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Importance: Increased myopic shift was found to be associated with 1 year of overminus spectacle treatment for children with intermittent exotropia (IXT). Persistence of myopic shift after discontinuing overminus spectacles is unknown., Objective: To compare refractive error change over 3 years in children with IXT originally treated with overminus vs nonoverminus spectacles., Design, Setting, and Participants: This study was an 18-month extension of the Trial of Overminus Spectacle Therapy for Intermittent Exotropia cohort, which previously randomized children aged 3 to 10 years with IXT and baseline spherical equivalent refractive error (SER) between -6.00 diopters (D) and 1.00 D to overminus spectacles (-2.50 D for 12 months, -1.25 D for 3 months, and nonoverminus for 3 months) or nonoverminus spectacles. Children were recruited from 56 sites from July 2010 to February 2022. Data were analyzed from February 2022 to January 2024., Interventions: After trial completion at 18 months, participants were followed up at 24 and 36 months. Treatment was at investigator discretion from 18 to 36 months., Main Outcomes and Measures: Change in SER (cycloplegic retinoscopy) from baseline to 36 months., Results: Of 386 children in the Trial of Overminus Spectacle Therapy for Intermittent Exotropia, 223 (57.8%) consented to 18 months of additional follow-up, including 124 of 196 (63.3%) in the overminus treatment group and 99 of 190 (52.1%) in the nonoverminus treatment group. Of 205 children who completed 36-month follow-up, 116 (56.6%) were female, and the mean (SD) age at randomization was 6.2 (2.1) years. Mean (SD) SER change from baseline to 36 months was greater in the overminus group (-0.74 [1.00] D) compared with the nonoverminus group (-0.44 [0.85] D; adjusted difference, -0.36 D; 95% CI, -0.59 to -0.12; P = .003), with 30 of 112 (26.8%) in the overminus group having more than 1 D of myopic shift compared with 14 of 91 (15%) in the nonoverminus group (risk ratio, 1.8; 95% CI, 1.0-3.0). From 12 to 36 months, mean (SD) myopic shift was -0.34 (0.67) D and -0.36 (0.66) D in the overminus and nonoverminus groups, respectively (adjusted difference, -0.001 D; 95% CI, -0.18 to 0.18; P = .99)., Conclusions and Relevance: The greater myopic shift observed after 1 year of -2.50-D overminus lens treatment remained at 3 years. Both groups had similar myopic shift during the 2-year period after treatment weaning and cessation. The risk of myopic shift should be discussed with parents when considering overminus lens treatment., Trial Registration: ClinicalTrials.gov Identifier: NCT02807350.

Purpose: To report 8-year outcomes from a randomized controlled trial (RCT) comparing bilateral lateral rectus muscle recession (BLRc) with unilateral recession-resection (R&R) for childhood intermittent exotropia (IXT)., Design: Eight-year follow-up of RCT cohort., Participants: Of 197 randomized participants, 123 agreed to continue follow-up after the 3-year outcome visit (baseline age, 3-< 11 years; basic-type IXT, 15-40 prism diopters [Δ] by prism and alternate cover test [PACT]; baseline stereoacuity, ≤ 400 arcsec; no prior surgery)., Methods: After the RCT primary outcome at 3 years, annual follow-up from 4 through 8 years with treatment at investigator discretion., Main Outcome Measures: Suboptimal surgical outcome by 8 years after randomization, defined as any of the following at any visit: exotropia of 10 Δ or more by simultaneous prism cover test (SPCT) at distance or near, constant esotropia (ET) of 6 Δ or more by SPCT at distance or near, loss of near stereoacuity by 0.6 log arcsec or more from baseline, or reoperation. Secondary outcomes included (1) reoperation by 8 years and (2) complete or near-complete resolution at 8 years, defined as exodeviation of less than 10 Δ by SPCT and PACT at distance and near and 10 Δ or more reduction from baseline by PACT at distance and near, ET of less than 6 Δ at distance and near, no decrease in stereoacuity by 0.6 log arcsec or more from baseline, and no reoperation or nonsurgical treatment for IXT., Results: The Kaplan-Meier cumulative probability of suboptimal surgical outcome through 8 years was 68% (55 events among 101 at risk) for BLRc and 53% (42 events among 96 at risk) for R&R (difference, 15%; 95% confidence interval [CI], -2% to 32%; P = 0.08). Complete or near-complete resolution at 8 years occurred in 15% (7/46) for BLRc and 37% (16/43) for R&R (difference, -22%; 95% CI, -44% to -0.1%; P = 0.049). The cumulative probability of reoperation was 30% for BLRc and 11% for R&R (difference, 19%; 95% CI, 2%-36%; P = 0.049)., Conclusions: Despite no significant difference for the primary outcome, the 95% CI did not exclude a moderate benefit of R&R, which together with secondary outcomes suggests that unilateral R&R followed by usual care may yield better long-term outcomes than BLRc followed by usual care for basic-type childhood IXT using these surgical doses., Financial Disclosure(s): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article., (Copyright © 2023 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Significance: This pilot randomized trial, the first to evaluate a specific base-in relieving prism treatment strategy for childhood intermittent exotropia, did not support proceeding to a full-scale clinical trial. Defining and measuring prism adaptation in children with intermittent exotropia are challenging and need further study., Purpose: This study aimed to determine whether to proceed to a full-scale trial of relieving base-in prism spectacles versus refractive correction alone for children with intermittent exotropia., Methods: Children 3 years old to those younger than 13 years with distance intermittent exotropia control score of ≥2 points on the Intermittent Exotropia Office Control Scale (Strabismus 2006;14:147-150; 0 [phoria] to 5 [constant]), ≥1 episode of spontaneous exotropia, and 16 to 35∆ by prism-and-alternate-cover test, who did not fully prism adapt on a 30-minute in-office prism-adaptation test were randomized to base-in relieving prism (40% of the larger of distance and near exodeviations) or nonprism spectacles for 8 weeks. A priori criteria to conduct a full-scale trial were defined for the adjusted treatment group difference in mean distance control: "proceed" (≥0.75 points favoring prism), "uncertain" (>0 to <0.75 points favoring prism), or "do not proceed" (≥0 points favoring nonprism)., Results: Fifty-seven children (mean age, 6.6 ± 2.2 years; mean baseline distance control, 3.5 points) received prism (n = 28) or nonprism (n = 29) spectacles. At 8 weeks, mean control values were 3.6 and 3.3 points in prism (n = 25) and nonprism (n = 25) groups, respectively, with an adjusted difference of 0.3 points (95% confidence interval, -0.5 to 1.1 points) favoring nonprism (meeting our a priori "do not proceed" criterion)., Conclusions: Base-in prism spectacles, equal to 40% of the larger of the exodeviations at distance or near, worn for 8 weeks by 3- to 12-year-old children with intermittent exotropia did not yield better distance control than refractive correction alone, with the confidence interval indicating that a favorable effect of 0.75 points or larger is unlikely. There was insufficient evidence to warrant a full-scale randomized trial., Competing Interests: Conflict of Interest Disclosure: None of the authors have reported a financial conflict of interest., (Copyright © 2023 American Academy of Optometry.)

Significance: A rigorously designed and calibrated symptom questionnaire for childhood intermittent exotropia would be useful for clinical care and for research., Purpose: The aim of this study was to Rasch-calibrate and evaluate the previously developed Child Intermittent Exotropia Symptom Questionnaire using data gathered as part of a randomized clinical trial., Methods: The questionnaire was administered to 386 children aged 3 to 10 years with intermittent exotropia who were enrolled in a randomized clinical trial comparing overminus with nonoverminus spectacles. Participants were followed at 6 and 12 months while on treatment and at 18 months off treatment. Factor analysis determined dimensionality, and Rasch analysis evaluated questionnaire performance. Logit values were converted to 0 (best) to 100 (worst). We evaluated differences in questionnaire scores between treatment groups and time points, and correlations with control scores., Results: The Child Intermittent Exotropia Symptom Questionnaire was unidimensional. Rasch analysis indicated that there was no notable local dependence and no significant differential item functioning for sex or age. There was suboptimal targeting (mean logit, -1.62), and person separation was somewhat poor (0.95). There were no significant differences in the Child Intermittent Exotropia Symptom score between overminus spectacles and nonoverminus spectacles at 6, 12, and 18 months. Combining data from both treatment groups, there was significant improvement from baseline at all follow-up visits (e.g., mean change from baseline to 12 months, -6.6 points; 95% confidence interval, -8.6 to -4.6). Child Intermittent Exotropia Symptom scores were not correlated with distance or near control scores at 12 months., Conclusions: The seven-item Rasch-scored Child Intermittent Exotropia Symptom Questionnaire is limited by suboptimal performance. Future study is needed to determine whether it may be useful for clinical practice and for research., Competing Interests: Conflict of Interest Disclosure: None of the authors have reported a financial conflict of interest., (Copyright © 2022 American Academy of Optometry.)

A test of suppression was developed to provide a standardized approach to detecting and grading density of suppression in children with intermittent exotropia when manifestly exotropic. This new Office Suppression Test is a three-step procedure to grade suppression on a 4-point scale (from 0 for "negligible suppression" to 3 for "dense suppression"). The test was performed in 57 children 3-13 years of age with intermittent exotropia (distance angle of 16 Δ -35 Δ , with spontaneous tropia) during enrollment in a randomized trial. Of the 57 children, 51 could complete testing: 28 (55%) had dense suppression, 12 (24%) had moderate suppression, 5 (10%) had mild suppression, and 6 (12%) had negligible suppression. In a subgroup of 20 untreated children, suppression was evaluated again at 8 weeks. There was moderate agreement between suppression scores at baseline and at 8 weeks (weighted κ = 0.65 [95% CI, 0.45-0.84])., (Copyright © 2021 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.)

Purpose: To determine whether health-related quality of life (HRQOL) scores improved or worsened over 3 years of observation in childhood intermittent exotropia without treatment., Methods: A total of 111 children aged 3-11 years with intermittent exotropia were assigned to observation in a previously reported randomized trial comparing patching with observation. The intermittent exotropia questionnaire (IXTQ) was administered at baseline, 6 months, and 36 months. Rasch-calibrated IXTQ domain scores (Child, Proxy, Parent-psychosocial, Parent-function, and Parent-surgery) were compared between time points. The Child IXTQ was administered only to children ≥5 years of age (n = 78)., Results: Overall, Child IXTQ and Proxy IXTQ scores showed no significant change over 36 months (mean improvement from baseline to 36 months of 3.2 points [95% CI, -1.9 to 8.2] and -2.4 points [95% CI: -7.9 to 3.1], resp.). By contrast, Parent-psychosocial, Parent-function, and Parent-surgery domain scores all improved over 36 months (mean improvements of 12.8 points [95% CI, 5.9-19.6] and 14.2 points [95% CI, 8.0-20.3] and 18.5 points [95% CI, 9.7-27.3], resp.)., Conclusions: HRQOL of children with intermittent exotropia remains stable with observation over 3 years (by both child and proxy report), whereas parental HRQOL improves., (Copyright © 2021 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.)

Purpose: To investigate health-related quality of life (HRQOL) after strabismus surgery in children with intermittent exotropia (IXT) and relationships between HRQOL and surgical success., Methods: A total of 197 children with IXT aged 3-11 years (and 1 parent of each child) were enrolled in a previously reported randomized clinical trial comparing two surgical procedures. The Intermittent Exotropia Questionnaire (IXTQ) was administered before surgery (baseline), and again at 6 and 36 months following surgery. The child version of the IXTQ was only completed by children 5-11 years of age (n = 123). Outcomes were classified as "resolved" (exodeviation of <10 Δ , no decreased stereoacuity, and no other nonsurgical treatment for IXT or reoperation), "suboptimal" (exotropia ≥10 Δ by simultaneous prism and cover test or constant esotropia ≥6 Δ or loss of ≥2 octaves of stereoacuity), or "intermediate." Mean changes in Rasch-calibrated IXTQ domain scores (Child, Proxy, Parent-psychosocial, Parent-function, and Parent-surgery; converted to a 0-100 scale) were compared., Results: Overall, mean IXTQ domain scores improved for all domains from baseline to 36 months after surgery, ranging from 10.7 points (Child IXTQ; P < 0.0001) to 34.5 points (Parent-surgery IXTQ; P < 0.0001). At 36 months after surgery, 62 (39%) children had resolved IXT, whereas 38 (24%) had suboptimal outcome. Greater improvement was found in all mean domain scores with resolved IXT (range, 19.8-46.0 points) compared with suboptimal outcome (all comparisons P < 0.05)., Conclusions: Successful surgery for childhood IXT results in measurable improvement in a child's quality of life, in parental assessment of the child's quality of life, and in quality of life for the parent., (Copyright © 2021 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.)

Importance: This is the first large-scale randomized clinical trial evaluating the effectiveness and safety of overminus spectacle therapy for treatment of intermittent exotropia (IXT)., Objective: To evaluate the effectiveness of overminus spectacles to improve distance IXT control., Design, Setting, and Participants: This randomized clinical trial conducted at 56 clinical sites between January 2017 and January 2019 associated with the Pediatric Eye Disease Investigator Group enrolled 386 children aged 3 to 10 years with IXT, a mean distance control score of 2 or worse, and a refractive error between 1.00 and -6.00 diopters (D). Data analysis was performed from February to December 2020., Interventions: Participants were randomly assigned to overminus spectacle therapy (-2.50 D for 12 months, then -1.25 D for 3 months, followed by nonoverminus spectacles for 3 months) or to nonoverminus spectacle use., Main Outcomes and Measures: Primary and secondary outcomes were the mean distance IXT control scores of participants examined after 12 months of treatment (primary outcome) and at 18 months (3 months after treatment ended) assessed by an examiner masked to treatment group. Change in refractive error from baseline to 12 months was compared between groups. Analyses were performed using the intention-to-treat population., Results: The mean (SD) age of 196 participants randomized to overminus therapy and 190 participants randomized to nonoverminus treatment was 6.3 (2.1) years, and 226 (59%) were female. Mean distance control at 12 months was better in participants treated with overminus spectacles than with nonoverminus spectacles (1.8 vs 2.8 points; adjusted difference, -0.8; 95% CI, -1.0 to -0.5; P < .001). At 18 months, there was little or no difference in mean distance control between overminus and nonoverminus groups (2.4 vs 2.7 points; adjusted difference, -0.2; 95% CI, -0.5 to 0.04; P = .09). Myopic shift from baseline to 12 months was greater in the overminus than the nonoverminus group (-0.42 D vs -0.04 D; adjusted difference, -0.37 D; 95% CI, -0.49 to -0.26 D; P < .001), with 33 of 189 children (17%) in the overminus group vs 2 of 169 (1%) in the nonoverminus group having a shift higher than 1.00 D., Conclusions and Relevance: Children 3 to 10 years of age had improved distance exotropia control when assessed wearing overminus spectacles after 12 months of overminus treatment; however, this treatment was associated with increased myopic shift. The beneficial effect of overminus lens therapy on distance exotropia control was not maintained after treatment was tapered off for 3 months and children were examined 3 months later., Trial Registration: ClinicalTrials.gov Identifier: NCT02807350.

Purpose: To describe the clinical course of untreated intermittent exotropia (IXT) in children 12-35 months of age followed for 3 years., Methods: We enrolled 97 children 12-35 months of age with previously untreated IXT who had been randomly assigned to the observation arm of a randomised trial of short-term occlusion versus observation. Participants were observed unless deterioration criteria were met at a follow-up visit occurring at 3 months, 6 months, and 6-month intervals thereafter for 3 years. The primary outcome was deterioration of the IXT by 3 years, defined as (1) a constant exotropia ≥10 prism dioptres (∆) at distance and near (i.e., motor deterioration) or (2) treatment prescribed despite not having met motor deterioration. The primary analysis used the Kaplan-Meier method to determine the cumulative proportion of participants meeting deterioration by three years and 95% confidence interval (CI)., Results: The cumulative probability of deterioration by 3 years was 28% (95% CI = 20%-39%). Of the 24 participants meeting the primary outcome of deterioration, seven met motor deterioration and 17 were prescribed treatment without meeting motor deterioration. The cumulative probability of motor deterioration by 3 years was 10% (95% CI = 5%-19%)., Conclusions: Given the modest rate of motor deterioration over three years, watchful waiting may be a reasonable management approach in 12- to 35-month-old children with IXT. To confirm this recommendation would require a long-term randomised trial of immediate treatment versus observation followed by deferred treatment if needed., (© 2020 The Authors Ophthalmic & Physiological Optics © 2020 The College of Optometrists.)

Purpose: To describe the course of intermittent exotropia (IXT) in children followed up without treatment for 3 years., Design: Observation arm from randomized trial of short-term occlusion versus observation., Participants: One hundred eighty-three children 3 to 10 years of age with previously untreated IXT and 400 seconds of arc (arcsec) or better near stereoacuity., Methods: Participants were to receive no treatment unless deterioration criteria were met at a follow-up visit occurring at 3 months, 6 months, or 6-month intervals thereafter for 3 years., Main Outcome Measures: The primary outcome was deterioration by 3 years, defined as meeting motor criterion (constant exotropia ≥10 prism diopters [Δ] at distance and near) or near stereoacuity criterion (≥2-octave decrease from best previous measure). For the primary analysis, participants also were considered to have deteriorated if treatment was prescribed without meeting either deterioration criterion., Results: The cumulative probability of protocol-specified deterioration by 3 years was 15% (95% confidence interval, 10%-22%), but that was likely an overestimate, partly because of misclassification. Among 25 deteriorations, 2 met motor deterioration, 11 met stereoacuity deterioration, and 12 started treatment without meeting either criteria (7 for social concern, 1 for diplopia, 4 for other reasons). Among the 132 participants who completed the 3-year visit and had not been treated during the study, only 1 (<1%) met motor or stereoacuity deterioration criteria at 3 years. Of the 4 participants completing the 3-year visit who met deterioration criteria previously and had not started treatment, none still met deterioration criteria. Between the baseline and 3-year examination for these 132 patients, improvement occurred in distance and near stereoacuity (mean improvement, 0.14 and 0.14 logarithm of arcsec; P ≤ 0.001 and P ≤ 0.001, respectively), distance exotropia control (mean improvement, 0.6 points; P ≤ 0.001), and distance exodeviation magnitude (mean improvement, 2.2 Δ; P = 0.002)., Conclusions: Among children 3 to 10 years of age with IXT for whom surgery was not considered to be the immediately necessary treatment, stereoacuity deterioration or progression to constant exotropia over 3 years was uncommon, and exotropia control, stereoacuity, and magnitude of deviation remained stable or improved slightly., (Copyright © 2019 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Purpose: To determine the relationships between stereoacuity, control of exotropia, and angle of deviation in children with intermittent exotropia (IXT)., Methods: Data collected for 652 participants 3 to <11 years of age with IXT meeting eligibility criteria for enrollment into one of two multicenter, randomized clinical trials were used to evaluate relationships between stereoacuity, control, and angle of deviation at enrollment., Results: Any level of stereoacuity and angle of deviation could be accompanied by any level of control. Worse distance exotropia control was weakly associated with poorer distance stereoacuity (R = 0.26; 99% CI, 0.17-0.36) and larger angles of deviation at distance (R = 0.27; 99% CI, 0.17-0.36). Worse near exotropia control was weakly associated with poorer near stereoacuity (R = 0.17; 99% CI, 0.07-0.27) and moderately associated with larger angles of deviation at near (R = 0.37; 99% CI, 0.28-0.45). There was no association between stereoacuity and angle of deviation at distance (R = 0.07; 99% CI, -0.03 to 0.17) or at near (R = 0.02; 99% CI, -0.08 to 0.12)., Conclusions: Although weak and moderate associations were found between stereoacuity, control, and angle of deviation, a child may exhibit any combination of stereoacuity, control, and angle of deviation. The specific roles of control, stereoacuity, and angle of deviation in the diagnosis, management, and pathogenesis of IXT are unclear, and each appears to yield somewhat independent information., (Copyright © 2017 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.)

Purpose: To determine the effectiveness of part-time patching for treating intermittent exotropia (IXT) in young children., Design: Multicenter, randomized clinical trial., Participants: Two hundred one children 12 to 35 months of age with untreated IXT meeting the following criteria: (1) IXT at distance OR constant exotropia at distance and either IXT or exophoria at near, and (2) 15-prism diopter (Δ) or more exodeviation at distance or near by prism and alternate cover test (PACT) but at least 10 Δ exodeviation at distance by PACT., Methods: Participants were assigned randomly to either observation (no treatment for 6 months) or patching prescribed for 3 hours daily for 5 months, followed by 1 month of no patching., Main Outcome Measures: The primary outcome was deterioration, defined as constant exotropia measuring at least 10 Δ at distance and near or receipt of nonprotocol treatment for IXT., Results: Of the 177 participants (88%) completing the 6-month primary outcome examination, deterioration occurred in 4.6% (4 of 87) of the participants in the observation group and in 2.2% (2 of 90) of the participants in the patching group (difference, 2.4%; P = 0.27; 95% confidence interval, -3.8% to +9.4%). Motor deterioration occurred in 2.3% (2 of 87) of the observation group and in 2.2% (2 of 90) of the patching group (difference, 0.08%; P = 0.55; 95% confidence interval, -5.8% to +6.1%). For the observation and patching groups, respectively, 6-month mean PACT measurements were 27.9 Δ versus 24.9 Δ at distance (P = 0.02) and 19.3 Δ versus 17.0 Δ at near (P = 0.10); 6-month mean exotropia control scores were 2.8 versus 2.3 points at distance (P = 0.02) and 1.4 versus 1.1 points at near (P = 0.26)., Conclusions: Among children 12 to 35 months of age with previously untreated IXT, deterioration over 6 months was uncommon, with or without patching treatment. There was insufficient evidence to recommend part-time patching for the treatment of IXT in children in this age group., (Copyright © 2015 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Objective: To determine the effectiveness of prescribed part-time patching for treatment of intermittent exotropia (IXT) in children., Design: Multicenter, randomized clinical trial., Participants: Three hundred fifty-eight children 3 to <11 years of age with previously untreated (except for refractive correction) IXT and near stereoacuity of 400 seconds of arc or better were enrolled. Intermittent exotropia met the following criteria: (1) IXT at distance OR constant exotropia at distance and either IXT or exophoria at near; (2) exodeviation (tropia or phoria) of at least 15 prism diopters (PD) at distance or near by prism and alternate cover test (PACT); and (3) exodeviation of at least 10 PD at distance by PACT., Methods: Participants were assigned randomly either to observation (no treatment for 6 months) or to patching for 3 hours daily for 5 months, with a 1-month washout period of no patching before the 6-month primary outcome examination., Main Outcome Measures: The primary outcome was deterioration at either the 3-month or the 6-month follow-up visit, defined as: (1) constant exotropia measuring at least 10 PD at distance and near by simultaneous prism and cover test, and/or (2) near stereoacuity decreased by at least 2 octaves from baseline, both assessed by a masked examiner and confirmed by a retest. Participants who were prescribed any nonrandomized treatment without first meeting either deterioration criteria also were counted as having deteriorated., Results: Of the 324 participants (91%) completing the 6-month primary outcome examination, deterioration occurred in 10 of the 165 participants (6.1%) in the observation group (3 of these 10 started treatment without meeting deterioration criteria) and in 1 of the 159 participants (0.6%) in the part-time patching group (difference, 5.4%; lower limit of 1-sided exact 95% confidence interval, 2.0%; P = 0.004, 1-sided hypothesis test)., Conclusions: Deterioration of previously untreated childhood IXT over a 6-month period is uncommon with or without patching treatment. Although there is a slightly lower deterioration rate with patching, both management approaches are reasonable for treating children 3 to 10 years of age with IXT., (Copyright © 2014 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Objective: To investigate risk factors associated with esotropia or exotropia in infants and young children., Design: Population-based cross-sectional prevalence study., Participants: Population-based samples of 9970 children 6 to 72 months of age from California and Maryland., Methods: Participants were preschool African-American, Hispanic, and non-Hispanic white children participating in the Multi-Ethnic Pediatric Eye Disease Study and the Baltimore Eye Disease Study. Data were obtained by parental interview and ocular examination. Odd ratios and 95% confidence intervals were calculated to evaluate the association of demographic, behavioral, and clinical risk factors with esotropia and exotropia., Main Outcome Measures: Odds ratios (ORs) for various risk factors associated with esotropia or exotropia diagnosis based on cover testing., Results: In multivariate logistic regression analysis, esotropia was associated independently with prematurity, maternal smoking during pregnancy, older preschool age (48-72 months), anisometropia, and hyperopia. There was a severity-dependent association of hyperopia with the prevalence of esotropia, with ORs increasing from 6.4 for 2.00 diopters (D) to less than 3.00 D of hyperopia, to 122.0 for 5.00 D or more of hyperopia. Exotropia was associated with prematurity, maternal smoking during pregnancy, family history of strabismus, female sex, astigmatism (OR, 2.5 for 1.50 to <2.50 D of astigmatism, and 5.9 for ≥2.5 D of astigmatism), and anisoastigmatism in the J0 component (OR, ≥2 for J0 anisoastigmatism of ≥0.25 D)., Conclusions: Prematurity and maternal smoking during pregnancy are associated with a higher risk of having esotropia and exotropia. Refractive error is associated in a severity-dependent manner to the prevalence of esotropia and exotropia. Because refractive error is correctable, these risk associations should be considered when developing guidelines for the screening and management of refractive error in infants and young children., Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article., (Copyright © 2011 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)