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We evaluated whether doses of bilateral medial rectus recessions greater than Parks's tables yielded superior outcomes for adult-onset divergence insufficiency. Forty-two patients underwent bilateral medial rectus recessions. Dose was analyzed as the average total per muscle (surgery + suture adjustment if performed) and compared with the standard dose tables (based on preoperative distance esodeviation), as difference between dose performed and dose indicated by Parks's tables. Each participant was classified as having received either Parks's dose (within 0.5 mm) or a dose greater than Parks's dose. Success was defined as "rarely" or "never" diplopia in distance straight-ahead gaze and reading. For patients classified as success, the mean difference between actual surgical dose performed and Parks's dose was calculated. Success was 91% (29/32) in those receiving greater than Parks's dose versus 67% (6/9) with Parks's dose (difference = 24%; 95% CI, -5% to 60%). The mean surgical dose was 1.0 mm greater than Parks's tables for the 35 successes (at 10 weeks) versus 0.7 mm greater for the 6 failures (difference = 0.4 mm; 95% CI, -0.2 to 0.9). For medial rectus recessions in adult-onset divergence insufficiency-type esotropia, a surgical dose 1 mm greater than Parks's tables, for each muscle, is a reasonable strategy., (Copyright © 2024 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.)

Purpose: To compare the double-Maddox rod test with other methods of measuring cyclodeviation DESIGN: Retrospective cohort study., Methods: We retrospectively identified 153 adults in a clinical practice with cyclodeviation assessed using double-Maddox rods, of whom 105 were also assessed using fusible synoptophore targets, 73 using nonfusible synoptophore targets, 118 using single-Maddox rod, and 43 using fundus photography. Relationships between double-Maddox rod and other tests were evaluated by calculating mean differences with 95% confidence intervals (CI), intraclass correlation coefficients (ICC), and Bland-Altman plots with linear regression., Results: Synoptophore cross-in-circle targets and the largest (of right or left) single-Maddox rod values were similar to double-Maddox values (mean differences: -1.2° and 0.1°, respectively; ICC: 0.79 and 0.82, respectively). Synoptophore house targets measured less excyclodeviation (mean difference: -2.7°; ICC: 0.71). Mean summed single-Maddox rod values were somewhat similar to double-Maddox values (mean difference: 1.5°; ICC: 0.85), but differences increased with greater cyclodeviation (r 2  = 0.2678; P < .001). Fundus photographs showed large, uncorrelated differences compared with double-Maddox rod test, when summing right and left eyes and when using the largest of right or left (mean differences: 12.2° and 6.2°; ICC: -0.02 and 0.21, respectively), and differences increased with greater cyclodeviation (r 2  = 0.4094; P < .001 and r 2 = .1143; P= .03, respectively)., Conclusions: There was good agreement between double-Maddox and the largest single- Maddox test values and synoptophore cross-in-circle targets but poorer agreement with other tests. Further study is needed to understand which measurements best reflect true cyclodeviation and relationships with symptoms., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Purpose: To describe frequency of postoperative diplopia after strabismus surgery in nondiplopic adults with childhood-onset strabismus and to report health-related quality-of-life (HRQOL) outcomes., Methods: We prospectively enrolled 79 adults with no diplopia in any gaze who had childhood-onset strabismus and were scheduled for strabismus surgery. Diplopia was assessed preoperatively and at 6 weeks and 1 year postoperatively using a standardized diplopia questionnaire with 5 response options in 7 gaze positions. HRQOL was assessed using the Adult Strabismus-20 (AS-20) questionnaire, with self-perception, interactions, reading function, and general function domains., Results: Constant diplopia in straight-ahead distance and reading gaze occurred in 1 patient (1% [95% CI, 0%-7%] at 6 weeks and 2% [95% CI, 0%-10%] at 1 year). Regarding the rate of any diplopia (including rarely) in any gaze, 15 of 78 patients (19%) reported diplopia at 6 weeks, of whom 13 had diplopia in straight-ahead distance gaze; 8 (10%), in reading gaze. At 1 year, 8 of 51 patients (16%) reported any diplopia (including rarely) in any gaze, of whom 7 had diplopia in straight-ahead distance gaze and 4 (8%) in reading gaze. Mean AS-20 scores improved at 1 year overall (by 32, 19, 14, and 15 points, resp., per domain) and for the 8 diplopic patients (by 21, 13, 16, and 11 points)., Conclusions: In adults with nondiplopic strabismus, constant postoperative diplopia is rare, although the rate of intermittent diplopia is higher. Even when postoperative diplopia occurs, HRQOL often improves., (Copyright © 2019 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.)

Adult strabismus is often characterized by surgical complexity. In recent years, several innovative techniques for the management of complex strabismus have been developed. Strabismus surgeons should understand the indications for various strabismus surgical techniques in the management of these difficult cases. This workshop describes several new surgical techniques to manage complex strabismus, including small-angle incomitant and very large-angle strabismus, torsional diplopia, and restrictive, paralytic, and secondary strabismus. Because strabismus surgery is an ever-evolving field, it is important to continue to refine our surgical armamentarium. Strabismus surgeons may wish to add these techniques to their surgical repertoire for select cases., (Copyright © 2019 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.)

Purpose: To compare long-term outcomes after bilateral lateral rectus recession (BLRc) or unilateral lateral rectus recession combined with medial rectus resection in the same eye (R&R) for primary treatment of childhood intermittent exotropia (IXT)., Design: Multicenter, randomized clinical trial., Participants: One hundred ninety-seven children 3 to younger than 11 years of age with basic-type IXT, a largest deviation by prism and alternate cover test at any distance of 15 to 40 prism diopters (PD), and near stereoacuity of at least 400 seconds of arc., Methods: Random assignment to BLRc or R&R and masked examinations conducted every 6 months after surgery for 3 years., Main Outcome Measures: Proportion of participants meeting suboptimal surgical outcome by 3 years, defined as: (1) exotropia of 10 PD or more at distance or near using simultaneous prism and cover test (SPCT); or (2) constant esotropia of 6 PD or more at distance or near using SPCT; (3) loss of 2 octaves or more of stereoacuity from baseline, at any masked examination; or (4) reoperation without meeting any of these criteria., Results: Cumulative probability of suboptimal surgical outcome by 3 years was 46% (43/101) in the BLRc group versus 37% (33/96) in the R&R group (treatment group difference of BLRc minus R&R, 9%; 95% confidence interval [CI], -6% to 23%). Reoperation by 3 years occurred in 9 participants (10%) in the BLRc group (8 of 9 met suboptimal surgical outcome criteria) and in 4 participants (5%) in the R&R group (3 of 4 met suboptimal surgical outcome criteria; treatment group difference of BLRc minus R&R, 5%; 95% CI, -2% to 13%). Among participants completing the 3-year visit, 29% (25 of 86) in the BLRc group and 17% (13 of 77) in the R&R group underwent reoperation or met suboptimal surgical outcome criteria at 3 years (treatment group difference of BLRc minus R&R, 12%; 95% CI, -1% to 25%)., Conclusions: We did not find a statistically significant difference in suboptimal surgical outcome by 3 years between children with IXT treated with BLRc compared with those treated with R&R. Based on these findings, we are unable to recommend one surgical approach over the other for childhood IXT., (Copyright © 2018 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Purpose: To report the dose-response relationship of adjustable Harada-Ito surgery, and postoperative stability of cyclodeviation., Design: Retrospective cohort study., Methods: Twenty patients underwent a unilateral adjustable Harada-Ito advancement of the anterior fibers of the superior oblique tendon, with or without resection. The surgical dose was calculated as resection plus advancement plus adjustment. Cyclodeviation was measured using double Maddox rods at preoperative and postoperative time points. We assessed dose effect by calculating change in cyclodeviation from preoperatively to postadjustment and evaluated the dose-response relationship by Spearman rank methods. Postoperative stability of cyclodeviation was assessed by comparing postadjustment measurements with 1-day and 6-week measurements, and also 1- and 5-year measurements, when available., Results: Change in cyclodeviation from preoperatively to postadjustment ranged from 7 to 20 degrees of incyclo effect. There was a dose effect of 1.3 degrees per mm (r s  = 0.52, P = .019). Postoperative incyclodeviation unwound a mean of 3.6 degrees ± 2.5 degrees between postadjustment and day 1. Overall change between postadjustment and the 6-week window was 6.5 ± 2.9 degrees in an excyclo direction. Unwinding continued with a mean change of 0.2 ± 2.6 degrees between the 6-week and 1-year windows, and of 0.4 ± 2.1 degrees between 1-year and 5-years windows., Conclusions: Adjustable Harada-Ito advancement of the anterior fibers of the superior oblique tendon has a dose response of 1.3 degrees per millimeter, but its effect regresses over time. Based on our data, an immediate postoperative target incyclodeviation of 7 degrees is reasonable., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Importance: Health-related quality of life (HRQOL) typically improves following strabismus surgery. Nevertheless, for some patients, HRQOL does not improve, and reasons for this are unknown., Objective: To identify factors associated with failure of adult strabismus-20 (AS-20) HRQOL scores to improve following strabismus surgery., Design, Setting, and Participants: Prospective observational case series at the Mayo Clinic, Rochester, Minnesota, comprising 276 adults, between July 2012 and August 2016., Main Outcomes and Measures: Participants completed the AS-20 HRQOL questionnaire, diplopia questionnaire, Center for Epidemiologic Studies Depression Scale-Revised (CESD-R) (depressive symptoms), and Type-D Scale 14 questionnaire (type-Distressed [type-D] personality) both preoperatively and 6 weeks postoperatively. To assess factors associated with failure of HRQOL to improve (no change or decrease in score), univariate and multiple logistic regression analyses were performed. Each of the 4 AS-20 domains (self-perception, interactions, reading function, and general function) were analyzed separately including only patients able to improve at least by the magnitude of previously defined 95% limits of agreement. Factors assessed were age (at onset and at surgery), sex, number of previous surgeries, presence of visually obtrusive facial anomaly, visual acuity, preoperative and postoperative diplopia questionnaire scores, alignment (as a vector), presence of esotropia, presence of a vertical deviation, CESD-R scores, and type-D personality. Stepwise multiple logistic regression analyses were performed to assess factors associated with failure of AS-20 scores to improve for each domain., Results: Of the 276 participants, the median age was 57 years (range, 18-91 years), 153 were women (55%), and 266 were white (96%). Failure to improve was associated with worse diplopia postoperatively on the self-perception (adjusted risk ratio [RR], 1.01; 95% CI, 1.00-1.02), reading function (adjusted RR, 1.02; 95% CI, 1.01-1.03), and general function domains (adjusted RR, 1.02; 95% CI, 1.01-1.03). In addition, failure to improve on the self-perception domain was associated with type-D personality postoperatively (adjusted RR, 4.26; 95% CI, 1.90-9.57) and failure to improve on the interactions domain was associated with postoperative depressive symptoms (adjusted RR, 1.04; 95% CI, 1.02-1.06) and coexisting visually obtrusive anomaly (adjusted RR, 2.12; 95% CI, 1.04-4.32)., Conclusions and Relevance: Postoperative diplopia, depressive symptoms, type-D personality, and visually obtrusive facial anomalies were associated with failure of AS-20 scores to improve (remaining the same or worsening) following strabismus surgery. The association of nonstrabismus factors may have implications for patient treatment and is worthy of continued study.

Purpose: To evaluate the associations of clinical and surgical factors with atypical postoperative drift following surgery for consecutive exotropia., Methods: A total of 66 patients with consecutive exotropia (≥10 Δ at distance), after historical surgery for esotropia were retrospectively identified at a tertiary medical center. All patients underwent unilateral lateral rectus recession (on adjustable suture) with medial rectus advancement and/or resection. Immediate postoperative target angle was 4 Δ -10 Δ of esotropia at distance, anticipating mild postoperative exodrift. Actual postoperative drift was calculated as change in distance deviation from immediately postadjustment to 6 weeks. Typical drift was defined as 0 Δ -9 Δ of exodrift. Excessive exodrift was defined as ≥10 Δ . Esodrift was defined as 1 Δ or more. Univariate and multiple logistic regression analyses were performed to evaluate for associations with a wide range of clinical and surgical factors., Results: Overall there was a median exodrift (4 Δ , quartiles 0 Δ -10 Δ ). Of the 66 patients, 18 (27%) showed excessive exodrift; 15 (23%), esodrift. In multiple logistic analyses, larger preoperative distance exodeviation was associated with excessive exodrift (P = 0.01), and non-normal medial rectus attachment status (abnormal [stretched scar, pseudo-tendon], attached to pulley, or behind pulley) was associated with esodrift (P = 0.02)., Conclusions: Approximately half of patients show atypical drift following unilateral surgery for consecutive exotropia, with larger preoperative distance exodeviation associated with exodrift and non-normal medial rectus muscle status with esodrift. Knowing these associations may help when counseling patients regarding surgical outcomes., (Copyright © 2017 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.)

Purpose: To compare 1-muscle vs 2-muscle surgery for moderate-angle hyperdeviations owing to presumed unilateral fourth nerve palsy., Design: Retrospective chart review., Methods: Seventy-three patients (aged 5-86 years) underwent either 1- or 2-muscle surgery at our institution for moderate hyperdeviation owing to presumed unilateral fourth nerve palsy, measuring 14-25 prism diopters (PD) in straight-ahead gaze at distance fixation. Six-week and 1-year motor success was defined as zero vertical deviation or 1-4 PD undercorrection at distance, overcorrection as any reversal of hypertropia, and undercorrection as >4 PD. Diplopia success was defined as no diplopia, or only rarely for distance straight ahead and reading., Results: Twenty-eight patients underwent 1-muscle surgery, and 45 patients underwent 2-muscle surgery. Motor success was similar (64% vs 67%, P > .99 at 6 weeks; 47% vs 55%, P = .8 at 1 year, n = 46), but there were more undercorrections at 6 weeks with 1-muscle surgery (36% vs 16%, P = .09) and more overcorrections at 6 weeks with 2-muscle surgery (0% vs 18%, P = .02). Diplopia success was also somewhat similar between 1- and 2-muscle surgery at 6 weeks (73% vs 60%, P = .5) and 1 year (45% vs 59%, P = .5)., Conclusion: For moderate-angle hyperdeviations owing to presumed unilateral fourth nerve palsy, there appears no clear advantage of 2-muscle surgery for motor outcomes. Diplopia success was similar between 1- and 2-muscle surgery, owing to a greater number of less symptomatic undercorrections with 1-muscle surgery and a smaller number of more symptomatic overcorrections with 2-muscle surgery., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Purpose: Consecutive exotropia may be associated with limited adduction, which has been reported to be caused by 1 or more anatomic abnormalities of rectus muscles or their insertions. We studied the relative frequency of grades of adduction deficit and the relative frequency of abnormal anatomic findings., Design: Retrospective cohort study., Participants: Patients undergoing surgery for consecutive exotropia., Methods: Preoperative duction deficits were graded on a -5 (severe limitation) to 0 (normal) scale. Operative reports were reviewed to classify intraoperative factors: (1) medial rectus muscle attachment type (normal, abnormal [slipped or stretched scar], attached to pulley, behind pulley, or mixed [a tenuous normal attachment, but with muscle fibers also attached to the pulley or behind the pulley]), (2) medial rectus muscle distal fiber location (millimeters from original insertion), and (3) lateral rectus muscle tightness (normal, mild restriction, moderate restriction)., Main Outcome Measures: Relationship of grade of adduction deficit to each intraoperative factor., Results: Of 143 eyes, 124 (87%) had an adduction deficit. Eyes with abnormal (n = 23), pulley (n = 9), behind pulley (n = 8), or mixed (n = 7) attachments had worse adduction deficits than normal attachments (n = 96; P < 0.02). There was a significant correlation between distal medial rectus muscle fiber location (0-19.5 mm recessed) and grade of adduction deficit (P < 0.0001). Eyes with mild or moderate lateral rectus muscle tightness on forced duction testing (n = 48/143 eyes) had worse adduction deficits than eyes without tightness (P < 0.001). Nevertheless, despite overall correlation, there was considerable individual variability. For example, for -1 and -2 adduction deficits, medial rectus muscle attachment could be at the pulley, behind the pulley, or include the pulley (19/87 eyes [22%]), and the lateral rectus muscle was tight in 36 of 87 eyes (41%)., Conclusions: Adduction deficits are common in patients with consecutive exotropia. Overall, more severe preoperative adduction deficits are associated with medial rectus muscle insertion abnormalities and abnormal forced ductions, but frequently there are exceptions. Severe medial rectus muscle insertion abnormalities, including lost muscles, may be found despite mild preoperative adduction deficits., (Copyright © 2017 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Purpose: Bilateral fourth nerve palsy may be symmetric or asymmetric with combined vertical and excylotropic deviations and so there may be an advantage to independent adjustment of vertical and torsional components. We report a surgical technique that allows such independent adjustment., Design: Retrospective interventional case series., Methods: Fifteen patients, aged 17-73 years, underwent adjustable bilateral superior oblique tendon advancements for bilateral fourth nerve palsy: 11 symmetric (≤2 prism diopters [pd] hyperdeviation in straight-ahead gaze) and 4 asymmetric. Motor alignment was assessed with double Maddox rods and prism and alternate cover tests preoperatively, pre- and postadjustment, and 6 weeks postoperatively., Results: Preoperative torsion ranged from 7 to 30 degrees excyclotropia (mean 17 ± 7 degrees) and hyperdeviation from 0 to 10 pd. Preadjustment torsion ranged from 5 degrees excyclotropia to 40 degrees incyclotropia, and hyperdeviation from 0 to 8 pd. Twelve of the 15 patients (80%) were adjusted to a target of 0 pd hyperphoria and 10 degrees incyclotropia (actual mean 9 degrees incyclotropia, range 2-13 degrees incyclotropia). At 6 weeks postoperatively there was expected excyclodrift (to mean 4 degrees excyclotropia, range 0 degrees incyclotropia to 15 degrees excyclotropia), but 13 (87%) had 5 degrees or less excyclotropia and 14 (93%) had 2 pd or less hyperdeviation. Mean torsional correction from preoperative to preadjustment was 31 ± 14 degrees (P < .0001), and from preoperative to 6 weeks was 13 ± 6 degrees (P < .0001)., Conclusions: Adjustable bilateral superior oblique tendon advancement allows independent control of torsional and vertical components of the deviation, and therefore may be useful in cases of bilateral superior oblique palsy., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Purpose: To evaluate interexaminer agreement in classifying medial rectus muscle attachment in patients with consecutive exotropia., Methods: A series of intraoperative photographs of 26 eyes in 25 patients who underwent surgery for consecutive exotropia were retrospectively studied. Two examiners independently classified the medial rectus attachment as either normal, stretched scar, slipped muscle, or lost muscle. Agreement between examiners was evaluated using the weighted kappa (κ) statistic, and causes of disagreement were assessed., Results: Agreement was found in 15 of 26 eyes (58%), signifying "moderate" agreement (κ = 0.41). Approximately two-thirds of the disagreements, 7 of 11 eyes (64%), were between stretched scar and slipped muscle, with characteristics of each entity being present in the same muscle., Conclusions: The clinical distinction between stretched scar and slipped muscle appears to be obscure. We propose that they should be considered a single entity, which could be referred to as "abnormal scleral attachment.", (Copyright © 2016 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.)

Purpose: To evaluate changes in health-related quality of life (HRQOL) in adult strabismus patients classified as surgical failures by standard motor and diplopia criteria., Design: Prospective cohort study evaluating outcomes., Methods: Adults undergoing strabismus surgery in a single clinical practice, with preoperative and 1-year-postoperative Adult Strabismus-20 HRQOL questionnaires, were included. Motor and diplopia criteria were applied to classify outcomes (success, partial success, or failure). For those classified as failure, the medical record of the 1-year examination was reviewed to determine whether the patient reported subjective improvement. We evaluated improvement in HRQOL, defined as exceeding 95% limits of agreement on at least 1 of the 4 Adult Strabismus-20 domains. We compared proportions exceeding 95% limits of agreement in those reporting subjective improvement vs those who did not., Results: Forty of 227 patients (18%) were classified as failure by motor and diplopia criteria, with 39 of 40 able to exceed Adult Strabismus-20 95% limits of agreement. Overall, 21 of 39 (54%) showed improved HRQOL by exceeding 95% limits of agreement on at least 1 of the 4 Adult Strabismus-20 domains (54% vs predicted 10% by chance alone; P < .0001). Twenty-five patients (64%) reported subjective improvement, of whom 16 (64%) showed improved HRQOL exceeding 95% limits of agreement., Conclusions: Many apparent surgical failures report subjective improvement, often reflected in improved HRQOL scores. We propose incorporating quantitative HRQOL criteria into the assessment of strabismus surgery outcomes, defining success as either meeting motor and diplopia criteria or showing improvement in HRQOL beyond test-retest variability., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Background: The term "strabismus" describes misalignment of the eyes. One or both eyes may deviate inward, outward, upward, or downward. Dissociated vertical deviation (DVD) is a well-recognized type of upward drifting of one or both eyes, which can occur in children or adults. DVD often develops in the context of infantile- or childhood-onset horizontal strabismus, either esotropia (inward-turning) or exotropia (outward-turning). For some individuals, DVD remains controlled and can only be detected during clinical testing. For others, DVD becomes spontaneously "manifest" and the eye drifts up of its own accord. Spontaneously manifest DVD can be difficult to control and often causes psychosocial concerns. Traditionally, DVD has been thought to be asymptomatic, although some individuals have double vision. More recently it has been suggested that individuals with DVD may also suffer from eyestrain. Treatment for DVD may be sought either due to psychosocial concerns or because of these symptoms. The standard treatment for DVD is a surgical procedure; non-surgical treatments are offered less commonly. Although there are many studies evaluating different management options for the correction of DVD, a lack of clarity remains regarding which treatments are most effective., Objectives: The objective of this review was to determine the effectiveness and safety of various surgical and non-surgical interventions in randomized controlled trials of participants with DVD., Search Methods: We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (2015, Issue 8), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to August 2015), EMBASE (January 1980 to August 2015), PubMed (1948 to August 2015), Latin American and Caribbean Health Sciences Literature Database (LILACS) (1982 to August 2015), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com) (last searched 3 February 2014), ClinicalTrials.gov (www.clinicaltrials.gov), and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 3 August 2015., Selection Criteria: We included randomized controlled trials (RCTs) of surgical and non-surgical interventions for the correction of DVD., Data Collection and Analysis: We used standard procedures expected by Cochrane. Two review authors independently completed eligibility screening, data abstraction, 'Risk of bias' assessment, and grading of the evidence., Main Results: We found four RCTs eligible for inclusion in this review (248 eyes of 151 participants between the ages of 6 months to 22 years). All trials were assessed as having unclear risk of bias overall due to insufficient reporting of study methods. One trial was conducted in Canada and compared anteriorization of the inferior oblique muscle with resection versus anteriorization of the inferior oblique muscle alone; one in the USA compared superior rectus recession with posterior fixation suture versus superior rectus recession alone; and two in the Czech Republic compared anteriorization of the inferior oblique muscle versus myectomy of the inferior oblique muscle.Only one trial reported data that allowed analysis of the primary outcome for this review, the proportion of participants with treatment success. The difference between inferior oblique anteriorization plus resection versus inferior oblique anteriorization alone was uncertain when measured at least four months postoperatively (risk ratio 1.13, 95% confidence interval 0.60 to 2.11, 30 participants, very low-quality evidence). Three trials measured the magnitude of hyperdeviation, but did not provide sufficient data for analysis. All four trials reported a relatively low rate of adverse events; hypotropia, limited elevation, and need for repeat surgery were reported as adverse events associated with some of the surgical interventions. No trials reported any other secondary outcome specified for our review., Authors' Conclusions: The four trials included in this review assessed the effectiveness of five different surgical procedures for the treatment of DVD. Nevertheless, insufficient reporting of study methods and data led to methodological concerns that undermine the conclusions of all studies. There is a pressing need for carefully executed RCTs of treatment for DVD in order to improve the evidence for the optimal management of this condition.

Purpose: To evaluate the performance of a series of summary measures of control and to assess reliability in quantifying exodeviation control in intermittent exotropia., Methods: 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)., Results: 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., Conclusions: 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., (Copyright © 2015 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.)

Introduction: We evaluated the use of botulinum toxin A in adults with convergence insufficiency in whom prior treatment had failed., Methods: We studied 8 patients (median age 36 years, range 17 to 77 years) with reading symptoms due to convergence insufficiency defined as an exodeviation greater at near, not exceeding 10 PD in the distance measured by prism and alternate cover test, and either convergence near point>6 cm or reduced fusional amplitudes. All patients were still symptomatic after prior treatment by convergence exercises (n=8), base-in prism glasses (n=5) or strabismus surgery (n=2). Five patients received injection of 5 IU botulinum toxin in 0.1 ml saline to one lateral rectus muscle, two received 2.5 IU, and one received 2.5 IU to both lateral rectus muscles., Results: At 1 month post injection, all patients had an initial reduction of exodeviation from baseline (median 9 PD, p=0.008) at near, although 2 patients had a temporary intermittent esotropia in the distance with diplopia associated with difficulty driving. At 6 months, when the pharmacological effect of botulinum toxin had completely worn off, patients still maintained a small reduction of exodeviation (median 4 PD, p=0.3) at near. Reading symptoms improved in 7 of 8 patients at 1-month post injection, and in all patients at 6 months. Two patients had health-related quality of life assessed with the Adult Strabismus 20 Questionnaire, showing improved Reading Function scores at 6 months. Interestingly, 3 patients reported improved reading despite returning to the baseline angle at 6 months, and 2 of 4 with 12-month follow-up still reported improvement., Conclusions: In adult convergence insufficiency, botulinum toxin injection to a lateral rectus muscle improves reading symptoms beyond the duration of the pure pharmacological effect. Botulinum toxin injection may be useful in management of adult convergence insufficiency, although repeat injections may be needed.

Background: We have previously reported improvement in psychosocial scores after strabismus surgery on the patient-derived health-related quality of life (HRQOL) Adult Strabismus 20 (AS-20) questionnaire in adults with nondiplopic strabismus. Unexpectedly, we also found improvement in the function domain. The aim of the present study was to identify which specific aspects of function-related quality of life improved postoperatively., Methods: We retrospectively identified non diplopic adult patients with a history of childhood onset strabismus who underwent surgery and who had preoperative and 1-year postoperative AS-20 questionnaires (scored from 0 [worst] to 100 [best]). Change in scores for each item was evaluated using signed-rank tests., Results: A total of 20 patients were included. Of the 10 function-related AS-20 items, 9 showed significant mean improvement postoperatively (improvement ranged from 12.5 to 32.5 points, all P < 0.05). Rasch-derived mean scores improved in both reading function and general function domains (71.0 to 86.5 and 66.4 to 87.5, respectively; both P < 0.0001). Specific areas of function-related benefit were concentration, depth perception, hobbies, strain, reading, stress, and worry., Conclusions: We found specific function-related quality of life benefits after strabismus surgery in nondiplopic adult patients, particularly those with childhood onset strabismus., (Copyright © 2014 American Association for Pediatric Ophthalmology and Strabismus. Published by Mosby, Inc. All rights reserved.)

Objective: To assess associations between health-related quality of life (HRQOL) and the decision to perform strabismus surgery for children with intermittent exotropia., Design: Retrospective chart review., Participants: Children with intermittent exotropia., Methods: Included subjects, identified in a clinical practice, had assessment of HRQOL using the intermittent exotropia questionnaire (IXTQ), comprising child, proxy, and parent components (parent domains: function, psychosocial, and surgery). The IXTQ scores were evaluated for association with surgery, along with standard clinical measures: prism and alternate cover test (PACT), stereoacuity, and control score (mean of the 3 most recent scores). Included data were from preoperative examination (surgical cohort) or from most recent follow-up examination (nonsurgical cohort). Univariate and multivariate logistic regression analyses were performed, and relative risk (RR) ratios were calculated. Spearman rank correlations were calculated to identify highly correlated items., Main Outcome Measures: Association of individual factors with the decision to perform surgery, calculated using RR ratios., Results: One hundred six children with intermittent exotropia (median age, 6 years; range, 2-16 years) were eligible for inclusion. Nineteen (18%) of 106 underwent surgery. Using all available data, the IXTQ proxy score, IXTQ parent function score, IXTQ parent psychosocial score, distance control score, near control score, near PACT, and Randot Preschool stereoacuity (Stereoptical Co, Inc, Chicago, IL) were associated with undergoing surgery (P<0.1). Sixty-nine of 106 patients had complete data on all factors identified in univariate analysis and were included in multivariate analyses. Fourteen (20%) of these 69 patients underwent surgery. In multivariate analyses, poor distance control score (RR, 1.83; 95% confidence interval [CI], 1.25-2.68) and reduced IXTQ parent function score (RR, 0.96; 95% CI, 0.92-0.99) were associated with surgical intervention. Repeat multivariate analyses retaining only 1 of the highly correlated items showed IXTQ proxy, IXTQ parent psychosocial, larger near PACT, and worse near control were also associated with surgery., Conclusions: After accounting for poorer exodeviation control at distance, reduced parent and proxy HRQOL were associated with undergoing strabismus surgery for childhood intermittent exotropia. Recognizing reduced parental HRQOL may be important, with a possible role for educational or counselling interventions., (Copyright © 2014 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Purpose: To compare long-term postoperative outcomes when performing an adjustment to achieve a desired immediate postoperative alignment versus simply tying off at the desired immediate postoperative alignment, when using adjustable sutures for strabismus surgery., Methods: We retrospectively identified 89 consecutive patients who underwent a reoperation for horizontal strabismus with the use of adjustable sutures and also had a 6-week and 1-year outcome examination. In each case, the intent of the surgeon was to tie off and only to adjust if the patient was not within the intended immediate postoperative range. Postoperative success was predefined on the basis of the angle of misalignment and diplopia at distance and near., Results: Of the 89 patients, 53 (60%) were adjusted and 36 (40%) were tied off. Success rates were similar between patients who were simply tied off immediately after surgery and those who were adjusted. At 6 weeks, the success rate was 64% for the nonadjusted group versus 81% for the adjusted group (P = 0.09; difference of 17%; 95% CI, -2% to 36%). At 1 year, the success rate was 67% for the nonadjusted group versus 77% for the adjusted group (P = 0.3; difference of 11%; 95% CI, -8% to 30%)., Conclusions: Performing an adjustment to obtain a desired immediate postoperative alignment did not yield inferior long-term outcomes compared with tying off to obtain that initial alignment. If patients who were outside the desired immediate postoperative range had not been adjusted, it is possible that their long-term outcomes would have been worse. Therefore, overall, an adjustable approach may be superior to a nonadjustable approach., (Copyright © 2013 American Association for Pediatric Ophthalmology and Strabismus. Published by Mosby, Inc. All rights reserved.)

Purpose: To evaluate the performance of motor, diplopia, and health-related quality of life (HRQOL) criteria when analyzing outcomes of adult strabismus surgery., Design: Cohort study., Participants: We studied 159 adults undergoing 171 strabismus surgeries., Methods: All patients underwent clinical assessment preoperatively and 6 weeks postoperatively, including completion of Adult Strabismus-20 HRQOL questionnaires. Preoperatively, strabismus was classified as either diplopic (n = 117), nondiplopic (n = 38), or atypical diplopic (n = 16). To assess performance of motor, diplopia, and HRQOL criteria, success was defined a priori and applied separately and in combinations. For success: (1) motor criteria, <10 prism diopters by simultaneous prism cover test; (2) diplopia criteria, none or only rare in primary distance and for reading; (3) HRQOL criteria, exceeding previously reported 95% limits of agreement (LOA)., Main Outcome Measures: Surgical success rate when applying motor, diplopia, and HRQOL criteria alone and in combinations., Results: Overall, success rates were 90% for motor criteria, 74% for diplopia criteria, and 60% for HRQOL criteria. Combining criteria, the highest success rate was for motor plus diplopia criteria (67%) and the lowest success rate was when combining motor, diplopia, and HRQOL criteria (50%)., Conclusions: Applying motor criteria alone yields the highest success rates when evaluating outcomes in adult strabismus surgery, but motor criteria do not fully represent the patient's postoperative status. Combining diplopia criteria with motor criteria provides a more clinically relevant standard for judging the success of adult strabismus surgery. For HRQOL criteria, exceeding 95% LOA at 6 weeks postoperatively seems to be a difficult hurdle to clear for some individual patients, and evaluating change in HRQOL score may be more useful in cohort studies., (Copyright © 2012 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Purpose: To report masked superior oblique muscle tightness as a possible mechanism causing A-pattern exotropia with intorsion after inferior rectus muscle recession in the context of thyroid eye disease., Methods: Three patients with thyroid eye disease and involvement of the superior oblique muscle are presented, along with a fourth comparison case without superior oblique muscle involvement. Intraoperative torsion assessment and exaggerated traction testing were performed after detachment of the involved rectus muscles. A surgical procedure involving recession of tight superior oblique muscle(s) when recessing inferior rectus muscle(s) is presented, along with surgical results., Results: The first case illustrated the problem of A-pattern exotropia and intorsion after inferior rectus muscle recessions and subsequent treatment with superior oblique tendon recessions. Patients 2 and 3 demonstrated signs of coexisting inferior rectus muscle involvement and superior oblique muscle involvement both preoperatively and intraoperatively, with a tight superior oblique muscle and marked intorsion, suggesting the need for superior oblique tendon recession at the time of inferior rectus recession. Postoperatively there was no symptomatic intorsion or A-pattern exotropia and both patients were heterophoric distance and near, with only rare diplopia. The fourth case, without superior oblique involvement, illustrated management with inferior rectus muscle recessions alone., Conclusions: Superior oblique muscle involvement may be masked by coexistent inferior rectus muscle involvement and if not identified and addressed at the time of the first surgery may result in symptomatic intorsion and A-pattern exotropia. The clinical finding of minimal extorsion, or frank intorsion, in the presence of a tight inferior rectus muscle, may be an important sign of masked superior oblique muscle tightness. Intraoperative assessment of torsion and superior oblique tension may also help identify patients at risk. Superior oblique tendon recession, at the time of inferior rectus muscle recession, prevented development of a postoperative A-pattern exotropia and intorsion., (Copyright © 2012 American Association for Pediatric Ophthalmology and Strabismus. Published by Mosby, Inc. All rights reserved.)

Purpose: To report changes in health-related quality of life (HRQOL) 1 year following strabismus surgery., Design: Retrospective cohort study., Methods: Seventy-three adults undergoing strabismus surgery in a single clinical practice completed the Adult Strabismus-20 (AS-20) HRQOL questionnaire preoperatively and at 6 weeks and 1 year postoperatively. All included adults were successfully aligned at 6 weeks postoperatively. Success was defined based on clinical criteria. Change in AS-20 psychosocial and function scores was evaluated as: 1) difference in scores between 6 weeks and 1 year postoperatively and 2) proportions exceeding previously published limits of agreement at 6 weeks and 1 year., Results: For patients successfully aligned at both 6 weeks and 1 year (n=51), further improvement in median scores was seen from 6 weeks to 1 year for both the psychosocial scale (83.8 vs 93.8; P<.0001) and the function scale (72.5 vs 77.5; P=.007). Also, a greater proportion exceeded limits of agreement at 1 year than at 6 weeks (psychosocial: 48% vs 30%; P=.007, function: 67% vs 51%; P=.01). For patients who became partial success (n=18) or failure (n=4) at 1 year there was a numerical decrease in scores at 1 year., Conclusions: Adult strabismus patients who remain successfully aligned show continued improvement in both psychosocial and function scores from 6 weeks to 1 year postoperatively, indicating that improvement in HRQOL is long-lasting. Evaluation of HRQOL should be considered when reporting strabismus surgery outcomes in clinical trials, and may prove helpful in assessing outcomes in clinical practice., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Background: Total transposition of the superior and inferior rectus muscle laterally, with augmentation sutures, may be complicated by induction of an undesirable vertical deviation. Induced vertical misalignment may be associated with changes in torsion. We have developed a simple method to monitor intraoperative torsion that may reduce the incidence of vertical deviations., Methods: We reviewed consecutive cases of total abducens palsy or esotropic Duane syndrome treated with augmented lateral transposition of the superior and inferior rectus muscles, where the 12 o'clock and 6 o'clock intraoperative positions were initially marked with a dot at the limbus using a surgical pen. The location of the marks was monitored during tying of the augmentation sutures; changes in torsion were monitored intraoperatively., Results: Records of 9 cases of augmented vertical rectus transposition were reviewed. On the basis of intraoperative assessment of torsion, by observing the position of preplaced limbal dots, the inferior rectus augmentation suture was tied less tightly than the superior rectus suture, leaving a gap of 1 to 3 mm between the inferior and lateral rectus muscles in 8 of 9 cases. The augmentation suture was totally removed in 1 case. After these intraoperative adjustments, there was no induced intraoperative torsion, whereas further tightening of the inferior suture induced extorsion. Six weeks postoperatively, 8 of 9 patients did not experience a symptomatic vertical deviation., Conclusions: When performing augmented transposition procedures, intraoperative monitoring of torsion may reduce the incidence of inadvertent vertical deviations and torsion. This technique may also be useful in other cases where correction or avoidance of torsion is needed., (Copyright © 2012 American Association for Pediatric Ophthalmology and Strabismus. Published by Mosby, Inc. All rights reserved.)

Purpose: We describe a new surgical treatment for lateropulsion and torticollis arising from an ocular tilt reaction., Methods: Visual sensory parameters and postural abnormalities were retrospectively reviewed in a patient with a partial ocular tilt reaction who was treated with horizontal transposition of the vertical rectus muscles to surgically augment preexisting binocular torsion., Results: Torsional augmentation eliminated the sensation of lateropulsion and produced almost complete resolution of her torticollis and associated body tilt., Conclusions: Binocular torsional augmentation can be used to reduce both lateropulsion and torticollis in the setting of an ocular tilt reaction., (Copyright © 2012 American Association for Pediatric Ophthalmology and Strabismus. Published by Mosby, Inc. All rights reserved.)

Purpose: To develop and validate an improved measure of control in intermittent exotropia (XT)., Design: Prospective, noninterventional case series., Methods: Twelve children with intermittent XT were evaluated during 4 sessions (2 hours apart) over a day, on 2 separate days (8 sessions per child). Control was standardized using a scoring system and quantified 3 times during each examination. Overall control for a day was calculated as the mean of all 12 measures. Single measures of control and the mean of 2 (double) and 3 (triple) measures over the examination were compared with the respective day mean, and first-day measures were compared to the second-day mean., Results: At distance, 17% (49/287, 95% confidence interval [CI] 13% to 22%) of single measures differed from the day mean, whereas only 8% (16/191, 95 CI 5% to 13%) of double measures and 5% (5/95, 95% CI 2% to 12%) of triple measures differed. Comparing day 1 measures to overall mean for day 2, 17% (24/143, 95% CI 11% to 24%) of single measures and 17% (22/130, 95% CI 11% to 24%) of double measures differed by more than 1 level, whereas 11% (5/47, 95% CI 4% to 23%) of triple measures differed., Conclusions: The mean of 3 assessments of control during a clinic examination better represents overall control than a single measure., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Introduction: Apparent inferior oblique overaction and apparent superior oblique underaction are common in strabismus associated with craniosynostosis, and in many cases are likely due to excyclotorsion of the globes, with the rectus muscles acting with oblique vectors. We present a patient with craniosynostosis who underwent bilateral superior oblique tucks to specifically address the excyclotorsion of the globes., Methods: A 16-year-old male with Saethre-Chotzen syndrome presented with apparent bilateral inferior oblique overaction and apparent bilateral superior oblique underaction. He had 30 prism diopter (PD) esotropia and 5 PD left hypertropia by simultaneous prism and cover test (SPCT) at distance and near fixation. Fundus exam revealed marked excyclotorsion of both globes. The superior oblique tendons were tucked 10 mm bilaterally, using a 6-0 mersilene suture and the medial rectus muscles were recessed 5.5 mm on an adjustable suture with a 10-mm inferior displacement. Surgical results were reviewed at 6 weeks and 2 years postoperatively., Results: At 6 weeks and 2 years postoperatively, apparent inferior oblique overaction, apparent superior oblique underaction, and V-pattern esotropia were markedly improved. At 2 years, SPCT measurements were 8 PD esotropia in primary position at distance and 4 PD esotropia and 3 PD left dissociated vertical deviation at near., Conclusions: Bilateral superior oblique tucks are useful in addressing the excyclotorsion that leads to apparent inferior oblique overaction and V-pattern strabismus associated with craniosynostosis.

Background: Some authors have suggested that a posterior fixation suture on the lateral rectus muscle is ineffective because of the muscle's long arc of contact with the globe. We report a small case series of patients successfully treated using a lateral rectus posterior fixation suture., Methods: The surgical database of one surgeon (JMH) was reviewed for all patients undergoing lateral rectus posterior fixation surgery for mechanical or paretic strabismus. In all cases, the lateral rectus muscle was disinserted from the sclera, and a Mersilene posterior fixation suture was placed 17 mm to 19 mm back from the insertion. The lateral rectus muscle was simultaneously recessed in all cases using a novel approach to allow adjustment of the recession if needed while maintaining the posterior fixation suture. Outcome was assessed at least 1 year after surgery., Results: Three patients were identified. Adduction deficit of the affected eye was caused by previous sinus surgery in 2 cases and scleral buckle surgery in 1 case. The lateral rectus muscle posterior fixation suture on the unaffected eye induced the planned matching -1 limitation of abduction, with resulting improvement in incomitance of the exotropia and reduced angle of exodeviation on prism cover testing., Conclusions: In this case series, a lateral rectus muscle posterior fixation suture was useful in addressing incomitant exodeviations. It is unknown whether this technique is superior to alternative surgical approaches., (Copyright 2010 American Association for Pediatric Ophthalmology and Strabismus. Published by Mosby, Inc. All rights reserved.)

Purpose: To examine the effect of preoperative alignment stability on postoperative motor outcomes in children who underwent surgery for esotropia., Methods: One hundred sixty-seven subjects (68 with infantile esotropia and 99 with acquired esotropia) aged less than 6 years had surgery after completing 18 weeks of follow-up as part of an observational study. Preoperative alignment was classified as stable, uncertain, or unstable, based on measurements taken at baseline and every 6 weeks for 18 weeks. Distance alignment measured by prism and alternate cover test was compared among stability classification groups at 6 weeks and 6 months after surgery., Results: Among subjects with infantile esotropia, median 6-week postoperative deviation was 2(Delta), 6(Delta), and 2(Delta) for subjects with stable, uncertain, and unstable preoperative alignment, respectively (p = 0.73 for stable vs unstable). Median 6-month postoperative deviation was 1(Delta), 9(Delta), and 1(Delta) for stable, uncertain, and unstable, respectively (p = 1.00 for stable vs unstable). Among subjects with acquired esotropia, median 6-week postoperative deviation was 6(Delta), 4(Delta), and 4(Delta) for subjects with stable, uncertain, and unstable preoperative alignment, respectively (p = 0.69 for stable vs unstable). Median 6-month postoperative deviation was 8(Delta), 4(Delta), and 6(Delta) for stable, uncertain, and unstable, respectively (p = 0.22 for stable vs unstable)., Conclusions: Postoperative alignment at 6 weeks and 6 months appears similar in children with stable versus unstable preoperative esotropia. Nevertheless, our finding should be interpreted with caution due to small sample size.

Objective: Instability of ocular alignment may cause surgeons to delay surgical correction of childhood esotropia. The authors investigated the stability of ocular alignment over 18 weeks in children with infantile esotropia (IET), acquired nonaccommodative esotropia (ANAET), or acquired partially accommodative esotropia (APAET)., Design: Prospective, observational study., Participants: Two hundred thirty-three children aged 2 months to less than 5 years with IET, ANAET, or APAET of less than 6 months' duration., Methods: Ocular alignment was measured at baseline and at 6-week intervals for 18 weeks., Main Outcome Measures: Using definitions derived from a nested test-retest study and computer simulation modeling, ocular alignment was classified as unstable if there was a change of 15 prism diopters (PD) or more between any 2 of the 4 measurements, as stable if all 4 measurements were within 5 PD or less of one another, or as uncertain if neither criteria was met., Results: Of those who completed all 3 follow-up visits within time windows for analysis, 27 (46%) of 59 subjects with IET had ocular alignment classified as unstable (95% confidence interval [CI], 33%-59%), 20% as stable (95% CI, 11%-33%), and 34% as uncertain (95% CI, 22%-47%). Thirteen (22%) of 60 subjects with ANAET had ocular alignment classified as unstable (95% CI, 12%-34%), 37% as stable (95% CI, 25%-50%), and 42% as uncertain (95% CI, 29%-55%). Six (15%) of 41 subjects with APAET had ocular alignment classified as unstable (95% CI, 6%-29%), 39% as stable (95% CI, 24%-56%), and 46% as uncertain (95% CI, 31%-63%). For IET, subjects who were older at presentation were less likely to have unstable angles than subjects who were younger at presentation (risk ratio for unstable vs stable per additional month of age, 0.85; 99% CI, 0.74-0.99)., Conclusions: Ocular alignment instability is common in children with IET, ANAET, and APAET. The impact of this finding on the optimal timing for strabismus surgery in childhood esotropia awaits further study., Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Purpose: To describe the interobserver test-retest variability of both simultaneous prism and cover testing (SPCT) and alternate prism and cover testing (APCT) in horizontal deviations, and to calculate 95% limits of agreement that might be used to define real change., Design: Prospective cohort study., Methods: Twenty-three patients with sixth nerve palsy and three controls were independently examined by two experienced strabismus surgeons. SPCT and APCT were performed at distance and near fixation. Test-retest variability and agreement between tests were evaluated using Bland-Altman plots and 95% limits of agreement were calculated., Results: For SPCT, the 95% limits of agreement half-widths were 6.3 prism diopters (pd) at distance fixation and 6.9 pd at near. For APCT, the 95% limits of agreement half-widths were 10.2 pd at distance and 9.2 pd at near., Conclusions: Based on 95% limits of agreement half-widths between two examiners, a change in strabismus measurements of less than 10 pd may be attributable to test-retest variability. Changes of 10 pd or more are likely to represent real change and might be used as the threshold for management decisions.

Background: There is controversy regarding whether or not visually mature individuals can permanently lose stereoacuity and under what conditions stereoacuity can be regained. Some have proposed a critical duration of misalignment in adults beyond which recovery of fine stereoacuity is not possible, despite successful surgical alignment., Methods: Twenty-one adult patients (median age 59 years) with large-angle acquired strabismus and who were successfully surgically aligned after 7 to 501 months of misalignment were studied. Subjects had no evidence of motor or sensory fusion since the onset of strabismus, on preoperative exam, or by history. Stereoacuity was measured using 1 or more of the Frisby, Preschool Randot and Titmus tests, at 8 weeks and at 12 months. Data from tests with monocular clues were not used., Results: At total of 67% of patients with chronic acquired strabismus and no preoperative fusion regained measurable stereoacuity and 44% regained fine stereoacuity of at least 60 seconds of arc. Of 10 patients with no or subnormal stereoacuity 8 weeks postoperatively, 6 (60%) showed improvement at the 12-month visit. Misalignment for up to 4 years did not preclude the development of postoperative stereoacuity., Conclusions: Although a minority of adult strabismus patients may permanently lose stereoacuity despite successful alignment for acquired strabismus, the majority do show recovery. Such recovery of stereoacuity may take several months to occur. In our adult series, duration of misalignment did not predict failure to recover stereoacuity.