High-grade stereo acuity after early surgery for congenital esotropia

Characteristic Thinning of Temporal Parafoveal Retinal Thickness in Patients With Intermittent Exotropia

PURPOSE

To quantitatively compare the temporal parafoveal retinal thickness between intermittent exotropia (IXT) and healthy controls using optical coherence tomography, exploring the relationship between retinal structural changes and retinal correspondence.

DESIGN

Cross-sectional study.

METHODS

Twenty basic type IXT with an exodeviation angle of 35 prism diopters (PD) were compared with 20 age-matched healthy controls. All enrolled participants underwent a comprehensive ophthalmic evaluation, including optical coherence tomography, axial length, prism alternate cover test, retinal correspondence, and stereoacuity. The retinal thickness at parafoveal position corresponding to the exodeviation angle of 25 PD, 30 PD, 35 PD, 40 PD, and 45 PD were measured. Interocular symmetries of the retinal thickness were analyzed according to ocular laterality or dominance in the IXT group. Comparative analysis of temporal parafoveal retinal thickness was conducted between the IXT group and the normal control group. According to the retinal correspondence, IXT patients were divided into the anomalous retinal correspondence (ARC) group and the non-ARC group, and further comparative analysis was conducted on retinal thickness between the two groups.

RESULTS

The temporal parafoveal retinal thickness was symmetrical between the eyes in IXT patients without significant interocular difference (P > .05). However, the retinal thickness at the corresponding parafoveal position of the exodeviation angle (35 PD) was significantly reduced in IXT patients (P < .0001), which was thinner in the nondominant eyes of the ARC group (P = .007).

CONCLUSIONS

Patients with IXT showed characteristic thinning of the retinal thickness in the temporal parafoveal region corresponding to the exodeviation angle, presenting a structure similar to a shallow "pseudo-fovea." The relationship between structural changes and correspondence in the retina needs to be further investigated.

The incidence, clinical features, and management of essential infantile esotropia in the United Kingdom. A British Ophthalmology Surveillance Unit (BOSU) study

BACKGROUND/OBJECTIVES

A national study was undertaken through the British ophthalmology surveillance unit (BOSU) to determine the incidence, presenting features and management of essential infantile esotropia (EIE) in the UK.

METHODS

Data from a prospective national observational study of newly diagnosed EIE presenting to clinicians in the United Kingdom over a 12-month period were collected. Cases with a confirmed diagnosis by a clinician of a constant, non-accommodative esotropia ≥20 prism dioptres (PD), presenting at ≤12 months, with no neurological or ocular abnormalities were identified through BOSU. Follow-up data were collected at 12 months.

RESULTS

A total of 57 cases were reported giving an incidence of EIE of 1 in 12,828 live births. The mean age of diagnosis and intervention were 7.05 ± 2.6 months (range 2-12) and 14.7 ± 4.9 months (range 6.5-28.1), respectively. Management was surgical in 59.6%, botulinum toxin alone in 22.8%, and 17.5% were observed. The preoperative angle of esotropia was smaller in the observation group (P = 0.04). The postoperative angle of esotropia was not statistically significant between botulinum toxin or surgery (P = 0.3), although the age of intervention was earlier in the botulinum group (P = 0.007). Early intervention (before 12 months of age) did not influence the post-intervention motor outcomes between 0 and 10 prism dioptres of esotropia (P = 0.78).

CONCLUSIONS

The incidence of EIE in the UK is considerably lower than reported in other population-based studies. The preferred method of treatment was surgical with earlier intervention in those treated with botulinum toxin. An early age of intervention (<12 months) did not influence motor outcomes.

Interventions for infantile esotropia

BACKGROUND

Infantile esotropia (IE) is the inward deviation of the eye. Various aspects of the clinical management of IE are unclear; mainly, the most effective type of intervention and the age at intervention.

OBJECTIVES

To examine the effectiveness and optimal timing of surgical and non-surgical treatment options for IE to improve ocular alignment and achieve or allow the development of binocular single vision.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, one other database, and three trials registers (November 2021). We did not use any date or language restrictions in the electronic searches for trials.  SELECTION CRITERIA: We included randomized trials and quasi-randomized trials comparing any surgical or non-surgical intervention for IE.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology and graded the certainty of the body of evidence for six outcomes using the GRADE classification.

MAIN RESULTS

We included two studies with 234 children with IE. The first study enrolled 110 children (mean age 26.9 ± 14.5 months) with an onset of esotropia before six months of age, and large-angle IE defined as esotropia of ≥ 40 prism diopters. It was conducted between 2015 and 2018 in a tertiary care hospital in South Africa. It compared a maximum of three botulinum toxin injections with surgical intervention of bimedial rectus muscle recession, and children were followed for six months. There were limitations in study design and implementation; the risk of bias was high, or we had some concerns for most domains.  Surgery may increase the incidence of treatment success, defined as orthophoria or residual esotropia of ≤ 10 prism diopters, compared with botulinum toxin injections, but the evidence was very uncertain (risk ratio (RR) of treatment success 1.88, 95% confidence interval (CI) 1.27 to 2.77; 1 study, 101 participants; very low-certainty evidence). The results should be read with caution because 23 children with > 60 prism diopters at baseline in the surgery arm also received botulinum toxin at the time of surgery to augment the recessions. There was no evidence of an important difference between surgery and botulinum toxin injections for over-correction (> 10 prism diopters) of deviation (RR 0.29, 95% CI 0.06 to 1.37; 1 study, 101 participants; very low-certainty evidence), or additional interventions required (RR 0.66, 95% CI 0.36 to 1.19; 1 study, 101 participants; very low-certainty evidence). No major complications of surgery were observed in the surgery arm, while children experienced various complications in the botulinum toxin arm, including partial transient ptosis in 9 (16.7%) children, transient vertical deviation in 3 (5.6%) children, and consecutive exotropia in 13 (24.1%) children. No other outcome data for our prespecified outcomes were reported.  The second study enrolled 124 children with onset of esotropia before one year of age in 12 university hospitals in Germany and the Netherlands. It compared bilateral recession with unilateral recession surgeries, and followed children for three months postoperatively. Very low-certainty evidence suggested that there was no evidence of an important difference between bilateral and unilateral surgeries in the presence of binocular vision (numbers with event unclear, P = 0.35), and over-correction (RR of having exotropia 1.09, 95% CI 0.45 to 2.63; 1 study, 118 participants). Dissociated vertical deviation, latent nystagmus, or both were observed in 8% to 21% of participants.

AUTHORS' CONCLUSIONS

Medial rectus recessions may increase the incidence of treatment success compared with botulinum toxin injections alone, but the evidence was very uncertain. No evidence of important difference was found between bilateral surgery and unilateral surgery.  Due to insufficient evidence, it was not possible to resolve the controversies regarding type of surgery, non-surgical intervention, or age of intervention in this review. There is clearly a need to conduct good quality trials in these areas to improve the evidence base for the management of IE.

Computer vision-based system for early diagnosis of stereoscopic vision alterations

Stereopsis is the three-dimensional perception capability, which is possible when binocular vision is present. Development of binocular vision system ends around 7-year-old, and after this time brain connections are already set, therefore, it will be difficult to recover stereopsis. Early diagnosis of Stereoscopic Visual Alterations (SVA) in the childhood is paramount to receive an appropriate treatment as soon as possible. Currently, to detect SVA, ophthalmologists commonly carry out tests based on cards. All these tests are based on the random-dot-stereogram principle, with different seconds of arc images, which allows doctors to graduate stereopsis. Some limits of this tests have been identified, such as monocular clues (e.g., the contours of the objects), or the non-standardized range levels depending on the test. This paper presents a novel concept of measuring stereopsis based on computer vision techniques. The system detects SVA in patients and calculates the degree of the perceived depth. As early diagnosis of SVA may suppose a therapeutic possibility, this platform is aimed at children by using stereoscopic models with varied and attractive designs. To validate the proposal, an early-stage prototype has been implemented and an objective evaluation of the measurement accuracy and reliability has been carried out with satisfactory results.

Factors Determining Improvement in Stereopsis and Binocularity After Good Postoperative Alignment in Patients With Childhood-Onset Strabismus

Introduction: The purpose of the present study was to determine the factors that affect the outcome of strabismus surgery in terms of improvement in stereopsis and binocularity.

Methods: Data were collected prospectively from patients with childhood-onset, concomitant, constant strabismus greater than 30 prism diopters (PD) with postoperative alignment within 10 PD. Pre- and postoperative stereopsis and binocularity testing were performed using the Titmus fly test, random dot test, Bagolini striated glass test, and Worth four dot test at one, four, and 12 weeks postoperatively.

Results: A total of 73 patients (55% males and 45% females) who underwent surgery at our center were studied. The mean age at the time of surgery was 16 ± 7.7 years (range: 5-35 years). We found that factors such as age of strabismus onset, type of deviation, and amblyopia had a statistically significant influence on the postoperative surgical outcome. A statistically insignificant relationship was noted with gender, refractive error, and duration of strabismus. Patients who had strabismus after six months of age noticed a significant improvement in stereopsis (p-value = 0.000) than those who had strabismus before six months of age (p-value = 0.660). Further, there was a statistically significant improvement in patients having exotropia (p-value = 0.018) or combined horizontal and vertical deviations (p-value = 0.000), but there was no significant improvement in patients with esotropia (p-value = 0.180). Moreover, non-amblyopes had a significantly better postoperative stereopsis than amblyopes (p-value = 0.006). Although there was no association between preoperative deviation and improvement in stereopsis (p-value = 0.081), patients having preoperative deviation in the range of 31-45 PD had a statistically significant improvement in stereopsis (p-value = 0.000). There was no significant difference between postoperative residual deviation and final stereopsis (p-value > 0.05). All the results were the same for both the Titmus test and the random dot test. Binocular fusion was observed in 34 subjects, and uniocular suppression was noted in 38 subjects preoperatively. It was observed that only one patient gained binocular single vision postoperatively.

Conclusion: The presence of amblyopia, esotropia, early onset of strabismus (within six months of age), and a larger preoperative deviation (>45 PD) were associated with poorer stereopsis. In patients with horizontal strabismus, the coexistence of vertical deviation had a positive impact on the postoperative stereopsis. Gender, refractive error, and duration of strabismus did not influence the final stereopsis in our study.

Timing of surgery in essential infantile esotropia - What more do we know since the turn of the century?

This review summarizes the results and interpretations of studies pertaining to the long-standing debate regarding the timing of surgery in infantile esotropia, more recently referred to as essential infantile esotropia. A systematic search of studies from the year 2000 onward pertaining to the timing of surgery in infantile esotropia as listed in PubMed, Google Scholar, and the Cochrane database was performed. Appropriate cross-references from the articles were also included. Data collected included demographics, presentation, time of surgery, complications, and outcomes. Very early surgery, that is, within 6 months of the onset of infantile esotropia, offers significant advantages in terms of the quality of stereopsis and binocular vision as well as promoting the development of cortical visual processing, thereby benefiting cortical development in human infants. However, the postoperative alignment was not found to be significantly different in the very early, early, or late surgery groups. The reduction in the incidence of manifest dissociated vertical deviation postoperatively in the very early surgery group also showed measurable benefits. The results of this recent literature review demonstrated that very early surgery, within 6 months of misalignment, showed demonstrable benefits in essential infantile esotropia.

Fixation eye movement abnormalities and stereopsis recovery following strabismus repair

We evaluated the effects of strabismus repair on fixational eye movements (FEMs) and stereopsis recovery in patients with fusion maldevelopment nystagmus (FMN) and patients without nystagmus. Twenty-one patients with strabismus, twelve with FMN and nine without nystagmus, were tested before and after strabismus repair. Eye-movements were recorded during a gaze-holding task under monocular viewing conditions. Fast (fixational saccades and quick phases of nystagmus) and slow (inter-saccadic drifts and slow phases of nystagmus) FEMs and bivariate contour ellipse area (BCEA) were analyzed in the viewing and non-viewing eye. Strabismus repair improved the angle of strabismus in subjects with and without FMN, however patients without nystagmus were more likely to have improvement in stereoacuity. The fixational saccade amplitudes and intersaccadic drift velocities in both eyes decreased after strabismus repair in subjects without nystagmus. The slow phase velocities were higher in patients with FMN compared to inter-saccadic drifts in patients without nystagmus. There was no change in the BCEA after surgery in either group. In patients without nystagmus, the improvement of the binocular function (stereopsis), as well as decreased fixational saccade amplitude and intersaccadic drift velocity, could be due, at least partially, to central adaptive mechanisms rendered possible by surgical realignment of the eyes. The absence of improvement in patients with FMN post strabismus repair likely suggests the lack of such adaptive mechanisms in patients with early onset infantile strabismus. Assessment of fixation eye movement characteristics can be a useful tool to predict functional improvement post strabismus repair.

Detection of Static and Dynamic Stereopsis after Femtosecond Laser Small Incision Lenticule Extraction for High Myopia

Purpose

The purpose of this study is to test binocular visual function after femtosecond laser small incision lenticule extraction (SMILE) for high myopia. The traditional Titmus stereotest and dynamic stereotest based on the visual perception biological model were used for comparative analysis.

Methods

A total of 43 patients were enrolled in this prospective study. At Week 1, Month 1, and Month 3 after surgery, the Titmus stereotest and dynamic stereotest generated by MATLAB were conducted. Dynamic stereopsis consists of randomly flickering Gabor spots and is divided into two models of high energy and low energy according to flicker frequency.

Results

The preoperative manifest refraction spherical equivalent was −7.21 ± 0.70 D. The preoperative anisometropia was 0.52 ± 0.54D. The quartiles of static stereoacuity in preoperation and 3 follow-ups were as follows: 50.00 (25.00, 100.00) in preoperation, 63.00 (40.00, 63.00) at Week 1, 40.00 (32.00, 63.00) at Month 1, and 40.00 (25.00, 50.00) at Month 3. Static stereopsis improved at Month 1 and Month 3 compared with preoperation and Week 1 (P < 0.05). There were statistically significant differences in high energy dynamic stereopsis at Week 1 and Month 1 compared to preoperation (P < 0.05). In addition, significant differences in low energy dynamic stereopsis were detected between Month 1 and preoperation and also at Month 3 compared to Month 1 (P < 0.05).

Conclusion

Most high myopia patients have a dynamic stereopsis deficiency before refractive correction. SMILE surgery can improve both static and dynamic stereopsis early in the postoperation period. However, in the long term, there is no significant difference or even a decrease in dynamic stereopsis.

Multiple Short Daily Periods of Normal Binocular Vision Preserve Stereopsis in Strabismus

Purpose

Infantile strabismus impedes the development of stereopsis. In optically strabismic monkeys, 2 continuous hours of normal binocular vision per day has been shown to preserve near-normal stereopsis. In this study, we investigated whether, as in learning, multiple shorter periods of intervention would further boost performance.

Methods

To simulate infantile esotropia, infant monkeys were reared with 30 prism diopters base-in starting at 4 weeks of age. Daily periods of normal binocular vision were provided by replacing prisms with plano lenses. Altogether, 14 monkeys were prism reared: 2 with continuous prism, 2 with 2 continuous hours of normal binocular vision per day, 6 with 2 noncontinuous hours, and 4 with 1 noncontinuous hour of binocular vision each day. Seven normally reared monkeys provided control data. Behavioral methods were employed to measure spatial contrast sensitivity, eye alignment, and stereopsis.

Results

One monkey reared with continuous prism had poor stereopsis, and the other had no stereopsis. Ten of the 12 monkeys reared with periods of normal binocular vision had stereopsis, and those with longer and more continuous periods of binocular vision had stereopsis approaching that of normally reared monkeys.

Conclusions

During early development, multiple short periods of binocular vision were effective in preserving clinically significant stereopsis in monkeys. These results suggest that by providing relatively short multiple daily intervention periods, stereopsis may be preserved in strabismic human children.

[Long term outcomes of botulinum toxin injections in infantile esotropia]

PURPOSE

To evaluate long terms outcomes of botulinum toxin in infantile esotropia by measuring the amount of microtropia 24 months after injection. Secondary purpose was to identify predictive factors of microtropia.

METHODS

A retrospective, single-center study was performed at the university medical center in Bordeaux between 2001 and 2018, including all patients with infantile esotropia greater than 20 D. All patients received 5 or 7,5 IU of botulinum toxin A in each medial rectus, once or twice depending on the angle of deviation after the first injection and after wearing full optical correction at least two months. We noted the angle at 1, 6, 12 and 24 months, the occurrence of any complications and the need for later strabismus surgery. The primary endpoint was the achievement of a microtropia less than 8 diopters (D) at 24 months post-injection. We evaluated the predictive factors for microtropia with a Fischer's test.

RESULTS

We included 30 patients with esotropia greater than 20 D. The mean follow-up after injection was 48 months ±30. The mean age was 16.24 months (7-29 months) with a female predominance in the population (SR=0.43). The mean pre-injection deviation was 41.25±12.17 D. The majority of patients were mildly (40%) or moderately (40%) hyperopic. At 24 months, 46.7% microtropias were obtained (95% CI: 28.9%-64.5%). The change in mean angle at 1, 6, 12 and 24 months post-injection was -8.57±25.21 D; 14.48±13.40 D; 18.38±12.07 D and 21.23±14.97 D, respectively. No factors were predictive of microtropia. Of the 30 children, 3 had transient ptosis requiring strips and 12 showed an exotropia at 1 month. All complications were self-limited and without consequences. 3 children had a second injection of botulinum toxin, which in 2/3 of the cases resulted in a long-lasting microtropia. 26.7% (n=8) of the children underwent secondary surgery. Obtaining a microtropia 24 months after injection statistically significantly reduced the need for secondary strabismus surgery: 92.9% P=0.039% CI 95% (0.002; 1.0606).

CONCLUSION

Botulinum toxin appears to be a less invasive and more conservative alternative to surgery in children with infantile esotropia. In 46.7% of cases, microtropia is achieved. An improvement was noted in 90% (n=27) of the children with a reduction of half (21.23 D) of the mean post-injection angle at 24 months. When effective, it significantly reduces the need for secondary surgery.

Relationship between stereopsis outcome and timing of surgical alignment in infantile esotropia

PURPOSE

To clarify the relationship between stereopsis outcome and timing of surgical alignment in infantile esotropia.

METHODS

The medical records of otherwise healthy patients with infantile esotropia who underwent surgery by 8 years of age were divided into the following groups according to age at time of surgery: very early surgery (≤8 months), early surgery (>8 to ≤24 months) and late surgery (>24 months). Binocular response and stereopsis were compared between groups.

RESULTS

A total of 76 patients were included: 22 in the very early group, 30 in the early group, and 24 in the late group. Binocular response at near was found in 96% of the very early group and in 80% of the early group, significantly higher than the 50% of the late group (P < 0.001 and P < 0.05 [Dunn test], resp.). Stereopsis was present in 77% of the very early group, significantly higher than the 20% of the early group and 13% of the late group (P < 0.001 [Dunn test]). A significant correlation was also found between age (months) at surgery and stereopsis (seconds) outcome (logarithmic fit: y = 2539.4ln(x) + 147.2; R² = 0.2691; P < 0.001).

CONCLUSIONS

In this study cohort, earlier surgery was associated with better binocularity in patients with infantile esotropia. Our results suggest that very early surgery, at ≤8 months, can improve the chance for postoperative stereopsis, with the caveat that some infants might have had spontaneous esotropia resolution.

Long term motor and sensory outcome after surgery for infantile esotropia and risk factors for residual and consecutive deviations

Purpose: To present long-term motor and sensory outcomes after surgery for infantile esotropia and assess risk factors for residual and consecutive deviations.Methods: Data of infantile esotropia patients operated between 2002 and 2016 with minimum follow-up of 2 years were retrospectively reviewed.Results: Among a total of 62 patients, 35 had a successful motor outcome (alignment within 10 PD from orthotropia) after one surgery (Group A), while 27 required horizontal reoperation (Group B). Patients with residual esotropia had larger preoperative angle of deviation (P = .005) and younger age at first surgery (P = .01), while consecutive exotropia was associated with longer follow-up (P = .03) and higher rate of DVD (P = .003) compared to patients in Group A. Stereopsis was present in 30.3% of patients in Group A and associated with younger age at first surgery (P = .03).Conclusions: Successful motor alignment may be obtained with single surgery in infantile esotropia; however, reoperations are common. Younger age at first surgery may be associated with both higher rate of stereopsis and risk of reoperation. Careful preoperative assessment and surgical timing, with long-term postoperative follow-up is required to achieve satisfactory outcome.

Stereoacuity and Related Factors in Healthy Preschool Children: The Nanjing Eye Study

Purpose: To assess the distribution of stereoacuity and related factors in healthy preschool children aged 48-60 months in eastern China. Methods: This cross-sectional study was part of the Nanjing Eye Study, a longitudinal population-based cohort study. In 2016, preschool children without any neurological problems or ophthalmological abnormalities completed comprehensive eye examinations, including visual acuity, ocular alignment and movements, cycloplegic refraction, axial length, interpupillary distance, Titmus stereotest, anterior segment, and fundus examination. Multivariate linear regression model was used to determine the factors associated with stereoacuity score, and logistic regression model was used to determine the factors associated with subnormal stereoacuity (worse than 40 arc-seconds). Results: Among 942 healthy preschool children (mean age = 55 months), the mean (SD) stereoacuity was 81 (2.3) arc-seconds with majority (76.5%) worse than 40 arc-seconds. In the multivariate analysis, older age (p = 0.001) and better presenting visual acuity (PVA) (p = 0.01) were independently associated with better stereoacuity score. Older age was also associated with low risk of subnormal stereoacuity (odds ratio = 0.37,p < 0.001 for age 57-60 months compared to age 48-51 months). Conclusions: The maturation of stereopsis has not completed by the age of 48-60 months. Age and PVA should be taken into account when evaluating stereopsis in healthy preschoolers. The significant associations of age and PVA with stereoacuity provide valuable insights into possible intervention for healthy preschool children with poor stereoacuity.

The pursuit of stereopsis

BACKGROUND

Pediatric ophthalmologists are increasingly expected to promote, preserve, and restore binocular vision.

METHODS

Clinical studies on restoring alignment and stereopsis in the management of amblyopia, esotropia, exotropia, and complex strabismus are reviewed from the perspective of the author's published work and personal experiences.

RESULTS

Treatment of amblyopia by means of optical rehabilitation, occlusion, or penalization has been reinforced by medical treatment and perceptual training with monocular or binocular video games. Studies indicate that early management of esotropia and alignment within 8^Δ is required for regaining stereopsis. In the surgical management of intermittent exotropia, distance stereopsis by Frisby Davis Distance stereotest can predict better stereopsis, with patients having preoperative distance stereopsis of <70 arcsec less likely to improve after surgery. The surgeon's armamentarium for correcting alignment and restoring binocular vision include procedures such as adjustable, partial vertical rectus muscle transposition in cases of exotropic Duane syndrome and lateral rectus palsy, periosteal fixation of the globe or of the lateral rectus muscle, and medial transposition of the split lateral rectus muscle.

CONCLUSIONS

The goal for present-day strabismologists is not merely to correct strabismus but also to achieve alignment of eyes in time to ensure normal development of stereopsis in children and to restore alignment and stereopsis in adults.

Long-Term Changes in Refractive Error and Clinical Evaluation in Partially Accommodative Esotropia after Surgery

We investigate the changes in refractive error and clinical evaluation in partially accommodative esotropia(PAET) after surgery. A total of 68 patients PAET who received at least 2 years of follow-up after surgery were enrolled in this study. We performed a retrospective study in patients who underwent unilateral or bilateral medial rectus recession for a non-accommodative component of PAET between January 2005 and March 2013. Patients were divided into groups according to the presence of dominancy (dominant, non-dominant, alternative eye), and presence of amblyopia (amblyopic, fellow, normal eye). Changes and changing pattern in SE refractive error were analyzed in all patients and compared between groups. Patients were divided into two groups, those weaned off of hyperopic glasses and those who continued using them, then factors that significantly influenced the continued use of glasses were analyzed. The changes and changing pattern in SE refractive error according to time after operation and presence of amblyopia or dominancy. The mean length of follow-up was 4.89±1.74 years after surgery and the mean change in SE refractive error rate per year was -0.284±0.411 diopters (D). The pattern of changes in the mean SE refractive error for those with dominant, non-dominant, and alternative eyes was not significantly different (p = 0.292). The pattern of changes in the mean SE refractive error for those with amblyopic, fellow, and normal eyes was significantly different (p = 0.0002). Patients were successfully weaned off of hyperopic glasses at an average age of 9.41±2.74 years. The average SE refractive error in the group weaned off of hyperopic glasses was significantly lower than that in the group maintained on hyperopic glasses (p = 0.0002). The change of SE refractive error in amblyopic eyes decreased less than that in fellow or normal eyes, which may be correlated with the presence of amblyopia. Patients with a smaller esodeviated angle without hyperopic correction, a lower degree of hyperopia, and who were older at the time of disease onset were discontinued from hyperopic glasses sooner after surgery.

Surgical Results of Symmetric and Asymmetric Surgeries and Dose-Response in Patients with Infantile Esotropia

Objectives:

To evaluate the results of symmetric and asymmetric surgery and responses to surgical amounts in patients with infantile esotropia.

Materials and Methods:

The records of patients with infantile esotropia who underwent bilateral medial rectus recession (symmetric surgery) and unilateral medial rectus recession with lateral rectus resection (asymmetric surgery) were analyzed. The results of the cases with symmetric (group 1) and asymmetric (group 2), successful (group 3) and failed (group 4) surgeries were compared, and responses to the amount of surgery were investigated.

Results:

There were no significant differences between group 1 (n=71) and group 2 (n=13) cases in terms of gender, refraction, preoperative distance deviation, anisometropia and postoperative deviation angles, binocular vision, surgical success or follow-up period (p>0.05). The rate of amblyopia, near deviation and amount of surgery were higher in group 2 cases (p<0.05). Between group 3 (n=64) and group 4 subjects (n=20), no significant differences were detected in terms of gender, surgical age, refraction, amblyopia, anisometropia, preoperative deviation angles, the number of symmetric and asymmetric surgeries, the amount of surgery, or postoperative binocular vision (p>0.05). The average postoperative follow-up period was 15.41±19.93 months (range, 6-98 months) in group 3 cases and 40.45±40.06 months (range, 6-143 months) in group 4 cases (p=0.000). No significant difference was detected in the amount of deviation corrected per 1 mm of surgical procedure between the successful cases in the symmetric and asymmetric groups (p>0.05).

Conclusion:

Symmetric or asymmetric surgery may be preferable in patients with infantile esotropia according to the clinical features. It is necessary for every clinic to review its own dose-response results.

Comparison between medial rectus pulley fixation and augmented recession in children with convergence excess and variable-angle infantile esotropia

PURPOSE

To compare the outcomes of medial rectus (MR) muscle pulley fixation and augmented recession in children with convergence excess esotropia and variable-angle infantile esotropia.

METHODS

This was a prospective randomized interventional study in which children with convergence excess esotropia or variable-angle infantile esotropia were randomly allocated to either augmented MR muscle recession (augmented group) or MR muscle pulley posterior fixation (pulley group). In convergence excess, the MR recession was based on the average of distance and near angles of deviation with distance correction in the augmented group, and on the distance angle of deviation in the pulley group. In variable-angle infantile esotropia, the MR recession was based on the average of the largest and smallest angles in the augmented group and on the smallest angle in the pulley group. Pre- and postoperative ductions, versions, pattern strabismus, smallest and largest angles of deviation, and angle disparity were analyzed.

RESULTS

Surgery was performed on 60 patients: 30 underwent bilateral augmented MR recession, and 30 underwent bilateral MR recession with pulley fixation. The success rate was statistically significantly higher (P = 0.037) in the pulley group (70%) than in the augmented group (40%). The postoperative smallest and largest angles and the angle disparity were statistically significantly lower in the pulley group than the augmented group (P < 0.01).

CONCLUSIONS

Medial rectus muscle pulley fixation is a useful surgical step for addressing marked variability of the angle in variable angle esotropia and convergence excess esotropia.

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.

Stereoscopic perception of 3-D images by patients after surgery for esotropia

PURPOSE

Patients with esotropia (ET) have generally poor stereopsis; however, it is not clear whether they can see the recently developed 3-D images stereoscopically. We investigated the ability of postoperative ET patients to have stereoscopic perception of 3-D attraction images which have large crossed disparities, and also 3-D movies which have generally small uncrossed disparities.

METHODS

Twenty-seven ET patients (infantile ET = 12, late-onset ET = 15) were examined postoperatively. They were examined with the 4-dot test, Titmus fly test, and questionnaires to determine whether they had stereoscopic vision when observing 3-D attraction images and 3-D movies. McNemar tests were used for statistical evaluations.

RESULTS

The number of patients who passed the Titmus fly test was smaller than the number that were able to see 3-D attraction images stereoscopically (fly test 13; 48%, 3-D attraction 22; 81%; P = 0.016). However, the number was not significantly different from that of those who could perceive 3-D movies stereoscopically. The number of patients who passed the Titmus fly test was significantly smaller than the number who can perceive 3-D attraction images stereoscopically in the infantile ET group (fly test 2, 17%, 3-D attraction 10, 83%; P = 0.013) but was not different in the late-onset ET group postoperatively. The minimum angle of fusion for the 4-dot test was smaller in the Titmus fly-positive patients than in the Titmus fly-negative patients (P = 0.03).

CONCLUSIONS

These results suggest that children who cannot pass the Titmus fly test might be able to experience 3-D attractions stereoscopically but not be able to see 3-D movies stereoscopically.

Management of infantile esotropia

PURPOSE OF REVIEW

Surgical treatment has been the accepted mode of treatment for infantile esotropia for decades. The present review of recent literature evaluates the current standing of: type of surgery performed and best timing of surgery to achieve optimal results.

RECENT FINDINGS

Recent studies suggest that early surgical intervention is of benefit by improving the probability of developing stereopsis. A significant advantage of the type of surgical intervention has yet to be demonstrated by the current studies. Botulinum toxin continues to be used for treatment of infantile esotropia, although it has not been shown to be a superior treatment.

SUMMARY

Although many theories exist, the true cause of infantile esotropia remains unknown. The literature suggests that treatment before age 2 and perhaps even earlier improves the potential for binocular vision. After significant review of literature, it is clear that surgery is the treatment of choice for infantile esotropia but no method has a clear advantage. Efforts to define the best surgical procedure and timing of surgery through prospective, randomized multicenter trials are warranted.

Does dominance of crossing retinal ganglion cells make the eyes cross? The temporal retina in the origin of infantile esotropia – a neuroanatomical and evolutionary analysis

A closer look at the evolution of the eye and the brain provides a possible explanation for both the origin of infantile esotropia and its motor characteristics. In the course of evolution, the eyes have moved from a lateral to a frontal position. Consequently, the monocular visual fields started to overlap resulting in a binocular visual field. In lateral-eyed animals, the retinae project to the contralateral visual cortices only. These projections are also found in binocular mammals and birds with binocular visual fields but in addition there are uncrossed projections from the temporal retinae to the visual cortex. The partial chiasmal decussation and the corpus callosum provide the necessary structure that allows binocular vision to develop. Disruption of normal binocular development causes a loss of binocularity in the primary visual cortex and beyond. Beyond the primary visual cortex, the contralateral eye dominates while the temporal retinal signal appears to lose influence. Loss or absence of binocular vision in infantile esotropia may be caused by inadequate retinotopic matching between the nasal and temporal retinal signals like in albinism with an abnormal or asymmetric chiasmal decussation or agenesis of the corpus callosum. Dominance of the crossing retinal signal might also explain the motor characteristics of infantile esotropia (asymmetric OKN, latent nystagmus, DVD). A normal binocular cortical signal will predominate over the evolutionary older, originally non-binocular, retinal projections to the superior colliculi (CS) and the accessory optic system (AOS). A suppressed temporal retinal signal paves the way for the re-emergence of eye movements driven by one eye, as in lateral-eyed non-binocular animals.

Factors influencing the development and severity of dissociated vertical deviation in patients with infantile esotropia

PURPOSE

To investigate the factors associated with the development and the severity of dissociated vertical deviation (DVD) in patients who underwent surgery for infantile esotropia.

METHODS

The medical records of consecutive patients who underwent surgery from March 1998 to December 2011 for infantile esotropia were reviewed retrospectively. The development, severity, and onset of DVD were assessed. Patients were divided into three groups: spontaneous, latent, and no DVD. The age at the time of the initial surgery, the angle of deviation of esotropia, anisometropia, amblyopia, stereopsis measured at the final visit, and history of prematurity were compared.

RESULTS

A total of 90 patients were included. DVD was detected in 52 (58%). Of these, 34 patients demonstrated spontaneous DVDs and 18 showed latent DVDs. In the spontaneous DVD group, 71% underwent surgery after 24 months and 50% had a large angle of esodeviation (>60(Δ)), compared to the latent DVD group, in which 22% underwent later surgery and 11% had large-angle esodeviations (P < 0.001 and P = 0.002, respectively), and the no DVD group, in which 16% underwent later surgery and 13% had large-angle esodeviations (P < 0.001 each). Multivariate logistic regression analysis between groups revealed that later surgery (OR = 8.23; P < 0.001) and large-angle esodeviation (OR = 6.32; P = 0.003) were associated that greater development of spontaneous DVD.

CONCLUSIONS

Surgical correction for infantile esotropia prior to 24 months of age, especially in cases with a large amount of esodeviation, decreased the incidence of spontaneous DVD.

To evaluate stereoacuity in patients with acquired esotropia and to determine factors associated with favourable outcomes

AIM

To evaluate stereoacuity in patients with acquired esotropia and determine the factors associated with favorable outcomes.

MATERIALS AND METHODS

A total of 68 subjects aged 6 years and above were included in the study. Thorough clinical evaluation including binocular status examination using the Bagolini-striated glass test, The Netherland Organization (TNO), and Randot stereo test were done. The subjects were divided into two groups 1 and 2, based on the amount of deviation. Statistical analysis of the result was performed.

RESULT

The duration of misalignment in the group with deviation less than or equal to 8 prism diopters (PD) was 1.49 ± 0.86 years, whereas in the group with deviation more than or equal to 10 PD was 4.64 ± 2.99 years (P = 0.000). Among the subjects in group 1, 89.5% achieved fusion and 52.6% had stereoacuity on both TNO and Randot, whereas in group 2 40% achieved fusion and 3.3% stereopsis on both TNO and Randot (one case with only coarse stereopsis). A subanalysis within group 1 revealed a statistically significant difference for the duration of misalignment (P = 0.02), but a marginal difference for the amount of deviation (P = 0.3).

CONCLUSION

A horizontal deviation up to 8 PD was compatible with stereopsis. Also, the duration of constant misalignment affects the attainment of stereopsis despite successful realignment.

The relationship of age when motor alignment is achieved and the subsequent development of stereopsis in infantile esotropia

PURPOSE

To determine the oldest age beyond which the chance of developing stereopsis is not possible even with excellent motor alignment in patients with infantile esotropia.

METHODS

The medical records of children with infantile esotropia who underwent a single operation and had alignment within 10(Δ) of orthotropia at all follow-up examinations were retrospectively reviewed. Patients were assessed for stereopsis after the age of 48 months.

RESULTS

A total of 38 children were included. There was a statistically significant inverse correlation between age at surgery and final stereopsis (r = 0.494, P = 0.002). There was a significant difference at mean age at surgery between patients having stereopsis better than 1000 arcsec and those having no stereopsis (P = 0.002). Post hoc power analysis revealed a value of 85%. Receiver operating characteristic curve analysis revealed that the optimum cut-off value of the age at surgery for predicting stereopsis was 16 months (Youden index = 0.474; area under ROC curve, 0.784; 95% CI: 0.62-0.90; P = 0.0002).

CONCLUSIONS

Surgery for infantile esotropia is most likely to result in measureable stereopsis if patient age at alignment is not more than 16 months.

Analysis of risk factors for consecutive exotropia and review of the literature

PURPOSE

To evaluate the possible risk factors in patients with consecutive exotropia following esotropia surgery.

METHODS

Medical records of patients who had comitant esotropia surgery between June 1999 and April 2011 were reviewed. Those who developed consecutive exotropia composed the exotropia group; patients matched for age and duration of follow-up who did not develop consecutive exotropia composed the no exotropia group. The charts of the patients were reviewed and possible risk factors for development of consecutive exotropia were investigated.

RESULTS

The average ages of 47 patients in the exotropia group and 54 patients in the no exotropia group were 10.8 ± 8.7 years (range: 1 to 41 years) and 8.5 ± 6.3 years (range: 1 to 30 years), respectively (P = .292). Amblyopia was detected in 31 (66%) and 12 (22.2%) patients in the exotropia and no exotropia groups, respectively (P = .004). Anisometropia was observed in 20 patients (42.6%) in the exotropia group and 5 patients (9.3%) in the no exotropia group (P = .003). Preoperative average esodeviation values were 42.5 ± 8.3 prism diopters (PD) (range: 25 to 60 PD) in the exotropia group and 42 ± 9.4 PD (range: 20 to 65 PD) in the no exotropia group (P = .673). Postoperative deviations were 32.8 ± 23 PD exotropia (range: 10 to 90 PD exotropia) in the exotropia group and 4.4 ± 4.2 PD esotropia (range: 0 to 10 PD esotropia) in the no exotropia group (P = .000). Asymmetric surgery had been performed in 61.7% of the exotropia group (n = 29) and 9.3% of the no exotropia group (n = 5) (P = .000). Limitation of adduction was detected in 14 patients (29.8%) in the exotropia group; none was noted in the no exotropia group (P = .000). The mean interval between the initial surgery and the onset of consecutive exotropia was 11.1 ± 15.1 months (range: 0 to 126 months).

CONCLUSIONS

Anisometropia, amblyopia, asymmetric surgery, and postoperative adduction deficit were associated with the development of consecutive exotropia. Long-term follow-up should be considered because consecutive exotropia can develop after months or years.

Interventions for infantile esotropia

BACKGROUND

Infantile esotropia (IE) is the inward deviation of the eye. Various aspects of the clinical management of IE are unclear; mainly, the most effective type of intervention and the age at intervention.

OBJECTIVES

The objective of this review was to assess the effectiveness of various surgical and non-surgical interventions for IE and to determine the significance of age at treatment with respect to outcome.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2013, Issue 5), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE, (January 1950 to June 2013), EMBASE (January 1980 to June 2013), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to June 2013), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 10 June 2013. We manually searched the conference proceedings of the European Strabismological Association (ESA) (1975 to 1997, 1999 to 2002), International Strabismological Association (ISA) (1994) and American Academy of Paediatric Ophthalmology and Strabismus meeting (AAPOS) (1995 to 2003). Efforts were made to contact researchers who are active in the field for information about further published or unpublished studies.

SELECTION CRITERIA

We included randomised trials comparing any surgical or non-surgical intervention for infantile esotropia.

DATA COLLECTION AND ANALYSIS

Each review author independently assessed study abstracts identified from the electronic and manual searches.

MAIN RESULTS

No studies were found that met our selection criteria and therefore none were included for analysis.

AUTHORS' CONCLUSIONS

The main body of literature on interventions for IE are either retrospective studies or prospective cohort studies. It has not been possible through this review to resolve the controversies regarding type of surgery, non-surgical intervention and age of intervention. There is clearly a need for good quality trials to be conducted in these areas to improve the evidence base for the management of IE.

Amblyopia and binocular vision

Amblyopia is the most common cause of monocular visual loss in children, affecting 1.3%-3.6% of children. Current treatments are effective in reducing the visual acuity deficit but many amblyopic individuals are left with residual visual acuity deficits, ocular motor abnormalities, deficient fine motor skills, and risk for recurrent amblyopia. Using a combination of psychophysical, electrophysiological, imaging, risk factor analysis, and fine motor skill assessment, the primary role of binocular dysfunction in the genesis of amblyopia and the constellation of visual and motor deficits that accompany the visual acuity deficit has been identified. These findings motivated us to evaluate a new, binocular approach to amblyopia treatment with the goals of reducing or eliminating residual and recurrent amblyopia and of improving the deficient ocular motor function and fine motor skills that accompany amblyopia.

The prevalence of reoperation and related risk factors among patients with congenital esotropia

PURPOSE

To determine the prevalence rate and related risk factors of reoperation among patients with congenital esotropia.

METHODS

One hundred fifty-seven children with congenital esotropia were divided into two groups after at least one operation: children with deviation within 10 PD (n = 89; success group) and those with deviation greater than 10 PD or history of reoperation (n = 68; failure group). The relationship of risk factors such as age at first operation and primary congenital esotropia of less than 30 or more than 50 PD and accompanying factors such as inferior oblique muscle overaction (> +1), dissociated vertical deviation, lateral rectus muscle underaction, and A-V pattern with reoperation were studied. Final sensory status of children 5 years and older was evaluated by Worth 4-dot and Titmus tests.

RESULTS

Reoperation was indicated in 32.4% of children who had residual esotropia greater than 15 PD after 3 months following their first operation. Congenital esotropia greater than 30 PD (P = .002) and lateral rectus muscle underaction of −1 to −2 (P < .005), were statistically different between the two groups. Initial operation at younger than 3 years was more likely to achieve gross stereopsis in children 5 years and older (P = .032).

CONCLUSION

Congenital esotropia greater than 30 PD and lateral rectus muscle underaction were found to be risk factors of reoperation.

Quadrantal macular retinal thickness changes in strabismus subjects with abnormal binocular vision development

PURPOSE

To investigate retinal morphological changes in strabismus patients with abnormal binocular vision development by comparing differences in quadrantal macular retinal thickness.

METHODS

Six strabismus patients (6 dominant and 5 non-dominant eyes) with abnormal binocular vision (mean age 22 years), and 11 control subjects (11 dominant and 11 non-dominant eyes) (mean age 21 years) were enrolled. Macular retinal thickness measurements were performed by optical coherence tomography, with total macular retinal (TMR) and ganglion cell complex (GCC) thicknesses measured in 3- and 6-mm regions in each quadrant. Measurement values were then used to determine quadrant ratios.

RESULTS

Compared to the dominant eyes of the controls, the superior/inferior (S/I) ratio of the TMR thickness and GCC thickness in the 3-mm region was significantly lower in the dominant eyes of the strabismus group (P < 0.05, each). The superior temporal/inferior temporal (ST/IT) ratio of the GCC thickness in the dominant eyes of the strabismus group was also significantly lower (P < 0.01).

CONCLUSIONS

Dominant eyes of the strabismus group with abnormal binocular vision development exhibited thinner superior temporal GCC thicknesses in the 3-mm region. Retinal ganglion cells in this region might be affected by efferent neural degeneration that originates in the visual pathway responsible for adaptations to the visual experience.

Decorrelation of cerebral visual inputs as the sufficient cause of infantile esotropia

BACKGROUND AND PURPOSE

Human infants at greatest risk for esotropia are those who suffer cerebral insults that could decorrelate signals from the two eyes during an early critical period of binocular, visuomotor development. The authors reared normal infant monkeys under conditions of binocular decorrelation to determine if this alone was sufficient to cause esotropia, and associated behavioral as well as neuroanatomic deficits.

METHODS

Binocular decorrelation was imposed using prism-goggles for durations of 3-24 weeks (control monkeys wore plano goggles), emulating unrepaired strabismus of durations 3 months to 2 years in human infants. Behavioral recordings were obtained, followed by neuroanatomic analysis of ocular dominance columns and binocular, horizontal connections in the striate visual cortex (area V1).

RESULTS

Concomitant, constant esotropia developed in each monkey exposed to decorrelation for a duration of 6-24 weeks. The severity of ocular motor signs (esotropia angle; dissociated vertical deviation; latent nystagmus; pursuit / optokinetic tracking asymmetry; fusional vergence deficits), and the loss of V1 binocular connections increased as a function of decorrelation duration. Stereopsis was deficient and motion visually evoked potentials were asymmetric. Monkeys exposed to decorrelation for 3 weeks showed transient esotropia, but regained normal alignment, visuomotor behaviors, and binocular V1 connections.

CONCLUSIONS

Binocular decorrelation is a sufficient cause of infantile esotropia when imposed during a critical period of visuomotor development. The systematic relationship between severity of visuomotor signs and severity of V1 connectivity deficits provides a neuroanatomic mechanism for these signs. Restoration of binocular fusion and V1 connections after short durations of decorrelation helps explain the benefits of early strabismus repair in humans.

Best age for surgery for infantile esotropia

Infantile esotropia (IE) is defined as an esotropia before the age of 6 months, with a large angle, latent nystagmus, dissociated vertical deviation, limitation of abduction, and reduced binocular vision, without neurological disorder. Prematurity, low birth weight, and low Apgar scores are significant risk factors for IE. US standard age of first surgery is 12-18 months, in Europe 2-3 years. The only study to date with prospectively assigned early- and late-surgery groups and evaluation according to intention-to-treat, was the European Early vs. Late Infantile Strabismus Surgery Study (ELISSS). In that study 13.5% of children operated around 20 months vs. 3.9% (P = 0.001) of those operated around 49 months had gross stereopsis (Titmus Housefly) at age 6. The reoperation rate was 28.7% in children operated early vs. 24.6% in those operated late. Unexpectedly, 8% in the early group vs. 20% in the late group had not been operated at age 6, although all had been eligible for surgery at baseline at 11 SD 3.7 months. In most of these children the angle of strabismus decreased spontaneously. In a meta-regression analysis of the ELISSS and 12 other studies we found that reoperation rates were 60-80% for children first operated around age 1 and 25% for children operated around age 4. Based on these findings, the endpoints to consider when contemplating best age for surgery in an individual child with IE should be: (1) degree of binocular vision restored or retained, (2) postoperative angle and long-term stability of the angle and (3) number of operations needed or chance of spontaneous regression. IE is characterized by lack of binocular connections in the visual cortex that cannot develop, e.g. because the eyes squint, or do not develop, e.g. after perinatal hypoxia. As the cause of IE, whether motor or sensory, is a determinant of surgical outcome, a subdivision of IE according to cause is needed. As similarities exist between IE and cerebral palsy we propose to adapt the working definition formulated by the Surveillance of Cerebral Palsy in Europe and define IE as "a group of permanent, but not unchanging, disorders with strabismus and disability of fusional vergence and binocular vision, due to a nonprogressive interference, lesion, or maldevelopment of the immature brain, the orbit, the eyes, or its muscles, that can be differentiated according to location, extent, and timing of the period of development."

Outcome of surgery in long-standing infantile esotropia with cross fixation

BACKGROUND

This is a retrospective study to determine the outcomes of the surgical correction in long-standing infantile esotropia with cross fixation.

METHODS

Medical charts of a group of patients with esotropia who had cross fixation and underwent surgery for strabismus between January 1991 and December 2004 were reviewed. The mean follow-up time was 4.7 years. Binocularity was measured by the Worth 4-dot test and Titmus stereo test. Twenty-six patients underwent surgery for strabismus. Twenty-one patients aged 8 to 26 years with a minimum 3-year postoperative follow-up were included. Five patients were excluded because they were lost to follow-up after surgery.

RESULTS

Bimedial recession and resection of one lateral rectus muscle were performed in all patients. Recession of the inferior oblique muscle with anteriorization was performed in patients who had inferior oblique overaction. Orthotropia was attained in 14 patients, whereas residual esotropia was diagnosed in 5 patients. Two patients were diagnosed as having exotropia. Two patients required a second surgery for dissociated vertical deviation. Overall, 9 of the 21 patients had indications of binocular function and 12 remained the same in their stereoacuity.

CONCLUSION

Surgical correction of long-standing infantile esotropia with cross fixation in young adults may improve binocular function and allow long-term alignment stability.

Comparison of psychosocial and emotional consequences of childhood strabismus on the families from rural and urban India

Purpose:

To compare the psychosocial consequences of horizontal comitant strabismus in children between the families of urban and rural India.

Materials and Methods:

In this cohort study, an eight-question quality-of-life instrument was administered by trained staff to the guardians of strabismic children from rural and urban areas by a live interview.

Results:

This study included 93 strabismic-children aged 4-16 years of which 52 were females. Forty-one had esodeviation and 52 had exodeviation. Seventy per cent parents were extremely distressed due to squint, 65% were extremely distressed due to people's remarks, 65% were extremely worried, 55% children were extremely distressed due to people's remarks, 57% children were severely ostracized, 38% had severe difficulty in communication and 50% had difficulty to cope; 64% parents were not advised a corrective surgery. The difference between families from rural and urban areas, or whether a male child was affected or a female child or for an esodeviation or an exodeviation was statistically not significant. The questionnaire had a good internal consistency (Cronbach's Alpha = 0.71).

Conclusions:

There was a significant negative psychosocial and emotional impact of childhood strabismus that was not affected by the rural or urban location of the family or the gender of the strabismic child or type of the deviation. The quality-of-life instrument can be used as part of the clinical examination for strabismic children.

Short-Term Motor and Sensory Outcomes in Acquired Nonaccommodative Esotropia of Childhood

Information on the management of acquired nonaccommodative esotropia (ANAET) of childhood is incomplete. Most prior reports combine the results of patients with both accommodative and nonaccommodative esodeviations. The primary objective of this study was to describe the early postoperative motor and sensory results of children with acquired nonaccommodative esotropia. The medical records of 72 consecutive children with ANAET who underwent surgical correction at East Tennessee State University College of Medicine from August 1, 1995 through October 1, 2001 were retrospectively reviewed. The median age at surgery for the 72 study patients was 43.8 months with a median angle of deviation of 30 prism diopters (PD) at both distance and near. Ten patients (13.9%) required a second surgical procedure while one patient (1.4%) required a third. The cumulative probability of a second surgery within two years of the first procedure was 24% (95% CI 4-43%). During a median postoperative follow-up period of 7.1 months, 64 (88.9%) patients were within 8 PD of orthotropia on the last postoperative examination. Normal postoperative stereoacuity was achieved in several children whose deviation began after 30 months of age, as well as in one child who was misaligned for at least two years prior to surgery. Although the postoperative follow-up on these patients with acquired nonaccommodative esotropia managed without prism adaptation is short, the motor results are similar to other studies on patients with acquired esotropia, with sensory outcomes superior to those obtained in children with congenital esotropia.

Long-term follow-up of congenital esotropia in a population-based cohort

PURPOSE

To report the long-term outcomes of a population-based cohort of children diagnosed with congenital esotropia during a 30-year period.

METHODS

The medical records of all patients diagnosed with congenital esotropia as residents of Olmsted County, MN, from January 1, 1965, through December 31, 1994, were retrospectively reviewed.

RESULTS

A total of 130 children were diagnosed during the 30-year period at a median age of 7.4 months with a mean deviation of 30(Delta). During a median follow-up of 11.9 years, 126 patients underwent a mean of 1.8 strabismus surgeries. The risk for undergoing a second surgery was significantly greater in patients with a larger presenting angle (p = 0.017) and a younger age at first surgery (p = 0.006). The Kaplan-Meier rate of having a second surgery was 51% at 10 years and 66% at 20 years. For those with 6 weeks or more of follow-up from the final surgery, last examined at a mean age of 15.1 years, 42 of 94 (45%) were within 8(Delta) of orthotropia and 30 of 98 had some level of stereopsis (</=3000 arcsec).

CONCLUSIONS

In this population-based study of children with congenital esotropia, a second surgery was necessary in half the patients after 10 years and was more likely in those patients with a larger presenting angle and a younger age at first surgery. Approximately half of the patients were within 8(Delta) of orthotropia and one-third had measurable stereopsis after a mean of 10.9 years of follow-up.

Timing of surgery for infantile esotropia: sensory and motor outcomes

Infantile esotropia is a common ophthalmic disorder in childhood. It is often accompanied by profound maldevelopment of stereopsis, motion processing, and eye movements, despite successful surgical realignment of the eyes. The proper timing of surgery has been debated for decades. There is growing evidence from clinical and animal studies that surgery during the early critical periods enhances sensory and ocular motor development. The Congenital Esotropia Observational Study has defined a clinical profile of infants who will benefit most from early surgery, and several other studies have shown that early surgery does not lead to adverse long-term effects. Clinicians now should consider offering early surgery to patients with large-angle, constant infantile esotropia at or before 10 months of age.

Instability of ocular alignment in childhood esotropia

OBJECTIVE

Instability of ocular alignment may cause surgeons to delay surgical correction of childhood esotropia. The authors investigated the stability of ocular alignment over 18 weeks in children with infantile esotropia (IET), acquired nonaccommodative esotropia (ANAET), or acquired partially accommodative esotropia (APAET).

DESIGN

Prospective, observational study.

PARTICIPANTS

Two hundred thirty-three children aged 2 months to less than 5 years with IET, ANAET, or APAET of less than 6 months' duration.

METHODS

Ocular alignment was measured at baseline and at 6-week intervals for 18 weeks.

MAIN OUTCOME MEASURES

Using definitions derived from a nested test-retest study and computer simulation modeling, ocular alignment was classified as unstable if there was a change of 15 prism diopters (PD) or more between any 2 of the 4 measurements, as stable if all 4 measurements were within 5 PD or less of one another, or as uncertain if neither criteria was met.

RESULTS

Of those who completed all 3 follow-up visits within time windows for analysis, 27 (46%) of 59 subjects with IET had ocular alignment classified as unstable (95% confidence interval [CI], 33%-59%), 20% as stable (95% CI, 11%-33%), and 34% as uncertain (95% CI, 22%-47%). Thirteen (22%) of 60 subjects with ANAET had ocular alignment classified as unstable (95% CI, 12%-34%), 37% as stable (95% CI, 25%-50%), and 42% as uncertain (95% CI, 29%-55%). Six (15%) of 41 subjects with APAET had ocular alignment classified as unstable (95% CI, 6%-29%), 39% as stable (95% CI, 24%-56%), and 46% as uncertain (95% CI, 31%-63%). For IET, subjects who were older at presentation were less likely to have unstable angles than subjects who were younger at presentation (risk ratio for unstable vs stable per additional month of age, 0.85; 99% CI, 0.74-0.99).

CONCLUSIONS

Ocular alignment instability is common in children with IET, ANAET, and APAET. The impact of this finding on the optimal timing for strabismus surgery in childhood esotropia awaits further study.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Duration of binocular decorrelation in infancy predicts the severity of nasotemporal pursuit asymmetries in strabismic macaque monkeys

PURPOSE

Strabismus in human infants is linked strongly to nasotemporal asymmetries of smooth pursuit, but many features of this co-morbidity are unknown. The purpose of this study was to determine how the duration of early-onset strabismus (or timeliness of repair) affects the severity of pursuit asymmetries in a primate model.

METHODS

Binocular image decorrelation was imposed on infant macaques by fitting them with prism goggles on day 1 of life. The goggles were removed after 3 weeks (n=2), 12 weeks (n=2) or 24 weeks (n=3), emulating surgical repair of strabismus in humans at 3, 12, and 24 months of age, respectively. Two control monkeys wore plano lenses. Several months after the goggles were removed, horizontal smooth pursuit was recorded using binocular search coils and a nasal-bias index (NBI) was calculated.

RESULTS

Each animal in the 12- and 24-week groups developed a constant, alternating esotropic strabismus and a nasotemporal asymmetry of pursuit when viewing with either eye. Spatial vision was normal (no amblyopia). The 3-week duration monkeys were indistinguishable from control animals; they had normal eye alignment and symmetric pursuit. In the 12- and 24-week monkeys, the longer the duration of binocular decorrelation, the greater the pursuit asymmetry: for 15 degrees /s target motion, the NBI in the 12-week and 24-week animals was 16x and 22x greater respectively, than that in the 3-week animals (ANOVA, P=0.03).

CONCLUSIONS

Binocular decorrelation in primates during an early period of fusion development causes permanent smooth pursuit asymmetries when the duration exceeds the equivalent of 3 months in human. These findings support the conclusion that early correction of infantile strabismus promotes normal development of cerebral gaze pathways.

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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Improvement in motor development following surgery for infantile esotropia

PURPOSE

Infantile esotropia is associated with abnormal visual development and thus may delay the achievement of developmental milestones. Although early surgery can improve visual function, less is known about its effect on motor development. Here we address whether early surgery can improve motor development.

METHODS

Recently, our lab devised the Infant Developmental Skills Survey, a 25-item questionnaire designed to assess sensorimotor and gross motor development. The questionnaire was completed by the parents of 3- to 10-month-old patients with infantile esotropia prior to surgery (n = 143) and the parents of 6- to 11-month-old patients following surgery (n = 58). A subset of parents (n = 40) completed the questionnaire both before and after surgery. For comparison, the questionnaire was completed by the parents of infants with normal ocular alignment (n = 194).

RESULTS

Before surgery 4-, 5-, 6-, 7-, 9-, and 10-month-old patients showed delayed achievement of sensorimotor milestones (p < 0.01), and 5-, 9-, and 10-month-old patients demonstrated delayed attainment of gross motor milestones (p < 0.05) compared with normal children. However, following surgery, patients demonstrated a greater rate of sensorimotor development than age-matched controls (p < 0.0001) and caught up with normal children on both sensorimotor and gross motor skills.

CONCLUSIONS

Prior to surgery, patients with infantile esotropia were delayed in their achievement of developmental milestones. However, following surgery, a comparison group of patients showed rapid development and possessed motor skills comparable to those of normal children, suggesting that early surgery is beneficial to both visual and motor development.