Pilot Study Assessing the Effect of Exam Room Length on the Measurement of Strabismus.

PURPOSE: Our study aims to investigate the effect of decreasing distance from the patient to the fixation target on the measurement of strabismus with a known distance-near disparity. METHODS: Strabismus measurements were taken by one pediatric ophthalmologist at our standard distance of 18 feet and compared to those taken at 16, 14, 12, and 10 feet from the fixation target. A clinically meaningful difference was defined as >2.5 prism diopters (PD), since a difference of that magnitude may alter surgical planning. RESULTS: Thirty-nine subjects, including 22 exotropes and 17 esotropes, were included in this study. Mean prism diopter difference (PDD) in the exotrope group at lengths of 16, 14, 12, and 10 feet compared to 18 feet were 1.3 (SD 1.9, range 0-6), 1.3 (SD 2.2, range 0-8), 1.7 (SD 3.2, range 0-14), and 2.8 (SD 4.4, range 0-14), respectively. Among esotropes, the mean PDD at the same distances were 1.1 (SD 1.9, range 0-7), 2.1 (SD 2.6, range 0-7), 3.9 (SD 4.9, range 0-19), and 4.3 (SD 5.1, range 0-19). The percentages of exotropes with a PDD of >2.5 at 16, 14, 12, and 10 feet compared to 18 feet were 13.6% (n = 3), 13.6% (n = 3), 18.2% (n = 4), and 27.3% (n = 6), respectively. In the esotrope group, 11.8% (n = 2), 35.3% (n = 6), 47.1% (n = 8), and 47.1% (n = 8) had a PDD of >2.5 at the same distances, respectively. CONCLUSION: This pilot study is the first to investigate the change in measured angle of strabismus at various non-mirrored distances from the patient to the fixation target. Our methodology defines a framework that could be used in a higher-powered study to further our understanding of the effect of room length on strabismus evaluation.

Mechanisms for Positive Bielschowsky Head Tilt Testing in Horizontal Strabismus.

PURPOSE: To elucidate the induced effects of horizontal strabismus on the Bielschowsky Head Tilt Test (BHTT). DESIGN: Prospective clinical study. METHODS: Prospective analysis of BHTT testing in 85 patients with exotropia and 71 patients with esotropia who were examined in a strabismus clinic. RESULTS: Eighty-four of 85 patients with exotropia (98.82%) showed a positive BHTT with an induced hyperdeviation on the side of the tilt (to both sides in 67% and to one side in 32%). Fifty-seven of 71 patients with esotropia (80.2%) showed a positive BHTT with an induced hypodeviation on the side of the tilt (to both sides in 57.7% and to one side in 22.5%). These induced vertical deviations were greater in patients with larger horizontal deviations and in those with constant rather than intermittent deviations; however, they were not influenced by the presence or absence of associated primary oblique muscle overaction. CONCLUSIONS: Exotropia and esotropia produce hyperdeviations during BHTT testing, with a hyperdeviation on the side of the tilt observed in patients with exotropia, and hypotropia on the side of the tilt observed in patients with esotropia. These diametrical results are not attributable to any preexistent alteration of neurologic output inherent to these two forms of horizontal strabismus or to associated torsion. Rather, they arise directly from the altered anatomical positions of the two eyes, which cause the eyes to approximate their visual axes more closely to the vertical rectus muscles (in exotropia) and the oblique muscles (in esotropia), enabling the vertical actions of specific cyclovertical muscles to predominate in response to altered utricular output generated by the BHTT.

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.

Ophthalmic features of Lamb-Shaffer syndrome: a case series.

Lamb-Shaffer syndrome (LSS) is a rare neurodevelopmental disorder, genetically diagnosed in fewer than 100 individuals worldwide. We present a case series of 6 pediatric patients with LSS and describe its ophthalmic manifestations. Strabismus was present in 5 patients, with exotropia being most common. All subjects had significant refractive errors; 5 had astigmatism of at least 2 D. All patients had optic nerve abnormalities, including pallor (4), hypoplasia (2), and anomalous appearance (1), with retinal nerve fiber layer thinning demonstrated in a single subject. Other ophthalmic disorders detected were ptosis (1), nasolacrimal duct obstruction (1), and nystagmus (2).

Diagnostic Importance of OCT Pachymetry in Keratoconus.

AIMS: To demonstrate changes in distance and near fusional vergence measured with prism bars, while compensating for present heterophoria using current ametropia correction. In addition, to determine the differences in values of the AC/A ratio determined by the heterophoric (calculation) and gradient methods. MATERIAL AND METHODS: The basic sample includes 19 subjects with a mean age of 21.5 ±3.0 years (min. 18, max. 27). We used the Von Graefe technique for examination of distance and near phoria, and prism bars for examination of fusion vergences measured in prism diopters. We divided the basic cohort into six research sets according to the size of distance and near heterophoria. This was a cohort of patients with distance (D OR) and near orthophoria (N OR), a cohort of patients with distance (D EX) and near exophoria (N EX) and a set of patients with distance (D ES) and near esophoria (N ES). RESULTS: In the case of both groups with exophoria (distance, near) we found a statistically significant result only for negative fusion vergence (NFV). There was a statistically significant increase in NFV in the sample with distance and near exophoria (D EX, p = 0.01 and B EX, p = 0.02, respectively). In our study, we also demonstrated a statistically significant difference (p < 0.001) in the values of the AC/A ratio measured by the gradient and heterophoric methods. The values determined by the gradient method are lower (3.0 ±1.1 pD/D versus 5.8 ±0.9 pD/D) than by the heterophoric method. CONCLUSION: By comparing fusion vergence values in patients with exophoria and orthophoria, we demonstrated that in the presence of distance or near exophoria there is an increase in ipsilateral fusion vergence. In the case of an increase in ipsilateral fusion vergence, the finding was statistically significant both distance and near (p = 0.01 and p = 0.02, respectively). By contrast, we were unable to prove this fact in the group of patients with esophoria. In our study, we also demonstrated a statistically significant difference (p < 0.001) in the values of the AC/A ratio measured by the gradient and heterophoric methods. The values determined by the gradient method are lower (3.0 ±1.1 pD/D versus 5.8 ±0.9 pD/D) than by the heterophoric method.

The Effect of Heterophoria on the Size of Distance and Near Fusion Vergence.

AIMS: To demonstrate changes in distance and near fusional vergence measured with prism bars, while compensating for present heterophoria using current ametropia correction. In addition, to determine the differences in values of the AC/A ratio determined by the heterophoric (calculation) and gradient methods. MATERIAL AND METHODS: The basic sample includes 19 subjects with a mean age of 21.5 ±3.0 years (min. 18, max. 27). We used the Von Graefe technique for examination of distance and near phoria, and prism bars for examination of fusion vergences measured in prism diopters. We divided the basic cohort into six research sets according to the size of distance and near heterophoria. This was a cohort of patients with distance (D OR) and near orthophoria (N OR), a cohort of patients with distance (D EX) and near exophoria (N EX) and a set of patients with distance (D ES) and near esophoria (N ES). RESULTS: In the case of both groups with exophoria (distance, near) we found a statistically significant result only for negative fusion vergence (NFV). There was a statistically significant increase in NFV in the sample with distance and near exophoria (D EX, p = 0.01 and B EX, p = 0.02, respectively). In our study, we also demonstrated a statistically significant difference (p < 0.001) in the values of the AC/A ratio measured by the gradient and heterophoric methods. The values determined by the gradient method are lower (3.0 ±1.1 pD/D versus 5.8 ±0.9 pD/D) than by the heterophoric method. CONCLUSION: By comparing fusion vergence values in patients with exophoria and orthophoria, we demonstrated that in the presence of distance or near exophoria there is an increase in ipsilateral fusion vergence. In the case of an increase in ipsilateral fusion vergence, the finding was statistically significant both distance and near (p = 0.01 and p = 0.02, respectively). By contrast, we were unable to prove this fact in the group of patients with esophoria. In our study, we also demonstrated a statistically significant difference (p < 0.001) in the values of the AC/A ratio measured by the gradient and heterophoric methods. The values determined by the gradient method are lower (3.0 ±1.1 pD/D versus 5.8 ±0.9 pD/D) than by the heterophoric method.

Visual and auditory attention defects in children with intermittent exotropia.

BACKGROUND: Previous studies have shown that children with intermittent exotropia (IXT) have a higher rate of psychiatric abnormalities as they grow up, such as attention deficit. This study explored visual and hearing attention among children with IXT, and evaluated its association with clinical characteristics and cognitive development. METHODS: Forty-nine children with a diagnosis of IXT and 29 children with traditional development were recruited. The Integrated Visual and Auditory Continuous Performance Test (IVA-CPT) was used to measure the subjects' full-scale response control quotient (FSRCQ), full-scale attention quotient (FSAQ), auditory response control quotient (ARCQ), auditory attention quotient (AAQ), visual response control quotient (VRCQ), and visual attention quotient (VAQ). The Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV) was used to assess their cognitive function. The differences between the scores of children with IXT and normal controls were analyzed. RESULTS: The results showed that the FSRCQ, FSAQ, ARCQ, AAQ, VRCQ, and VAQ of children with IXT were all lower than those of normal controls with the same age (P < 0.05). The level of attention was significantly correlated with the age of strabismus onset (P < 0.05), but not with the degree of strabismus, stereopsis, or fusion control score. In addition, audiovisual attention was correlated significantly with their cognitive development level. The random forest classifier prediction model showed that age of strabismus onset was an important predictor of attention. CONCLUSION: Children with IXT have lower visual and auditory attention and control than their peers, and the age of onset of strabismus may be a major factor.

Nonsurgical Consecutive Exotropia Following Childhood Esotropia: A Multicentered Study.

PURPOSE: Nonsurgical consecutive exotropia (NCX) occurs when an esotropia (ET) spontaneously converts to exotropia (XT) without surgical intervention. Although NCX is considered to occur in early-onset accommodative ET with high hyperopia, consensus on causation is lacking. We report the clinical characteristics of NCX and assess the response to conservative management. DESIGN: Retrospective, multicenter, observational case series. METHODS: Patients aged 6 months and older with an initial diagnosis of ET who converted to XT without surgical intervention. Sensory strabismus was excluded. Age, visual acuity, cycloplegic refraction, glasses prescriptions, deviation, and binocular vision were collected. RESULTS: Forty-nine children were included with a mean age of 3.5 ± 1.6 years and 8.4 ± 3.6 years at the time of ET and NCX, respectively. Mean refractive error was +4.40 ± 2.13 diopters (D) and +4.05 ± 2.74 D at the time of ET and NCX, respectively. Accommodative ET occurred in 60% of cases, and only 35.7% were high hyperopes. All but 1 patient presented with XT at distance. In response to the XT, a mean decrease in hyperopic prescription of 1.55 ± 0.48 D was given (N = 17); only 1 case reverted to ET. Eventually, 43% underwent XT surgery, with similar rates between those who had refractive management and those who did not. CONCLUSIONS: NCX occurs in both accommodative and nonaccommodative ET; high hyperopia is present in only one-third of cases. On average, drift to XT occurs within 5 years. Refractive management has a modest result. No predictive risk factors were identified. Our findings challenge hyperopia-linked theories of causation. Nonrefractive explanations, such as the role of the vergence system, deserve further study.

Inferior displacement of the lateral rectus muscle insertion in exotropia with mild V-pattern or vertical deviation.

BACKGROUND: To describe clinical features and intraoperative findings of the patients with exotropia who presented mild V-pattern or vertical deviation, and to investigate the surgical outcomes of anatomical relocation of inferiorly displaced lateral rectus (LR) muscle insertion. METHODS: Detailed ophthalmological evaluations were obtained in 42 consecutive patients, and the horizontal rectus muscle insertions were detected intraoperatively. The displaced insertion of LR muscle was corrected accompanied with classic recession-resection procedure. RESULTS: The inferiorly displaced LR muscle insertions were detected in 19 patients (Group A), while the remaining 23 patients (Group B) had normal insertions. The mean distance of displaced insertion from the normal position was 2.92 ± 1.05 mm (range: 1.0-4.0). Mild V-pattern was more common in Group A (78.9%, 15/19) than Group B (47.8%, 11/23), and the magnitude of V-pattern in Group A (6.16 ± 3.91 PD) was also greater than Group B (3.43 ± 3.92 PD). The fundus extorsions of the affected eyes (9.68 ± 4.77 °) were greater than the contralateral eyes (5.91 ± 5.82 °) in Group A. At the 2 months follow-up, mild V-pattern and mild vertical deviation were corrected by upward transposition. The significant correlations were identified between the pre-operative misalignments and the amounts of misalignments correction. CONCLUSIONS: Nearly half of the cases with mild V-pattern or vertical deviation resulted from the inferiorly displaced LR muscle insertion, so the intraoperative exploration of the LR muscle insertion is strongly suggested. Upward transposition may effectively correct both the mild V-pattern and vertical deviation.

Relationship between strabismus associated with Angelman syndrome and orbital anomaly.

PURPOSE: To investigate the relationship between the details of strabismus and orbital abnormalities determined by ocular motility tests and orbital imaging examinations in 9 cases with Angelman syndrome (AS). STUDY DESIGN: A retrospective, clinical report. METHODS: The 9 AS cases (mean age at initial visit: 4.6 ± 8.0 years) were confirmed by genetic diagnosis of the chromosome 15q11-13 region. In all cases, axial imaging of the orbit in the transverse plane of the horizontal extraocular muscles was obtained. The opening angle between both lateral walls of the orbit (greater wing of sphenoid) was measured as the biorbital angle, and compared with the 95% confidence interval of the orbital angle in normal children. RESULTS: All cases had exotropia with means of the distance and near of angle 32.2 prism diopters (Δ) ± 9.7Δ and 32.8Δ ± 8.3Δ. The mean of the biorbital angle was 107.7° ± 7.6°, greater than the biorbital angle of 94.3° ± 5.1° previously reported in 129 normal children (P < 0.0001, t-test). Except for one biorbital angle of 93° in the 25-year-old patient, all the biorbital angles in the 8 children were larger than the upper 95% confidence interval in normal children. Astigmatic and hyperopic ametropic amblyopia were detected in 3 cases and 1 case, respectively. CONCLUSIONS: The frequency of exotropia in AS is higher than previously reported, with our results strongly suggesting that the enlarged biorbital angle is related to the pathogenesis of exotropia in AS.

Double-bellied inferior rectus muscles with aplasia of medial rectus muscles.

This report describes a rare occurrence of double-bellied inferior rectus muscle with aplasia of the medial rectus muscle in both eyes of a young woman seeking cosmetic correction for her strabismus. The patient presented with a large-angle exotropia and a -4 limitation of adduction in each eye. On attempted adduction, there was minimal downshoot and upper eyelid retraction. Magnetic resonance imaging of the orbit revealed hypoplastic medial rectus muscles; however, intraoperatively the muscle was not found at the insertion or when traced back as far as possible. The inferior rectus muscles were noted to have double bellies converging close to each other at the insertion. The patient underwent a bilateral lateral rectus recession with nasal transposition of the inferior rectus muscles and was cosmetically well aligned, with a residual exotropia of 4Δ at 3 months' follow-up. This unusual anatomical variation may be the result of deviation of muscle paths.

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

PURPOSE: To identify different types of exotropia in children less than 16 years and their clinical presentation. The secondary objective is to identify the age of onset, age of presentation, birth history, and ocular and systemic associations as well as to evaluate their motor and sensory status. METHODS: This hospital-based descriptive observational study was conducted from September 2018 to December 2019. Patients with a clinical diagnosis of exotropia of age less than 16 years, and exotropia of ≥ 10 PD were included in the study. Data were collected using a structured proforma. All statistical calculations were performed using Microsoft Excel Office version 2016 and R version 4.0.2. RESULTS: Two hundred eighty-six (286) consecutive children with exotropia were analyzed. Intermittent exotropia (72%) was the most common form of exotropia, followed by exotropia with a neurological association (11%), infantile (8%), sensory (6%), restrictive (2%), and paralytic (1%) types. Exotropia with neurological association had a significantly earlier age of presentation (median = 42months) as compared to other types (P = 0.039). CONCLUSION: We recorded a huge amount of cases of exotropia associated with neurological abnormalities and this group of patients had significantly more number of preterm and low birth weight children. This study has its limitations as it is not a population-based study and prevalence rates could not be calculated.

Comparative Analysis of Strabismus Measurement Using a Video Oculagraphy System and Alternate Prism Cover Test.

PURPOSE: The aim of the study was to compare distance vision measurements obtained with video oculography (VOG) and an alternate prism cover test (APCT). DESIGN: Single-center, retrospective, and cross-sectional. METHODS: Eighty-seven subjects with strabismus were included. All patients underwent an optometric examination. The measurement of strabismus in distance vision was performed with the best optical correction using the APCT and the VOG GazeLab. Subjects were divided according to the type of strabismus; 41 were esotropic and 46 were exotropic. RESULTS: The general comparison of APCT and VOG showed a mean difference of 0.60±2.74 prism diopters (Δ), not observing statistical differences between both methods ( P =0.059) and presenting a correlation of 0.976 ( P <0.001). Using APCT, the mean amount of esotropia for the group was 18.31±11.64 Δ and that of exotropia was 19.62±8.80 Δ. Compared with the VOG, the mean value of esotropia for the group was 18.65±11.65 Δ and that of exotropia was 19.48±8.62 Δ. The means are statistically different for the esotropia group ( P =0.005) but not for the exotropia group ( P =0.318). There was a high direct correlation between the methods of measurement for both the esotropic ( R =0.980; P <0.001) and exotropic patients ( R =0.975; P <0.001). Bland-Altman analysis shows a mean difference of 1.37±2.76 Δ for the esotropia patients and 0.31±2.66 Δ for the exotropic patients, respectively. CONCLUSIONS: This study demonstrated comparable results in measuring strabismus between VOG and APTC for esotropia and exotropia, with an excellent correlation between both methods and good agreement, especially in subjects with exotropia.

Small-angle strabismus detection by telemedicine in an experimental model.

PURPOSE: To evaluate the ability of observers to accurately detect strabismus using an alternate cover testing approach via telemedicine and to assess the effect of various factors related to video conditions on the accuracy rate. METHODS: Videos were made by the authors in which different angles of strabismus, up to 12Δ, were induced by prism and recorded using alternate cover testing. The videos were made under a variety of conditions that incorporated various head postures, lighting, fixation target position and motion, and viewing angle. The videos were shown to observers of varying levels of expertise. The accuracy of detecting the deviation was assessed and analyzed for statistical significance. RESULTS: The overall rate of detection was significantly affected by the angle of deviation, with 12Δ being correctly detected with 94% accuracy, 8Δ with 72% accuracy, and 4Δ with <50% accuracy. Esotropia and hypertropia were more accurately detected than exotropia for all angles tested. The level of training of the observer did not correlate with detection accuracy. However, accuracy was negatively affected by backlighting and movement of the fixation target during cover testing. CONCLUSIONS: Our data demonstrate that detection of even relatively small angles of strabismus can be accomplished with a high level of accuracy using telemedicine and an alternate cover testing strategy. For optimal results, it is important to consider conditions related to the fixation target and lighting.

Objective assessment of control compared with clinical triple office control score in children with intermittent exotropia.

Poor control of intermittent exotropia may be used as an indication for surgery. However, control fluctuates during the day and from day to day. The standardized triple office control score (mean of three scores on a 6-point ordinal scale) is representative of repeated assessments throughout the day, but lacks validation against an objective measure of eye movements. We report the agreement between the triple office control score measured by the referring eyecare professional and lab-measured vergence instability using an EyeLink video eye tracker. Near and distance triple office control scores were moderately correlated with vergence instability. Near, but not distance, triple office control score was moderately correlated with the percentage of time intermittent exotropia was manifest during EyeLink recording. Larger triple office control scores for intermittent exotropia provide a meaningful description of larger vergence instability, supporting its use in clinical decisions and as a measure in clinical trials.

Divergence excess and basic exotropia types of intermittent exotropia: a major review. Part 1: prevalence, classification, risk factors, natural history and clinical characteristics.

INTRODUCTION: Intermittent exotropia (IXT) is a common form of strabismus. It is an outward deviation of one eye typically when viewing at distance. Symptoms include, but are not limited to double vision, eyes feeling tired, excessive blinking, and reduced quality of life. Its clinical characteristics are distinctive from other types of strabismus. This paper provides a comprehensive review of prevalence, classification, risk factors, natural history and clinical characteristics of the divergence excess and basic exotropia types of IXT. METHODS: Search strategies involving combination of keywords including intermittent exotropia, exotropia, divergences excess, basic exotropia, prevalence, incidence, classification, terminology, risk factor, natural history, observation, angle of deviation, control, control score, symptom, quality of life, suppression, anomalous retinal correspondence, AC/A, accommodative convergence/accommodation, accommodative convergence, convergence, accommodation, vergence, incomitance and vertical were used in Medline. All English articles from 1900/01/01 to 2020/09/01 were reviewed. The reference list of the identified article was also checked for additional relevant article. Studies focused on animal model or strabismus associated with neurologic disorder or injury were excluded. RESULTS: The estimated prevalence of IXT in children ranges from 0.1% to 3.7%. Hypoxia at birth and being female are potential risk factors of IXT. Using validated measures of control, multicenter prospective studies showed that the rate of conversion from IXT to constant exotropia is low. The angle of deviation is the most reported outcome measure in studies of IXT. It is often used to represent the severity of the condition and has been suggested as one of the four core outcomes for studies of the surgical management of IXT. Control of exodeviation is one of the four suggested core outcomes for study of surgery of IXT and is considered the main parameter of disease severity. Several validated tools for quality of life score are available to evaluate the subjective severity of IXT. DISCUSSION: We reviewed the prevalence, classification, risk factors, natural history and clinical characteristics of the divergence excess and basic exotropia types of IXT. Further research into these areas, especially its clinical characteristics (e.g. suppression, dual retinal correspondence), will increase our understanding of this condition and potentially lead to better management of this common form of strabismus.

Short-Term Effect of Spinal Manipulation on the Magnitude of Exophoria in Adults Who Are Asymptomatic: A Randomized Controlled Trial.

OBJECTIVE: This study aimed to assess the immediate and short-term effects of cervical spinal manipulation (SM), compared with a placebo, on the magnitude of near and distance exophoria in adults with asymptomatic exophoria. METHODS: In this single-blind, randomized controlled trial, individuals with a clinical diagnosis of horizontal exophoria confirmed with the prism alternating cover test (PACT) were allocated to a single intervention session using a high-velocity, low-amplitude cervical SM technique or a sham intervention (manual contact under the head). Outcomes were the magnitude of horizontal heterophoria, as a measure of binocular vision efficiency at near (40 cm) or distance (4 m) fixation, using the PACT. Evaluations were made at baseline, immediately after intervention, and at a 1-week follow-up. RESULTS: From May to September 2021, 44 volunteers (23 women), with a mean age of 35 (SD = 9.5) years, were recruited and equally distributed into the study groups. All participants completed follow-up assessments, and no adverse events were reported. There was a significant time × group interaction for exophoria at near vision, but not at distance fixation. The SM group showed a significant decrease of near exophoria compared with the control group at the 1-week follow-up (mean difference = -1.09 prism diopters; 95% CI = -0.20 to -1.98 prism diopters). CONCLUSION: The use of cervical SM therapy resulted in a significant reduction of the magnitude of horizontal exophoria at near vision (medium effect size), compared with the placebo, in young adults who are asymptomatic. However, these effects were not observed at distance fixation and should be considered cautiously due to the pre-post design with a single intervention session and the short-term follow-up. IMPACT: The findings suggest short-term benefits of SM therapy can manage undiagnosed ocular convergence disorders, although changes were not clinically relevant.

Initial postoperative plasticity as a predictor of mid-term stereoacuity outcome after surgery for intermittent exotropia.

BACKGROUND: Intermittent exotropia (IXT) would cause different degrees of damage to stereopsis. We aimed to introduce a visual perception plasticity score (VPPS) that reflects initial postoperative plasticity and evaluate its effectiveness in predicting the mid-term surgical outcome in IXT patients. METHODS: A total of 149 patients with intermittent exotropia who underwent surgery in November 2018 and October 2019 were recruited. All subjects underwent detailed ocular examinations before and after surgery. VPPS were calculated based on visual perception examination system at one week postoperatively. Demographic, angle of deviation and stereopsis were collected and analyzed with regard to the VPPSs preoperatively and at one week, one month, three months, six months postoperatively. Predictive performances of VPPS were assessed using receiver operating characteristic (ROC) curves, the area under the curve (AUC) and cut-offs were obtained. RESULTS: Of the 149 patients, the average deviation was 43Δ at distance and 46Δ at near. The average rate of normal stereopsis before surgery was 22.81% at distance and 29.53% at near. Higher VPPS was associated with preoperative better near stereoacuity (r = 0.362, p = 0.000), less angle of deviation at distance (r=-0.164, p = 0.046), and better near (r = 0.400, p = 0.000) and distant stereoacuity (r = 0.321, p = 0.000) during the early postoperative period (1 week). The areas under the curves suggested that VPPS could be an effective predictor of sensory outcome(AUC>0.6). Cut-off values of 50 and 80 were calculated for VPPS using ROC curve analysis. CONCLUSION: Higher VPPSs were associated with a greater possibility of stereopsis improvement in patients with IXT. VPPS is a potentially promising indicator to predict the mid-term surgical outcome of intermittent exotropia.

Evaluation of Strabocheck® as an objective measurement method of comitant horizontal strabismus in children undergoing surgery.

The gold standard of angle measurement is the prism alternating cover test (PCT). This method requires cooperation from the child, experience, and presents a significant inter-observer variability. Strabocheck®(SK) is a new simple tool for objective and semi-automated angle measurement. Our purpose is to evaluate Strabocheck® in children undergoing surgery for comitant horizontal strabismus. The study population was divided into 3 groups: infantile esotropia, partially accommodative esotropia and intermittent exotropia. The primary endpoint was the agreement between Strabocheck®and the PCT. A total of 44 children were included prospectively. The correlation between the angle measured by the PCT and the angle measured by SK was strong (R = 0.87). The mean absolute difference in the angle measured by the two methods was Δ = 11.9+/- 9.8 diopters. The Bland-Altman plot shows a 95% interval limit between -30.0 [-34.4; -25.6] and 31.0 [26.7; 35.4] diopters. SK is an interesting tool to evaluate the angle of strabismus in children. However, the residual discordance between PCT and SK leads us to question the real value of the angle, which can only be approximated. A better clinical experience of this new tool in relation to the clinical condition and the PCT will allow to have a more accurate idea on the true angle and will probably help the surgeon to adapt this procedure.

Quality of life in intermittent exotropia for Korean children and their parents.

BACKGROUND: Patients with strabismus are more likely to have mental health problems, including high rates of depressive symptoms and social phobia. Intermittent exotropia (IXT) typically occurs in early childhood and is more common in Asian populations. We aim to assess the health-related quality of life (HRQOL) concerns in children with intermittent exotropia (IXT) using the Intermittent Exotropia Questionaire (IXTQ), and their associations with the clinical severity of IXT and the parents' HRQOL concerns. METHODS: IXT, defined as both distance and near exodeviation ≥ 10 prism diopters were eligible for inclusion. The final IXTQ score is calculated using the mean score for all items, and ranges from 0 (worst HRQOL) to 100 (best HRQOL). The correlations of child IXTQ scores with their deviation angle and stereoacuity were measured, as were those with their parent's IXTQ scores. RESULTS: One hundred twenty-two children with IXT (aged 5-17 years) and one parent for each child completed the child and parent IXTQ, respectively. The greatest HRQOL concern for each child with IXT and their parent was "Worry about eyes" (frequency 88%, score 35.0 ± 27.8). Lower child IXTQ scores were associated with a larger distance (r = 0.24, p = 0.007) and near deviation angle (r = 0.2, p = 0.026). "It bothers me because I have to wait for my eyes to clear up" and "Waiting for their eyes to clear up" were more common in children with a larger deviation angle (both p < 0.05). The parent IXTQ scores (52.1 ± 25.3) were lower than the child ones (79.7 ± 15.8) and showed a positive correlation with child IXTQ scores (r = 0.26, p = 0.004). Lower parent IXTQ scores were associated with poor distance stereoacuity (r = 0.23, p = 0.01). CONCLUSION: The HRQOL of IXT children was positively related to that of their parents. A larger deviation angle and worse distance stereoacuity function may predict more-negative impacts on children and their parents, respectively.