Relationship among clinical factors in childhood intermittent exotropia.
ABSTRACT: To determine the relationships between stereoacuity, control of exotropia, and angle of deviation in children with intermittent exotropia (IXT).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.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).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.
Project description: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 [?] 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 ?; 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.
Project description: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.
Project description:To determine the effectiveness of prescribed part-time patching for treatment of intermittent exotropia (IXT) in children.Multicenter, randomized clinical trial.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.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.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.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).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.
Project description:In this paper the optimum timing for the postoperative functional cure of basic intermittent exotropia is explored based on support vector machine (SVM). One hundred and thirty-two patients were recruited in this prospective cross-sectional study with 6 months of follow-up. Examinations included angle of deviation, central and peripheral fusion, controllability, and near and distance stereopsis. Influencing factors of postoperative alignment and stereopsis were analyzed with a chi-squared test and univariate and multivariate logistic regression analyses. At 6 months post-operation, there were 84 successful procedures for the angle of deviation, with 4 overcorrections and 44 undercorrections. The success rate was 63.6%. The angle of deviation on postoperative day 1 was the only significant associated factor. One hundred and thirty patients had normal near stereoacuity, 60 had normal distance stereoacuity according to a Functional Visual Analyzer assessment, and 108 had normal stereoacuity as assessed by the Frisby Davis Distance (FD2) stereotest. The age of onset and preoperative distance stereoacuity with FD2 were the influencing factors of postoperative distance stereopsis restoration. The accuracy of this method of SVM was 82.1%. The angle of deviation for distance on postoperative day 1 was the only significant factor that correlated with alignment at 6 months post-operation, and the model of SVM was useful to determine the optimal time of the postoperative functional cure.
Project description:To determine the effectiveness of part-time patching for treating intermittent exotropia (IXT) in young children.Multicenter, randomized clinical trial.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 (?) or more exodeviation at distance or near by prism and alternate cover test (PACT) but at least 10 ? exodeviation at distance by PACT.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.The primary outcome was deterioration, defined as constant exotropia measuring at least 10 ? at distance and near or receipt of nonprotocol treatment for IXT.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 ? versus 24.9 ? at distance (P = 0.02) and 19.3 ? versus 17.0 ? 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).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.
Project description:The aim of this study was to investigate whether the limbus-insertion distance (LID) of the lateral rectus (LR) muscle can be a useful indicator for predicting the surgical effect of recession surgery in intermittent exotropia (IXT). Patients who underwent unilateral or bilateral LR recession for the basic type of IXT were included. The distance between the corneal limbus and the posterior edge of the insertion of LR muscle (limbus-insertion distance) was measured intraoperatively using surgical calipers (graded with 0.25 mm precision). We calculated the actual dose-response effect as the difference between the angle of preoperative deviation and the angle of postoperative deviation, and then divided the figure by the total amount of recession at postoperative months 1, 3, and 6. The correlation between the limbus-insertion distance (LID) of LR muscle and each dose-response effect was statistically analyzed. A total of 60 subjects were enrolled in this study. The mean LID of LR muscle was 5.8±0.7 mm. The dose-response effect was 3.2±1.0 prism diopters (PD)/mm at postoperative month 1, 3.4±1.0 PD/mm at postoperative month 3, and 3.4±1.1 PD/mm at postoperative month 6. The LID of the LR muscle was significantly correlated with dose-response effects in cases of unilateral and bilateral LR recession at postoperative months 3 and 6 (P = 0.01, <0.01, 0.04 and <0.01 respectively). As the LID of the LR muscle increased by 1 mm, the dose-response effect increased by 0.2PD/mm in unilateral LR recession, and by 0.4 PD/mm in bilateral LR recession at postoperative month 6. In conclusion, the LID of the LR muscle can be used as one predictor of the recession effect to assist in surgical planning for IXT. Moreover, undercorrection at the time of LR recession might be considered in patients with long LID of the LR muscle.
Project description:To evaluate whether distance stereoacuity improves following surgery for intermittent exotropia using the Frisby Davis Distance (FD2) and Distance Randot stereotests.Eighteen patients (median age, 24 years; range, 5 to 68 years) with intermittent exotropia were prospectively enrolled. Stereoacuity was measured pre- and 6 weeks postoperatively using the FD2 and Frisby near tests (real depth tests) and Preschool Randot and Distance Randot tests (polaroid vectographs).Distance stereoacuity measured with the FD2 improved from a median preoperative value of 80 to 40 arcsec postoperatively (p = 0.04) and stereoacuity measured with the Distance Randot improved from a median of nil to 200 arcsec (p = 0.06). In those that had subnormal stereoacuity preoperatively, there was even more marked improvement in distance stereoacuity (FD2 median nil vs 40 arcsec, p = 0.002; Distance Randot median nil vs 200 arcsec, p = 0.004). Near stereoacuity measured with Frisby and Preschool Randot remained unchanged pre- to postoperatively (median, 60 and 80 arcsec, respectively).There was improvement in distance stereoacuity measured with both the FD2 and the Distance Randot stereotests in patients who underwent surgery for intermittent exotropia. The FD2 and Distance Randot may be useful outcome measures in future clinical trials of interventions for intermittent exotropia.
Project description:To evaluate the short-term effectiveness of overminus spectacles in improving control of childhood intermittent exotropia (IXT).Randomized, clinical trial.A total of 58 children aged 3 to <7 years with IXT. Eligibility criteria included a distance control score of 2 or worse (mean of 3 measures during a single examination) on a scale of 0 (exophoria) to 5 (constant exotropia) and spherical equivalent refractive error between -6.00 diopters (D) and +1.00 D.Children were randomly assigned to overminus spectacles (-2.50 D over cycloplegic refraction) or observation (non-overminus spectacles if needed or no spectacles) for 8 weeks.The primary outcome was distance control score for each child (mean of 3 measures during a single examination) assessed by a masked examiner at 8 weeks. Outcome testing was conducted with children wearing their study spectacles or plano spectacles for the children in the observation group who did not need spectacles. The primary analysis compared mean 8-week distance control score between treatment groups using an analysis of covariance model that adjusted for baseline distance control, baseline near control, prestudy spectacle wear, and prior IXT treatment. Treatment side effects were evaluated using questionnaires completed by parents.At 8 weeks, mean distance control was better in the 27 children treated with overminus spectacles than in the 31 children who were observed without treatment (2.0 vs. 2.8 points, adjusted difference = -0.75 points favoring the overminus group; 2-sided 95% confidence interval, -1.42 to -0.07 points). Side effects of headaches, eyestrain, avoidance of near activities, and blur appeared similar between treatment groups.In a pilot randomized clinical trial, overminus spectacles improved distance control at 8 weeks in children aged 3 to <7 years with IXT. A larger and longer randomized trial is warranted to assess the effectiveness of overminus spectacles in treating IXT, particularly the effect on control after overminus treatment has been discontinued.
Project description:The aim of this study was to determine whether objective ocular torsion in intermittent exotropia (IXT) changes after recession surgery, and to evaluate the relationship between change in ocular torsion and clinical parameters in IXT. Sixty patients between 3 and 14 years of age underwent lateral rectus (LR) recession for IXT. Digital fundus photographs were obtained from both eyes of each subject and the disc-foveal angle (ocular torsion) was calculated using image software. We compared the preoperative and postoperative amount of ocular torsion, and analyzed the correlation between the difference in ocular torsion (DOC) and clinical parameters including age, duration of strabismus, stereoacuity, amount of preoperative exodeviation, and mean dose response. We categorized the patients according to DOC value: positive DOC value as group 1, and negative DOC value as group 2. A correlation between ocular torsion dominance and fixation preference was also investigated using the Kappa test. The mean ocular torsion was 15.8 ± 4.6 degrees preoperatively and 13.7 ± 5.1 degrees postoperatively. Compared with preoperative values, the mean ocular torsion showed a significant decrease after LR recession (p<0.001), and a greater preoperative ocular torsion was significantly associated with the amount of DOC (r = 0.37, p<0.001). Degree of stereopsis, mean dose-response, and postoperative exodeviation were significantly different between group 1 (positive DOC) and group 2 (negative DOC) (p<0.001, 0.030, and 0.001 respectively). The Kappa test showed that there was a significant correlation between the dominance of ocular torsion and fixation preference (p = 0.020). Therefore, change in ocular torsion after LR recession can be a useful supplementary indicator for evaluating the degree of fusional control and for predicting postoperative surgical response in IXT.
Project description:The purpose of this study was to investigate current patterns of management and outcomes of intermittent distance exotropia [X(T)] in the UK.This was an observational cohort study which recruited 460 children aged < 12 years with previously untreated X(T). Eligible subjects were enrolled from 26 UK hospital ophthalmology clinics between May 2005 and December 2006. Over a 2-year period of follow-up, clinical data were prospectively recorded at standard intervals from enrolment. Data collected included angle, near stereoacuity, visual acuity, control of X(T) measured with the Newcastle Control Score (NCS), and treatment. The main outcome measures were change in clinical outcomes (angle, stereoacuity, visual acuity and NCS) in treated and untreated X(T), 2 years from enrolment (or, where applicable, 6 months after surgery). Change over time was tested using the chi-square test for categorical, Wilcoxon test for non-parametric and paired-samples t-test for parametric data.At follow-up, data were available for 371 children (81% of the original cohort). Of these: 53% (195) had no treatment; 17% (63) had treatment for reduced visual acuity only (pure refractive error and amblyopia); 13% (50) had non surgical treatment for control (spectacle lenses, occlusion, prisms, exercises) and 17% (63) had surgery. Only 0.5% (2/371) children developed constant exotropia. The surgically treated group was the only group with clinically significant improvements in angle or NCS. However, 8% (5) of those treated surgically required second procedures for overcorrection within 6 months of the initial procedure and at 6-month follow-up 21% (13) were overcorrected.Many children in the UK with X(T) receive active monitoring only. Deterioration to constant exotropia, with or without treatment, is rare. Surgery appears effective in improving angle of X(T) and NCS, but rates of overcorrection are high.