Control Of Intermittent Exotropia Research Articles

Vergence and accommodation responses in the control of intermittent exotropia.

Individuals with different types of intermittent exotropia (IXT) may use neurally coupled accommodation and vergence responses differently from those without exotropia to achieve eye alignment. This study examined the relationship between simultaneously recorded accommodation and vergence responses in children and young adults with a range of types of IXT while aligned and deviated. Responses of 29 participants with IXT (4-31 years) and 24 age-matched controls were recorded using simultaneous eye-tracking and eccentric photorefraction while they watched a movie in binocular or monocular viewing at varying viewing distances. Gradient response AC/A ratios and fusional vergence ranges were also assessed. Eight participants had divergence or pseudo-divergence excess type IXT, 5 had convergence insufficiency and 16 had basic IXT. Control and IXT participants accommodated similarly both in monocular and binocular-aligned conditions to visual targets at 80 and 33 cm. When deviated in binocular viewing, most participants with IXT exhibited changes in accommodation <0.5D relative to alignment. Gradient response AC/A ratios were similar for control [0.56 MA/D (IQR: 0.51 MA/D)] and IXT participants [0.42 MA/D (0.54 MA/D); p = 0.60]. IXT participants showed larger vergence to accommodation ratios with changes from distance to near fixation [1.19 MA/D (1.45 MA/D)] than control participants [0.78 MA/D (0.60 MA/D); p= 0.02], especially among IXT participants with divergence or pseudo-divergence excess. Participants with IXT exhibited typical fusional divergence ranges beyond their dissociated position [8.86 Δ (7.10 Δ)] and typical fusional convergence ranges from alignment [18 Δ (15.75 Δ)]. This study suggests that control of IXT is typically neither driven by accommodative convergence alone nor associated with over-accommodation secondary to fusional convergence efforts. These simultaneous measurements confirmed that proximal vergence contributed significantly to IXT control, particularly for divergence or pseudo-divergence excess type IXT. For IXT participants in this study, achieving eye alignment did not conflict with having clear vision.

The Influence of Overminus Lens Therapy on Control of Intermittent Exotropia: A Meta-Analysis of Randomized Clinical Trials

Background: Intermittent exotropia (IXT) is the most common type of strabismus, overminus lens (OML) therapy is frequently prescribed to treat IXT. Objectives: The purpose of this study was to compare the effectiveness of OML and observation in the treatment of IXT. Method: An exhaustive search of the literature in PubMed, Embase, Web of Science, and Cochrane Library databases was performed until July 2022. No language restrictions were used. The literature was rigorously screened according to eligibility criteria. Weighted mean differences and 95% confidence intervals (CIs) were calculated. Results: A total of 4 articles with 561 participants were included in this meta-analysis. Our pooled results showed that OML demonstrated superior outcomes compared with observation, with greater decreases in distance and near exodeviation control (MD = −1.08, 95% CI: −1.96 to −0.20, p = 0.02; MD, −0.64, 95% CI: −1.15 to −0.13, p p p p = 1.00). Conclusions: The present meta-analysis indicated that OML therapy was effective in improving the control and decreasing exodeviation angle of IXT. However, it seemed not to be effective in improving the level of near stereopsis.

The Influence of Part-Time Occlusion Therapy on Control of Intermittent Exotropia: A Meta-Analysis of Randomized Controlled Trials

Background: Intermittent exotropia is the most prevalent subtype of exotropia in children. Part-time occlusion (PTO) as an anti-suppression therapy was applied for nonsurgical management of intermittent exotropia. Objective: The aim of the study was to compare the effectiveness of PTO therapy and observation in the treatment of intermittent exotropia. Method: An exhaustive search of the literature from PubMed, Embase, Web of Science, and Cochrane Library databases was carried out until July 2022. No language restrictions were applied. The literature was rigorously screened against eligibility criteria. Weighted mean differences and 95% confidence interval (CI) were calculated. Results: A total of 4 articles with 617 participants were included in this meta-analysis. Our pooled results showed that PTO exhibited superior effects compared to observation, with greater decrease in exotropia control at distance and near (MD = −0.38, 95% CI: −0.57 to −0.20, p p p = 0.001), and there was greater improvement in near stereoacuity among the PTO group in comparison with the observation group (p Conclusions: The present meta-analysis indicated that PTO therapy showed a better effect in improving control and near stereopsis and decreasing distance exodeviation angle of children with intermittent exotropia in comparison with observation.

Binocular contrast sensitivity in patients with intermittent exotropia in relation to angle of strabismus and level of compensation

ABSTRACT Intermittent exotropia (IXT) causes photophobia, and photophobia has been studied by measurement of contrast sensitivity (CS). CS was reduced in children with IXT. We compared binocular CS (BCS) in patients with IXT and normal subjects in relation to the angle of strabismus and control of IXT. This case–control study was performed on 40 patients with IXT and 40 normal subjects who were examined with the CSV1000 CS device in mesopic (3 cd/m2) and photopic (85 cd/m2) conditions with and without a glare stimulus at 3, 6, 12, and 18 cycle/degree (cpd) spatial frequencies. The angle of strabismus and near stereoacuity were also measured. The patient’s IXT compensation was graded based on the office control scale. The mean age for IXT and normal participants were 12.30 ± 0.60 (range, 6–18) and 11.00 ± 0.78 (range, 6–18) years, respectively (P = .34). The IXT patients had lower binocular CS than controls at all spatial frequencies (P < .001). The largest decrease in CS occurred at 6 cpd spatial frequency under mesopic condition (1.61 ± 0.07 vs 1.38 ± 0.15, P < .001) and photopic condition with glare (2.03 ± 0.06 vs 1.77 ± 0.13, P < .001). Patients with better control scores had higher levels of BCS; also, the score of BCS showed a significant decrease in patients with a deviation of 25 prism diopter or more, compared to those with less deviation. BCS correlated at 3 and 6 cpd with near stereoacuity (r = −0.652, P < .001 and r = −0.613, P < .001). Binocular CS in patients with IXT correlates with the angle of strabismus and level of compensation.

Understanding the Use of the Newcastle, PEDIG, and LACTOSE Control Scores Among Pediatric Ophthalmologists for Intermittent Exotropia.

To determine the clinical use patterns of control scores for intermittent exotropia. The Newcastle Control Score, Pediatric Eye Disease Investigator Group (PEDIG) score, and Look And Cover, then Ten seconds of Observation Scale for Exotropia (LACTOSE) Control Score were developed to quantify control of exodeviations. A short survey was posted on the American Association for Pediatric Ophthalmology and Strabismus forum in August and September 2021. Respondents were asked about their assessment of control in intermittent exotropia, including knowledge and use of the various control scales. One hundred fourteen pediatric ophthalmologists responded; 54.4% (n = 62) reported not using any specific control score for intermittent exotropia, although 61.4% (n = 70) were familiar with the PEDIG score, 37.7% (n = 43) with the Newcastle Control Score, and 7.9% (n = 9) with the LACTOSE Control Score. The PEDIG score was the most widely used (26.3%, n = 30), but 36.7% (n = 11) of respondents reported that the scale is too time-intensive, limiting its use. To improve the use of the control scores, participants recommended promoting wider understanding of the scales (45.6%, n = 52). Most responding pediatric ophthalmologists do not use a specific control score in managing intermittent exotropia. The PEDIG score is the most frequently used but is reported as time-intensive. Although the LACTOSE Control Score was designed to provide a quicker alternative, it is not widely known. Promoting wider awareness and understanding of intermittent exotropia control scores may be helpful to allow for more objective quantification of control in intermittent exotropia. [J Pediatr Ophthalmol Strabismus. 2023;60(2):131-138.].

First Visit Characteristics Associated with Future Surgery in Intermittent Exotropia

ABSTRACT Purpose Identify demographic and clinical characteristics at the first presentation associated with later having surgery for intermittent exotropia (IXT). Methods Retrospective cohort study of 228 children with IXT and 5+ years of follow-up. Demographic and clinical data were extracted from medical records. A total 97 participants who underwent surgery during follow-up were compared to 131 participants who did not. Best subset regression was used to identify first visit variables associated with later having strabismus surgery. Surgery was then regressed on the selected variables using logistic models. Results Age and control were the only first visit variables significantly associated with having surgery for IXT. Notably, neither angle of deviation nor stereopsis were associated with later surgery. In an adjusted logistic model, each one-month increase in age at presentation was associated with a 1% decrease in the odds of having surgery (OR = 0.991, 95% CI: 0.982–0.999, P = .04). Children with poor control at initial visit had almost five times greater odds of having surgery than those with good control (OR = 4.95, 95% CI: 2.31–10.98, P < .0001). Conclusions Age and control of IXT are important factors at presentation associated with future surgical intervention for IXT. The magnitude of deviation and stereopsis was not significantly associated with future surgical treatment for IXT.

Relationship Between the Clinical Factors and Deviation Control in Intermittent Exotropia.

To establish whether clinical factors were correlated with deviation control in intermittent exotropia. This retrospective study included 54 patients with intermittent exotropia. The patient's sex, family history, age at first admission, best corrected visual acuity, refractive errors after cycloplegia, angles of ocular deviation at near and distance, and near, distance, and total deviation control were evaluated. Ocular deviation controls were determined according to the Mayo Clinic's office-based scale. Correlation analysis was performed between the deviation control and the determined clinical factors. Spearman correlation analyses revealed a mild correlation between age with total exotropia control score and age with the control of near exotropia control score (r = 0.320, P = .018 and r = 0.339, P = .012, respectively). The angle of deviation at near showed a significant moderate correlation between total exotropia control score and near exotropia control score (r = 0.523, P < .001 and r = 0.780, P < .001, respectively). The deviation angle at distance showed a mild correlation with distance exotropia control score and total exotropia control score (r = 0.423, P = .001 and r = 0.288, P = .034, respectively). The angle of deviation at distance showed a mild correlation with the angle of deviation at near (r = 0.359, P = .008). The deviation angle at distance was established as an independent factor for predicting total exotropia score (P = .037, P = .015, respectively). The high deviation angle correlates positively with poor deviation control. The distance deviation angle is an independent predictor of total deviation control for the first time in the literature. [J Pediatr Ophthalmol Strabismus. 2022;59(1):53-59.].

Intermittent exotropia ‒ follow up and control

Intermittent exotropia is the most common form of exotropia. According to clinical studies the frequency of this type of horizontal strabismus increases. The article covers current approaches of follow up and control of intermittent exotropia. It summarizes the conservative treatment (optical, prism correction, occlusion) and the surgical option from the literature. This is compared with the author’s personal experience.

The influence of alternate part-time patching on control of intermittent exotropia: a randomized clinical trial.

To evaluate the effect of alternate part-time patching on deviation control in patients with intermittent exotropia in comparison to observation. In a randomized clinical trial, untreated 3-8-year-old children with intermittent exotropia were randomly divided into patching group who treated with alternate part-time patching and observation group. Deviation control was assessed with 3-point and 6-point scales. Stereoacuity and suppression were evaluated with Titmus and Worth-4-dot tests respectively. All exams were repeated 3 and 6 months after beginning of treatment. Seventy-six patients (35 in patching and 41 in observation group) with a mean age of 4.99 ± 1.33 years completed the 6-month course of study. Based on 3-point scale, deviation control was significantly better in patching group after 3 and 6 months at near and after 3 months at far (p = 0.011, 0.011, and 0.03, respectively) but non-significant after 6 months at far (p = 0.16). According to 6-point scale, deviation control was also significantly better in patching group after 3 months (p = 0.03 at far, 0.003 at near) and 6 months (p = 0.03 at far, 0.003 at near). Three and 6 months stereoacuity was not significantly different between groups (p = 0.86 for both). However, there was greater stereoacuity changes among patching group in comparison with observation group from baseline to 3 and 6 months (p = 0.006 for both). Patching seems effective in improving deviation control of 3-8-year-old children with intermittent exotropia in comparison with observation based on two common office control scales. NCT03700632 (10/9/2018).

Management of Intermittent Exotropia in Children

Background: Intermittent exotropia (IXT) is a common form of childhood exotropia, accounting for about 50–90% of all the exotropia and affecting about 1% of the general population. Objective: The purpose of this study was to evaluate difference modalities for treatment of intermittent exotropia either by non-surgical and surgical methods. Patients and Methods: this study included 40 patients of both sexes with exodeviation divided into 2 groups; Group (A): 20 patients subjected to non-surgical treatment and Group (B): 20 patients underwent surgical treatment; bilateral lateral rectus recession (BLR). Results: In non-surgical group the success rate was 55% after 12 months of treatment. Overminus glasses are more effective in control of IXT than part-time occlusion (PTO) and convergence exercise. The success rate was 86%. While the success rate in PTO was 43% and the success rate of convergence exercise was 33%. Poor compliance in PTO and convergence exercise therapy affect the treatment effectiveness. In surgical group (BLR) the success rate was 75%. Under-correction was 20% and the overcorrection was 5%. No complications were found. No lateral incomitance was observed. Conclusion: Surgical method is more effective in treatment of IXT than non-surgical methods, but the non-surgical method is more important in younger children. The over-minus glasses is more effective in treatment of IXT than the other non-surgical method due to poor compliance among children in PTO and Convergence exercise therapy. A larger trial for a longer duration is warranted to assess the effectiveness of different modalities of treatment of IXT

Management of Intermittent Exotropia in Children

Background: Intermittent exotropia (IXT) is a common form of childhood exotropia, accounting for about 50–90% of all the exotropia and affecting about 1% of the general population. Objective: The purpose of this study was to evaluate difference modalities for treatment of intermittent exotropia either by non-surgical and surgical methods. Patients and Methods: this study included 40 patients of both sexes with exodeviation divided into 2 groups; Group (A): 20 patients subjected to non-surgical treatment and Group (B): 20 patients underwent surgical treatment; bilateral lateral rectus recession (BLR). Results: In non-surgical group the success rate was 55% after 12 months of treatment. Overminus glasses are more effective in control of IXT than part-time occlusion (PTO) and convergence exercise. The success rate was 86%. While the success rate in PTO was 43% and the success rate of convergence exercise was 33%. Poor compliance in PTO and convergence exercise therapy affect the treatment effectiveness. In surgical group (BLR) the success rate was 75%. Under-correction was 20% and the overcorrection was 5%. No complications were found. No lateral incomitance was observed. Conclusion: Surgical method is more effective in treatment of IXT than non-surgical methods, but the non-surgical method is more important in younger children. The over-minus glasses is more effective in treatment of IXT than the other non-surgical method due to poor compliance among children in PTO and Convergence exercise therapy. A larger trial for a longer duration is warranted to assess the effectiveness of different modalities of treatment of IXT

The effect of alternate occlusion on control of intermittent exotropia in children.

The aim is to investigate the effect of alternate occlusion on control of intermittent exotropia in children 3 to 8 years old. The ability of 28 children to control of the deviation at far and near was evaluated based on 3-point and 6-point control scales. Stereopsis and fusion were assessed using the Titmus and Worth 4-dot tests, respectively. Two-hour alternate daily occlusion was prescribed for children with no dominancy. For children with a dominant eye, 2-h occlusion of the dominant eye for 5 days and the non-dominant eye for 2 days. All measurements were repeated at 3, 6, and 9 months after the treatment. For all children with a mean age of 4.7 ± 1.56 years, deviation control at far improved significantly after 3, 6, and 9 months of treatment using both control scales when compared with baseline (p = 0.005 after 3 months and p = 0.008 after 6 and 9 months for the 3-point scale, and p < 0.001 after 3 and 6 months and p = 0.010 after 9 months for the 6-point scale). Control at near showed a significant improvement after 3, 6, and 9 months of treatment based on the 6-point scale (p = 0.007 for 3 months, p = 0.004 for 6 months, and p = 0.014 for 9 months). Near stereopsis improved significantly after 9 months of treatment (p = 0.043). Alternate occlusion is significantly effective on control of intermittent exotropia. As a result, it can be used as a useful method to postpone or even eliminate the need for surgery in intermittent exotropia.

Role of overminus therapy in intermittent exotropia

Aim: The aim is to study the change in Newcastle Control Score (NCS) and angle of deviation after a trial of overminus therapy in intermittent exotropia (IXT). Context: Overminus therapy in IXT. Settings and Designs: This prospective observational study was conducted at Comtrust Eye Hospital, Calicut, Kerala, which is a tertiary eye care center from July 2015 to May 2017. Materials and Methods: Fifty-three children with IXT, aged 1–5 years, were recruited. NCS scores and angle of deviation were recorded. Treatment was instigated with the minimum minus lens required to achieve control of the manifest deviation. NCS and angle of deviation were recorded with the overminus glasses at 6 weeks, 6 months, and 1 year. Statistical Analysis: Data were tabulated and analyzed using the SPSS software (SPSS statistics for Windows 17.0 Chicago, SPSS Inc). Paired t-test was used to compare change in NCS and angle of deviation before and after treatment. P Results: Fifty-three children were recruited, 31 females and 22 males with a mean age of 3.6 ± 1.633 years. Majority were of the basic type of IXT. The NCS at 1 year showed significant reduction from baseline values. At 1 year, 27% patients had the same NCS as baseline, 32% showed a reduction by 1, 21% reduced by 2, and 5% showed a reduction by 3 in the total score. The angle of deviation with the overminus for both distance and near also showed significant reduction. Conclusion: This study showed definite improvement in control of IXT with overminus, and hence, a trial of overminus therapy is recommended for IXT in children below 5 years, as surgery has its own side effects like overcorrection, leading to consecutive esotropia with loss of stereopsis and high amount of recurrence.

Surgical Outcome of Intermittent Exotropia With Improvement in Control Grade Subsequent to Part-time Preoperative Occlusion Therapy.

To evaluate the effect of improvement in the control grade of intermittent exotropia using part-time occlusion therapy on the final postoperative outcome. Control of intermittent exotropia was graded as good, fair, or poor in 89 consecutive patients with intermittent exotropia during their first visit. The patients were reevaluated after part-time preoperative occlusion therapy and divided into two groups (improvement and no improvement) according to whether they showed improvement in control grade. The surgical success rate was compared retrospectively between the two groups. The mean angle of deviation on the first visit was 27.61 ± 5.40 prism diopters (PD) at distance and 29.82 ± 5.28 PD at near. There were significant improvements in the angles of deviation for distance (26.17 ± 5.09 PD) and near (27.26 ± 5.56 PD) after part-time occlusion (both P < .001). The 49 patients who had a significantly improved control grade had a significantly better surgical success rate (77.6%) than the 40 patients who did not (50%; P = .007). Part-time occlusion therapy improves the control grade of intermittent exotropia, leading to a better likelihood of successful surgery and a reduction of the angles of deviation for distance and near. [J Pediatr Ophthalmol Strabismus. 2018;55(1):59-64.].

Far distance control scores for assessing intermittent exotropia

To assess the level of control in intermittent exotropia by applying the office-based 6-point control scale to far-distance testing. Fifty-two children with intermittent exotropia were enrolled in this prospective, noninterventional case series. Control of exodeviation was assessed at indoor distance (ID) of 3m and near distance of 33cm using the office-based 6-point control scale, which was additionally applied to indoor far distance (IFD) fixation of 30m and outdoor far distance (OFD) fixation of 50m. In all 52 patients, the level of control at OFD fixation was either worse than (31%) or the same as (70%) the level of control at IFD fixation and the level of control at IFD fixation was worse than (64%) or the same as (35%) the level of control at ID fixation. The level of control at OFD fixation was worse than (69%) or the same as (31%) the level of control at ID fixation for all 52 patients. The differences between mean control scores of OFD and IFD fixation (P=0.002), IFD and ID fixation (P<0.001), OFD and ID fixation (P<0.001) were statistically significant. The outdoor and indoor far distance control scores can increase the sensitivity of the office-based 6-point control scale. The office control scale for assessing control in patients with intermittent exotropia could have application for the management of intermittent exotropia.

Binocular Summation and Control of Intermittent Exotropia

ABSTRACTBackground: Binocular summation (BiS), or improvement in binocular vision exceeding the better eye alone, is affected by strabismus. Being easily measured, BiS may be a useful indicator for subjective outcomes like stereopsis in strabismus. This study aims to investigate the relationship between BiS and measures of control of intermittent exotropia (IXT). Methods: Patients with IXT were recruited before undergoing strabismus surgery and underwent tests of binocular and monocular high- and low-contrast visual acuity, stereopsis at distance and near, and Newcastle Control Score (NCS), a score developed by incorporating home control and clinic control criteria into a control rating scale. BiS was calculated using high-contrast Early Treatment of Diabetic Retinopathy Study (ETDRS) and Sloan low-contrast acuity charts (LCA) at 2.5% and 1.25% contrast as the difference between the binocular score and that of the better eye. The relationship between BiS and measures of IXT control (NCS and distance near stereoacuity disparity) was evaluated using a correlation analysis by Spearman correlation coefficients and the Kruskal-Wallis test. Results: Thirty-four patients were included (mean [± standard deviation (SD)] age 19±16 years) having a mean (±SD) of 26±16Δ IXT at distance and 20±16Δ at near. Mean (±SD) BiS for ETDRS and Sloan LCA at 2.5% and 1.25% was 0.8±3.6, 1.9±6.0, and -2.3±7.2, respectively. The Spearman correlation coefficient of BiS and NCS was -0.53 (95% CI -0.85 to -0.25) for 2.5% LCA and -0.43 (95% CI -0.77 to -0.13) for 1.25% LCA. BiS at 2.5% LCA (P=0.006) and at 1.25% LCA (P=0.029) significantly differed between the groups based on NCS score groupings (1-3, 4-6, and 7-9), with patients who had better control scores having higher levels of BiS. BiS did not differ significantly between patients grouped according to the difference between stereoacuity measured at near versus distance. Conclusion: Significantly lower low-contrast BiS in patients with higher NCS may suggest that decreased BiS is associated with less control in IXT. This finding suggests that BiS may reflect control in IXT across a population of patients with IXT.

Does occlusion therapy improve control in intermittent exotropia?

PurposeThe aim of this study was to evaluate the effectiveness of occlusion therapy in the control of intermittent exotropia (IXT) in children between 4 and 10years in Saudi Arabia. This study will highlight the importance of patching IXT patients and assist to approach the proper use of occlusion therapy. MethodsA clinical, prospective cohort pilot study was performed on 21 untreated IXT patients. Evaluation of the deviation angle, amplitudes, stereopsis and control before, during and after occlusion therapy was performed. ResultsEleven percent of the subjects demonstrated a decrease in the deviation angle by 50% while 55.5% attained normal ranges for base-out fusional amplitudes and 77% attained success for the control. ConclusionWe suggest that alternate occlusion therapy can improve the sensory status and strengthen the fusional amplitudes but does not improve the deviation angle and therefore is useful to postpone surgery in young children and may improve surgical outcome.

Accommodative and Fusional Convergence in Intermittent Exotropia

Background and PurposeThe purpose of this paper is to provide a systematized review of the published literature addressing accommodative and fusional convergence in intermittent exotropia. This paper will summarize a variety of clinical techniques suggested to enhance assessment of intermittent exotropia.MethodA search of published, peer-reviewed literature available in the English language was performed using MEDLINE, PubMed, CINAHL, Health Source, and PsycINFO databases. There was no date limitation set. Key words used were exotropia, intermittent exotropia, convergence, fusional convergence, and accommodative convergence. In addition, relevant classic articles cited in the retrieved articles not appearing in the initial search were reviewed.ResultsFifty relevant articles were reviewed and summarized. The topics fell into several distinct categories: general descriptions of the characteristics of intermittent exotropia and vergence; the relationship of several types of convergence to the features of intermittent exotropia; methods of accurately assessing the angle of the deviation; and surgical vs. nonsurgical options for treatment of this disorder.ConclusionAccurate clinical assessment is crucial in the eventual successful management of intermittent exotropia. Understanding the interaction of fusion and accommodation with convergence in the control of intermittent exotropia will enhance targeted decision making in the development of treatment plans.

Quantifying variability in the measurement of control in intermittent exotropia

To evaluate the performance of a series of summary measures of control and to assess reliability in quantifying exodeviation control in intermittent exotropia. A large, simulated dataset of control scores for 10,000 hypothetical patients with intermittent exotropia was created using Monte Carlo simulations. These data were based on children with intermittent exotropia in whom control was assessed twice during one clinical examination, using the office control score (0-5). Each simulated patient had a baseline and 11 subsequent control scores. The repeatability of a series of summary measures of control (the mean of 2 vs the mean of 3 up to the mean of 6), was calculated using 95% limits of agreement (LOA). A total of 322 examinations in 152 patients were used to provide representative distributions of control scores. From the resultant Monte Carlo simulations, the 95% LOAs were 2.60 for 1 distance control score measure, 1.76 for the average of 3, and 1.28 for the average of 6. Therefore using the average of 3 scores, a change of <1.76 would be consistent with short-term variability, whereas a change of >1.76 would suggest a real change in control. The large dataset of simulated control scores allowed us to assess the variability of specific summary measures of control. We recommend the average of 3 scores (a triple control score) as a new standard for assessing control, providing improved reliability over a single measure, while remaining implementable in clinical practice.

Fusional vergence detected by prism bar and synoptophore in chinese childhood intermittent exotropia.

Purpose. To measure the changes in fusional vergence in Chinese children with intermittent exotropia (IXT) and the association with the control of IXT. Methods. Ninety-two patients with IXT (8–15 years old) were compared with 86 controls. Exodeviation control was evaluated using the Revised Newcastle Control Score. Angle of deviation was measured using prism and alternate cover testing at distance and near. Fusional vergence was measured using prism bar and synoptophore. This study was registered with ChiCTR-RCC-13003920. Results. Using prism bar, convergence break points were lower whereas divergence break points were higher in children with IXT at distance (P < 0.001) and near (P < 0.001) compared with controls. There was no significant difference in mean divergence amplitudes between the two groups when testing using a synoptophore (P = 0.53). In children with IXT, the distance between recovery point and break point in both convergence (distance: P = 0.02; near: P = 0.02) and divergence (distance: P < 0.001; near: P < 0.001) was larger than controls when detected by prism bar and synoptophore (convergence: P = 0.005; divergence: P = 0.006). Conclusions. Children with IXT have reduced convergence amplitudes as detected by both prism bar and synoptophore.