereopsis were noted.

RESULTS

493 children (72%) were exotropic, the majority (92%) of whom had intermittent exotropia, X(T). The divergence excess type X(T) was most common (59.5%), followed by basic (29.0%) and convergence-weakness (11.5%). Children with X(T) demonstrated stereopsis for near in 92% and distance in 50%. Esotropia was present in 191 (28%) children (23% infantile and 53% accommodative). Children with infantile esotropia presented significantly younger (2.8 years vs 4.5 years), had larger squint size (35D vs 26D) and were less hyperopic (+0.78D vs +2.79D). Amblyopia or ocular preference was noted in 50% of children with infantile esotropia, and 43% with accommodative esotropia.

CONCLUSION

Twice as many Singaporean children presented with exotropia than esotropia. However, within the exotropia and esotropia groups, the distribution and characteristics of various strabismus subtypes bore similar characteristics to those described in the West.

Síndrome de Brown bilateral associada com hipermobilidade articular benigna: relato de caso

Brown's syndrome is characterized by a limitation of elevation in adduction, slight or normal limitation of elevation in abduction, divergence in straight upgaze (V-pattern), intorsion in upgaze and positive forced duction. It is caused by a tight or inelastic superior oblique tendon. Benign joint hypermobility is a hereditary disease of the connective tissue characterized by an increase of mobility in diverse joints. Its prevalence is very changeable regarding age range, sex and ethnicity, varying from 2 to 35% in men and 5 to 57% in women. In this case the authors describe a case of Brown's syndrome associated with Benign joint hipermobility and call attention to a little described association in the literature. J.C.S, male, 6 years old, mulatto, student, was referred to the University of Santo Amaro with complaint of exotropia for 2 years that it increased in supraversion. The patient with the diagnosis of bilateral Brown's syndrome, was diagnosed as having benign joint hipermobility by the reumatologist. The patient with benign joint hipermobility can develop symptoms such as arthralgia caused by a joint inflammation. We believe in the possibility that Brown syndrome has occurred, caused by an inflammatory process in the trochlea that started because of the benign joint hypermobility.

Filamentary Keratopathy Caused by Corneal Occlusion by Large-Angle Paralytic Strabismus

PURPOSE

To report a case of filamentary keratopathy in a patient with large-angle paralytic strabismus.

METHODS

A 31-year-old man who had a traffic accident was diagnosed to have third cranial nerve palsy and a large-angle exotropia in his right eye. The patient complained of foreign body sensation in his right eye 2 months after the accident.

RESULTS

Slit-lamp examination showed multiple filaments on the right cornea. Debridement of the filaments and artificial tears relieved the symptoms and were used until the paralysis resolved.

CONCLUSION

Large-angle paralytic strabismus with ptosis and poor elevation and depression of the eye may occlude the cornea and lead to filamentary keratopathy.

Prevalence and associations of anisometropia and aniso-astigmatism in a population based sample of 6 year old children

AIM

To study the distribution of anisometropia and aniso-astigmatism in young Australian children, together with clinical and ocular biometry relations.

METHOD

The Sydney Myopia Study examined 1765 predominantly 6 year old children from 34 randomly selected Sydney schools during 2003-4. Keratometry, cycloplegic autorefraction, and questionnaire data were collected.

RESULTS

Spherical equivalent (SE) anisometropia (> or =1 dioptre) prevalence was 1.6% (95% confidence interval (CI) 1.1% to 2.4%). Aniso-astigmatism (>or =1D) prevalence was 1.0% (CI: 0.6% to 1.6%). Both conditions were significantly more prevalent among moderately hyperopic (SE > or =2.0D) than mildly hyperopic (SE 0.5-1.9D) children. Myopic children (SE < or =-0.5D) had higher anisometropia prevalence. Neither condition varied by age, sex, or ethnicity. In multivariate analyses, anisometropia was significantly associated with amblyopia, odds ratio (OR) 29, (CI: 8.7 to 99), exotropia (OR 7.7, CI: 1.2 to 50), and neonatal intensive care unit (NICU) admission (OR 3.6, CI: 1.1 to 12.6). Aniso-astigmatism was significantly associated with amblyopia (OR 8.2, CI: 1.4 to 47), maternal age >35 years (OR 4.0, CI: 1.3 to 11.9), and NICU admission (OR 4.6, CI: 1.2 to 17.2). Anisometropia resulted from relatively large interocular differences in axial length (p<0.0001) and anterior chamber depth (p = 0.0009). Aniso-astigmatism resulted from differences in corneal astigmatism (p<0.0001).

CONCLUSION

In this predominantly 6 year old population, anisometropia and aniso-astigmatism were uncommon, had important birth and biometry associations, and were strongly related to amblyopia and strabismus.

Strabismus in pediatric pseudophakia

OBJECTIVE

To evaluate strabismus associated with pediatric pseudophakia.

DESIGN

Retrospective case series.

PARTICIPANTS

Charts of 94 pediatric patients who underwent cataract extraction with primary intraocular lens implantation from 1990 to 2003 at Indiana University School of Medicine were reviewed. Only those patients who had pre-cataract extraction and post-cataract extraction alignment measurements were included.

METHODS

Data were collected on gender, race, age at presentation, age at time of cataract surgery, and type of cataract. Pre-cataract extraction and post-cataract extraction data on visual acuity (VA), alignment, and amblyopia were recorded. Results of strabismus surgery were also evaluated.

MAIN OUTCOME MEASURES

Frequency, type and amount of strabismus, and results of strabismus surgery.

RESULTS

Ninety-four pediatric pseudophakia patients were identified, and 37 (39%) had strabismus. Exotropia (46%) was more common than esotropia (41%). Factors not associated with the development of strabismus included age at presentation, interval between diagnosis and cataract extraction, race, and type of cataract. Factors statistically associated with the development of strabismus include pre-cataract extraction and post-cataract extraction VA, type of strabismus, and post-cataract extraction amblyopia. The mean pre-cataract extraction deviation of the group that had strabismus surgery was 22 prism diopters, and 75% were aligned at the last examination (mean follow up, 24 months).

CONCLUSION

Strabismus occurs more frequently in pseudophakic pediatric patients than in the general pediatric population. Pseudophakic children should be monitored carefully for the development of strabismus, which in many cases can be successfully treated.

The need for optometric investigation in suspected Meares-Irlen syndrome or visual stress

Meares-Irlen syndrome is characterised by symptoms of eye strain, headaches and visual perceptual distortions when viewing text. The symptoms are alleviated with individually prescribed coloured filters, such as precision tinted lenses. Meares-Irlen syndrome, and the related condition of visual stress, are likely to result from hyperexcitability of the visual cortex, which can also occur in migraine. The symptoms of Meares-Irlen syndrome and visual stress are non-specific and the condition needs to be differentially diagnosed from other optometric conditions, such as refractive error, binocular vision anomalies, and accommodative anomalies. Three case reports are described of patients who consulted the author with suspected Meares-Irlen syndrome but were found to have other causes for their symptoms: posterior sub-capsular cataract, high uncorrected astigmatism, and decompensated convergence weakness exophoria. These cases highlight the need for professional eye care for people with suspected Meares-Irlen syndrome. Although this advice is stressed in literature on the well-established MRC/Wilkins Intuitive Colorimeter system, it is not always stressed in literature about other systems. This may be a cause for concern.

Characteristic ocular findings in patients with craniofacial cleft

PURPOSE

To identify the characteristic ocular findings in patients with craniofacial cleft (CFC).

METHODS

Ophthalmologic examination was performed for a 16-year-old girl with no. 3 CFC and a 3-year-old boy with no. 5 CFC.

RESULTS

Exotropia was found in the 3-year-old boy with no. 5 CFC involving the lateral orbit, and esotropia in the 16-year-old girl with craniofacial cleft no. 3 involving the medial orbit. Hypotropia, lower eyelid coloboma, amblyopia and an absence of stereopsis were common to both patients. Visual acuity was improved from hand motion to 20/30 by means of occlusion therapy for amblyopia in the 3-year-old boy. Strabismus surgery resulted in exophoria of 8 prism diopters (PD) in the 3-year-old boy and left esotropia of 8 PD in the 16-year-old girl.

CONCLUSIONS

Amblyopia, hypotropia, esotropia (no. 3) and exotropia (no. 5) should be verified in cases of CFC nos. 3 and 5. Ophthalmologic examination and early intervention for amblyopia may be mandatory for patients with CFC involving the orbit.

The Clinical Features of Korean Patients with Duane's Retraction Syndrome

PURPOSE

To describe the clinical features of Duane's retraction syndrome (DRS) in Korean patients.

METHODS

We retrospectively analyzed the 78 DRS cases that presented to our department between 1995 and 2004. The clinical features investigated included sex distribution, laterality, type of presentation, deviation in primary position, anomalous vertical movements, face turn, amblyopia and anisometropia.

RESULTS

There were 38 (48.7%) affected males and 40 (51.3%) females. Left eye predominance (83.3%) was observed, as was type I presentation (85.9%). Orthotropia was found to be the most common primary position in 46 cases (59.0%). Face turn in unilateral DRS was noted in 13 patients (17.1%). There were 6 cases (7.7%) with anisometropia and 4 (5.1%) with amblyopia.

CONCLUSIONS

The clinical manifestations of DRS in our study were different from those of equivalent Caucasian studies yet similar to those previously reported for Asian groups. Racial and regional differences were noted, for which further research is needed to elaborate the reasons and mechanisms.

Temporal influences on retinal correspondence: ocular motor findings in paradoxical spatial projection

BACKGROUND

Paradoxical diplopia is a condition in which objective eye position contradicts subjective localization in visual space. The term "paradoxical" is usually reserved for instances when known sensory adaptations cannot explain the contradiction. The development of this condition begins with infantile or childhood strabismus, followed by the development of a common sensory adaptation, anomalous retinal correspondence (ARC). ARC causes a reduction in the subjective angle of strabismus compared with the objective angle, and in its completed form the subjective angle decreases to zero. There is no "adaptive" mechanism that would increase the subjective angle such that it would be greater than the objective. In cases of treatment by corrective surgery, the anatomically based motor correction leads to a contradiction between eye position and binocular perception. In this event, the objective angle is less than the subjective, and the result is a paradoxical perception. We encountered a 25-year-old woman who experiences paradoxical localization on cover testing in the absence of a manifest strabismus and with no previous surgical intervention.

METHODS

Using a magnetic search coil technique, we evaluated eye movements during fixation, smooth pursuit, saccades, and during cover test conditions to determine how these eye movements correlated to the subjective perception in space.

RESULTS

Although smooth pursuit and saccades were normal, there were two elements during cover test that could explain the paradoxical projection. One was the phenomenon that during the cover test the paradoxical projection appeared only when the eye was covered for >4 s. The second was that there was a regression from the full exophoria position toward the midline while the eye was under cover that correlated with a possible paradoxical projection situation.

DISCUSSION

ARC, usually associated with a beneficial sensorimotor adaptation, can express itself as a detrimental sensorimotor manifestation. Paradoxical perception also can exist without previous surgical intervention and without the influence of prisms and instrumentation such as the synoptophore. Further studies are indicated to explore the sensorimotor feedback mechanism between eye position and spatial perception.

Association between schizophrenia with ocular misalignment and polyalanine length variation in PMX2B

The increased incidence of minor physical anomalies (MPAs) in schizophrenia is the fundamental basis for the neurodevelopmental hypothesis of schizophrenia etiology. Ocular misalignment, or strabismus, falls into the category of MPAs, but this phenotype has not been assessed in schizophrenia. This study reveals that a subtype of strabismus, constant exotropia, displays marked association with schizophrenia (P=0.00000000906). To assess the genetic mechanisms, we examined the transcription factor genes ARIX (recently identified as a causative gene for syndromic strabismus) and its paralogue, PMX2B. We identified frequent deletion/insertion polymorphisms in the 20-alanine homopolymer stretch of PMX2B, with a modest association between these functional polymorphisms and constant exotropia in schizophrenia (P=0.029). The polymorphisms were also associated with overall schizophrenia (P=0.012) and more specifically with schizophrenia manifesting strabismus (P=0.004). These results suggest a possible interaction between PMX2B and other schizophrenia-precipitating factors, increasing the risk of the combined phenotypes. This study also highlights the unique nature of the polyalanine length variations found in PMX2B. In contrast with other transcription factor genes, the variations in PMX2B show a high prevalence, with deletions being more common than insertions. Additionally, the polymorphisms are of ancient origin and stably transmitted, with mild phenotypic effects. In summary, our study lends further support to the disruption of neurodevelopment in the etiology of schizophrenia, by demonstrating the association of a specific MPA, in this case, constant exotropia with schizophrenia, along with molecular variations in a possible causative gene.

[Schizophrenia and ocular misalignment: phenotypic and genetic association analysis]

The increased incidence of minor physical anomalies (MPAs) in schizophrenia is the fundamental basis for the neurodevelopmental hypothesis of schizophrenia etiology. Ocular misalignment falls into the category of MPAs, but this phenotype has not been assessed in schizophrenia. This study reveals that constant exotropia displays marked association with schizophrenia. To assess the genetic mechanisms, we examined the transcription factor genes ARIX and its paralogue, PMX2B. We identified frequent deletion/insertion polymorphisms in the 20-alanine homopolymer stretch of PMX2B, with a modest association between these functional polymorphisms and constant exotropia in schizophrenia. The polymorphisms were also associated with overall schizophrenia and more specifically with schizophrenia manifesting strabismus. These results suggest a possible interaction between PMX2B and other schizophrenia-precipitating factors, increasing the risk of the combined phenotypes. This study also highlights the unique nature of the polyalanine length variations found in PMX2B.

The Clinical Course of Intermittent Exotropia

PURPOSE

To report the clinical course for patients with intermittent exotropia.

METHODS

The clinical records of patients diagnosed with intermittent exotropia from 1983 to 1991 who had at least 4 years of follow-up were reviewed. All patients with neurological or medical abnormalities, developmental delays, ocular disease, or having strabismus surgery during the follow-up period were excluded.

RESULTS

Of the 468 records reviewed, 73 met the inclusion criteria. Forty-four patients were female, and 29 were male. Fifty-two patients had basic intermittent exotropia, 11 patients had divergence excess intermittent exotropia, and 10 patients had convergence insufficiency intermittent exotropia. The mean age at initial visit was 20 years (range, 1 to 63 years). The mean follow-up was 10 years (range, 4 to 23 years). Four patients had amblyopia of 20/30 or worse, nine patients had a vertical deviation in the primary position, and 10 patients had undergone extraocular muscle surgery before coming to our clinic. Sixty patients received some form of treatment during follow-up. The mean stereoacuity at the initial and final visits were 59 and 70 s arc, respectively. The initial mean spherical equivalent refraction was -0.48 D and increased to -1.15 D at the end of the study. The mean exodeviation changed from 17.2 Delta at distance and 17.6 Delta at near at the initial visit to 13.7 Delta at distance and 13.5 Delta at near at the final visit. At the initial visit, 63 patients were exotropic and 10 patients were either heterophoric or orthophoric at distance, whereas, 60 patients were exotropic and 13 patients were either heterophoric or orthophoric at near. At the final visit, 37 patients were exotropic and 36 patients were either heterophoric or orthophoric at distance whereas 33 patients were exotropic and 39 were either heterophoric or orthophoric at near. One patient was esotropic at near at the last visit. Changes in the size and quality of the exodeviation, although statistically significant (p < 0.001), were not associated with any specific treatment regimen or with longer periods of follow-up. Measurements exhibited a regression toward the mean.

CONCLUSIONS

Intermittent exotropia improved for many patients quantitatively and qualitatively over time. That the improvement was unrelated to any treatment and length of follow-up suggests that the changes at least quantitatively are not associated with any physiologic process and may be due, in part, to regression toward the mean.

Convergence defects in patients with temporomandibular disorders

The aim of this study is to show the presence of a correlation between ocular convergence defects (OCD) and temporomandibular disorders (TMD) among a group of adult subjects. The group studied was made up of 48 subjects (12 males and 36 females). The average age was 35 with a range of 19-45 years of age. The subjects presented with TMD and muscular pain and/or dysfunction. Forty-eight subjects with TMD for the case study were matched by gender and age to 48 control subjects seeking routine dental care (control group). All the subjects were examined by the same orthoptist who classified the ocular convergence degree using two tests. The first test evaluated the distances (in centimeters) of the convergence near point (3-4 cm: normal; 5-7 cm: sufficient; > 7 cm: insufficient). The second test assessed the fusional convergence using a Berens prism test (> 25 diopters: normal; between 18-25: sufficient; < 18 diopters: insufficient). In the TMD group, 36 subjects (75%) showed a compromise of convergence: 13 (36%) were classified in the 5-7 degree range and 23 (48%) in the > 7 cm degree range. The Berens test showed ten subjects (28%) in the group < 18D and 26 (72%) in the group 18-25D. The control-group presented ten (21%) subjects with compromise of convergence: three classified in the group < 18D and seven in the group 18-25D. The TMD subjects presented a higher statistical percentage (p < 0.0001) of ocular convergence defects. The TMD patients also reported a strong association referred to specific signs and symptoms, i.e., limited maximal opening or myofascial pain. There were some subjective reports also of headaches and torcicollis (neck stiffness) which appeared significantly more frequently in subjects with a compromise of convergence. The study showed a much higher prevalence of ocular convergence defects in patients with head, neck, and shoulder pain.

Presbyopia complicating pre-existing strabismus

BACKGROUND

Presbyopia may affect pre-existing sensory adaptations or aggravate previously asymptomatic heterophoria. We describe the presentation, underlying problem and management of 11 patients with pre-existing strabismus or heterophoria who presented with new symptoms of double vision attributable to presbyopic change, an association not previously reported.

METHODS

Patients with new strabismic symptoms attributable to presbyopia were recruited prospectively over a 1-year period.

RESULTS

The 11 patients had had a recent decrease of accommodative amplitude that resulted in blurred vision at near with a breakdown of pre-existing heterophoria (2 patients), alteration of fixation pattern (6 patients), symptomatic alternating fixation (2 patients) or intolerance to correction owing to restrictive strabismus (1 patient).

INTERPRETATION

At the onset of presbyopia, symptoms may be varied and subtle. Ophthalmologists and orthoptists should carefully determine the exact nature of the symptoms. Any pre-existing fixation pattern should then be established from the history, old photographs or suppression characteristics. Refractive or surgical management should be aimed at returning the patient to his or her long-standing sensory adaptation. Other important issues, such as incomplete correction of hypermetropia by refractive surgery and problems using bifocals with vertical restrictive strabismus, should be noted.

Divergent strabismus fixus--a case report

Strabismus fixus is a rare condition and usually is of convergent type in which one or both eyes are anchored in a position of extreme adduction. Convergent type strabismus fixus is considered to be a congenital disorder and a part of congenital extraocular muscle fibrosis syndrome. Villasecca and Martinez described an acquired type of strabismus fixus. Hayashi et al reported that progressive esotropia could develop into the acquired type of convergent strabismus fixus. There are very few reports of divergent strabismus fixus in the literature. It may or may not be accompanied by ptosis or generalized extraocular muscle fibrosis. In our report, a case of divergent type strabismus fixus is described and discussed.

When the patient says no. Management of exotropia with hemianopic visual field defects

BACKGROUND

A homonymous hemianopia can be compensated for by an exotropia in the direction of the visual field defect.

CASE REPORTS (AND LITERATURE REVIEW)

Two young males with visual field defects and exotropia are reported. Both refused surgery when they were advised of the risk of reduction of their binocular visual field with the alignment of their eyes.

CONCLUSION

Mapping of the binocular visual field is mandatory in patients with exotropia and neurological involvement to search for this rare combination which could produce a disappointing surgical outcome.

[Progression of subjective refraction after artificial divergence surgery and its relation to a possible myopic spasm]

PURPOSE

To study the effect on subjective refraction of artificial divergence surgery in congenital nystagmus with blocking convergence.

METHODS

Retrospective study on 139 cases, with a study of visual acuity and optical correction with habitual glasses 1-5 years after operation, according to age and ocular alignment (orthophoria or exophoria).

RESULTS

Increased myopia with glasses of approximatively 1 diopter, but likely to be due to eye growth in this young population (mean age, 14 years). This myopic shift is higher in the exophoric population, but there is a tendency to prescribe a stronger correction to help control the phoria. A few rare cases of true myopic spasm were noted.

CONCLUSION

After artificial divergence surgery, true cases of increased myopia were rare. Tonic vergence is stronger than accommodative vergence.

Objective improvement from base-in prisms for reading discomfort associated with mini-convergence insufficiency type exophoria in school children

PURPOSE

To determine whether base-in prism glasses could diminish asthenopia, and improve reading abilities (speed, accuracy and comprehension).

METHODS

All patients aged 8-18 years, from one practice, were examined and considered prospectively over a six month period. Ten percent (72) of these 703 patients met initial criteria of an exodeviation greater at near than distance and reading discomfort. At initial examination these 72 were asked to read orally, with and without base-in prisms. If the senior examiner noted they read faster and with fewer mistakes, and the patient reported increased reading comfort, then reading (only) glasses with 2 to 3 diopters base-in prism OU were prescribed. Of the 72, 33 were so treated. After 3 weeks they were given the Gray Oral Reading Test (GORT-3). This test has two equal parts which were administered one with, and one without, prisms. A subjective questionnaire was also administered.

RESULTS

The overall mean improvement in reading speed, accuracy and comprehension on the GORT- 3 with base-in prisms, was from the 34th to the 66th percentile. The improvements in reading were "statistically significant" at p<.001. Patients also reported subjective improvement in asthenopic symptoms and headaches.

CONCLUSION

Base-in prism glasses improve subjective reading comfort and abilities (speed, accuracy and comprehension) in these patients.

Optometric function in visually sensitive migraine before and after treatment with tinted spectacles

Optometrists frequently encounter patients with migraine and patients and practitioners sometimes suspect that visual stimuli or visual anomalies trigger headaches. There is a lack of evidence-based research on the issue, however. Some patients with migraine may be hypersensitive to visual stimuli, and it has been suggested that individually prescribed coloured filters might be an effective treatment to reduce symptoms from such stimuli. A recent randomised controlled trial showed such a treatment to be effective and the present paper reports on the optometric characteristics of the patients in this study. Twenty-one patients with neurologically diagnosed migraine were compared with 11 controls. No significant differences were found between the two groups with respect to refractive error, ocular pathology, colour vision, contrast sensitivity, accommodative function, strabismus and hyperphoria. The migraine group tended to be a little more exophoric, but by most criteria they were able to compensate for their exophoria as well as the control group. The migraine group were more prone to pattern glare than the controls (p = 0.004). The effects of precision tinted and control tinted lenses were investigated. The only variable to show a consistent and marked improvement with tinted lenses was pattern glare. The most likely mechanism for the benefit from individually prescribed coloured filters in migraine is the alleviation of cortical hyperexcitability (Wilkins et al. 1994) and associated pattern glare.

Intermittent exotropia

The ideal approach to the management of intermittent exotropia remains unclear. Well designed, prospective studies are limited. Furthermore, the criteria for success vary among health care professionals. Long-term outcomes of surgical intervention are not known, and the role of non-surgical treatment modalities has not been agreed upon. A multicenter study comparing surgical and nonsurgical treatment method has been proposed. If carried out, a study of this nature would greatly benefit many individuals affected by this common condition. Until then, intermittent exotropia will continue to be one of the most difficult problems to treat.