Strabismus in infancy

Infantile nystagmus syndrome: An observational, retrospective, multicenter study

SIGNIFICANCE

This multicenter study assessed clinical and psychological aspects of infantile nystagmus syndrome (INS) focusing on its management and nonsurgical treatment.

PURPOSE

This study aimed to assess clinical features, management, relationship life, and psychological impact in a group of patients with nystagmus onset in pediatric age.

METHODS

This observational study included patients diagnosed with INS referred to two Italian centers from January 1, 2017, to December 31, 2020. Ophthalmologic and orthoptic features and impact of visual function on quality of life, according to nystagmus-specific nystagmus quality of life questionnaire, were analyzed within the overall sample and in any of INS subgroups.

RESULTS

Forty-three patients were included; 65.1% of them had idiopathic INS (IINS), and 34.9% had INS associated with ocular diseases (INSOD). The median age was 15.4 years (interquartile range [IQR], 10.4 to 17.3 years), significantly different between groups (median, 15.8 years among those with IINS vs. 12.3 years among those with INSOD; p<0.001). In the INSOD subgroup, strabismus was significantly more prevalent (93.3 vs. 57.1%; p=0.017). Binocular distance best-corrected visual acuity in primary position was significantly higher in the IINS subsample (p<0.001). Such behavior was further confirmed at anomalous head position evaluation (p<0.001). At near best-corrected visual acuity assessment, differences between groups were more remarkable in primary position (p<0.001) than in anomalous head position. Contrast sensitivity showed significantly higher values in the IINS subgroup (p<0.001). The nystagmus quality of life questionnaire disclosed a significantly lower score in IINS as compared with INSOD (median total score, 90.5 [IQR, 84 to 97] vs. 94 [IQR, 83.0 to 96.5]; p<0.001).

CONCLUSIONS

The IINS group showed significantly better ophthalmologic and orthoptic outcomes than the INSOD group. The psychological and quality-of-life impact was instead significantly greater in the IINS group. To the best of our knowledge, this is the first multicenter study investigating the clinical features of IIN and comparing the two main subgroups, IINS and INSOD.

Do infants with isolated congenital sixth nerve palsy require comprehensive work-up? A retrospective cohort and review of the literature

PURPOSE

The purpose of this study is to describe a case series of infants with isolated congenital sixth nerve palsy (ICSNP) and suggest a management algorithm based on our experience and a review of the literature.

METHODS

A retrospective cohort design was used. The clinical database of a single tertiary medical center was reviewed to identify all patients diagnosed with ICSNP from January 2020 to November 2022. Data were collected as follows: demographic parameters, age at initial presentation, presenting symptoms and signs, findings on ophthalmic and neurologic examinations, findings on follow-up, and outcome.

RESULTS

Six patients were included. All were born at term. The average gestational weight was 3675.7 ± 262.7 g. Three mothers had gestational diabetes. Five deliveries necessitated labor induction either by oxytocin (n = 4) or by membrane stripping followed by oxytocin (n = 1). One had also gone a forceps assisted delivery. Symptoms were noticed in all newborns by their parents within the first week of life. Ophthalmological and neurological examinations were otherwise unremarkable apart of one patient with a head turn to the side of the involved eye. Four patients underwent brain imaging that were unremarkable. All abduction deficits resolved by 1 to 3 months of age. Follow up examinations were unremarkable (mean follow up 14.3 ± 5.0 months, range 4-23).

CONCLUSIONS

This case series, together with previous reports, support ICSNP's benign nature. We suggest an initial basic work-up that solely includes ophthalmological and neurological examinations which will be elaborated in case of any additional pathologic findings or if ICSNP does not fully resolve by 3 months.

Clinical profile of childhood exotropia in a tertiary eye care center in North India

PURPOSE

To identify different types of exotropia in children less than 16 years and their clinical presentation. The secondary objective is to identify the age of onset, age of presentation, birth history, and ocular and systemic associations as well as to evaluate their motor and sensory status.

METHODS

This hospital-based descriptive observational study was conducted from September 2018 to December 2019. Patients with a clinical diagnosis of exotropia of age less than 16 years, and exotropia of ≥ 10 PD were included in the study. Data were collected using a structured proforma. All statistical calculations were performed using Microsoft Excel Office version 2016 and R version 4.0.2.

RESULTS

Two hundred eighty-six (286) consecutive children with exotropia were analyzed. Intermittent exotropia (72%) was the most common form of exotropia, followed by exotropia with a neurological association (11%), infantile (8%), sensory (6%), restrictive (2%), and paralytic (1%) types. Exotropia with neurological association had a significantly earlier age of presentation (median = 42months) as compared to other types (P = 0.039).

CONCLUSION

We recorded a huge amount of cases of exotropia associated with neurological abnormalities and this group of patients had significantly more number of preterm and low birth weight children. This study has its limitations as it is not a population-based study and prevalence rates could not be calculated.

Screening, Diagnosis, and Treatment of Pediatric Ocular Diseases

Vision is an important aspect of a child's quality of life and intellectual, social, and emotional development. Disruptions to vision during infancy and early childhood can cause lifelong vision impairment or blindness. However, early identification and treatment of eye disease can prevent loss of sight and its consequent long-term effects. Therefore, screening guidelines exist to guide physicians in detecting the most common threats to sight in the different stages of infancy and childhood. This review describes common causes of pediatric vision impairment, the recommended screening guidelines for diagnosing them, and current treatment modalities.

Characteristics and long-term surgical outcomes of horizontal strabismus

PURPOSE

Our aim was to report the characteristics and long-term surgical outcomes of three subgroups of horizontal strabismus in a single institution (divided by strabismus subtype) in a developing country and look into pre-operative factors predictive of surgical success.

METHODS

Two hundred and forty-four complete charts of patients, divided into 152 esotropes (ET) and 92 exotropes (XT) who had undergone horizontal strabismus surgeries, were retrospectively reviewed. Charts of patients with muscle palsy, Duane syndrome and consecutive strabismus were excluded; 172 patients were included divided into partially accommodative ET, congenital ET and intermittent XT. Surgical success was defined as a post-operative angle deviation of 12 prism diopters or less.

RESULTS

The mean follow-up period of all patients was 31.64 ± 23.12 months. The subgroups were divided into partially accommodative ET (60 patients), congenital ET (60 patients), and intermittent XT (52 patients). Esotropes (both partially accommodative and congenital) presented earlier (p < 0.001). Also, partially accommodative ET had a significantly higher spherical equivalent (SE) compared to congenital ET patients, who had a higher SE than intermittent XT (p < 0.001). Congenital ET patients had a significantly larger angle of deviation (for both far and near) than both partially accommodative ET and intermittent XT patients (p < 0.001). The overall success rate was 72.67% for the whole group with no significant differences among subgroups. Success rate of partially accommodative ET surgery was 78.33% compared to that of congenital ET at 66.67% and intermittent XT at 73.07%. Significant post-operative improvement in sensory fusion was observed mainly for patients with partially accommodative esotropia and intermittent exotropia.

CONCLUSION

Our results showed that esotropes (both partially accommodative and congenital) presented earlier, with a higher spherical equivalent in the partially accommodative ET subgroup, while the congenital ET subgroup had the largest angle of deviation for both distance and near. The overall surgical success rate for horizontal strabismus surgery was 72.67% with the 3 subgroups having similar success rates. A younger age at presentation and absence of amblyopia were positively correlated with surgical success in the partially accommodative esotropia group.

Ophthalmological findings in children with non-syndromic craniosynostosis: preoperatively and postoperatively up to 12 months after surgery

Aims

Craniosynostosis is a congenital condition characterised by premature fusion of one or more cranial sutures. The aim of this study was to analyse ophthalmic function before and after cranial surgery, in children with various types of non-syndromic craniosynostosis.

Methods

Children referred to Uppsala University Hospital for surgery of non-syndromic craniosynostosis were examined preoperatively. Visual acuity was measured with Preferential Looking tests or observation of fixation and following. Strabismus and eye motility were noted. Refraction was measured in cycloplegia and funduscopy was performed. Follow-up examinations were performed 6–12 months postoperatively at the children’s local hospitals.

Results

One hundred twenty-two children with mean age 6.2 months were examined preoperatively. Refractive values were similar between the different subtypes of craniosynostosis, except for astigmatism anisometropia which was more common in unicoronal craniosynostosis. Strabismus was found in seven children, of which four had unicoronal craniosynostosis.

Postoperatively, 113 children were examined, at mean age 15.9 months. The refractive values decreased, except for astigmatism and anisometropia in unicoronal craniosynostosis. Strabismus remained in unicoronal craniosynostosis. Two new cases with strabismus developed in unicoronal craniosynostosis and one in metopic, all operated with fronto-orbital techniques. No child had disc oedema or pale discs preoperatively or postoperatively.

Conclusion

Ophthalmic dysfunctions were not frequent in children with sagittal craniosynostosis and preoperative ophthalmological evaluation may not be imperative. Children with unicoronal craniosynostosis had the highest prevalence of strabismus and anisometropia. Fronto-orbital techniques used to address skull deformity may be related to a higher prevalence of strabismus postoperatively.

Different surgical outcomes in infantile exotropia according to onset time

PURPOSE

To determine whether age of onset influences surgical outcomes in infantile exotropia.

METHODS

The medical records of patients at our tertiary care facility who underwent bilateral lateral rectus recession for infantile exotropia during the period 2004-2013 were reviewed retrospectively. Patients were grouped by onset age: 6 months or earlier (E6 group) or later than 6 months (L6 group). Motor outcomes, near stereoacuity, and distance fusional status in both groups were evaluated.

RESULTS

A total of 134 patients were included: 35 in the E6 group and 99 in the L6 group. At a mean follow-up of 4.6 years, recurrence occurred in 12 (34%) of the E6 group and 38 (38%) of the L6 group (P = 0.496). Overcorrection occurred in 3 (9%) of the E6 group and in 4 (4%) of the L6 group (P = 0.341). In the analysis of 109 patients eligible for sensory examinations, the E6 group demonstrated a higher proportion of patients with reduced stereoacuity of 80 arcsec or worse (54% vs 25% [P = 0.007]) and suppression (46% vs 12% [P < 0.001]) compared with those in the L6 group. In logistic regression analyses, onset of ≤6 months was significantly associated with reduced stereoacuity (OR = 6.42) and suppression (OR = 37.67) but not with recurrence or overcorrection.

CONCLUSIONS

In our study cohort, age of onset ≤6 months was associated with worse sensory prognosis for children with infantile exotropia but not with a difference in motor outcomes.

Age at Craniosynostosis Surgery and Its Impact on Ophthalmologic Diagnoses: A Single-Center Retrospective Review

BACKGROUND

Ocular abnormalities in craniosynostosis are a persistent concern for patients and providers, and some surgeons feel that early surgical intervention for synostosis alleviates the progression of ophthalmologic abnormalities. In contradistinction, the authors hypothesize that operating early will have no bearing on postoperative ophthalmologic outcomes.

METHODS

Single-suture craniosynostosis patients who underwent surgical correction between 1989 and 2015 were reviewed. Patients with multisuture craniosynostosis, syndromic diagnoses, no preoperative ophthalmology evaluation, and less than 2 years of follow-up were excluded. Logistic regression was used to determine odds of preoperative and postoperative ophthalmologic abnormalities by age, while controlling for patient-level covariates.

RESULTS

One hundred seventy-two patients met inclusion criteria. The median age at surgery was 10 months (interquartile range, 7 to 12.9 months). Increasing age at the time of surgery was associated with increased odds of preoperative ophthalmologic diagnoses (OR, 1.06; p = 0.037) but not postoperative diagnoses (OR, 1.00; p = 0.91). Increasing age at surgery was also not associated with increased odds of ophthalmologic diagnoses, regardless of timing (OR, 1.04; p = 0.08). Patients with coronal synostosis (OR, 3.94; p = 0.036) had significantly higher odds of preoperative ophthalmologic diagnoses. Patients with metopic (OR, 5.60; p < 0.001) and coronal (OR, 7.13; p < 0.001) synostosis had significantly higher odds of postoperative ophthalmologic diagnoses.

CONCLUSIONS

After reviewing an expansive cohort, associations of both overall and postoperative ophthalmologic diagnoses with age at surgery were not found. The authors' findings thus run counter to the theory that early surgical intervention lessens the likelihood of postoperative ophthalmologic diagnoses and improves ophthalmologic outcomes.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, III.

Virtual Interactive Environment for Low-Cost Treatment of Mechanical Strabismus and Amblyopia

This study presents a technique that uses an interactive virtual environment for the rehabilitation treatment of patients with mechanical strabismus and/or amblyopia who have lost eye movement. The relevant part of this treatment is the act of forcing the two eyes to cooperate with each other by increasing the level of adaptation of the brain and allowing the weak eye to see again. Accordingly, the game enables both eyes to work together, providing the patient with better visual comfort and life quality. In addition, the virtual environment is attractive and has the ability to overcome specific challenges with real-time feedback, coinciding with ideal approaches for use in ocular rehabilitation. The entire game was developed with free software and the 3D environment, which is made from low-cost virtual reality glasses, as well as Google Cardboard which uses a smartphone for the display of the game. The method presented was tested in 41 male and female patients, aged 8 to 39 years, and resulted in the success of 40 patients. The method proved to be feasible and accessible as a tool for the treatment of amblyopia and strabismus. The project was registered in the Brazil platform and approved by the ethics committee of the State University of Piaui—UESPI, with the CAAE identification code: 37802114.8.0000.5209.

Long-term Surgical Outcomes for Large-angle Infantile Esotropia

PURPOSE

To report the long-term surgical outcomes for a cohort of children with large-angle infantile esotropia.

DESIGN

Multicenter, nonrandomized clinical study.

METHODS

Setting: Two tertiary-care pediatric hospitals.

STUDY POPULATION

Children with large-angle (≥55 prism diopters) infantile esotropia.

INTERVENTION

Surgical treatment of infantile esotropia.

MAIN OUTCOME MEASURE

Success rate at final follow-up (postoperative deviation ≤ 10 prism diopters and no need for retreatment).

RESULTS

A total of 88 patients with large-angle infantile esotropia were treated during the 13-year study period. Treatment was bilateral medial rectus muscle recessions in 70 patients, botulinum toxin-augmented surgery in 15 patients, and 3-muscle surgery in 3 patients. After a mean follow-up of 40 months, 20 patients (23%) had a successful outcome compared to 68 treatment failures (77%). Of the 68 treatment failures, 59 had residual or recurrent esotropia and 9 had sequential exotropia. On multivariate logistic regression, treatment modality was the only factor significantly associated with a successful outcome. Specifically, patients treated with botulinum toxin-augmented surgery were more likely to have a successful outcome compared to patients treated with bilateral medial rectus muscle recessions. For the 26 patients (30%) who underwent retreatment, the mean number of procedures was 2.1, and 7 (27%) had a deviation of ≤10 prism diopters at final follow-up.

CONCLUSIONS

The overall success rate for treatment of large-angle infantile esotropia was poor in this cohort, with most failures owing to recurrent or residual esotropia. Botulinum toxin-augmented surgery was associated with a higher success rate at final follow-up.

Spontaneous consecutive esotropia

PURPOSE

Although less frequent than consecutive exotropia, consecutive esotropia is a well-known type of strabismus when it follows the surgical correction of an exotropia. Spontaneous conversion from initial constant, large-angle exotropia beyond the age of 3 months to esotropia or orthophoria, however, is not common. We describe a series of infants who presented a spontaneous evolution from a large-angle infantile exotropia to either an orthophoria or a spontaneously consecutive esotropia.

METHODS

Cases of infants examined in the pediatric neuro-ophthalmology clinic of a tertiary ophthalmology department between 2009 and 2015, and having presented an early large-angle exotropia that spontaneously converted into an esotropia or orthophoria-i.e., without any previous surgery or botulinum toxin injection-were studied.

RESULTS

Ten cases (6 M:4 F) were followed up. Median age at first exotropia assessment was 3.88 months (SD = 6.35). Median age at spontaneous conversion to esotropia or orthophoria was 7.23 months (SD = 14.73). Six patients suffered from severe neurologic or metabolic diseases, three had neonatal respiratory distress syndrome, and one was healthy.

CONCLUSION

Spontaneous conversion from initial large-angle exotropia to esotropia or orthophoria can be encountered. The cerebral maturation of visual structures probably accounts for this uncommon strabismus sequence.

Early versus late surgery for infantile exotropia

PURPOSE

To determine whether age at surgery influences postoperative outcome in infantile exotropia.

METHODS

This longitudinal, retrospective study included children who underwent bilateral lateral rectus recession between 2004 and 2012 for an exotropia with onset by 12 months of age. Surgical outcomes were considered failures if recurrence with exodeviation of >8^Δ or overcorrection with esodeviation of >5^Δ developed during postoperative period. Univariate and multivariate analyses were conducted to compare the association of age at surgery with development of recurrence and overcorrection.

RESULTS

A total of 93 children were included. Mean age at surgery was 3.2 years. At a mean follow-up of 3.6 years, 19 of 93 patients (20.4%) experienced recurrence and 3 (3.2%) had overcorrection. In the multivariate analyses, increased age at surgery was associated with higher risk for recurrence (OR = 1.031 per 1-month; 95% CI, 1.003-1.060). In subgroup analyses, the association was significant only in the constant exotropia group (OR = 1.410; 95% CI, 1.037-1.917) and not in the intermittent exotropia group (OR = 0.995; 95% CI, 0.938-1.056). In both groups, overcorrection was not associated with any factors, including age at surgery.

CONCLUSIONS

Older age at surgery was associated with risk of recurrence in infantile exotropia with constant deviation, but it was not correlated with surgical outcomes for patients with intermittent exotropia in this study.

Neural mechanisms of oculomotor abnormalities in the infantile strabismus syndrome

Infantile strabismus is characterized by numerous visual and oculomotor abnormalities. Recently nonhuman primate models of infantile strabismus have been established, with characteristics that closely match those observed in human patients. This has made it possible to study the neural basis for visual and oculomotor symptoms in infantile strabismus. In this review, we consider the available evidence for neural abnormalities in structures related to oculomotor pathways ranging from visual cortex to oculomotor nuclei. These studies provide compelling evidence that a disturbance of binocular vision during a sensitive period early in life, whatever the cause, results in a cascade of abnormalities through numerous brain areas involved in visual functions and eye movements.

Eye pathologies in neonates

In the United Kingdom, newborn assessment incorporates a screening eye examination for any structural abnormalities, observation of neonate's visual behaviour and direct ophthalmoscopy examination looking for red reflex. Early identification and immediate management of eye related pathologies should commence soon after birth as early diagnosis and prompt intervention may have significant impact on the prognosis for many potentially blinding but treatable disorders such as congenital cataracts and retinoblastoma. If left undetected and untreated, such problems may potentially lead to irreversible damage to the vision which persists into adulthood resulting in lack of self-confidence together with difficulties in educational attainment and job opportunities.

Essential Infantile Esotropia: Postoperative Sensory Outcomes of Strabismus Surgery

BACKGROUND

The optimum age for Essential Infantile Esotropia surgery is a controversial subject. Sensory status was evaluated in patients who underwent surgery at different ages in a retrospective study. The setting of the study is the ophthalmology department of a teaching hospital.

METHODS

Different clinical characters were analyzed pre- and postoperatively; nine different surgeries were performed. A total of 188 patients presented valid postoperative sensorial data, divided in two groups: surgery at ≤2 years (n=69) or >2 years (n=119). Sensory status was dichotomized in binocular single vision (BSV) and exclusion. Univariate differences were assessed with the chi-square test (or Fisher exact test). To identify the independent role of factors associated with the sensory status, all variables showing in univariate analyses a significant association (p<0.05) with the outcome variable were entered into a multivariate logistic regression model. All statistical tests were two-sided.

RESULTS

Multivariate analysis confirmed that children operated >2 years were 0.4 times less likely to obtain BSV compared with children operated at ≤2 years (AOR. 0.38, 95% C.I. 0.17-0.89, p=0.025). Patients operated on by OO MR rec.+ OO LR res. + OO IO rec.-ap. (intervention type 6) were about 11 times more likely to have BSV than those by OO rec.MR + unilateral res. LR (operation type 2); AOR.: 10.67, 95% C.I.: 1.34 - 85.29, p=0.026). Twenty-nine patients (12.1%) operated at ≤2 years of age underwent a reoperation, compared to 33 (8.6%) who underwent surgery after two years (p>0.05).

CONCLUSIONS

Our findings suggest to perform EIE surgery between age 1 and 2 and, when indicated, to prefer a six-muscle approach in order to achieve a better sensory function.

Adaptability of the Immature Ocular Motor Control System: Unilateral IGF-1 Medial Rectus Treatment

PURPOSE

Unilateral treatment with sustained release IGF-1 to one medial rectus muscle in infant monkeys was performed to test the hypothesis that strabismus would develop as a result of changes in extraocular muscles during the critical period of development of binocularity.

METHODS

Sustained release IGF-1 pellets were implanted unilaterally on one medial rectus muscle in normal infant monkeys during the first 2 weeks of life. Eye position was monitored using standard photographic methods. After 3 months of treatment, myofiber and neuromuscular size, myosin composition, and innervation density were quantified in all rectus muscles and compared to those in age-matched controls.

RESULTS

Sustained unilateral IGF-1 treatments resulted in strabismus for all treated subjects; 3 of the 4 subjects had a clinically significant strabismus of more than 10°. Both the treated medial rectus and the untreated ipsilateral antagonist lateral rectus muscles had significantly larger myofibers. No adaptation in myofiber size occurred in the contralateral functionally yoked lateral rectus or in myosin composition, neuromuscular junction size, or nerve density.

CONCLUSIONS

Sustained unilateral IGF-1 treatment to extraocular muscles during the sensitive period of development of orthotropic eye alignment and binocularity was sufficient to disturb ocular motor development, resulting in strabismus in infant monkeys. This could be due to altering fusion of gaze during the early sensitive period. Serial measurements of eye alignment suggested the IGF-1-treated infants received insufficient coordinated binocular experience, preventing the establishment of normal eye alignment. Our results uniquely suggest that abnormal signaling by the extraocular muscles may be a cause of strabismus.

Eye disorders in newborn infants (excluding retinopathy of prematurity)

A screening eye examination is an essential part of the newborn assessment. The detection of many ocular disorders in newborn infants can be achieved through careful observation of the infant's visual behaviour and the use of a direct ophthalmoscope to assess the ocular structures and check the red reflex. Early diagnosis and subspecialty referral can have a critical impact on the prognosis for many ocular conditions, including potentially blinding but treatable conditions such as congenital cataracts, life-threatening malignancies such as retinoblastoma and harbingers of disease elsewhere such as sporadic aniridia and its association with the development of Wilms tumour.

Changes in angle of optic nerve and angle of ocular orbit with increasing age in Japanese children

Purpose

To study changes in the opening angle of the optic nerve and the angle of the ocular orbit with increasing age in normal Japanese children.

Methods

We studied 147 normal children (aged 6 months to 18 years) who had undergone CT as a diagnostic procedure. Measurements were performed on axial CT images that included the entire optic nerve of both eyes. The opening angle of the optic nerve was defined as the angle formed by the intersection of a line running through the left optic nerve and a vertical line passing through the centre of the nose. The opening angle of the orbit was defined as the angle formed by the intersection of a line running tangentially along the deep lateral wall of the left orbit and a vertical line passing through the centre of the nose. The relationship between age and these opening angles was analysed by regression analysis.

Results

The correlation between age and opening angle of the optic nerve was not significant. In contrast, the opening angle of the orbit decreased relatively rapidly until about 2–3 years of age, and then it stabilised. The decrease in the opening angle of the orbit with increasing age was significant (p<0.001). The relationship between these two parameters was best fitted by a logarithmic regression curve.

Conclusions

Because the opening angle of the orbit decreased significantly with increasing age, this factor must be considered when diagnosing and treating strabismus in children.

Essential infantile esotropia: postoperative motor outcomes and inferential analysis of strabismus surgery

BACKGROUND

The aim of this retrospective study is a long-term evaluation of postoperative motor outcomes and the inferential analysis of strabismus surgery in infant eyes with essential infantile esotropia.

METHODS

576 patients were compatible with the criteria: confirmed EIE diagnosis, angle ≥ 30 pD, absence of associated ocular anomalies, onset by 6 months of age, absence of hyperopia > 3 Diopters, operation before age 4. Preoperative deviation classes (30-40 pD, 41-59 pD, ≥ 60 pD) were established, different types of surgery were performed. Follow-up was conducted for 5 years after surgery. Longitudinal data were analyzed using general linear mixed models stratified according to the class of pre-operative deviation. A random intercept and a random slope with time (in months) was assumed with an unstructured within subject correlation structure for repeated measurements.

RESULTS

In patients with preoperative angle ≤ 40 pD, a significant interaction effect for intervention by time (F5,155.9 = 3.56, p = 0.004) and a significant intervention effect (F5,226.1 = 6.41, p < 0.001) on residual deviation were observed; only the intervention 5 showed a residual deviation inside the limits of a partial success. In Class 41-59, a significant interaction effect for intervention by time (F4,166.7 = 5.16, p = 0.001), intervention (F4,178.1 = 2.48, p = 0.046) and time (F1,174.6 = 9.99, p = 0.002) on residual deviation were observed; intervention 7 had the highest degree of stability showing an outcome within the range of a partial success. In Class ≥ 60 pD no significant effect for intervention (F4,213.9 = 0.74, p = 0.567), time (F1,169.5 = 0.33, p = 0.569) or intervention by time (F4,160.9 = 1.08, p = 0.368) on residual deviation was observed; intervention 3,6 and 7 resulted in a residual deviation within the range of a partial success.

CONCLUSIONS

We suggest, where possible, a two-horizontal muscles approach in small angle EIE, while a multiple muscles surgery in large angle EIE.

Why do only some hyperopes become strabismic?

Children with hyperopia greater than +3.5 diopters (D) are at increased risk for developing refractive esotropia. However, only approximately 20% of these hyperopes develop strabismus. This review provides a systematic theoretical analysis of the accommodation and vergence oculomotor systems with a view to understanding factors that could either protect a hyperopic individual or precipitate a strabismus. The goal is to consider factors that may predict refractive esotropia in an individual and therefore help identify the subset of hyperopes who are at the highest risk for this strabismus, warranting the most consideration in a preventive effort.

Bilateral changes in foveal structure in individuals with amblyopia

PURPOSE

To examine foveal structure in amblyopia using spectral-domain optical coherence tomography (SD-OCT).

DESIGN

Prospective, cross-sectional study.

PARTICIPANTS AND CONTROLS

Two subject groups were recruited to the study: 85 amblyopes (34 adults, 51 children) and 110 visually normal controls (44 adults, 66 children).

METHODS

A detailed eye examination, including an SD-OCT scan, was performed in all participants. A total of 390 eyes of 195 subjects were imaged using a 3-dimensional (3D) macula scan covering a nominal 6 × 6-mm area with a resolution of 256 × 256 (65,536 axial scans). Data from the B-scans bisecting the fovea both horizontally and vertically were fitted with a mathematical model of the fovea to determine a range of foveal parameters.

MAIN OUTCOME MEASURES

Foveal thickness, foveal pit depth, and foveal pit slope.

RESULTS

Bilateral differences between the eyes of amblyopes compared with visually normal controls were found. The difference between foveal structure in amblyopic participants relative to structure in subjects with normal vision persisted even when variables such as age, ethnicity, axial length, and sex were taken into account. Amblyopes showed increased foveal thickness (+8.31 μm; P = 0.006) and a reduction in pit depth in the horizontal meridian (-10.06 μm; P = 0.005) but not in the vertical meridian (P = 0.082) when compared with subjects with normal vision. Foveal pit slopes were found to be approximately 1 degree flatter in the nasal (P = 0.033) and temporal (P = 0.014) meridians in amblyopes, but differences between amblyopes and controls in the superior (P = 0.061) and inferior (P = 0.087) meridians did not reach statistical significance. No statistically significant interocular differences were found in the foveal structure between amblyopic and fellow eyes.

CONCLUSIONS

Differences were found in the foveal structure in both eyes of amblyopes compared with subjects with normal vision. These differences consisted of increased foveal thickness, reduced pit depth when measured along the horizontal meridian, and flattening of the nasal and temporal sides of the foveal pit.

Bell's phenomenon during screening examination for retinopathy of prematurity

PURPOSE

Bell's phenomenon (BP), which may disturb screening examinations for retinopathy of prematurity (ROP), is known to present infrequently in premature babies. Stress associated with the examinations can influence expression of BP. The authors of the present study evaluated BP during examinations for ROP.

METHODS

The present study included 102 eyes of 51 premature babies. Expression of BP was assessed at 3 steps of the examination in the following order: after insertion of a speculum, after illumination of an indirect ophthalmoscope and after scleral depression. The relationship between the expression of BP and the gestational age at the examination was analyzed in each step of the examination.

RESULTS

The frequency of BP after the speculum insertion and the illumination was 77% to 92% in infants 32 weeks of age or younger, and decreased significantly to 16% to 57% in infants 42 weeks of age or older (p < 0.005). BP after the scleral depression had no significant association with the gestational age. Frequency of BP increased significantly as the steps of the examination proceeded (p < 0.01).

CONCLUSIONS

BP was frequent in premature infants during ROP examination in spite of neurological immaturity. The examiner should take BP into consideration, which frequently occurs in younger infants.

Optic disc area and retinal area in amblyopia

PURPOSE

To compare retinal area to optic disc rim area ratios of hyperopic normal, strabismic eyes with equal acuity, amblyopic, and fellow eyes.

METHODS

Neuroretinal rim areas of 293 amblyopic and fellow eyes, and 77 non-amblyopic hyperopic right eyes, and 84 non-amblyopic strabismic right eyes were measured by magnification corrected retinal photography and planimetry. Retinal area estimates were based on axial lengths.

INCLUSION CRITERIA

All subjects had bilateral hyperopia. Patients with glaucoma or known optic nerve atrophy were excluded. The normal and strabismic groups had equal visual acuity in each eye better than 20/40. The amblyopic group had acuity worse than 20/40 in one eye uncorrectable with lenses and without gross anatomic defects.

RESULTS

The amblyopic group included 137 with strabismus and 89 with anisometropia exceeding 1.5 diopters. There were highly significant differences between the ratio of retinal area to optic disc rim area of the amblyopic and of normal eyes (unpaired t-test, p = 8.6 x 10(-6)), the amblyopic and strabismic right eyes (unpaired t-test, p = 4.22 x 10(-8)) as well between the fellow and amblyopic eyes (paired t-test, p = 2.13 x 10(-5)). The difference between the normal and strabismic eyes without amblyopia was not significant (p = 0.82). There was a 20 percent increase in the retinal receptor areas of hyperopic amblyopic eyes as compared to hyperopic eyes without amblyopia despite reduced retinal areas in the amblyopic eyes. Dysplastic and/or asymmetric optic discs were present in 163 of 293 (56 percent) amblyopic patients, 47 of 84 (56 percent) strabismic, and 10 of 77 (13 percent) normal patients.

CONCLUSIONS

The increase in the receptor area may be an explanation for diminished acuity and impaired visual function in amblyopic eyes.

Timing of surgery for infantile esotropia in humans: effects on cortical motion visual evoked responses

PURPOSE

Infantile esotropia is associated with maldevelopment of cortical visual motion processing, manifested as directional asymmetry of motion visual evoked potentials (mVEPs). The purpose of this study was to determine whether early surgery at or before age 11 months could promote the development of cortical visual motion processing in human infants, compared with standard surgery at age 11 to 18 months.

METHODS

Sixteen children with a constant, infantile esotropia >or=30 prism diopters and onset before age 6 months were recruited prospectively. Eight of them underwent early surgery at

RESULTS

The mean asymmetry index and interocular phase difference in the early surgery group were comparable to that in age-matched control subjects, and they were significantly lower than those in the standard surgery group.

CONCLUSIONS

Early surgery for infantile esotropia promotes the development of cortical visual motion processing, whereas standard surgery is associated with abnormal mVEPs. The results provide additional evidence that early strabismus repair is beneficial for cortical development in human infants.

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Key Words Collapse

MESH Headings

• Evoked Potentials, Visual/physiology
• Eye Movements/physiology
• Female
• Humans
• Infant
• Male
• Motion Perception/physiology
• Nystagmus, Congenital/physiopathology
• Nystagmus, Congenital/surgery
• Oculomotor Muscles/surgery
• Prospective Studies
• Tendons/surgery
• Time Factors
• Visual Cortex/physiology

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Grants

• 67104 CIHR

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Affiliation(s)

Christina Gerth Department of Ophthalmology and Vision Science, The Hospital for Sick Children and University of Toronto, Toronto, Ontario, Canada
Giuseppe Mirabella
Xiaoqing Li
Thomas Wright
Carol Westall
Linda Colpa
Agnes M F Wong

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Variables associated with the incidence of infantile esotropia

PURPOSE

Infantile esotropia (manifesting from birth to 6 months) is a common type of strabismus, accounting for 28% to 54% of all esotropias and with an incidence of 1% of the general population. The purpose of this cohort study was to evaluate risk factors for infantile esotropia. Such information may aid in early intervention to prevent manifestation of infantile esotropia.

METHODS

A retrospective chart review of 5,347 records (October 1, 1993, to September 30, 2003) of birth mothers and infants at the W.W. Hastings Indian Health Science Hospital in Tahlequah, Oklahoma, was performed to identify children with varying degrees of Native American blood who had infantile esotropia. A nonstrabismic birth cohort control group was also identified. Twenty-three medical records indicating a diagnosis of infantile esotropia that were complete enough to be used in analysis were identified. Normal infants were compared with infants with esotropia.

RESULTS

Infantile esotropia in this preliminary study was associated with 24 factors including prematurity, family ocular history, cardiovascular disease, systemic disease, pregnancy-associated hypertension and low birth weight (<2,500 g) among others.

CONCLUSIONS

Prematurity, family history or secondary ocular history, perinatal or gestational complications, systemic disorders, use of supplemental oxygen as a neonate, use of systemic medications, and male sex were found to be significant risk factors for infantile esotropia. Our results provide additional evidence that might help facilitate early detection and intervention in cases in which these risk factors are identified.

Movimentos oculares no bebê: o que eles nos indicam sobre o status oftalmológico e neurológico

Movimentos oculares anormais podem ser o resultado de um desenvolvimento visual anormal ou estar sinalizando a existência de uma doença neurológica ou neuromuscular. Assim, é importante que o clínico conheça essas anormalidades e possa distingui-las dos movimentos oculares normais, porém imaturos. Este trabalho oferece esclarecimentos sobre os diferentes tipos de movimentos oculares, como interpretá-los nos bebês saudáveis e quais os tipos de alterações encontradas nas diferentes doenças visuais e neurológicas.

Ocular motor outcomes after bilateral and unilateral infantile cataracts

We wished to study how the severity and duration of early onset visual deprivation affects eye alignment and ocular stability. Thirty-three patients (aged 1 week to 12.8 years) with infantile cataracts (16 bilateral, 17 unilateral) were examined for periods up to 61 months. Twenty-three patients were considered to have cataracts, which were a major obstacle to vision (major form deprivation), 9 of whom underwent surgery within 8 weeks of birth (mean and SD=5.2+/-2.3 weeks) and 10 after 8 weeks (mean and SD=33.9+/-29.7 months). Eye alignment and fixation stability was measured using infrared recording systems and video. Visual acuity was assessed using forced-choice preferential looking techniques in the neonates and infants and with optotypes in the children. Fifteen of the 23 (65%) patients who experienced major form deprivation exhibited a nystagmus, of which 11 (73%) were manifest latent nystagmus (MLN). Nineteen of the 23 (85%) had strabismus. Of the nine patients who underwent early surgery (< or =8 weeks), two displayed a preoperative nystagmus whilst between 10 and 39 months post-operatively 8 (89%) exhibited a nystagmus. Of the group of 10 patients with minor cataracts only 2 (1 late surgery, 1 no surgery) had nystagmus and 2 strabismus. We conclude that following optimal post-operative management of infantile cataracts a sustained nystagmus--typically an MLN--is the most likely ocular motor outcome, even when the period of deprivation is as short as 3 weeks.

Facteurs de risque de l'ésotropie précoce

To elucidate risk factors for congenital esotropia, this review reports on articles written on congenital esotropia during the past few years. The authors distinguish the significant risk factors of esotropia such as heredity, prematurity, perinatal difficulties, and minor risk factors such as ametropia, primary monofixation, and environmental factors.

Outcome study of the development of fusion in patients aligned for congenital esotropia in relation to duration of misalignment

PURPOSE

The results of recent studies have shown that the presence and quality of stereopsis in patients with congenital esotropia and subsequent surgically alignment are dependent upon the duration of the misalignment during the first 2 years of life. The purpose of this study was to investigate the presence of fusion in patients with different durations of misalignment whose eyes were aligned at different ages by age 2 years.

METHODS

Data previously obtained in a study of 90 patients with congenital esotropia aligned by 2 years of age, examined in a masked independent evaluation for binocularity, were analyzed. Patient age at alignment and duration of misalignment were correlated with the presence of fusion.

RESULTS

Fusion was present in 94% of all patients aligned by age 2 years and in 94% of patients with < or =21 months of misalignment. There was no statistically significant difference between those aligned by 6, 12, or 24 months (P > 0.05, power = 0.8). No significant difference was found between those aligned with duration of misalignment < or = 6, between 7 and 12, or between 13 and 21 months.

CONCLUSION

Unlike the findings of stereopsis studies, there was no significant difference in the proportion of patients who achieved fusion in congenital esotropes who had up to 21 months of misalignment and whose eyes were aligned at different ages within the first 24 months of life.

Common forms of childhood exotropia

OBJECTIVE

To determine the most common forms of childhood exotropia.

DESIGN

Retrospective, consecutive, observational case series.

PARTICIPANTS

All exotropic children (with >/=10 prism diopters) younger than 19 years from a predominantly rural Appalachian region evaluated from August 1, 1995 through July 31, 2001.

METHODS

Demographic and clinical data were collected on all patients.

MAIN OUTCOME MEASURES

The relative proportion of the various forms of childhood exotropia.

RESULTS

Two hundred thirty-five consecutive children without prior surgical treatment were evaluated for exotropia. Of the 235 study children, the specific forms of exotropia diagnosed and numbers were as follows: intermittent exotropia, 112 (47.7%); exotropia associated with congenital or acquired abnormalities of the central nervous system (CNS), 50 (21.3%); convergence insufficiency, 27 (11.5%); sensory exotropia, 24 (10.2%); paralytic exotropia, 5 (2.1%); congenital exotropia, 4 (1.7%); neonatal exotropia that resolved after 4 months of age, 3 (1.3%), whereas the remaining 10 (4.3%) had an undetermined form of exodeviation.

CONCLUSIONS

Intermittent exotropia was the most common form of divergent strabismus in this population. Exotropia associated with an abnormal CNS, convergence insufficiency, and sensory exotropia were also relatively common, whereas the congenital, paralytic, and late-resolving neonatal forms were uncommon.

Too much or too little: neonatal ocular misalignment frequency can predict later abnormality

BACKGROUND

214 orthoptists' infants have been followed for up to 15 years, relating neonatal misalignment (NMs) and first convergence onset to later childhood ocular abnormalities. NMs are shown in a companion paper to reflect the onset of first convergence, but if frequent or absent may predict a higher risk of refractive error and esodeviation.

METHODS

In a prospective postal survey, orthoptist mothers observed their own infants during the first months of life and regularly reported ocular behaviour and alignment, visual development, and any subsequent ocular abnormalities.

RESULTS

Later strabismus and refractive error were less common in infants who showed NMs occasionally compared with those who never or frequently did. There was a significant linear trend for fewer ocular abnormalities to be found in children with more frequent NMs (p<0.001). Hypermetropes were later to show first convergence than emmetropes or myopes (p = 0.006)

CONCLUSIONS

NMs usually reflect an emerging and normally developing vergence system. This study suggests that delayed onset of convergence (and lack of NMs) is associated with later defects, especially hyperopia. Possible causal relations are discussed.

Neonatal ocular misalignments reflect vergence development but rarely become esotropia

BACKGROUND

214 orthoptists' infants have been followed for up to 15 years, relating neonatal misalignment (NMs) behaviour to onset of convergence and 20 Delta base out prism response, and also to later childhood ocular abnormalities.

METHODS

In a prospective postal survey, orthoptist mothers observed their own infants during the first months of life and regularly reported ocular behaviour and alignment, visual development, and any subsequent ocular abnormalities.

RESULTS

Results confirm previously reported characteristics of NMs. Infants who were misaligned more frequently were misaligned for longer periods (p <0.01) and were later to achieve constant alignment (p <0.001) but were earlier to attempt first convergence (p = 0.03). Maximum NM frequency was usually found at or before the onset of first convergence (p = 0.0002).

CONCLUSIONS

NMs occur in the first 2 months of life and usually reflect a normally developing vergence system. They appear to represent early attempts at convergence to near targets. Emerging infantile esotropia is indistinguishable from frequent NMs before 2 months.

Exodeviation following monocular myopic regression after laser in situ keratomileusis

We report a 44-year-old woman with intermittent left exotropia of 35 prism diopters at distance who initially exhibited alignment of both eyes after bilateral laser in situ keratomileusis (LASIK). The exophoria was not preserved due to myopic regression in the dominant eye. An uneventful LASIK treatment was performed to correct -11.00 -0.50 x 130 in the right eye and -13.50 -1.50 x 145 in the left eye. The aim was to achieve emmetropia in both eyes. Although an examination revealed exophoria at near and distance during the 6 months following refractive surgery, the tropic aspect of the divergent deviation appeared in the right eye following the myopic regression. Laser in situ keratomileusis is an effective option to achieve binocular visual quality in myopic anisometropic patients. However, myopic regression after LASIK may disrupt the binocular visual quality.