Slanted and Standard Lateral Rectus Recession Procedures for Convergence Insufficiency-Type Intermittent Exotropia in Children: A Retrospective Cohort Study.

Purpose: To evaluate the efficacy and safety of slanted bilateral lateral rectus recession (BLR-rec) for treating convergence insufficiency-type intermittent exotropia (CI-IXT) in children. Methods: In this retrospective cohort study, 26 patients aged <16 years with CI-IXT who underwent BLR-rec between August 2016 and July 2021 with six months of follow-up data post-surgery were classified into slanted BLR-rec group (n = 14) and standard BLR-rec group (n = 12; equal-length recession of the upper and lower horns of the LR muscle). Surgical outcomes were compared between the groups. Results: In the slanted and standard groups, the preoperative distance exodeviation was 27.9 ± 5.5 and 30.8 ± 10.0 prism diopter (PD) (p = 0.63), near exodeviation was 41.1 ± 5.6 and 42.9 ± 9.2 PD (p = 0.75), and difference between near and distance deviation (N-D deviation difference) was 13.2 ± 3.2 and 12.1 ± 3.3 PD (p = 0.30), respectively. The ratio of postoperative and preoperative N-D deviation difference was compared between the slanted BLR and standard BLR groups at six months postoperatively. The results revealed that the ratio for slanted-BLR was 0.44 ± 0.19, and for standard-BLR was 0.84 ± 0.24. In the standard group, stereoacuity remained unchanged post-surgery compared to that pre-surgery, while the slanted group showed significant improvement (p < 0.05, Wilcoxon signed-rank test). Conclusion: Compared with the standard BLR-rec procedure, the slanted BLR-rec procedure reduced N-D deviation differences in CI-IXT, positively impacting gross stereopsis.

The effect of sunglass filters on contrast sensitivity, monocular eye closure, and blinking rate in people with intermittent exotropia.

CLINICAL RELEVANCE: Transient monocular eye closure and photosensitivity under bright light have been reported in people with intermittent exotropia (IXT). The exact mechanism of these symptoms has not been established. BACKGROUND: This study examines the effect of sunglass filters on contrast sensitivity (CS), transient monocular eye closure, and blinking rate under bright light in people with IXT. METHODS: Forty participants with IXT and complaints of photosensitivity were included in the study. The binocular CS test was performed under mesopic and photopic conditions with and without glare, and with and without two filters with different grades of light transmission (filter 1: 44-80%; filter 2: 20-43% light transmittance). The effect of two filters on transient eye closure, contrast sensitivity, and blinking rate was assessed under bright light. Also, participants were divided into 3 groups based on their degree of control of fusion (good, fair, and poor control). RESULTS: The mean age of the participants was 12.0 years ± 8.0 (standard deviation) (range: 7-40 years). There was no significant difference between the age (p = 0.139), stereopsis (p = 0.134), as well as the near and far degree of deviation (p = 0.516, and p = 0.237) between the three groups of fusion control. Under mesopic conditions with glare, mean binocular CS was significantly higher with filters (p < 0.001). Without filters, 57.5% of the participants exhibited monocular eye closure under a photopic setting with additional glare. No participant showed eye closure using filter 2. People in the poor control group showed exodeviation before monocular eye closure (62.5% without filter and 12.5% with filter 1, p = 0.01). The blinking rate decreased from 36.0 ± 4.0 blinks per minute without filter to 21.0 ± 3.0 using filter 1, and 20.0 ± 3.0 with filter 2. CONCLUSION: In people with IXT, wearing sunglass filters of different transmittance reduces monocular eye closure and blinking rate under bright light. To improve these symptoms, sunglasses can be considered for IXT.

Fibroblastic tumour in the medial rectus muscle presenting as a large-angle exotropia.

Objective: The aim is to report a very rare case of a fibroblastic tumour in the medial rectus muscle of the right eye in a young adult. Methods: A 28-year-old patient presented to the strabismus clinic with large-angle exotropia in the right eye. The patient had previously undergone strabismus surgery in both eyes, and the old photos showed increasing exotropia from childhood to adulthood. On examination, the patient had a best corrected visual acuity of 20/20, 85 PD of exotropia with a -4 limitation of adduction, and retinal evaluation was unremarkable. In view of the chronicity of the deviation, increasing exotropia over time, and limitation of the ocular motility in adduction, a magnetic resonance imaging was performed. Results: Orbital magnetic resonance imaging (MRI) undertaken to identify the extraocular muscle position revealed a bulky and thickened right medial rectus muscle with post-contrast enhancement and without fat stranding and orbital extension. A muscle biopsy was performed, and a series of histopathological stains revealed that the tumour cells were positive for CD34 and vimentin. Immuno histochemistry and histopathology suggested a benign fibroblastic tumour (superficial CD34+ fibroblastic tumour) with low malignant potential. Conclusion: This report describes a fibroblastic tumour of the eye muscle identified on neuroimaging and confirmed on histopathology. Such a presentation is very rare and to the best of our knowledge has not been previously reported in ophthalmic literature.

Association of Accommodation and Convergence with Axial Length Elongation in Children with Basic Intermittent Exotropia: A 12-Month Observational Study.

INTRODUCTION: The aim of the study was to investigate the association of parameters related to accommodation and convergence and axial elongation in basic intermittent exotropia (IXT) patients and the potential clinical predictors of axial length (AL) growth. METHODS: A total of 140 basic IXT patients were recruited in this study. The medians of AL growth in different age brackets were chosen to divide the subjects into group A (slower axial elongation group, n = 69) and group B (faster axial elongation group, n = 71). Parameters of dominant and nondominant eyes were compared and analyzed during the 12-month follow-up period. The parameters, including baseline refraction, angle of deviation, Newcastle control score (NCS), accommodative amplitude (AMP), accommodative facility (AMF), accommodative response, positive or negative relative accommodation (PRA/NRA), and near point of convergence (NPC), were analyzed via univariate and multivariate regression. RESULTS: Subjects in the faster axial elongation group tended to have more myopic spherical equivalents (t = 3.956, p < 0.001), greater AMPs of dominant eyes (t = -2.238, p = 0.027), and fewer near points of convergence (t = 2.347, p = 0.020) than in the slower axial elongation group. For dominant eyes, logistic and linear regression analysis revealed that more negative spherical equivalents (OR = 0.603, p < 0.001; ß = -0.045, p < 0.001), greater AMPs (OR = 1.201, p = 0.027; ß = 0.023, p = 0.010), and less near points of convergence (OR = 0.883, p = 0.021; ß = -0.012, p = 0.019) were correlated with the faster axial elongation. For nondominant eyes, a more myopic spherical equivalent (OR = 0.682; p = 0.001; ß = -0.029, p = 0.005) was the only parameter correlated with faster axial elongation through regression analysis. CONCLUSION: In children with basic IXT, faster axial elongation in the dominant eyes was associated with more myopic spherical equivalents, greater AMPs, and lower NPCs. These accommodative parameters can serve as potential clinical indicators for monitoring myopia progression in addition to AL.

Stability of the angle of deviation in basic intermittent exotropia (IXT) following surgical correction: a retrospective observational study from southern India.

Introduction: Intermittent exotropia (IXT) is commonly seen in areas with more sunlight, females and Asians. Surgical alignment is recommended to improve binocular function, but a high recurrence rate has been reported. This study aimed to assess the stability of ocular alignment and factors contributing to exodrift post-surgery for IXT over 6-month follow-up. Methods: We retrospectively reviewed the medical records of patients with IXT who underwent unilateral recess resect procedures and attended follow-up examinations for at least six months post-surgery. A significant exodrift was defined as exodrift of more than 10PD at distance and near. Ocular deviation, binocularity, and stereopsis at one and six-month post-operative visits were studied to assess the incidence of exodrift post-surgery and the probable factors causing such drift. Results: Of the 50 patients studied, 26 (52%) were males, 42 (84%) were <20 years. The median age at surgery was 10 years (range 6-14), and the median preoperative angle of deviation was 37 PD. Majority of patients (62%) had exodrift within six months of surgery, and about a quarter of the study population had significant exodrift >10 PD. No clinical factors were found to contribute significantly to exodrift in this study.16 (61.5%) patients attained near and distance BSV post-surgery (p-value: <0.001). Six (12%) and 10 (20%) patients with subnormal near and distance stereopsis, respectively, attained normal stereopsis post-surgery. Conclusion: Over half of the patients operated for IXT had some Exodrift, and one-fourth had significant exodrift within six months post-surgery. Despite improved BSV, many patients failed to attain normal stereopsis with just motor alignment.

A Case of Squint Correction With Toric Implantable Phakic Contact Lens (IPCL) Implantation: A Novel Approach to High Myopia With Sensory Exotropia.

A 39-year-old male patient presented to the outpatient department (OPD) with chief complaints of outward deviation of the right eye (RE) since six months of age, associated with a diminution of vision in the same eye since childhood. He had a history of spectacle use for distance for the past eight years. He was thoroughly evaluated in the OPD and diagnosed with RE high myopia with sensory exotropia. Lateral rectus (LR) recess with medial rectus (MR) resection with implantable phakic contact lens (IPCL) implantation was planned and executed for the patient. He was started on topical steroids, antibiotics, non-steroidal anti-inflammatory drugs (NSAIDs), and lubricants post-surgery and was closely followed up. IPCL implantation with strabismus correction surgery is not usually performed together, especially in a young population, considering the risks involved, but it was performed in our case and gave satisfactory results. The patient had a significant improvement in visual acuity, and the correction of deviation was substantial.

The Challenge of Strabismus Surgery for Patients with Hemianopic Visual Field Defects Associated with Ocular Deviations.

Homonymous and heteronymous hemianopias associated with strabismus are a therapeutic challenge because surgery may result in diplopia, decrease the visual field (VF), and/or lead to recurrence of the deviation. We present four cases: two homonymous hemianopias and two heteronymous hemianopias. Of the four patients, three had exotropia and one had esotropia. The origin of hemianopias was neoplastic in two cases and traumatic in two cases. Strabismus surgery was performed in three cases, but only one case had a good result; recurrence of the deviation and diplopia occurred in the other two cases. In conclusion, exotropia may develop as a compensatory mechanism in a patient with congenital or early-onset homonymous hemianopia and realigning the eyes could reduce the binocular VF and cause diplopia. In heteronymous hemianopias, there is little risk of the surgery causing diplopia, but the strabismus is unstable because of the absence of binocular vision and vergence reflexes if VF loss includes the macula. Further, strabismus, in association with hemianopia, may be caused by coexistent cranial nerve and/or gaze palsy. The prognosis, objective, and results of the strabismus operation should be clearly discussed with the patients or their guardians before it is performed if hemianopias are present.

Long-term Outcomes of Bilateral Lateral Rectus Recession Using a Modified Normogram for Targeting Small Overcorrection in Intermittent Exotropia.

Purpose: To evaluate the surgical outcomes of a modified normogram for bilateral lateral rectus recession (BLR) in the surgical management of intermittent exotropia, with a focus on achieving small overcorrection. Methods: A retrospective medical chart review of 242 patients who underwent surgery for intermittent exotropia between October 2014 and June 2020 was performed. Our modified normogram reducing amount of recession targeted for small postoperative overcorrection within 5 prism diopters (PD). Patients were observed for at least 3 years. Esodeviation was denoted by negative numbers and positive values indicated exodeviation. A satisfactory outcome was defined as if distant angle of deviation ranged between ≤10 PD of exotropia and ≤5 PD of esotropia. Recurrence was defined as an exodeviation of >10 PD at distance. Overcorrection was defined as an esodeviation of >5 PD at distance. Results: The mean preoperative deviation angles were 29.32±3.92 PD at distance and 29.88±4.41 PD at near. At postoperative day 1, the mean deviation angles at distance and near were -6.22±1.44 PD and -6.22±1.49 PD, respectively. Overcorrection within 6 PD of esodeviation was seen in 168 patients (69.42%), undercorrection with exophoria was noted in 11 patients (4.55%), and overcorrection by more than 6 PD of esodeviation was seen in 63 patients (26.03%) at postoperative day 1. The long-term success rate at postoperative 3 years was 77.27% (187/242), with a recurrence rate of 19.83% (48/242) and an overcorrection rate of 2.89% (7/242). A positive correlation between the angle of deviation at postoperative day 1 and 3 years was observed (r= 0.22, p=0.001). The final success rate at the final examination after a mean follow-up of 38.60±7.99 months was 83.06%. Conclusion: Our modified normogram for BLR in intermittent exotropia surgery resulted in successful surgical outcomes with small overcorrection, reducing the risk of consecutive esotropia due to excessive overcorrection.

Demographic and clinical characteristics and risk factors of stereoacuity in convergence insufficiency-type intermittent exotropia.

Purpose: To investigate characteristics and risk factors of poor stereoacuity of Convergence insufficiency-type Intermittent Exotropia (CI-type X(T)). Design: Observational, cross-sectional study. Methods: The medical records of 615 CI-type X(T) and 222 basic-type intermittent exotropia (X(T)) were enrolled from January 2018 to January 2022. The characteristics were compared between the two types, and the associations between clinical factors and poor stereoacuity were examined using logistic regression. Results: Compared with basic-type X(T), earlier surgery age, shorter misalignment duration, and the smaller distance exodeviation were observed in CI-type X(T). The CI-type X(T) demonstrated better sensory status and lower incidence of ocular muscle dysfunction than did the basic-type X(T). The surgery age between 6 and 12 years (odds ratio [OR], 0.595; compared with ≤6 years) was inversely associated with poor near stereoacuity, whereas duration more than 4 years (OR, 2.474), amblyopia (OR, 4.057), large distance exodeviation (>60PD: OR, 2.462) and anisometropia (>2.00D: OR, 3.874) were positively associated with poor near stereoacuity. The onset age older than 6 years (6-9 years: OR, 0.397; >9 years: OR, 0.317) was associated with better distance stereoacuity, whereas large distance exodeviation (>60PD: OR, 23.513), and dominant eye best corrected visual acuity (BCVA) worsen than 0.20 (OR, 2.987) were positively associated with poor distance stereoacuity. Conclusion: CI-type X(T) declined surgery early, with small distance exodeviation, better sensory status, and low incidence of ocular muscle dysfunction. A strong dose-dependent link between early onset age, long misalignment duration, worse dominant eye BCVA, distance exodeviation, amblyopia, anisometropia, and poor stereoacuity was confirmed.

Disconjugacies of saccade duration and trajectories in strabismus.

Introduction: For decades, the saccadic system has been a favorite target of neurophysiologists seeking to elucidate the neural control of eye movements, partly because saccades are characterized by a set of highly stereotyped relationships between amplitude, duration, and peak velocity. There is a large literature describing the dynamics and trajectories of these movements in normal primates, but there are no similarly detailed analyses for subjects with infantile strabismus syndrome. Previous studies have shown the amplitudes and directions of saccades often differ for the two eyes in this disorder, but it is unknown whether a similar disconjugacy exists for duration. The present study was designed to determine whether or not saccade duration differs for the two eyes in strabismus, and whether there are abnormalities involving the trajectories of these movements. Methods: Dynamic analyses of saccade trajectories and durations were performed for two normal monkeys, two with esotropia and two with exotropia. The amount of curvature was compared for the two eyes. For each monkey with strabismus, the amount of curvature was compared to normal controls. Saccades were placed into 12 bins, based on direction; for each bin, the mean saccade duration was compared for the two eyes (duration disconjugacy). The duration disconjugacy for each bin was then compared for monkeys with strabismus, versus normal control animals. Results: Surprisingly, the amount of curvature was not consistently greater in subjects with pattern strabismus. However, saccade curvature differed for the two eyes by a significantly greater amount for all monkeys with strabismus, compared to normal controls. In addition, for a subset of saccades in subjects with strabismus, saccade duration differed for the two eyes by more than 10 ms, even when the animal was fully alert. Discussion: To the best of the author's knowledge, this is the first study to show that, in strabismus, saccade durations can differ for the two eyes by an abnormally large amount. These data also suggest that, in monkeys with pattern strabismus, abnormal horizontal-vertical crosstalk in brainstem can lead to directional disconjugacy without significantly impairing component stretching. These results place important constraints on future attempts to model the neural mechanisms that contribute to directional disconjugacy in pattern strabismus.

Lateral Rectus Disabling and Simultaneous Modified Nishida Procedure for Exotropic Duane Retraction Syndrome.

Exotropic-Duane Syndrome (XT-DRS) is a congenital cranial nerve dysinnervation disorder characterized by exotropia, anomalous head posture (contralateral face turn), limited adduction, globe retraction, palpebral fissure narrowing, upshoot and downshoot in adduction, and varying levels of limitation of abduction. Patients with XT-DRS often have poor convergence because attempted convergence induces co-contraction of the lateral rectus muscle (LR) due to anomalous LR innervation. We describe two patients with XT-DRS who underwent simultaneous lateral rectus muscle (LR) disinsertion and periosteal fixation (LRDAPF) and modified Nishida procedure (MNP) and discuss their outcome. In one patient, we combined this procedure with a contralateral LR recession. Anomalous head posture, exotropia, globe retraction, and palpebral fissure narrowing were reduced. Upshoot and downshoot were also reduced. Convergence improved in both patients.

Exploring WNT2 polymorphisms in comitant strabismus: A genetic association study.

BACKGROUND: Strabismus is a complex oculomotor condition characterized by a misalignment of the visual axis. The genetics of strabismus are poorly defined although a few candidate genes have been identified, among which is the WNT2 gene. Our study was designed to assess the association of single nucleotide polymorphisms (SNPs) of WNT2 in Pakistani strabismus patients. METHODS: A total of six SNPs, three intronic and three in the 3́ untranslated region, were screened in the current study. Logistic regression was performed using a dominant, recessive and additive model to determine the association of SNPs with strabismus and its clinical subtypes: esotropia and exotropia. Furthermore, haplotype analysis was performed. RESULTS: Regression analysis revealed an association of rs2896218, rs3779550, rs2285544 and rs4730775 with strabismus under the dominant model. When analyzed separately, rs2896218 and rs2285544 were found to be associated with both esotropia and exotropia, while rs4730775 was significantly associated only with exotropia under the dominant model. Based on clinical parameters, rs2896218, rs2285544 and rs4730775 were also found to be associated with the group of strabismus patients who were diagnosed at birth, but not in the group of patients who were diagnosed later in life. Haplotype analysis revealed that the haplotype A T T (corresponding to rs2896218, rs3779550 and rs2285544) was significantly more prevalent in the strabismus group. CONCLUSION: Overall, the results of the present study suggest an association of WNT2 polymorphisms with strabismus and its subtypes in the Pakistani population, though further studies are needed to elucidate their role in strabismus etiology.

Nasal loop myopexy for management of exotropia-hypotropia complex associated with high myopia.

INTRODUCTION: Exotropia-hypotropia complex is an uncommon phenomenon associated with high myopia. However, some literature reports cases of the exotropia-hypotropia complex where residual hypotropia is managed through a secondary surgery following the conventional recession-resection of the lateral rectus (LR) and medial rectus (MR). Nasal Loop myopexy as a primary surgical procedure for the management of exotropia-hypotropia complex has been rarely reported in the literature. METHODS: A 24-year-old male with unilateral high myopia presented with a large angle exotropia-hypotropia complex with limitation of elevation in abduction in his left eye. His ocular deviation was successfully managed through a nasal loop myopexy of the superior rectus (SR) and MR using a non-absorbable suture, combined with large LR recession and MR resection. RESULTS: Postoperatively, the patient had satisfactory ocular alignment with improved hypotropia and normal elevation in abduction, contributing to enhanced binocular vision and better cosmesis. DISCUSSION: Managing the exotropia-hypotropia complex in the context of high myopia demands a comprehensive approach that addresses both vertical and horizontal deviations. The surgical strategy employed in this case, which included loop myopexy of SR and MR along with LR recession and MR resection, achieved positive outcomes regarding alignment, elevation, and binocular vision. The case supports variations in muscle path and the potential benefits of tailored surgical strategies for complex strabismus cases associated with high myopia.

Genome-Wide Association Study with Three Control Cohorts of Japanese Patients with Esotropia and Exotropia of Comitant Strabismus and Idiopathic Superior Oblique Muscle Palsy.

Esotropia and exotropia in the entity of comitant strabismus are multifactorial diseases with both genetic and environmental backgrounds. Idiopathic superior oblique muscle palsy, as the predominant entity of non-comitant (paralytic) strabismus, also has a genetic background, as evidenced by varying degrees of muscle hypoplasia. A genome-wide association study (GWAS) was conducted of 711 Japanese patients with esotropia (n= 253), exotropia (n = 356), and idiopathic superior oblique muscle palsy (n = 102). The genotypes of single nucleotide polymorphisms (SNPs) were determined by Infinium Asian Screening Array. Three control cohorts from the Japanese population were used: two cohorts from BioBank Japan (BBJ) and the Nagahama Cohort. BBJ (180K) was genotyped by a different array, Illumina Infinium OmniExpressExome or HumanOmniExpress, while BBJ (ASA) and the Nagahama Cohort were genotyped by the same Asian array. After quality control of SNPs and individuals, common SNPs between the case cohort and the control cohort were chosen in the condition of genotyping by different arrays, while all SNPs genotyped by the same array were used for SNP imputation. The SNPs imputed with R-square values ≥ 0.3 were used to compare the case cohort of each entity or the combined entity with the control cohort. In comparison with BBJ (180K), the esotropia group and the exotropia group showed CDCA7 and HLA-F, respectively, as candidate genes at a significant level of p < 5 × 10-8, while the idiopathic superior oblique muscle palsy group showed DAB1 as a candidate gene which is involved in neuronal migration. DAB1 was also detected as a candidate in comparison with BBJ (ASA) and the Nagahama Cohort at a weak level of significance of p < 1 × 10-6. In comparison with BBJ (180K), RARB (retinoic acid receptor-ß) was detected as a candidate at a significant level of p < 5 × 10-8 in the combined group of esotropia, exotropia, and idiopathic superior oblique muscle palsy. In conclusion, a series of GWASs with three different control cohorts would be an effective method with which to search for candidate genes for multifactorial diseases such as strabismus.

Relationships between fusional convergence, suppression depth, and exotropia control in intermittent exotropia.

Purpose: To assess the correlation between the contribution rates of fusional convergence from the dominant and non-dominant eye and suppression depth and exotropia control. Study design: Cross-sectional prospective study. Methods: The fusional convergence of 25 participants with intermittent exotropia (mean age 10.8 ± 3.4; range 6-18 years) was measured with an eye-tracking system. The contribution rate was defined based on the amplitude of fusional convergence during refusion relative to the exo-deviation angle. The suppression depth was assessed, and exotropia control was evaluated using the intermittent exotropia Office Control Score. We analyzed the correlations between the contribution rate from the dominant and non-dominant eyes and the suppression depth or control score. Results: There was a negative correlation between the dominant eye's contribution rate and the suppression depth in both eyes (r = -0.85, 95% confidence interval [CI]: -0.97 to - 0.20 in the fixated dominant eye and r = -0.91, 95%CI: -0.95 to - 0.40 in the fixated non-dominant eye). There was a negative correlation between the dominant eye's contribution rate and the control score at a 4-meter distance (r = -0.53, 95%CI: -0.76 to - 0.17). Conclusion: Suppression in intermittent exotropia patients could affect the fusional convergence in the dominant eye.

Divergence excess and basic exotropia types of intermittent exotropia: a major review. Part 2: non-surgical and surgical treatment options.

INTRODUCTION: Currently, there is no consensus regarding the management of intermittent exotropia (IXT), which includes both surgical and non-surgical treatment options. Nonsurgical management of IXT has been suggested and includes watchful observation, patching, overminus lenses, prism, and vision therapy/orthoptics. While a significant portion of IXT patients are treated by surgery, it is reported that there is a substantial tendency for reoperation or recurrence of IXT. This paper provides a comprehensive review of non-surgical and surgical treatment options for the IXT. METHODS: Search strategies involving combination of keywords including intermittent exotropia, divergence excess, basic exotropia, refractive error, glasses, spectacles, natural history, untreated, observe, occlusion, patch, overminus, overcorrecting minus, prism, vision therapy, orthoptic, anti-suppression, fusion exercise, and surgery were used in Medline. All English articles from 01/01/1900 to 01/09/2020 were reviewed. The reference list of the identified articles was also checked for additional relevant articles. Studies focused on animal models or strabismus associated with neurologic disorders or injury were excluded. The following filters were used for surgical management due to the abundance of reports: full text, randomized controlled trial, review, in the last 5 years. RESULTS: Appropriate optical correction of refractive error is generally the starting point for all management approaches, but there is a lack of randomized clinical trial data regarding this treatment modality. Randomized clinical trial data indicate that both observation and occlusion are reasonable management options for children 3-10 years old, and there were insufficient data to recommend occlusion for children 12-35 months old. While overminus lenses were found to improve the control of IXT when assessed wearing overminus spectacles, this improvement did not persist after the treatment ended. The result of the only randomized clinical trial on the effectiveness of base-in prism indicated that this treatment is no more effective than nonprism spectacles for improving control. A recent randomized clinical trial showed that vision therapy/orthoptics is effective in improving the control of IXT when compared to observation alone. Surgery was found to alter a number of clinical characteristics of IXT, including reducing the distance and near angle of deviation, reducing photophobia, improving health-related quality of life, stereopsis, and the Newcastle Control Score. However, there are no randomized clinical trial data comparing surgery with a control group such as placebo or a no treatment observation group. DISCUSSION: Rigorously designed clinical trials to investigate the effectiveness of non-surgical and surgical treatments for intermittent exotropia are needed.

Characteristics and Trends of Strabismus Surgeries at a Tertiary Hospital Over 2 Decades - What Can Be Learned for Years to Come?

PURPOSE: To analyze characteristics and trends of strabismus surgeries in an Israeli hospital over 2 decades. METHODS: A descriptive, retrospective study including all strabismus surgeries (666) performed during 2000-2019 at an Israeli tertiary hospital. Electronic medical records (EMRs) were directly retrieved to produce an anonymized database. RESULTS: No trends were evident for age, sex, or ethnicity (p = .294, 0.914 and p = .167, respectively). The mean number of horizontal muscles remained stable, while an increase was noted in the mean number of muscles operated on to repair vertical strabismus (p < .0001). Among acquired cases, a 2.67-fold increase was noted in the proportion of spontaneous strabismus and a decrease of traumatic causes to a third (p < .001). An increase was noted in the proportion of exotropia among horizontal strabismus corrections (p = .022), and esotropia correction techniques distribution changed (p = .004). Reoperations comprised a third of all cases during both decades (p = .198). Reoperations were more prevalent among younger and Jewish patients (p < .001 and p = .024, respectively). Techniques to correct esotropia and exotropia differed significantly between primary surgeries and reoperations (p < .00001 each). CONCLUSIONS: The complexity of surgical techniques increased over time. Ethnic minorities were less prone to reoperations.

Experience with Strabologic Surgery on Pediatric Patients with Divergence Excess Exotropia.

AIM: This retrospective clinical study evaluates the results of surgical treatment of patients diagnosed with intermittent exotropia of the divergence excess type. The study compares the results of surgery delayed due to the Covid-19 pandemic (patients underwent the surgery after the age of eight), versus a group of younger children. MATERIALS AND METHODS: The objective angle of deviation and quality of binocular functions were examined. The follow-up period was six months after surgery. The patients were divided into two groups according to age: 4-7 years and 8-13 years. Each group included 20 patients. The second group comprised patients whose surgery was postponed due to restrictions on elective surgery during the ongoing pandemic. The surgery took place at the University Hospital in Pilsen. Angle of deviation and binocular functions were examined before surgery, postoperatively, and three and six months after surgery. Data were collected retrospectively and statistically processed. The main values were plotted in charts. RESULTS: Accordance between the angle of deviation before surgery in both groups was statistically demonstrated. During the six-month follow-up period, the median angle of deviation was statistically without proof of disparity between the groups. Six months after surgery, an objective angle of deviation within the limit ±5 degrees was achieved in 65% of patients from the first group and in 75% from the second group. Binocular vision before surgery was statistically without proof of difference between both groups. However the statistical processing demonstrated a difference between the two groups six months after the surgery. Better binocular functions were achieved by the younger children in the first group. CONCLUSION: The objective deviation angle was comparable in both study groups prior to surgery as well as six months after the surgery. The first group of younger patients attained a higher quality of binocular functions within the six-month follow-up period compared to children operated on after the age of eight. This claim was statistically verified.

Impact of Online Video Game-Based Dichoptic Training on Binocular Vision Rehabilitation in Post-surgical Patients with Intermittent Exotropia.

INTRODUCTION: Dichoptic training has emerged as a promising rehabilitation approach for improving binocular visual function in patients with strabismus. A prospective observational study design was employed to assess the effectiveness of online video game-based dichoptic training in rehabilitating binocular visual function in patients who had undergone an operation for intermittent exotropia. METHODS: A total of 64 patients who had undergone an operation for intermittent exotropia were recruited and divided into the training group and the control group based on whether they would receive the dichoptic training. The dichoptic training was conducted for 3 months in the training group and the control group would not accept any form of orthoptic therapy. Assessments of binocular visual functions and deviation were conducted at baseline, 3-month and 6-month follow-up. RESULTS: Twenty-nine participants in the training group (mean 9.69 ± 2.66 years old) and 26 participants in the control group (mean 8.41 ± 2.64 years old) completed follow-up. At both 3- and 6-month follow-ups, the training group showed superior distance stereopsis compared to the control group, with near stereopsis only showing significant difference at the 6-month follow-up. Additionally, the training group exhibited significantly less distance exo-deviation drift than the control group at these times, and no significant difference was observed in near exo-deviation drift between the groups. The control group had a significantly higher rate of suboptimal surgical outcomes at both the 3- and 6-month follow-up. However, no significant differences were observed in simultaneous perception and fusion functions between the two groups. CONCLUSIONS: Online video game-based dichoptic training has the potential to become a novel postoperative rehabilitation strategy for patients with intermittent exotropia.

Self-Reported Findings of the Korean Intermittent Exotropia Multicenter Study Questionnaire.

PURPOSE: To determine subjective symptoms and medical history of patients with intermittent exotropia in a large study population. METHODS: The Korean Intermittent Exotropia Multicenter Study (KIEMS) is a nationwide, observational, cross-sectional, multicenter study conducted by the Korean Association for Pediatric Ophthalmology and Strabismus including 5,385 patients with intermittent exotropia. Subjective symptoms and medical history of patients with intermittent exotropia were extracted by a comprehensive survey based on a self-administered questionnaire according to the study protocol of the KIEMS. RESULTS: The mean age of symptom onset was 5.5 years. The most common symptom reported in patients with intermittent exotropia was photophobia (52.1%), followed by diplopia at near fixation (7.3%) and distance fixation (6.2%). Preterm birth was found in 8.8%, and 4.1% had perinatal complications. A family history of strabismus was present in 14.9%, and 5.5% of patients had a family member who underwent strabismus surgery. CONCLUSIONS: The KIEMS is one of the largest clinical studies on intermittent exotropia. Intermittent exotropia frequently caused photophobia and diplopia, and patients with a family history was not uncommon.