Distance Stereoacuity Research Articles

Factors affecting outcome of acquired comitant esotropia with restricted use of digital devices: ACEDD Study 3.

The objective of this study is to investigate factors associated with outcomes after 3 months of instructed usage of hand-held digital devices (DD) in patients with acquired comitant esotropia (ACE). This prospective multicentre observational study included patients with ACE, aged 5-35 years, who used DD within 1 year of onset and were followed up for clinical findings and instructed use of DD. The outcomes were classified into four groups: cured, improved, unchanged and worsened. After the analysis of group differences in the clinical and DD use-related factors by univariate analysis, we used ordinal logistic regression models to identify factors associated with favourable outcomes. Of 156 patients (mean age (SD): 16.4 (7.4) years), 10 (6%), 58 (37%), 67 (43%) and 21 (14%) were classified into the cured, improved, unchanged, and worsened, respectively. In the univariate analysis, consultation within 3 months of onset, small-angle strabismus at distance and good stereoacuity were associated with good outcomes. Ordinal logistic regression analysis on adjusting for age with stereoacuity or successful DD-use time halving showed that small-angle strabismus at distance (OR: 1.02, 95% CI 1.00 to 1.03, p=0.023), good stereoacuity (OR: 1.31; 95% CI 1.10 to 1.56; p=0.003) and successful halving of DD-use time (OR: 0.63; 95% CI 0.43 to 0.92; p=0.016) influenced favourable outcomes. Patients with small-angle esotropia, good stereoacuity on consultation and success in halving DD-use time had a higher chance of recovery through instructional DD usage. Further studies using objectively measurable systems are needed to ensure the accuracy of DD-use time.

Longitudinal follow-up and outcome analysis in patching resistant/patching noncompliant amblyopic subjects treated with dichoptic amblyopia training

Purpose: The purpose of the study was to estimate the efficacy of dichoptic amblyopia training (DAT) in patching resistant/patching noncompliant amblyopic subjects on best-corrected distance visual acuity and stereoacuity with 12-month follow-up. Methodology: In this study, 113 participants with anisometropic, isometropic, strabismic, and accommodative esotropia with amblyopia, with a mean age of 8 years (interquartile range [IQR] 7–10), using full-time spectacle correction and not improving with prescribed patching protocol in 2 subsequent visits 3 months apart were included in the study. Subjects with deprivational amblyopia, ocular comorbidity, or neuronal defects were excluded. Subjects were given 30 min of dichoptic gameplay with Bynocs DAT for 5 days a week for at least 6 weeks. Best-corrected distance visual acuity and stereoacuity of subjects were recorded before treatment, immediately after Bynocs DAT, 6 months, and at 12-month follow-up. Results: The age group of the participants was divided into three groups – (1) <9 years (64.6%), (2) 10–17 years (33.6%), and (3) >18 years (1.8%). The median (IQR) age of 113 participants was 8 years (7–10). The diagnosis of the participants was anisometropic amblyopia in 18 (15.9%), isometropic amblyopia in 72 (63.7%), accommodative esotropia with amblyopia in 18 (15.9%), and strabismic amblyopia in 5 (4.4%). Post dichoptic therapy, the best-corrected distance visual acuity improvement was statistically significant using the McNemar test and remained stable till the 12-month follow-up (P < 0.001). Post Bynocs DAT, stereoacuity improvement was statistically significant using the McNemar test and maintained till the 12-month follow-up (P < 0.001). Conclusion: Best-corrected distance visual acuity and stereoacuity improved after Bynocs DAT and remained stable in patching resistant/patching noncompliant subjects with anisometropic and isometropic amblyopia 12 months after cessation of treatment.

Distance stereopsis in patients with accommodative esotropia.

We aimed to evaluate distance stereoacuity (DS) in patients with successfully treated accommodative esotropia (AET) and its association with other clinical factors. The medical records of 176 children with refractive AET with a follow-up period ≥ 1year were reviewed to identify a cohort of patients who achieved a stable alignment within 4 prism diopters (PD) of orthotropia at both distance and near fixation. Age of onset, duration of misalignment, uncorrected near and distance deviation, accommodative convergence/accommodation ratio, refractive error, presence of anisometropia and amblyopia, near stereopsis were evaluated as predictors of outcome. DS was measured using the Distance Randot Stereo test and near stereoacuity by Randot Stereotest. The patient group was compared with 50 age-matched normal controls for DS. Fifty-six patients were included, and 38 patients had DS at the final visit. All patients with DS attained uncontoured near stereopsis (UCNS). UCNS was present only in 11 patients without DS (p = 0.001). Anisometropia (p = 0.997), uncorrected near deviation (p = 0.224), distance deviation with correction (p = 0.255), and high hypermetropia (p = 0.998) were not associated with DS. The multivariable regression model showed a significant positive correlation between UCNS and DS (OR = 31.14 (95% CI 2.25-430.48); p = 0.01). Contoured near stereopsis outcome was significantly different between the patients with and without DS (p = 0.001 for animals and p = 0.003 for circles). Compared with the control group, the patient group yielded lower DS scores (p = 0.001). Distance Randot Stereotest can be useful in measuring binocular vision recovery after successful realignment in refractive AET patients. Patients attaining normal scores for near stereopsis tests after optical correction revealed subnormal thresholds for DS.

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

PurposeTo investigate characteristics and risk factors of poor stereoacuity of Convergence insufficiency-type Intermittent Exotropia (CI-type X(T)). DesignObservational, cross-sectional study. MethodsThe 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. ResultsCompared 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. ConclusionCI-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.

Binocular Summation With Quantitative Contrast Sensitivity Function: A Novel Parameter to Evaluate Binocular Function in Intermittent Exotropia.

Intermittent exotropia (IXT) is the most common form of strabismus. Surgery can potentially improve binocular function in patients with IXT. We aimed to evaluate binocular function using a novel parameter-binocular summation ratio (BSR), measured using quantitative contrast sensitivity function (CSF) in patients with IXT before and after surgery. Prospective study of 63 patients with IXT and 41 healthy controls were consecutively enrolled and underwent quantitative CSF testing binocularly and monocularly. BSR was calculated by dividing the CSF of the binocular value by the better monocular value. Forty-eight patients with IXT underwent strabismus surgery. BSR, stereoacuity, fusion ability, and strabismus questionnaires were assessed pre-operatively and 2 months postoperatively. Sixty-three patients with IXT (median age = 9 years) compared with 41 healthy controls showed a worse mean BSR based on all CSF metrics at baseline (the area under the log CSF [AULCSF], spatial frequency [SF] cutoff, and contrast sensitivity at 1.0-18.0 cpd SF). All 48 patients with IXT showed successful alignment after surgery, and there were significant improvements in BSR based on the AULCSF, SF cutoff, and contrast sensitivity at 6.0, 12.0, and 18.0 cpd SF, respectively. The distance stereoacuity and fusion ability also improved after surgery, and a better BSR was associated with better stereoacuity and fusion. For strabismus questionnaires, the psychosocial subscale scores improved postoperatively, whereas the functional subscale scores did not change. BSR based on quantitative CSF can characterize binocular function across a range of spatial frequencies and can be used as a supplemental measurement for monitoring binocularity in patients with IXT in clinical settings.

Stereopsis after bilateral implantation of Toric intraocular lenses in high myopic cataract patients with astigmatism

PurposeTo evaluate near, intermediate, distance visual acuity and stereopsis after bilateral implantation of Toric intraocular lenses (IOLs) in high myopic patients with astigmatism. MethodsBilateral Toric or non-Toric IOL implantation (n ​= ​40 eyes each) was performed on high myopic cataract eyes with astigmatism. Best-corrected distance visual acuity (BCDVA), uncorrected intermediate visual acuity (UCIVA), uncorrected near visual acuity (UCNVA), residual refractive astigmatism (RRA), and near, intermediate, and distance stereoacuity were measured postoperatively at 7 days, 1 month, and 3 months. ResultsThe three-month postoperative BCDVA, UCIVA, and UCNVA of the Toric group were 0.08 ​± ​0.07, 0.30 ​± ​0.11, and 0.23 ​± ​0.14 LogMAR. All improved over the preoperative assessments (P ​< ​0.05). The RRA, UCIVA, and UCNVA were significantly better in the Toric group than the non-Toric group at all follow-up examinations (all P ​< ​0.05). At 3 months, the median near and intermediate stereoacuity of the Toric group were 100 (range 40 – 400) and 120 (range 50 – 400) arcsec, which were better than the non-Toric group (both P ​< ​0.05). Fine near stereopsis ≥100 arcsec was present in 65% of the Toric patients, and 50% had good intermediate stereopsis of ≥100 arcsec. However among non-Toric patients, only 15% and 5% achieved fine near and intermediate stereopsis. The postoperative BCDVA and best-corrected distance stereoacuity were similar in the two groups (P ​> ​0.05). ConclusionsIn bilateral high myopic cataract patients with astigmatism, Toric IOLs not only improved UCIVA, UCNVA, and RRA, but also enhanced near and intermediate stereopsis acuity.

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

BackgroundPatients 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.MethodsIXT, 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.ResultsOne 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).ConclusionThe 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.

Influence of Interocular Differences and Alcohol Consumption on Binocular Visual Performance.

The purpose of this study was to assess the influence of a moderate breath-alcohol content (BrAC of 0.40 mg/L) on binocular visual performance for different visual functions after inducing different levels of interocular differences with the use of filters. A total of 26 healthy young subjects were enrolled. The participants participated in two sessions: one without alcohol consumption and another after alcohol consumption. In each session and for the different filter conditions (subjects were wearing Bangerter foil of 0.8 and BPM2 fog filter on the dominant eye), monocular and binocular visual function was evaluated by measuring visual acuity, contrast sensitivity, visual discrimination capacity (and successively by calculating their corresponding binocular summations) and stereopsis (near and distance stereoacuity). In addition, interocular differences were calculated for different retinal-image quality and straylight parameters. All monocular and binocular visual functions were analyzed and stereopsis was significantly impaired by alcohol and filters (p < 0.05). Interocular differences for different ocular parameters and binocular summations for visual parameters were negatively affected by filters but not alcohol. Significant correlations (averaging all the experimental conditions analyzed) were found, highlighting: the higher the interocular differences, the lower the binocular summation and the poorer the stereopsis and, therefore, the worse the binocular visual performance.

Binocular function in patients with intermittent exotropia accompanied by unilateral congenital ptosis

Patients with intermittent exotropia (IXT) have a wide range of binocular deficits. This study aims to evaluate the effect of ptosis on the binocular function of patients with IXT. Clinical records of 45 IXT patients with congenital ptosis (IXT-ptosis group) and 58 age-matched IXT patients without ptosis (IXT only group) who presented for eye examination between January 2017 and June 2020 were retrospectively reviewed. Patients with amblyopia were excluded to rule out the effects of visual acuity on binocularity. Best-corrected visual acuity (BCVA), the magnitude of exodeviation at distance and at near, stereopsis, and office-based control scores at the first visit were reviewed. The binocular functions of the two groups were compared. The mean ± SD age of the overall patients was 6.6 ± 2.7 years. There were no significant differences in the distribution of age, sex, spherical equivalent refraction, or BCVA between the two groups (all p > 0.05). Although the office-based control scores at distance and near were slightly worse in the IXT-ptosis group, the differences were not statistically significant (at distance, 2.8 ± 1.87 vs. 2.2 ± 1.13, p = 0.08; at near, 1.8 ± 0.67 vs. 1.6 ± 0.74, p = 0.11). Furthermore, the IXT-ptosis group had worse stereopsis at distance (p = 0.01). There were no significant differences between the two groups in near stereopsis or exodeviation magnitude (p > 0.05). A larger proportion of patients had suppression on the Bagolini test in the IXT-ptosis group than in the IXT-only group (p = 0.04). The IXT-ptosis group had worse distance stereoacuity, and a larger proportion of patients had suppression on the Bagolini test than the IXT only group. In IXT patients, the presence of coexisting ptosis can have a further deleterious impact on binocular function.

Correlation between Frisby-Davis Distance Stereoacuity Scores and Long-term Surgical Outcomes in Intermittent Exotropia

Purpose: We analyzed postoperative Frisby-Davis distance (FD2) stereotest scores and changes in the angle of deviation, and the correlation between postoperative FD2 stereotest scores and long-term surgical outcomes, in patients with intermittent exotropia.Methods: This retrospective study included patients aged less than 12 years with intermittent exotropia who underwent at least 28 months of postoperative follow-up. We analyzed the changes in the postoperative angle of deviation and preoperative and postoperative Titmus and FD2 stereotest scores. Surgical success rates at 28 months postoperatively were compared between the good (FD2 at 10 months postoperatively ≤ 10 arcsec) and bad (FD2 at 10 months postoperatively ≥ 15 arcsec) stereotest groups. Surgical success was defined as a horizontal deviation on distance measurement of 5 prism diopter (PD) esodeviation to 10 PD exodeviation at 1 year postoperatively.Results: This study included 101 patients. No significant difference was identified between preoperative and postoperative Titmus test scores. However, the FD2 stereotest scores were significantly improved at 10 months postoperatively (p = 0.001). A significant, positive correlation was observed between FD2 stereotest scores at 10 months postoperatively and the angles of deviation at distance at 10, 16, 22, and 28 months postoperatively (p ≤ 0.001 for all). The surgical success rates at 28 months postoperatively were 73.1% and 43.5% in the good and bad stereotest groups, respectively (p = 0.008).Conclusions: Distance stereoacuity within 1 year postoperatively correlated with the postoperative angle of deviation at distance. Good distance stereoacuity (i.e., &lt; 10 arcsec) within 1 year postoperatively correlated with a higher surgical success rate compared to bad distance stereoacuity.

Effect of interocular differences on binocular visual performance after inducing forward scattering

PurposeTo assess binocular visual performance by means of binocular summation on visual function after inducing monocular forward scattering, and to study the influence of interocular differences on ocular parameters.MethodsSeven young healthy subjects were recruited. Four Bangerter foils and five fog filters were used to induce monocular forward scattering. To analyse the impact of the scatter, visual acuity, contrast sensitivity, visual discrimination capacity and distance stereoacuity were measured binocularly with the filter placed over the dominant eye. Additionally, interocular differences were calculated for four ocular parameters: the Objective Scatter Index (OSI), Strehl ratio (SR), modulation transfer function cut‐off (MTF cut off) and straylight (log[s]). Binocular summation was determined for these visual functions.ResultsA statistically significant deterioration in visual acuity, contrast sensitivity and stereoacuity was seen for all of the filter conditions with respect to the natural state (baseline), with the largest change being recorded for the Bangerter foils. Similarly, the interocular difference for the three retinal image quality parameters (OSI, SR and MTF cut‐off) and log(s) increased significantly for the Bangerter foil condition, but not for the fog filters (except log(s)). Binocular summation declined gradually with the Bangerter foils, but not for the fog filters. Statistically significant correlations were found, that is, the greater the interocular differences, the lower the binocular summation of the visual functions and the greater the distance stereoacuity.ConclusionIncreased forward scattering in the dominant eye resulted in interocular differences, which reduced the overall binocular visual performance, including the binocular summation of several visual functions and distance stereoacuity. The results suggest that marked interocular differences in ocular parameters should be avoided in cases of ocular pathology, amblyopia and emmetropisation procedures (such as refractive surgery) or a monovision correction for presbyopia.

Validity and repeatability of contour-based visotec distance stereoacuity test

ABSTRACTClinical RelevanceThe clinical assessment of distance stereoacuity is important in some ocular conditions. Given the different neurophysiological mechanism for crossed and uncrossed stereoacuities, evaluation of both may provide additional insight into binocular vision disorders.BackgroundClinical devices measuring distance crossed and uncrossed stereopsis are not readily available. Visotec Distance Stereo Test (VDST) is a contour-based device designed to measure both forms of distance stereoacuity. This study assesses the validity and test–retest reliability of the device in comparison to the random dot-based Randot Distance Stereo Test (RDST).MethodVDST and RDST were administered to a total of 107 children, that included 51 ‘normal’ and 56 ‘abnormal’ (37 intermittent exotropia and 19 amblyopia) between the ages of 5 and 15 years. Two examiners retested stereoacuities in a sub-set of 62 randomly selected subjects. Stereoacuity was transformed to log scale. 95% limits of agreement were calculated for test–retest reliability. The Bland–Altman plot was used to demonstrate the agreement between the tests and the examiners.ResultsThe mean ± SD crossed distance stereoacuities using VDST in normal, intermittent exotropia and amblyopic children were 93.1 ± 43.8, 161.9 ± 89.8 and 236.3 ± 122.4 arcseconds, respectively. For uncrossed stereoacuity, these were 104.7 ± 54.0, 187.6 ± 89.6 and 265.5 ± 144.0 arcseconds, respectively. Crossed stereoacuity was significantly better than uncrossed stereoacuity. 95% limits of test–retest agreement for crossed and uncrossed stereoacuities using the VDST were 0.27 and 0.30, respectively. An exact test–retest match using VDST was 84% in normals and 77% in abnormals for crossed and 83% in normal and 74% in abnormal for uncrossed stereoacuities.ConclusionVDST is a reliable, valid and easy-to-administer distance crossed and uncrossed stereoacuity measuring device. Further studies are required to establish the clinical importance of assessing these two forms stereoacuities in relation to various binocular vision disorders.

Longitudinal Rehabilitation of Binocular Function in Adolescent Intermittent Exotropia After Successful Corrective Surgery.

PurposeTo study the longitudinal rehabilitation of binocular visual function in adolescent intermittent exotropia (IXT) after successful surgery and compare the results with those of a normal population. The role of binocular function in ocular alignment stability was also evaluated postoperatively.MethodsIn this prospective study, 30 adolescents with IXT successfully corrected after 1 month were followed for 12 months, and 30 children with normal vision were enrolled as controls. Stereopsis, the fusional vergence amplitude, sensory fusion, and accommodative flexibility were measured to assess binocular function at baseline and 6 and 12 months postoperatively. The controls were tested once when they were enrolled in the study.ResultsThe deviation was −32.00 ± 8.60 prism diopters (PD) at distance fixation and −36.0 ± 9.10 PD at near fixation preoperatively with an average correction of 28.53 ± 3.79 PD and 30.67 ± 1.34 PD at 1 month postoperatively. Distance stereoacuity and near stereoacuity improved from 1 to 12 months postoperatively (p = 0.025 and p = 0.041, respectively). Compared with the controls, the fusional convergence reserve at distance (p = 0.025) and near (p = 0.033) fixations and fusion reserve ratio at distance (p = 0.000) and near (p = 0.000) fixations remained subnormal, whereas sensory fusion (p = 0.237), distance stereopsis (p = 0.120), and the fusional divergence amplitude at a distance (p = 0.168) were normal. However, no significant correlations were found between binocular functions at 1 month postoperatively and the postoperative drift.ConclusionBinocular function significantly improved from before to after successful corrective surgery and continued to improve from 1 to 12 months postoperatively in adolescents with IXT. No significant correlations were found between binocular functions at 1 month postoperatively and ocular alignment stability.

The effect of induced monocular blur by bangerter filters on measures of visual acuity and stereoacuity

ABSTRACT To evaluate the effect of monocular blur induced by Bangerter filters (BF) on visual acuity (VA) and stereoacuity. Monocular blur was induced by a range of Trusetal BF strengths (0.1, 0.2, 0.4, 0.6) to 23 visually normal adult volunteers (aged 18-25, mean age 20.33 ± 1.79 years). The right monocular and binocular logMAR VA and distance stereoacuity using the FD2 were measured at 6 m with no filter (baseline) and with each filter strength. The order of testing the filters was randomized. Results were analyzed using one factor repeated measures ANOVAs, t–tests using Bonferroni correction and Pearson’s product moment correlation. All filters degraded right monocular distance VA from baseline, but less significantly between the 0.4 and 0.6 filters than the other filters (p < .05 and p < .001, respectively). Degradation was in concordance with the labeled filter density, excluding filter strength 0.4. For all filter strengths, binocular VA was significantly but not clinically reduced from baseline (p < .05). Filters statistically and clinically significantly degraded distance stereoacuity from baseline (p < .001). A significant negative correlation existed between the mean degraded right monocular VA and stereoacuity (r = −0.998, p < .02). Trusetal BF significantly reduced monocular VA and stereoacuity but binocular VA remained within normal levels. The impact on VA and stereoacuity in a normal population can be of clinical relevance when applied to the use of BF for management of amblyopia and intractable diplopia. It is advised that clinicians ensure the desired level of degradation has been achieved in clinic before prescribing a particular filter strength.

Binocular integration and stereopsis in children with television torticollis

BackgroundTo observe the characteristics of binocular integration and stereopsis in children with television torticollis.MethodsA retrospective study was carried out, where data were collected from 25 children with television torticollis as the disease group after refractive error correction and 25 normal children as the control group. A virtual reality system was used to assess and analyze the characteristics of binocular integration by a contrast balance test and binocular stereopsis.ResultsThe 25 children in the disease group included 17 males and 8 females with an average age of 7.5 ± 1.9 years old and an average binocular spherical equivalent of − 0.35 ± 1.46D. The 25 children in the control group were also 17 males and 8 females with an average age of 7.3 ± 2.2 years old and the average binocular spherical equivalent of − 0.48 ± 0.93D. No significant differences were found in the horizontal bar contrast balance test between the 2 groups at near and far distances. Near-distance vertical bar contrast balance test was normal in 23 subjects and suppressed in 2 subjects in the control group, while it was normal in 13 subjects and suppressed in 12 subjects in the disease group, which showed a statistically significant difference (P = 0.002). Far distance vertical bar contrast balance test was normal in 24 subjects and suppressed in 1 subject in the control group, normal in 7 subjects and suppressed in 18 subjects in the disease group, showing a statistically significant difference (P = 0.000). All subjects in the 2 groups showed 100〞 as near distance stereoacuity. At far distance, the mean stereoacuity was 176.00〞 ± 92.56〞 in the control group, and 352.00〞 ± 270.99〞 in the disease group, with a statistically significant difference (P = 0.011).ConclusionBy using virtual reality technology, defects in binocular visual function were found in children whose television torticollis persisted after regular refractive error correction. Television torticollis may be associated with the deficit of binocular integration for vertical bars and far distance stereopsis.

Clinical Usefulness of a Computerized Vision Chart for Distance Stereoacuity Assessment in Children with Intermittent Exotropia

ABSTRACT Introduction The aim of this study is to evaluate distance stereoacuity in children with intermittent exotropia (IXT) using a computerized vision chart (CVC), to compare the results to the normal subjects, and to determine if any correlation between stereoacuity and IXT severity exits. Methods A prospective case–control study was conducted including 24 children with IXT and 25 age-matched normal subjects. The mean age was 8.9 ± 4.5 in IXT group and 9.4 ± 4.2 in control group. The majority of patients (n = 17) had basic type IXT. Full ophthalmic examinations, deviations and stereoacuity tests were evaluated. Stereoacuity was measured with the CVC for distance stereoacuity and Randot stereotest book for near stereoacuity. Level of fusional control in patients with IXT was assessed using Newcastle Control Score (NCS). Seven of the patients with IXT were also reevaluated postoperatively. Results Near stereoacuity was good in both IXT and control groups, and there was no significant difference between groups. There was a poor correlation between near stereoacuity and NCS (rs = 0.15, p = .48). Distance stereoacuity in the IXT group was significantly reduced compared to controls (p = .004). There was a positive correlation between distance stereoacuity values and NCS in patients with IXT (rs = 0.73, p < .001). Conclusion Diminished distance stereoacuity in children with IXT can be detected with the CVC and this test may be useful for deciding the timing of surgical intervention and postoperative evaluation.

Effect of Aniseikonia Induced by a Size Lens on Contrast Visual Acuity and Stereo Acuity and Eye-hand Coordination

Purpose : The purpose of this study is to find out the effect of unequal vision induced by a size lens on contrast visual acuity, and distance and near stereo acuity.Methods : Thirty people in their 20s and 30s were involved to measure for high and low contrast visual acuity, distance stereo acuity and near stereo acuity according to the magnification of 2, 4, and 6% of the size lens. Contrast visual acuity composed of a Randolt ring was measured using LogMAR visual acuity, and it was divided into high contrast (100%) and low contrast (25, 10%) visual acuity according to the contrast of the target. The distance stereo acuity was measured using a three-rod test, and the near stereo acuity was measured using a random dot test. For eyehand coordination, a device made with a t-wall as a motif was used.Results : Contrast visual acuity did not show any significant difference after 2% aniseikonia induction, but showed a significant difference and a decrease at 4 and 6% aniseikonia induction (p<0.050). Contrast visual-acuity decreased significantly as the degree of aniseikonia increased, and as the degree of contrast decreased. The distance and near stereo-acuity showed a significant difference and decreased when the aniseikonia of 4 and 6% was induced, except for the aniseikonia of 2% (p<0.050). Eye-hand coordination decreased significantly with increasing aniseikonia (p<0.050).Conclusion : It was identified that as the aniseikonia increased, contrast visual-acuity, stereo-acuity and the capability of eye-hand coordination were decreased. In clinical practice, aniseikonia should be considered when an optician prescribes aniseikonia. However, if the prescription is avoided in consideration of aesthetics, the difference in magnification must be induced to within 2%. Therefore, it is expected that it will contribute to improving the health and quality of life by preventing the factors deteriorating daily life that can be caused by aniseikonia.

Effect of Defocus Incorporated Multiple Segments Spectacle Lens Wear on Visual Function in Myopic Chinese Children.

PurposeTo compare visual function of myopic children who had worn either defocus incorporated multiple segment (DIMS) spectacle lenses or single vision (SV) spectacle lenses over two years.MethodsWe included 160 Chinese myopic (−1 diopter [D] to −5 D) children aged 8 to 13 years in a randomized clinical trial; they wore either DIMS lenses (DIMS; n = 79) or regular SV spectacles lenses (n = 81) full time for 2 years. Visual function, including high-contrast visual acuity (VA) and low-contrast VA at distance and near, binocular functions, and accommodation, before, during, and after 2 years of spectacle wear were assessed when both groups wore SV corrections. Changes of visual function between the two groups and within groups were compared.ResultsThere were no statistically significant differences in the 2-year visual function changes between DIMS and SV groups (repeated measures analysis of variance with group as factor; P > 0.05). Statistically significant improvement in the best-corrected distance high-contrast VA (P < 0.001) and stereoacuity score (P < 0.001) were found after DIMS lens wear over 2 years. Similar findings were observed after SV spectacle lens wear. For both the DIMS and SV groups, there were statistically significant decreases in accommodative lag, monocular and binocular amplitude of accommodation after two years (P < 0.01), but not in the changes in distance low-contrast VA, near high-contrast VA, near low-contrast VA, or phoria.ConclusionsAlthough changes in some visual function were shown during 2 years of DIMS lens wear, similar changes were found with SV lens wear. Wear of DIMS spectacle lenses for 2 years does not adversely affect major visual function when children return to SV corrections.Translational RelevanceDIMS spectacle lenses did not cause any adverse effects on visual function.

Can Clinical Measures of Postoperative Binocular Function Predict the Long-Term Stability of Postoperative Alignment in Intermittent Exotropia?

Purpose To evaluate whether clinical measures of postoperative binocular functions could predict the long-term stability of postoperative ocular alignment in children with intermittent exotropia. Methods A retrospective study was performed in thirty-nine children (median: 7 years) who have been surgically treated from intermittent exotropia without overcorrection (less than 10 prism diopters [pd] of exodeviation at 1 month postoperatively). Angles of deviation and binocular functions were measured preoperatively and at 1 month, 6 months, and the final follow-up visit (≥24 months) postoperatively. We examined the relationships between postoperative drift (change of ocular alignment) and binocular functions (sensory fusion, fusional convergence amplitude, and stereoacuity). Results The surgical success rate (esophoria/tropia ≤5 pd to exophoria/tropia ≤10 pd) dropped to 76.9% at 6 months after surgery and to 53.8% at individuals' last visit (mean: 37 months). The mean exodrift was 7.7 ± 9.2 pd from the postoperative month 1 to the final visit (p < 0.001) on distance fixation. Distance stereoacuity, central fusion, and fusional convergence amplitude significantly improved following surgery (p < 0.05). However, no significant correlation was found between their binocular functions measured at the beginning of each follow-up period and the postoperative drift (all p > 0.13). Conclusion Our findings suggest that the clinical measures of sensory fusion, fusional convergence amplitude, and stereoacuity cannot serve as a robust predictor for the long-term stability of postoperative ocular alignment in patients who underwent successful surgery without overcorrection at 1 month postoperatively.

The difference of distance stereoacuity measured with different separating methods.

BackgroundThe majority of tests to evaluate stereopsis should separate two eyes first. Whether different binocular separating manner may affect the test result of stereopsis is the main purpose of this study. Red-green anaglyphs, polarized light technology, active shutter 3D system, and auto-stereoscopic technique were chosen to evaluate distance stereoacuity.MethodsRed-green anaglyphs test system was established with an ASUS laptop with the aid of TNO Stereotest glasses. Active shutter 3D system was set up with the same ASUS laptop with the aid of NVidia 3D Vision 2 Wireless Glasses Kit. The polarized 3D system adopted the AOC display. A Samsung naked-eye 3D laptop was used to set up an auto-stereoscopic system. Thirty subjects were recruited. Distance stereoacuity was measured with those computer systems.ResultsThe auto-stereoscopic system was failed to measure distance stereopsis. A significant difference was found among red-green anaglyphs, polarized 3D system, and active shutter 3D system (Friedman Test, Chi-square =48.713, P<0.001). No significant difference was found between the polarized 3D system and an active shutter 3D system (Z=−1.134, P=0.257). The stereoacuity of the red-green glasses test was significantly worse than those of the other two test systems (versus shutter 3D test, Z=−4.553, P<0.001; versus polarized 3D test, Z=−4.618, P<0.001).ConclusionsDifferent separating methods may affect the test result of distance stereopsis.