Effects of vision therapy on near exodeviation in children with convergence insufficiency treated during the convergence insufficiency treatment trials.

PURPOSE: To report the change in the magnitude of near exodeviation in children with symptomatic convergence insufficiency successfully treated with office-based vergence/accommodative therapy in the Convergence Insufficiency Treatment Trial-Attention and Reading Trial. METHODS: A total of 131 children 9-14 years of age with symptomatic convergence insufficiency classified as successfully treated with office-based vergence/accommodative therapy at the 16-week outcome visit were included. Masked examiners measured the near ocular deviation by the prism and alternate cover test at baseline, primary outcome and 1-year post-treatment. The mean change in near deviation was calculated from baseline to primary outcome, from primary outcome to 1-year post-treatment and from baseline to 1-year post-treatment. RESULTS: Of the 131 participants successfully treated with vergence/accommodative therapy, 120 completed the 1-year post-treatment visit. A significant change in near exodeviation was observed at baseline to primary outcome (2.6Δ less exo, p < 0.001, moderate effect size d = 0.61) and at baseline to 1-year post-treatment (2.0Δ less exo; p < 0.001, small effect size d = 0.45). The change from primary outcome to 1-year post-treatment (0.6Δ more exo; p = 0.06, small effect size d = 0.11) was not significant. Forty per cent (48/120) of participants had a decrease in near exodeviation >3.5∆ (expected test/retest variability) between baseline and the primary outcome examination. Of the 120 participants, one (1.0%) was esophoric at the primary outcome and was subsequently exophoric at 1-year post-treatment. Four participants (3.3%) who were orthophoric or exophoric at the primary outcome were esophoric (all ≤3∆) at the 1-year post-treatment visit. CONCLUSION: On average, the near exodeviation was smaller in size immediately after the discontinuation of vergence/accommodative therapy (2.6∆, moderate effect size) and 1 year post vergence/accommodative therapy (2.0∆, small effect size) in children with convergence insufficiency who were successfully treated; 40% had a clinically meaningful decrease in exophoria. The development of near esophoria was rare.

Functional changes in fusional vergence-related brain areas and correlation with clinical features in intermittent exotropia using functional magnetic resonance imaging.

To explore the functional changes of the frontal eye field (FEF) and relevant brain regions and its role in the pathogenesis of intermittent exotropia (IXT) children via functional magnetic resonance imaging (fMRI). Twenty-four IXT children (mean age, 11.83 ± 1.93 years) and 28 normal control (NC) subjects (mean age, 11.11 ± 1.50 years) were recruited. During fMRI scans, the IXT children and NCs were provided with static visual stimuli (to evoke sensory fusion) and dynamic visual stimuli (to evoke motor fusion and vergence eye movements) with binocular disparity. Brain activation in the relevant brain regions and clinical characteristics were evaluated. Group differences of brain activation and brain-behavior correlations were investigated. For dynamic and static visual disparity relative to no visual disparity, reduced brain activation in the right FEF and right inferior occipital gyrus (IOG), and increased brain activation in the left middle temporal gyrus complex (MT+) were found in the IXT children compared with NCs. Significant positive correlations between the fusional vergence amplitude and the brain activation values were found in the right FEF, right IPL, and left cerebellum in the NC group. Positive correlations between brain activation values and Newcastle Control Scores (NCS) were found in the left MT+ in the IXT group. For dynamic visual disparity relative to static visual disparity, reduced brain activation in the right middle occipital gyrus, left cerebellum, and bilateral IPL was found in the IXT children compared with NCs. Significant positive correlations between brain activation values and the fusional vergence amplitude were found in the right FEF and right cerebellum in the NC group. Negative correlations between brain activation values and NCS were found in the right middle occipital gyrus, right cerebellum, left IPL, and right FEF in the IXT group. These results suggest that the reduced brain activation in the right FEF, left IPL, and cerebellum may play an important role in the pathogenesis of IXT by influencing fusional vergence function. While the increased brain activation in the left MT+ may compensate for this dysfunction in IXT children.

Interocular Suppression in Primary Visual Cortex in Strabismus.

People with strabismus acquired during childhood do not experience diplopia (double vision). To investigate how perception of the duplicate image is suppressed, we raised two male monkeys with alternating exotropia by disinserting the medial rectus muscle in each eye at age four weeks. Once the animals were mature, they were brought to the laboratory and trained to fixate a small spot while recordings were made in primary visual cortex (V1). Drifting gratings were presented to the receptive fields of 500 single neurons for eight interleaved conditions: (1) right eye monocular; (2) left eye monocular; (3) right eye's field, right eye fixating; (4) right eye's field, left eye fixating; (5) left eye's field, right eye fixating; (6) left eye's field, left eye fixating; (7) both eyes' fields, right eye fixating; (8) both eyes' fields, left eye fixating. As expected, ocular dominance histograms showed a monocular bias compared with normal animals, but many cells could still be driven via both eyes. Overall, neuronal responses were not affected by switches in ocular fixation. Individual neurons exhibited binocular interactions, but mean population indices indicated no net interocular suppression or facilitation. Even neurons located in cortex with reduced cytochrome oxidase (CO) activity, representing portions of the nasal visual field where perception is suppressed during binocular viewing, showed no net inhibition. These data indicate that V1 neurons do not appear to reflect strabismic suppression and therefore the elimination of diplopia is likely to be mediated at a higher cortical level.SIGNIFICANCE STATEMENT In patients with strabismus, images fall on non-corresponding points in the two retinas. Only one image is perceived, because signals emanating from the other eye that convey the duplicate image are suppressed. The benefit is that diplopia is prevented, but the penalty is that the visual feedback required to adjust eye muscle tone to realign the globes is eliminated. Here, we report the first electrophysiological recordings from the primary visual cortex (V1) in awake monkeys raised with strabismus. The experiments were designed to reveal how perception of double images is avoided.

Maintenance of normal fusion in intermittent exotropia.

PURPOSE: To evaluate the reliability of the Bagolini filter bar and striated lenses for measuring the fusion maintenance score, which is the ability of participants with intermittent exotropia to maintain normal sensorimotor fusion. METHODS: Thirty-two Chinese participants aged 7-20 years with intermittent exotropia (excluding the convergence insufficiency type) were enrolled in this prospective study. At the eligibility screening, visual acuity, cover test and assessment of the office control score were performed. At study visit 1, eligible participants underwent negative and positive fusional vergence tests at far and near, eye dominance test and the fusion maintenance test. All eligible participants returned for study visit 2 on the same day (2-4 h later) and the testing was repeated. The primary outcome measure was the intra-class correlation coefficient of the fusion maintenance score between the two study visits. RESULTS: The intra-class correlation coefficient of the fusion maintenance score was 0.84, indicating good reliability. There was no significant difference (mean difference = 0.05, p = 0.95) between the fusion maintenance scores for the first (5.62) and second study visits (5.57). The coefficient of repeatability and the smallest detectable change for the fusion maintenance scores were 7.6 and 6.3, respectively. The fusion maintenance score was significantly associated with the distance (Spearman correlation -0.57, p < 0.001) and near (Spearman correlation -0.4, p = 0.02) office control scores. CONCLUSION: These data demonstrate that the fusion maintenance score is a reliable tool to evaluate sensorimotor fusion in intermittent exotropia. These results suggest that the fusion maintenance score may be a useful outcome measure in future clinical trials to evaluate the effectiveness of treatments for intermittent exotropia.

Difference in myopia progression between dominant and non-dominant eye in patients with intermittent exotropia.

OBJECTIVE: To investigate the difference in the rate of myopia progression between the dominant and non-dominant eye in patients with intermittent exotropia (IXT). METHODS: We retrospectively reviewed the medical records of 33 patients who underwent surgery and later reoperation for IXT. We included only patients whose spherical equivalent refractive errors (SER) were ≤ - 0.50 diopter (D) in at least one eye at the time of reoperation. The main outcome measurement was the rate of myopia progression, which was defined as the mean annual change in SER between the first and second surgery. We classified patients into two groups: group A, which comprised 25 patients whose non-dominant eyes showed a faster myopia progression than their dominant eyes, and group B, which comprised the remaining 8 patients showing the opposite. RESULTS: Mean age of the patients at the time of the initial surgery was 5.64 years. Mean interval between the initial and second surgery was 4.45 years. Mean rate of myopia progression over the interval was - 0.37 D/year in the dominant eyes and - 0.50 D/year in the non-dominant eyes (P < 0.001). Group A had a significantly greater amount of distance deviation (31.0 vs. 25.6 PD, P = 0.020) and near deviation (30.8 vs 26.0 PD, P = 0.039) before the initial surgery and a significantly worse score of distance control (3.05 vs. 2.00, P = 0.023) before the second surgery than group B. CONCLUSIONS: The non-dominant eyes experienced a faster myopia progression than the dominant eyes in patients with IXT. This faster myopia progression demonstrated in the non-dominant eyes was associated with clinically severe exotropia in terms of the amount of deviation and the degree of control.

Binocular discrepancy in lateral rectus muscle attachment in intermittent exotropia with eye dominance.

PURPOSE: To determine whether there is asymmetry in the lateral rectus (LR) muscle attachment between both eyes in patients with intermittent exotropia (IXT) with a non-dominant eye, but without amblyopia or anisometropia. METHODS: In total, 109 patients who underwent bilateral lateral rectus recession for IXT were included, 81 with and 28 without eye dominance. The limbus-insertion distance and tendon width of the LR muscle were measured intraoperatively using callipers. The insertion-equator distance (presumed arc of contact), area of contact (arc of contact × tendon width), and torque value (radius of globe × arc of contact) of the LR muscle were calculated based on intraoperative measurements and axial length measured using a partial interferometer. Parameters regarding LR muscle attachment were compared between fellow eyes and between groups. RESULTS: Mean measurements in all parameters related to LR muscle attachments other than tendon width were not different between the two eyes or between groups. The mean tendon width of the non-dominant eye was 9.2 ± 0.7 mm, narrower than the 9.4 ± 0.5 mm width in either eye of patients without dominance (p = 0.020). However, there was no difference in all parameters in 21 pairs of patients after matching. The proportion of patients who showed binocular discrepancies in attachment measurements beyond that attributable to potential measuring errors did not differ between the two groups. CONCLUSIONS: Structural parameters related to LR muscle attachments did not differ based on eye dominance, suggesting that the anatomic structure of LR muscle attachments is not responsible for eye dominance in IXT.

The stability of horizontal ocular alignment of triad exotropia after one-step triple surgery.

PURPOSE: A-pattern exotropia, superior oblique muscle overaction, and dissociated vertical deviation may coexist and are referred to as triad exotropia. The present study evaluated the postoperative stability of horizontal ocular alignment of triad exotropia and possible prognostic factors. METHODS: Medical records of patients with triad exotropia who had one-step triple surgery of superior oblique muscle weakening, superior rectus muscle recession, and lateral rectus muscle recession were reviewed. The horizontal alignment and postoperative drift of triad exotropia were analyzed and compared with constant exotropia. RESULTS: The triad exotropia showed a mean of 7.7△ (± 8.5△) eso-drift, while the constant exotropia was (3.5△ ± 3.4△) exo-drift. Multiple linear regression analysis showed that the degree of superior oblique muscle overaction after surgery (P = 0.011) was the only factor associated with horizontal drift. Patients with superior oblique muscle underaction showed larger eso-drift when compared to patients without superior oblique muscle underaction (- 18.0△ ± 11.1△ vs. - 5.1△ ± 5.7△; P = 0.024). The final success rates of the triad exotropia and constant exotropia groups were 53.3% and 69.2%, respectively, and the overcorrection rates were 26.7% and 2.6% (P = 0.035). CONCLUSIONS: An overall trend of eso-drift in primary position occurred in triad exotropia after triple surgery up to a follow-up of 25 months. Patients presenting superior oblique muscle underaction after surgery seemed to have large angles of eso-drift, which might be taken into account in surgical planning and follow-up.

Risk factors associated with poor outcome after medial rectus resection for recurrent intermittent exotropia.

PURPOSE: To describe characteristics of recurrent intermittent exotropia after bilateral lateral rectus (BLR) recession, and identify factors associated with poor outcome after unilateral medial rectus (MR) resection for recurrent intermittent exotropia. METHODS: We retrospectively reviewed 124 patients who have undergone unilateral MR resection for recurrent intermittent exotropia after BLR recession. Patients were followed for at least 2 years after MR resection. Clinical characteristics and risk factors associated with poor outcome after unilateral MR resection were evaluated. Successful outcome was defined as distant deviation within the range of 4 prism diopters (PD) esotropia and 10 PD exotropia at last visit after MR resection. RESULTS: Among 124 patients, 50 patients (41.1%) were male, and the mean age at the time of MR resection was 9.5 ± 3.1 years. The average follow-up period after MR resection was 43.8 ± 23.7 months. Forty-seven patients (37.9%) were classified to have poor outcome at last visit, and 29 patients (23.4%) underwent third operation. None of the patients was overcorrected after MR resection. Multiple logistic regression analyses showed that distant deviation at post-operative 3 months and male gender were associated with poor outcome (OR 1.49; 95% CI 1.27-1.73; P < 0.001, and OR 5.19; 95% CI 1.42-18.98; P = 0.013, respectively). CONCLUSION: Ocular deviation at 3 months after unilateral MR resection for recurrent intermittent exotropia may play a valuable role in anticipating poor outcome. Patients whose exotropia exceeded 9 PD at distance at 3 months' follow-up tended to recur while those whose exotropia remained below 9 PD at distance showed a stable disease course.

Risk factors for excessive postoperative exo-drift after unilateral lateral rectus muscle recession and medial rectus muscle resection for intermittent exotropia.

BACKGROUND: To detect significant factors associated with excessive postoperative exo-drift in young patients with intermittent exotropia who had undergone unilateral lateral rectus muscle recession and medial rectus muscle resection. METHODS: We retrospectively examined the records of 64 consecutive patients < 18 years old who underwent surgery between April 2004 and December 2011. We sought risk factors for excessive postoperative exo-drift among patients' demographic and clinical characteristics using univariate and multivariable linear regression analysis. RESULTS: Younger patients (P = 0.007), and those with larger preoperative exo-deviation at distance (P = 0.033), a lower incidence of peripheral fusion at distance (P = 0.021) or a greater postoperative initial eso-deviation (P = 0.001), were significantly more likely to have an excessive postoperative exo-drift (> 20 prism diopters). Univariate analysis revealed significant associations between excessive postoperative exo-drift and age at surgery (P = 0.004), preoperative exo-deviation at distance (P = 0.017) and postoperative initial eso-deviation at distance (P < 0.001). Multivariable linear regression analysis showed that postoperative initial eso-deviation at distance (P = 0.008) was significantly associated with postoperative exo-drift. CONCLUSIONS: Postoperative exodrift in unilateral RR is predicted by the initial postoperative eso-deviation, which may offset the overcorrection. However, the exo-drift is greater in cases with a large preoperative exo-deviation and/or at a younger age, and should be followed carefully.

The efficacy of superior oblique posterior tenectomy in the treatment of A-pattern exotropia without ocular intorsion: A retrospective study.

BACKGROUND: Superior oblique weakening is a common method to treat A-pattern strabismus. This study aims to evaluate the surgical results of the bilateral superior oblique posterior tenectomy procedure to treat A-pattern strabismus patients who had bilateral superior oblique overaction without objective ocular intorsion. METHODS: The records of 18 consecutive patients who underwent surgery of superior oblique posterior tenectomy close to its insertion with superior oblique overaction (SOOA)-associated A-pattern strabismus between September 1, 2015 and August 31, 2018 were retrospectively reviewed. Ocular alignment, objective torsion, A-pattern and ocular motility were assessed. Ocular alignment was measured in the primary position, 25° upgaze, and 25° downgaze using the prism bar cover test, and torsion was measured using fundus photographs. RESULTS: A total of 18 patients (mean age: 15 years; 6 female, 12 male) underwent bilateral superior oblique posterior tenectomy and simultaneous horizontal rectus muscle surgery were included. The mean preoperative A-pattern deviation was 15 PD and the mean postoperative A-pattern deviation was 2.25 PD with a mean reduction of 12.75 PD. The mean preoperative superior oblique overaction was 2.28 and the mean postoperative superior oblique overaction was 0.43 with a mean reduction of 1.85. There was no significant correlation between the ocular torsional, vertical alignment change and the superior oblique posterior tenectomy procedure. CONCLUSIONS: Superior oblique posterior tenectomy surgery selectively improved the A-pattern and superior oblique overaction but not affect the primary position vertical deviation, as well as the ocular torsion. It is an effective procedure to treat the mild to moderate superior oblique overaction associated A pattern strabismus without ocular intorsion.

Three-year observation of children 12 to 35 months old with untreated intermittent exotropia.

PURPOSE: To describe the clinical course of untreated intermittent exotropia (IXT) in children 12-35 months of age followed for 3 years. METHODS: We enrolled 97 children 12-35 months of age with previously untreated IXT who had been randomly assigned to the observation arm of a randomised trial of short-term occlusion versus observation. Participants were observed unless deterioration criteria were met at a follow-up visit occurring at 3 months, 6 months, and 6-month intervals thereafter for 3 years. The primary outcome was deterioration of the IXT by 3 years, defined as (1) a constant exotropia ≥10 prism dioptres (∆) at distance and near (i.e., motor deterioration) or (2) treatment prescribed despite not having met motor deterioration. The primary analysis used the Kaplan-Meier method to determine the cumulative proportion of participants meeting deterioration by three years and 95% confidence interval (CI). RESULTS: The cumulative probability of deterioration by 3 years was 28% (95% CI = 20%-39%). Of the 24 participants meeting the primary outcome of deterioration, seven met motor deterioration and 17 were prescribed treatment without meeting motor deterioration. The cumulative probability of motor deterioration by 3 years was 10% (95% CI = 5%-19%). CONCLUSIONS: Given the modest rate of motor deterioration over three years, watchful waiting may be a reasonable management approach in 12- to 35-month-old children with IXT. To confirm this recommendation would require a long-term randomised trial of immediate treatment versus observation followed by deferred treatment if needed.

Disrupted neural signals in patients with concomitant exotropia.

PURPOSE: Decreased binocular and oculomotor function in strabismics has recently been considered as cortical in origin. This study aimed to investigate functional abnormalities using a frequency-specific neuroimaging method in patients with concomitant exotropia (XT), and to demonstrate the clinical implications. METHODS: Resting-state functional magnetic resonance imaging data were collected in 26 XT patients and 26 matched controls. To evaluate the local spontaneous neural activity, the amplitude of low frequency fluctuations (ALFF) was calculated in the typical frequency band (0.01-0.08 Hz) as well as five narrowly-defined frequency bands (slow-6: 0-0.01 Hz, slow-5: 0.01-0.027 Hz, slow-4: 0.027-0.073 Hz, slow-3: 0.073-0.167 Hz, and slow-2: 0.167-0.25 Hz), respectively. RESULTS: Patients with XT showed decreased ALFF in the bilateral parieto-occipital sulcus (POS), and increased ALFF in the bilateral thalamus within the typical frequency band. Frequency-dependent ALFF alterations were found in the higher visual areas such as the right lateral occipital complex (LOC). Furthermore, ALFF in the right LOC in the slow-5 band was positively correlated with fusion control score (r = 0.70, p < 0.0001) and binocular function score (r = 0.67, p = 0.0002). Regression analyses showed that early age of onset remained the only significant explanatory factor for ALFF reduction in the right POS in the typically-measured frequency band (also referred to as the typical frequency band) (Odds ratio, 0.038; 95% confidence interval, 0.001 to 0.075). CONCLUSIONS: Our findings provide spatial information regarding the functionally disrupted regions in XT. Moreover, the frequency-dependent ALLF alteration in the right LOC might reflect a potential plastic capacity in binocular function, which could be a potential objective index for evaluating disease severity.

[Morphological observation on the anterior ciliary vessels in the horizontal rectus muscles of patients with concomitant horizontal strabismus].

Objective: To observe the number of blood vessels and the anatomical characteristics of the anterior ciliary vessels (ACVs) in the horizontal rectus muscles of patients with concomitant horizontal strabismus. Methods: Cross-sectional study. From July 2016 to September 2019 patients with concomitant horizontal strabismus treated by realignment surgeries in Xiamen Eye Center of Xiamen University were included. Patients who had previous operations on eyes were excluded. The high resolution surgical imaging of ACVs in the horizontal rectus muscles was performed during operation. The photos of ACVs in muscles were tagged and observed to compare the distribution of the various numbers of blood vessels and morphological characteristics of the ACVs in the medial and lateral rectus muscles. In addition, muscle tissues about 4 mm with an intact sheath were gained from patients undergoing the muscle resection. The muscle sections were stained with hematoxylin-eosin staining, and the arteriovenous properties and their distribution in muscles and fascia tissues were observed. The chi-square test was used for statistical analysis. Results: A total of 387 patients with concomitant horizontal strabismus (176 with esotropia, 211 with exotropia) were enrolled in this study, among whom 198 were male and 189 were female. The age ranged from 1 to 68 years (median, 13 years). Photos of ACVs in 742 horizontal rectus muscles from 383 patients were observed. Of the 351 medial rectus muscles, 24 (6.8%) contained 1 major (or bundle of) ACV, 163 (46.4%) contained 2 major (or bundles of) ACVs, and 164 (46.7%) contained 3 or more major (or bundles of) ACVs. Of the 391 lateral rectus muscles, 161 (41.2%) contained 1 major (or bundle of) ACV, 156 (39.9%) contained 2 major (or bundles of) ACVs, and 74 (18.9%) contained 3 or more major (or bundles of) ACVs. The distribution of ACVs in the medial and lateral rectus muscles was statistically different (χ(2)=133.87, P<0.01). According to the number and morphological characteristics of vessels, the ACVs in the medial and lateral rectus muscles were divided into 4 and 3 categories, respectively, as well as various types and subtypes. The rate of patients whose both eyes had the same type of ACVs in the medial or lateral rectus muscles was 31.6% (25/79) and 26.1% (29/111), respectively, and there was no significant difference (χ(2)=0.69, P=0.41). However, the ACVs of the same type from both eyes of the same patient were not identical in morphology. The ACVs in the medial and lateral rectus muscles with collateral circulation accounted for 3.7% (13/351) and 24.3% (95/391), respectively, and the difference was statistically significant (χ(2)=63.07, P<0.01). The hematoxylin-eosin staining of the medial lateral rectus tissues from 4 patients showed that the ACVs contained arteries and veins. The vessels in the medial rectus muscles were distributed in muscle tissue and fascia tissue, while the vessels in the lateral rectus muscles were only distributed in fascia tissue. Conclusions: Compared with the lateral rectus muscles, there are about 50% medial rectus muscles contain more than 3 major (or bundles of) vessels in patients with concomitant horizontal strabismus. The accompanying patterns of arteries and veins of ACVs are varied. ACVs are distributed in muscle tissue of the medial rectus muscles and in fascia tissue of the medial and lateral rectus muscles. (Chin J Ophthalmol, 2020, 56: 197-204).

Functional anatomy of extraocular muscles during human vergence compensation of horizontal heterophoria.

We employed magnetic resonance imaging to quantify human extraocular muscle (EOM) contractility during intermittent convergent and divergent strabismus with each eye viewing monocularly at 20 cm compared with centered target fusion. Contractility, indicated by posterior partial volume change, was analyzed in transverse rectus and in medial and lateral superior oblique (SO) muscle compartments. In five subjects with intermittent esotropia, abduction of the deviated eye to monocular target fixation was associated with significant whole lateral rectus (LR) contraction, but with medial rectus (MR) relaxation that was significantly greater in the superior than inferior compartment. Esotropic eye abduction to binocular fusion was associated with similar relaxation in the two MR compartments, but with greater contraction in the LR's superior than inferior compartment. The whole diverging eye SO muscle relaxed. In three subjects with intermittent exotropia, converging eye fusional adduction was associated with significant whole LR relaxation and with MR contraction attributable to significantly greater contraction in the superior than inferior compartment. In adduction of the exotropic eye to monocular target fixation but not fusional adduction, the whole SO exhibited significant relaxation. Rectus pulley positions were not significantly altered by fusion of either form of intermittent strabismus. Globe rotational axis was eccentric in intermittent strabismus, rolling the eye so that rectus EOM lever arms facilitated vergence. These results confirm, and extend to fusion of intermittent horizontal strabismus, differential compartmental function in horizontal rectus EOMs and suggest a novel role for the SO in compensation of both intermittent esotropia and exotropia. NEW & NOTEWORTHY Disjunctive eye movements normally permit binocular fixation in near visual space but also compensate for mechanical imbalances in binocular alignment developing over the life span. Magnetic resonance imaging of the extraocular muscles demonstrates important differential function in muscle compartments during compensation of large-angle intermittent convergent and divergent strabismus in humans. Eye translation during rotation also enhances vergence compensation of intermittent strabismus.

Three-Year Observation of Children 3 to 10 Years of Age with Untreated Intermittent Exotropia.

PURPOSE: To describe the course of intermittent exotropia (IXT) in children followed up without treatment for 3 years. DESIGN: Observation arm from randomized trial of short-term occlusion versus observation. PARTICIPANTS: One hundred eighty-three children 3 to 10 years of age with previously untreated IXT and 400 seconds of arc (arcsec) or better near stereoacuity. METHODS: Participants were to receive no treatment unless deterioration criteria were met at a follow-up visit occurring at 3 months, 6 months, or 6-month intervals thereafter for 3 years. MAIN OUTCOME MEASURES: The primary outcome was deterioration by 3 years, defined as meeting motor criterion (constant exotropia ≥10 prism diopters [Δ] at distance and near) or near stereoacuity criterion (≥2-octave decrease from best previous measure). For the primary analysis, participants also were considered to have deteriorated if treatment was prescribed without meeting either deterioration criterion. RESULTS: The cumulative probability of protocol-specified deterioration by 3 years was 15% (95% confidence interval, 10%-22%), but that was likely an overestimate, partly because of misclassification. Among 25 deteriorations, 2 met motor deterioration, 11 met stereoacuity deterioration, and 12 started treatment without meeting either criteria (7 for social concern, 1 for diplopia, 4 for other reasons). Among the 132 participants who completed the 3-year visit and had not been treated during the study, only 1 (<1%) met motor or stereoacuity deterioration criteria at 3 years. Of the 4 participants completing the 3-year visit who met deterioration criteria previously and had not started treatment, none still met deterioration criteria. Between the baseline and 3-year examination for these 132 patients, improvement occurred in distance and near stereoacuity (mean improvement, 0.14 and 0.14 logarithm of arcsec; P ≤ 0.001 and P ≤ 0.001, respectively), distance exotropia control (mean improvement, 0.6 points; P ≤ 0.001), and distance exodeviation magnitude (mean improvement, 2.2 Δ; P = 0.002). CONCLUSIONS: Among children 3 to 10 years of age with IXT for whom surgery was not considered to be the immediately necessary treatment, stereoacuity deterioration or progression to constant exotropia over 3 years was uncommon, and exotropia control, stereoacuity, and magnitude of deviation remained stable or improved slightly.

A Randomized Trial Comparing Bilateral Lateral Rectus Recession versus Unilateral Recess and Resect for Basic-Type Intermittent Exotropia.

PURPOSE: To compare long-term outcomes after bilateral lateral rectus recession (BLRc) or unilateral lateral rectus recession combined with medial rectus resection in the same eye (R&R) for primary treatment of childhood intermittent exotropia (IXT). DESIGN: Multicenter, randomized clinical trial. PARTICIPANTS: One hundred ninety-seven children 3 to younger than 11 years of age with basic-type IXT, a largest deviation by prism and alternate cover test at any distance of 15 to 40 prism diopters (PD), and near stereoacuity of at least 400 seconds of arc. METHODS: Random assignment to BLRc or R&R and masked examinations conducted every 6 months after surgery for 3 years. MAIN OUTCOME MEASURES: Proportion of participants meeting suboptimal surgical outcome by 3 years, defined as: (1) exotropia of 10 PD or more at distance or near using simultaneous prism and cover test (SPCT); or (2) constant esotropia of 6 PD or more at distance or near using SPCT; (3) loss of 2 octaves or more of stereoacuity from baseline, at any masked examination; or (4) reoperation without meeting any of these criteria. RESULTS: Cumulative probability of suboptimal surgical outcome by 3 years was 46% (43/101) in the BLRc group versus 37% (33/96) in the R&R group (treatment group difference of BLRc minus R&R, 9%; 95% confidence interval [CI], -6% to 23%). Reoperation by 3 years occurred in 9 participants (10%) in the BLRc group (8 of 9 met suboptimal surgical outcome criteria) and in 4 participants (5%) in the R&R group (3 of 4 met suboptimal surgical outcome criteria; treatment group difference of BLRc minus R&R, 5%; 95% CI, -2% to 13%). Among participants completing the 3-year visit, 29% (25 of 86) in the BLRc group and 17% (13 of 77) in the R&R group underwent reoperation or met suboptimal surgical outcome criteria at 3 years (treatment group difference of BLRc minus R&R, 12%; 95% CI, -1% to 25%). CONCLUSIONS: We did not find a statistically significant difference in suboptimal surgical outcome by 3 years between children with IXT treated with BLRc compared with those treated with R&R. Based on these findings, we are unable to recommend one surgical approach over the other for childhood IXT.

Further delineation of the MECP2 duplication syndrome phenotype in 59 French male patients, with a particular focus on morphological and neurological features.

The Xq28 duplication involving the MECP2 gene (MECP2 duplication) has been mainly described in male patients with severe developmental delay (DD) associated with spasticity, stereotypic movements and recurrent infections. Nevertheless, only a few series have been published. We aimed to better describe the phenotype of this condition, with a focus on morphological and neurological features. Through a national collaborative study, we report a large French series of 59 affected males with interstitial MECP2 duplication. Most of the patients (93%) shared similar facial features, which evolved with age (midface hypoplasia, narrow and prominent nasal bridge, thick lower lip, large prominent ears), thick hair, livedo of the limbs, tapered fingers, small feet and vasomotor troubles. Early hypotonia and global DD were constant, with 21% of patients unable to walk. In patients able to stand, lower limbs weakness and spasticity led to a singular standing habitus: flexion of the knees, broad-based stance with pseudo-ataxic gait. Scoliosis was frequent (53%), such as divergent strabismus (76%) and hypermetropia (54%), stereotypic movements (89%), without obvious social withdrawal and decreased pain sensitivity (78%). Most of the patients did not develop expressive language, 35% saying few words. Epilepsy was frequent (59%), with a mean onset around 7.4 years of age, and often (62%) drug-resistant. Other medical issues were frequent: constipation (78%), and recurrent infections (89%), mainly lung. We delineate the clinical phenotype of MECP2 duplication syndrome in a large series of 59 males. Pulmonary hypertension appeared as a cause of early death in these patients, advocating its screening early in life.

Long-term surgical outcomes of patients with consecutive exotropia.

PURPOSE: To evaluate the long-term surgical outcome of patients with consecutive exotropia. METHODS: Patients who underwent surgery for the treatment of consecutive exotropia between January 2008 and July 2016 with a minimum follow-up period of 2 years were retrospectively reviewed. Surgical outcomes were classified based on postoperative angle of deviation at 2 years as follows: success (esodeviation ≤ 5 prism diopters [PD] to exodeviation ≤ 10 PD), and recurrence [exodeviation > 10 PD]). Postoperative angles of deviation at 1 week, 1 month, 6 months, 1 year, and 2 years and at the final follow-up were investigated. RESULTS: A total of 37 patients (28 in the success group and 9 in the recurrence group) were included. Surgical success rate at 2 years was 75.7%, and reoperation rate was 10.8% during a mean follow-up period of 42.4 ± 18.3 months after consecutive exotropia surgery. After surgery, exodrift occurred mostly during 1-month follow-up in both groups, and those with no exodrift within 1 month presented a higher surgical success. Thereafter, patients in the success group showed a more stable course during follow-up than those in the recurrence group. Stereopsis was an important factor associated with surgical outcome. CONCLUSIONS: Exodrift occurs mostly within 1 month after surgery for consecutive exotropia. Targeting initial overcorrection and establishing esodeviation at postoperative month 1 is important to achieve successful results.

Facial Asymmetry in Unilateral Duane Retraction Syndrome.

SIGNIFICANCE: The overall objective of this study was to evaluate facial asymmetry in patients with unilateral Duane retraction syndrome (DRS). The results showed a high frequency of facial asymmetry parameters of the opposite side of head turn in unilateral DRS patients. PURPOSE: The purposes of this study were to evaluate the characteristics of facial asymmetry in unilateral exotropic and esotropic DRS and to compare the findings with orthotropic subjects. METHODS: This cross-sectional comparative case series study was performed in 44 consecutive patients with head turn caused by DRS and 44 orthotropic subjects from 2016 to 2019. Four pictures were taken from the patients' faces. The first and second pictures were taken when patients had head turn and when the head was completely straight for calculating the facial angle and relative facial size, respectively. The third and fourth pictures were taken when the head was positioned downward (to compare the size of the cheek) and upward (to evaluate nose asymmetry). RESULTS: The mean ± SD age of DRS patients and orthotropic subjects was 16.23 ± 9.92 and 20.68 ± 11.82 years, respectively. The frequency of facial asymmetry and all facial parameters (cheek compression, nasal tip and columella deviation, and compression of one of the nostrils) was significantly higher in DRS patients compared with orthotropic subjects (P < .001). In DRS patients with facial asymmetry, columella and nasal tip deviation (P = .006) and cheek and face compression (P = .03) were significantly more prevalent in the opposite direction of head turn. In the DRS group, the mean ± SD age of the patients with and without facial asymmetry was 17.37 ± 9.76 and 7.40 ± 6.54 years, respectively (P = .02). CONCLUSIONS: The frequency of facial asymmetry and all facial parameters was significantly higher in DRS patients compared with orthotropic subjects. In unilateral DRS patients, the face was more commonly affected on the opposite side of head turn.

Office-based Vergence and Accommodative Therapy for the Treatment of Intermittent Exotropia: A Pilot Study.

SIGNIFICANCE: This study will help to demonstrate the potential value of office-based vergence/accommodative therapy for the treatment of intermittent exotropia and provide data that can be used for planning future clinical trials. PURPOSE: This study was designed to evaluate changes in the office control score after office-based vergence/accommodative therapy for intermittent exotropia. METHODS: This was a prospective, unmasked pilot study. Fourteen Chinese participants aged 6 to 18 years with intermittent exotropia (excluding the convergence insufficiency type) were enrolled. All participants received 60 minutes of office-based vergence/accommodative therapy with home reinforcement once per week for 12 weeks. Therapy included vergence, accommodation, saccades and pursuits, antisuppression, and monocular fixation in binocular field techniques. The primary outcome measure was the change in the office control score from the baseline visit to the 13-week outcome visit. RESULTS: All participants completed the study. The office control score at distance changed by -1.0 (95% confidence interval [CI] = -1.6 to -0.4; P = .005; Cohen's d effect size, 0.93). The distant Look And Cover, then Ten seconds Observation Scale for Exotropia score and distant Newcastle control score total score changed by -0.7 (95% CI, -1.2 to -0.2; P = .02; Cohen's d effect size, 0.55) and -1.9 (95% CI, -2.8 to -1.0; P < .001; Cohen's d effect size, 1.37), respectively. Although there was no significant change in the angle of distance exodeviation (-1.8 prism diopter [Δ] less exodeviation; 95% CI, -3.74 to 0.14Δ; P = .11), a significant change was observed in the near angle (-4.4Δ less exodeviation; 95% CI, -7.3 to -1.5Δ; P = .01; Cohen's d effect size, 0.79). There was no significant change in stereopsis or the Chinese Intermittent Exotropia Questionnaire score. CONCLUSIONS: In this select group of children with intermittent exotropia, 12 weeks of office-based vergence/accommodative therapy with home reinforcement resulted in a statistically and clinically significant improvement in the distance control of exodeviation and the near exodeviation magnitude. These results suggest that there is a need for a randomized clinical trial designed to determine the effectiveness of vision therapy as a treatment modality for intermittent exotropia.