Postoperative Esotropia Research Articles

Effect of 4-week preoperative prism adaptation in preventing postoperative residual esotropia.

Preoperative prism adaptation (PPA) simulates postoperative status and possibly can predict postoperative undercorrection before surgery in esotropia. The present study aimed to assess the effect of 4-week PPA in preventing postoperative residual esotropia. Seventy-five (75) esotropes who had undergone surgery at a single strabismus center were retrospectively enrolled. They included 25 basic, 31 acute comitant, 10 partially accommodative, and 9 recurrent esotropia patients. The preoperative deviation angle, which had been determined using the alternating prism and cover test, was fully corrected with press-on prisms 4 weeks before surgery. If there was an increase of 5 PD or more of esodeviation, the prisms were changed accordingly at 2 weeks. The deviation angle measured at 4 weeks was determined as the surgical target angle. Patients were then divided into increase (≥ 5 PD increase of angle during 4-week PPA) and non-increase groups. Success was defined as either esodeviation of 8 PD or under or exodeviation of 5 PD or under at distance at postoperative 6 months. The increase group included 44 patients (58.7%). The mean deviation angle before PPA was 27.4 PD, and after the 4-week PPA, there was an average increase of 9.4 PD. The success rate was 90.9% in the increase group and 96.8% in the non-increase group (p = 0.316). There were no intergroup differences in preoperative clinical characteristics, esotropia types, postoperative deviation angle or postoperative near stereopsis (p > 0.05). The results of this study indicated a beneficial effect of 4-week PPA in esotropia of various types, specifically by uncovering the hidden esodeviation in the increase group and simulating the postoperative alignment in both the increase and the non-increase groups.

Resection of orbital apex tumours in the medial orbit via four-handed endonasal and transcaruncular approaches.

To report the surgical outcomes of 4-handed endoscopic and transcaruncular approaches for orbital apex tumours located in the medial orbit. This retrospective, observational study included 6 patients (2 males and 4 females; 3 right and 3 left; mean age, 49.5 years; age range, 38-60 years) who underwent excision of an orbital apex tumour in the medial orbit via 4-handed endonasal and transcaruncular approaches. Data on age, sex, affected side, surgical record and complications, and results of pathological examinations, imaging studies, and ophthalmologic examinations were collected. Tumours pathologically corresponded to a cavernous haemangioma in 5 cases and a schwannoma in 1 case. The cavernous haemangioma was completely removed in all cases, while the schwannoma was only debulked because the tumour attached to the surrounding tissues. The medial orbital wall was reconstructed simultaneously in 1 case and 8 days after tumour resection in 1 case. Postoperatively, the visual acuity improved or was maintained in all patients. One patient without medial orbital wall reconstruction showed significant enophthalmos on the affected side after surgery. Another patient without medial orbital wall reconstruction did not obtain binocular single vision field in any direction of gaze after surgery due to severe esotropia. This report indicates that 4-handed endoscopic and transcaruncular approaches are useful for removal of an orbital apex tumour located in the medial orbit. Medial orbital wall reconstruction after tumour resection may be a better option for reducing the risk of postoperative enophthalmos and esotropia.

Impact of Adding Augmented Superior Rectus Transpositions to Medial Rectus Muscle Recessions When Treating Esotropic Moebius Syndrome

To describe outcomes after treatment of Moebius syndrome (MBS) esotropia by adjustable bilateral medial rectus recession (BMR) with and without augmented superior rectus transposition (SRT). Retrospective case series. Patients meeting 2014 diagnostic criteria for MBS and treated at Boston Children's Hospital between 2003 and 2019 were identified via billing records and chart review. Visual acuity, sensorimotor evaluations, strabismus procedures, and other clinical features were recorded. Surgical outcomes for patients treated with strabismus surgery (excluding those with prior surgery elsewhere) were evaluated. The primary outcome measure was postoperative alignment comparing treatment by adjustable BMR vs adjustable BMR+SRT. A total of 20 patients had MBS, and 12 of these (60%) were male. Fifteen patients (75%) had primary position esotropia, and all had bilateral abduction deficit. Eight of 20 patients met inclusion criteria for primary strabismus surgery outcome. Five had undergone adjustable BMR ranging from 4.5 to 6.5 mm. Three had undergone adjustable BMR+SRT, all with 4-mm medial rectus muscle recessions. Mean preoperative esotropia before treatment by BMR was 39.5 PD (± 15 PD) with mean postoperative esotropia 9 PD (± 7.9 PD) at 6 months. Mean preoperative esotropia before treatment by BMR+SRT was 70.8 PD (± 5.9 PD) with mean postoperative esotropia 2.5 PD (± 3.5 PD) at 6 months. Significantly greater reduction in esotropia resulted from BMR+SRT than from BMR (P=.036). BMR proved sufficient to treat esotropia <50 PD and BMR+SRT for greater esotropia in patients with MBS-associated abduction limitation.

Yokoyama procedure for esotropia associated with high myopia: real-world data from a large-scale multicentre analysis.

High myopic patients may develop strabismus due to globe dislocation out of the normal extraocular muscle cone. Surgical correction of this strabismus type is possible by joining the superior and lateral rectus muscles without the need for a scleral suture called the Yokoyama procedure. Data from large patient samples and the evaluation of a potential effect of an additional medial rectus recession (MRR) have been lacking so far. We pooled retrospective patient data of 14 departments of ophthalmology in Germany and Switzerland and analysed determinants of postoperative results using multivariable regression models. We included 133 patients (mean age: 59.7 ± 13.4 years, surgery between 2008 and 2017) with a mean preoperative esotropia (both Yokoyama with and without MRR) of 23.8°±4.6°. The angle of preoperative esotropia increased with age. The postoperative esotropia was 8.7° ± 9.9°, and six patients were overcorrected. While preoperative esotropia was highly associated with postoperative results, we found no association of additional MRR with any of our postoperative outcome measures. The Yokoyama procedure had a higher absolute effect in patients with higher preoperative esotropia. Our study confirms the positive effect of the Yokoyama procedure on strabismus due to high myopia in large-scale real-world data. In some cases, MRR may be needed because of muscle contracture, although additional MRR statistically did not affect the postoperative outcome. In patients with bilateral high myopic strabismus, correction of both eyes seems beneficial. The effect size of the Yokoyama procedure appears to be mainly driven by preoperative esotropia.

Visual Complications of Pediatric Posterior Fossa Tumors: Analysis of Outcomes

ObjectiveVisual abnormalities are common among children with posterior fossa tumors, resulting from disruption of ocular afferent and efferent systems due to the tumor or surgery. This study describes the visual complications and outcomes associated with these tumors. MethodsClinical and radiographic data of patients who underwent index surgery for resection of posterior fossa tumor from 2007 to 2016 were reviewed. Descriptive statistics, univariate, and multivariate regression were performed to assess factors contributing to visual acuity and postoperative strabismus. ResultsThere were 182 patients who underwent posterior fossa craniotomy for neoplasm were included. Ophthalmologic symptoms were the fourth most common presenting complaint; initial ophthalmologic examination was abnormal in 40% of patients. Evaluation of visual acuity demonstrated a good outcome in 88% of patients following treatment. The most common postoperative oculomotor finding was esotropia (29%) which resolved spontaneously in more than half of patients. A good outcome was obtained in all patients who underwent surgery for esotropia. Hypertropia was noted in 14% of the cohort and less than half resolved spontaneously; less than half undergoing strabismus surgery for hypertropia had a good outcome. Multivariate analysis confirmed the association between cerebellar mutism and postoperative esotropia and hypertropia. Clinically significant pathological nystagmus was seen in 8% of the cohort. ConclusionsOur results indicate a good visual outcome in the majority of pediatric patients undergoing resection of posterior fossa tumors. Ophthalmologic complications should be appropriately evaluated and addressed to allow for the best possible vision to survivors of posterior fossa tumors.

Postoperative Esotropia: Initial Overcorrection or Consecutive Esotropia?

To investigate the length of time required for diagnosing consecutive esotropia rather than initial overcorrection and examine risk factors for persistent postoperative esotropia after intermittent exotropia surgery. This is a retrospective case series in a tertiary medical center. Fifty consecutive patients with postoperative esotropia ≥6 prism diopters at 1 week following exotropia surgery, managed with nonsurgical management and followed up for more than 6 months from 2014 to 2015, were included. Patients were allocated to 1 of 2 groups depending on whether the postoperative esotropia was resolved at 1 month after surgery. Patients with ongoing nonsurgical management were reevaluated monthly. Timing that significant resolution occurred was assessed. Clinical characteristics and motor and sensory successes were evaluated at 6 months after surgery. Thirty-two patients were allocated to group 1 and 18 to group 2. Significant resolution occurred between 1 week and 1 month after surgery. Patients were older and preoperative deviation at distance was larger in group 2 than in group 1 (p = 0.006 and 0.015). A significantly larger proportion of patients in group 2 showed combined vertical deviation (p = 0.019). Motor and sensory success rates were comparable. When initial postoperative esotropia persists for more than 1 month, it should be regarded as consecutive esotropia. Older age, a larger preoperative deviation, and concurrent vertical deviation are risk factors for persistent postoperative esodeviations. Therefore, more postoperative attention should be given to these patients.

Early results of slanted recession of the lateral rectus muscle for intermittent exotropia with convergence insufficiency.

The aim of this study was to evaluate the efficacy of slanted recession of the lateral rectus muscle for intermittent exotropia with convergence insufficiency. This prospective study included 31 patients who underwent slanted lateral rectus recession for intermittent exotropia with convergence insufficiency between June 2010 and June 2012. Following parameters were recorded and analyzed: patient sex, age, preoperative and postoperative near and distance ocular alignment, and changes in stereopsis. The mean age of the patients was 9.2 years. The preoperative mean deviation angle was 32.4 PD at distance and 43.4 PD at near. After 6 months, slanted lateral rectus recession reduced the deviation angles to 2 PD at distance and 3.4 PD at near. In addition, the mean difference between distance and near deviation angles was significantly reduced from 11 PD to 1.4 PD at 6 months postoperatively. Slanted lateral rectus recession for intermittent exotropia with convergence insufficiency in children successfully reduced the distance and near exodeviations and the near-distance difference without increasing the risk of long-term postoperative esotropia or diplopia.

The use of postoperative botulinum toxin injection in large angle childhood esotropia

IntroductionThis study aimed to assess the influence of preoperative botulinum toxin (BT) injection upon the surgical correction of large angle esotropia (ET) in children and the stability of alignment following subsequent strabismus surgery.MethodsA retrospective review of children younger than 14 who had received BT prior to surgery for large angle ET (>50Δ) from January 2002 to April 2012 was undertaken. 27 patients who met inclusion criteria and had been treated with BT to both medial recti were identified. The angles for near and distance fixation, preBT, 3 months post BT, at last follow-up prior to surgery and at last postoperative follow-up were analyzed.Results3 months post BT the mean angle of deviation had reduced from 60Δ to 38Δ. This stayed stable (42Δ) after a mean follow-up of 11.8 months. 20 of the 27 patients (74%) had undergone or were awaiting 2-muscle surgery. Of those operated (n = 15), 11 were satisfactorily aligned but 4 exhibited a residual postoperative esotropia of 20Δ or more at final follow-up (range, 3 months to 3 years).DiscussionThe use of preoperative BT reduced the angle of deviation in children with large angle ET and enabled the use of less aggressive 2-muscle (instead of 3 or 4 muscle) strabismus surgery.ConclusionsBT injection prior to planned surgery in large-angle ET is an effective strategy for reducing the angle of esotropia to be surgically managed. We believe this is beneficial for the long term management of these patients who may require further strabismus procedures in their lifetime IntroductionThis study aimed to assess the influence of preoperative botulinum toxin (BT) injection upon the surgical correction of large angle esotropia (ET) in children and the stability of alignment following subsequent strabismus surgery. This study aimed to assess the influence of preoperative botulinum toxin (BT) injection upon the surgical correction of large angle esotropia (ET) in children and the stability of alignment following subsequent strabismus surgery. MethodsA retrospective review of children younger than 14 who had received BT prior to surgery for large angle ET (>50Δ) from January 2002 to April 2012 was undertaken. 27 patients who met inclusion criteria and had been treated with BT to both medial recti were identified. The angles for near and distance fixation, preBT, 3 months post BT, at last follow-up prior to surgery and at last postoperative follow-up were analyzed. A retrospective review of children younger than 14 who had received BT prior to surgery for large angle ET (>50Δ) from January 2002 to April 2012 was undertaken. 27 patients who met inclusion criteria and had been treated with BT to both medial recti were identified. The angles for near and distance fixation, preBT, 3 months post BT, at last follow-up prior to surgery and at last postoperative follow-up were analyzed. Results3 months post BT the mean angle of deviation had reduced from 60Δ to 38Δ. This stayed stable (42Δ) after a mean follow-up of 11.8 months. 20 of the 27 patients (74%) had undergone or were awaiting 2-muscle surgery. Of those operated (n = 15), 11 were satisfactorily aligned but 4 exhibited a residual postoperative esotropia of 20Δ or more at final follow-up (range, 3 months to 3 years). 3 months post BT the mean angle of deviation had reduced from 60Δ to 38Δ. This stayed stable (42Δ) after a mean follow-up of 11.8 months. 20 of the 27 patients (74%) had undergone or were awaiting 2-muscle surgery. Of those operated (n = 15), 11 were satisfactorily aligned but 4 exhibited a residual postoperative esotropia of 20Δ or more at final follow-up (range, 3 months to 3 years). DiscussionThe use of preoperative BT reduced the angle of deviation in children with large angle ET and enabled the use of less aggressive 2-muscle (instead of 3 or 4 muscle) strabismus surgery. The use of preoperative BT reduced the angle of deviation in children with large angle ET and enabled the use of less aggressive 2-muscle (instead of 3 or 4 muscle) strabismus surgery. ConclusionsBT injection prior to planned surgery in large-angle ET is an effective strategy for reducing the angle of esotropia to be surgically managed. We believe this is beneficial for the long term management of these patients who may require further strabismus procedures in their lifetime BT injection prior to planned surgery in large-angle ET is an effective strategy for reducing the angle of esotropia to be surgically managed. We believe this is beneficial for the long term management of these patients who may require further strabismus procedures in their lifetime

A comparison of ocular alignment success of hang-back versus conventional bilateral lateral rectus muscle recession for true divergence excess intermittent exotropia

To assess whether hang-back or conventional bilateral lateral rectus muscle recessions were more successful in achieving a satisfactory postoperative ocular alignment in patients with true divergence excess intermittent exotropia. The medical records of consecutive patients with true divergence excess intermittent exotropia who underwent bilateral lateral rectus muscle recession using hang-back or conventional techniques were retrospectively analyzed. All surgeries were performed by a single surgeon using the same standard table of surgical dosage. We compared the preoperative characteristics and motor surgical outcomes between the two groups. Success was defined as alignment within 10(Δ) of intermittent exotropias at distance and near. Any amount of postoperative esotropia was considered a failure. A total of 42 patients were included: 13 in the hang-back group and 29 in the conventional group. The mean age at surgery, mean preoperative deviation at near and distance, mean amount of lateral rectus muscle recession, and mean follow-up duration were not statistically significantly different between groups. At the most recent follow-up, the conventional group had a significantly greater success rate (≤10(Δ) of intermittent exotropia) than the hang-back group (83% vs 31%, P = 0.0009). There was no statistically significant difference in the mean amount of lateral rectus recession between patients with successful and unsuccessful surgical outcomes in both groups. Within the limitations of this study, conventional bilateral lateral rectus recessions were more effective than hang-back recessions in achieving a successful postoperative alignment in patients with true divergence excess intermittent exotropia.

Does amount of immediate postoperative esotropia predict later alignment after surgery for intermittent exotropia?

Introduction: It is well accepted that esotropic (ET) over-correction on post-operative-day 1 (POD1) is a desired outcome for long-term stability after surgery for intermittent exotropia (XT). It is unclear why some patients who are appropriately over-corrected eventually demonstrate recurrent XT while others maintain a stable deviation.

Surgical Treatment of Esotropia Associated with High Myopia: Unilateral versus Bilateral Surgery

To compare unilateral versus bilateral surgical treatment of esotropia associated with high myopia. This retrospective study comprised patients who underwent surgery for esotropia with high myopia performed by the first author (Y.M.) between 2003 and 2008. Surgical results and complications were compared between patients who underwent unilateral versus bilateral surgery. Nine patients were identified with average age of 44.9 years (range 8-70 years). All had bilateral high myopia (average -13.35 D, range -9.00 to -17.50 D) and esotropia of 20-75 diopters, together with hypotropia in 5 cases. Bilateral displacement of the lateral rectus inferiorly and superior rectus medially was demonstrated in each patient by computed tomography scan of the orbits and by observation during surgery. Five patients underwent bilateral surgery and 4 underwent unilateral surgery. After an average follow-up of 29 months (range 4-47 months), 4/5 patients who underwent bilateral myopexy achieved good results with postoperative esotropia of less than 8 diopters, as opposed to 2/4 patients who underwent unilateral surgery. No complications were noted. Bilateral superior and lateral rectus myopexy is the preferred method of surgical correction of esotropia associated with high myopia. Additional unilateral or bilateral medial rectus recession is probably not indicated in most cases. Patients who prefer unilateral surgery can benefit from unilateral superior and lateral rectus myopexy together with medial rectus recession. This unilateral approach may yield good results particularly in young patients without markedly restricted and tight extraocular muscles.

Tratamiento quirúrgico del síndrome de duane, tipo I mediante retroinserción del recto medial del lado afecto y faden del recto medial contralateral

Different surgical approaches have been described for the treatment of Duane's syndrome. The purpose of our study is to report the results of patients undergoing recession of the medial rectus (MR) muscle of the affected eye and placement of contralateral MR faden posterior fixation sutures. Retrospective study of 11 patients treated by a 4-7 mm recession of the MR of the affected eye and 13 mm faden posterior fixation suture of the contralateral MR in order to correct abnormal head position and esotropia in primary position. After surgery, there was no torticolis in 81.8% of patients, with less than 10 degrees of torticolis in the remainder. In all patients, postoperative esotropia was less than 5 prismatic dioptres. This is a safe and effective procedure in Duane's syndrome type I to treat moderate esotropia and torticolis.

Sensory results after lateral rectus muscle recession for intermittent exotropia operated before two years of age

Early surgical treatment of early-onset intermittent exotropia is controversial. The condition does not always progress, and postoperative esotropia can produce adverse consequences, such as suppression, amblyopia, and loss of binocular vision, particularly stereopsis. It is not known whether surgery before age two years affects the sensory outcome. Using a noncomparative (nonrandomized, uncontrolled) interventional case series, we reviewed the medical records during a 14-year period of 24 patients with intermittent exotropia with onset before age 1 year who also received bilateral lateral rectus muscle recessions before two years of age. Twelve patients were identified who received follow-up examinations at ages > or =4 years, when testing with Worth 4-Dot and Titmus stereo circles would likely be reliable. Mean age of the patients at last follow-up examination was 87 months. Stereoacuity was measured at 40 arcsec in 2 patients, 100 arcsec in 3 patients, 140-400 arcsec in 2 patients, and none in 5 patients. Among the 5 patients without demonstrated stereopsis, 1 had a history and clinical course consistent with congenital exotropia, and 1 had a nonstrabismic explanation for poor stereopsis. Overall, 7 patients (58%) ultimately obtained favorable motor alignment, defined as a phoria or intermittent tropia <10(Delta) at distance and near. No patient required treatment for amblyopia. Early-onset intermittent exotropia usually responds well to surgical treatment, and high-grade stereopsis can be achieved in some cases. More than one clinical entity presenting as intermittent exotropia in infancy probably exists.

Einfluss der Prismenüberkorrektur auf den postoperativen Restschielwinkel

Prism overcorrection is a complementary procedure to reduce the residual postoperative esotropia caused by anomalous retinal correspondence (ARC) after surgery for esotropia. We have investigated the results of this treatment. For Group 1, the files of 63 patients treated with postoperative prism overcorrection in the Department of Ophthalmology, University of Giessen, were evaluated regarding the pre-and postoperative squint angles (SPCT, simultaneous and APCT, alternate prism and cover test) and the angle of ARC, determined by the red filter test and by the increase of esotropia after neutralisation of the squint angle (APCT). Postoperatively, squint angles had been measured immediately (APCT) after removal of the eye patch and 10 minutes to 2 hours later (SPCT and APCT). Subsequently, prism overcorrection was performed with a Fresnel prism foil (40 PD basis temporally) in front of the fellow eye for a maximum of 3 months. After 3 months, SPCT and APCT were performed. For Group 2, the files of 28 patients with a preoperative angle of ARC of 5 degrees or more, treated in the Department of Ophthalmology, University of Heidelberg, were evaluated. These patients had not been treated with prism overcorrection. The squint angles had been measured (SPCT and APCT) on the preoperative day, on the first postoperative day, a few hours after removing the eye patch, and after three months. For Group 1, at surgery, the patients were 4 to 12 years old (median: 6.2 years). The preoperative squint angle ranged from + 5 degrees to + 27 degrees (median: + 12 degrees) in the SPCT and from + 7 degrees to + 27 degrees (median: + 14 degrees) in the APCT. The angle of ARC was between + 4 degrees and + 15 degrees (median: + 7 degrees). Both combined recess and resect surgery (with or without additional oblique muscle surgery) or bilateral retroequatorial medial rectus myopexy, in part depending on the squint angle pattern with medial rectus recession, were performed. Immediately after removing the patch, the squint angle (APCT) was between - 10 degrees and + 5 degrees (median: + 1 degrees). Ten minutes to 2 hours later, the manifest squint angle ranged from 0 to + 12 degrees (median: + 7 degrees). The angle had decreased significantly to - 6 to + 12 degrees (median: + 5 degrees) after 3 months. For Group 2, the patients' ages were between 5 and 12 years (median: 6.5 years). The squint angles ranged from + 11.5 degrees to + 35 degrees (median: + 20 degrees) in the SPCT and APCT. The angle of ARC was between + 5 degrees and + 17 degrees (median: + 8 degrees). Combined recess and resect surgery or bilateral recession of the medial rectus (with or without oblique muscle surgery both) were performed. The SPCT several hours after removal of the patch showed angles of - 4 degrees to + 14 degrees (median: + 4.25 degrees). Three months later the manifest squint angles ranged from - 5 degrees to + 14 degrees (median: + 3 degrees). After prism overcorrection (Group 1), there was a significant reduction of the residual esotropia. Without this additional treatment (Group 2), there was no significant change in the postoperative squint angle. However, neither the positive outcome in Group 1 nor the difference to Group 2 do unequivocally prove that there is a beneficial effect of prism overcorrection, since preoperative conditions were different and the sample size in Group 2 was small, especially after matching for equal preoperative conditions. A spontaneous reduction of the postoperative esotropia cannot be excluded. Further studies are necessary in order to investigate the specific effect of prism overcorrection.

Sensory results after lateral rectus muscle recession for intermittent exotopia operated before two years of age

Introduction: Early surgical treatment of early-onset intermittent exotropia is controversial. The condition does not always progress and postoperative esotropia can produce adverse consequences, such as suppression, amblyopia, and loss of binocular vision, particularly stereopsis. It is not known whether surgery prior to age 2 years improves or worsens the prospects for normal sensory outcome. Methods: We reviewed medical records of 23 patients with intermittent exotropia with onset before age 1 year and also received bilateral lateral rectus muscle recessions prior to age 2 years. Ten were identified who received follow-up examinations at age = 4 years, when testing with Worth 4-Dot and Titmus stereo circles would likely be reliable. Results: Mean age at follow-up examination was 82 months. Stereoacuity was measured at 40 arcsec in three patients, 100 arcsec in two patients, 140 to 400 arcsec in two patients, and none in three patients. Among the three patients without demonstrated stereoacuity, one had a history and clinical course consistent with congenital exotropia, and two were developmentally delayed. Overall, seven patients (70%) had favorable motor alignment, defined as a phoria or intermittent tropia <10Δ at distance or near with no deviation >15Δ. No patient required treatment for amblyopia. Conclusions: Early-onset intermittent exotropia appears to respond well to surgical treatment. Sensory outcomes demonstrate that high-grade stereopsis can be achieved in some cases. More than one clinical entity presenting as intermittent exotropia in infancy probably exists. It is not clear whether early surgical intervention improves sensory outcomes over nonsurgical management.

Unilateral recession–resection in children with exotropia of the convergence insufficiency type

The surgical success rates for intermittent exotropia of the convergence insufficiency type have been reported to be variable, and most were studied retrospectively in adults. The purpose of this study was to evaluate prospectively the long-term surgical results of unilateral lateral rectus (LR) muscle recession and medial rectus (MR) muscle resection in children with intermittent exotropia of the convergence insufficiency type. A total of 14 children with intermittent exotropia greater at near than at distance by 10 prism diopters (PD) or more were included in this prospective study. The amounts of resection and recession were based on near and distance deviation, respectively. Minimum follow-up was 1 year (mean 26.6 months; range, 12-68 months) after surgery. The paired t-test was used to compare preoperative and postoperative measurements of the angle of deviation at distance and near, near-distance difference. Significant postoperative reduction was achieved in terms of mean distance exodeviation, from 22.5 PD to 9.1 PD (P=0.000), and mean near exodeviation from 33.8 PD to 13.6 PD (P=0.000). Mean near-distance difference reduced from 11.3 PD preoperatively to 4.6 PD postoperatively (P=0.000). Fresnel prism was used temporarily to treat postoperative esotropia in only one patient for postoperative 6 months. Unilateral surgery biased to MR strengthening more than LR weakening in children with intermittent exotropia of the convergence insufficiency type, was found to successfully reduce both distance and near deviation and to collapse near-distance differences with a low risk of long-term postoperative esotropia.

Preoperative prism adaptation for acquired esotropia: Long-term results

Purpose: The efficacy of preoperative prism adaptation in subjects with acquired esotropia has been established at 6 and 12 months postoperatively. We evaluated the outcomes of subjects with acquired esotropia who had preoperative prism adaptation and were followed longer than 12 months. Methods: A retrospective analysis was undertaken of 2 groups of subjects with acquired esotropia who underwent bilateral medial rectus recessions based on the distance angle of deviation and were followed more than 12 months postoperatively. Group A subjects had preoperative prism adaptation to determine the target angle for corrective surgery. In Group B subjects, surgery was based on the maximum angle of strabismus at distance, determined by alternate prism cover test without preoperative prism adaptation. Results: We compared 17 subjects in Group A and 19 subjects in Group B. The postoperative follow-up period was 3 ± 1.7 years in Group A and 4.8 ± 1.8 years in Group B. The age at the last visit was 9.1 ± 2 years in Group A and 10 ± 2 years in Group B. Postoperative residual esotropia was 2.6 ± 2.5 PD at distance in Group A patients and 6.6 ± 5.9 PD in group B patients (P =.002). Residual esotropia at near was 3 ± 3.8 PD in Group A and 11.5 ± 8.12 PD in Group B (P <.01). More Group B subjects required bifocal spectacles to achieve optimal alignment at near (P =.001). Conclusion: Acquired esotropia subjects operated on for their distance prism-adapted angle maintained better motor alignment over a long-term follow-up period when compared with nonprism-adapted subjects operated on for their distance angle. (J AAPOS 2002;6:168-73)

Diagnosis and treatment of exotropia with a high accommodation convergence-accommodation ratio.

Patients with exotropia often have a slow-to-dissipate fusional mechanism at near, which masks the true near deviation. Consequently, determination of the accommodation convergence-accommodation (AC/A) ratio in patients with exotropia must be based on near measurements obtained after prolonged monocular occlusion (typically 1 hour). When determined in that manner, the presence of a high AC/A ratio before surgery in an exotropic patient has been reported to be predictive of an esotropia at near after surgery. To investigate the diagnosis and management of exotropia with a high AC/A ratio. Three hundred four consecutive patients with exotropia were studied. In addition to the usual measurements, measurements were obtained at near after 1 hour of monocular occlusion, with and without additional +3.00-diopter lenses. Also, a gradient AC/A ratio was obtained by using additional minus lenses at distance fixation. One hundred fifty-four (50.7%) of 304 patients would have been thought to have a high AC/A ratio if that diagnosis was based on measurements obtained before prolonged monocular occlusion. In fact, only 22 patients (7.2%) actually had a high AC/A ratio; 132 patients (43.4%) had a pseudo-high AC/A ratio. Six of 22 patients with a high AC/A ratio underwent surgery to correct the exotropia. The presence of a high AC/A ratio before surgery had sensitivity, specificity, and positive and negative predictive values of 100% for predicting a postoperative esotropia at near associated with a high AC/A ratio. The remaining 16 patients with high AC/A ratios were treated with overcorrecting minus lens therapy (including a bifocal). Ten of them have been followed up to at least 18 years of age, by which time 9 have shown normalization of the AC/A ratio. Near measurements used to calculate the AC/A ratio in exotropic patients must be made after prolonged monocular occlusion. Otherwise, many patients with a pseudo-high AC/A ratio will be thought to have a true high AC/A ratio. The presence of a high AC/A ratio is infrequent in patients with esotropia, but it is highly predictive of a postoperative esotropia at near fixation.

Surgical management of intermittent exotropia with high AC/A ratio

Background: A subgroup of patients with intermittent exotropia have a high AC/A ratio, which places them at risk for esotropia at near after surgical treatment of their distance deviation. Methods: A retrospective review of six patients with intermittent exotropia and a high AC/A ratio who were simultaneously treated with lateral rectus recessions to fully correct their exotropia at distance and placement of posterior fixation sutures on both medial rectus muscles in hopes of preventing an esotropia at near after surgery. Results: Despite the persistence of a high postoperative AC/A ratio as assessed by the gradient method, five of six patients achieved stable postoperative alignment at distance and near without bifocals. One patient required postoperative bifocal correction for intermittent esotropia at near. Conclusion: In patients with intermittent exotropia and a high AC/A ratio, posterior fixation of the medial rectus muscles at the time of lateral rectus recessions enables the surgeon to fully correct the distance deviation and minimizes the risk of postoperative esotropia at near.

Management of Intermittent Exotropia: For Surgery

Almost all patients with intermittent exotropia require surgical correction at some point. Nonoperative measures furnish normal binocular sensory input to the misaligned eyes to encourage compensation and proper binocular visual function, even under the abnormal motor circum-stances. However, while this is valuable adjunctive treatment, it rarely is sufficient alone. Surgery done while fusion is still exercised at least part-time gives better results, and reported studies indicating disappointing success rates may not have made this distinction. The dangers of early surgery in younger patients include persisting overcorrection and monofixation syndrome even when alignment is successfully restored. Permanent overcorrection is not more likely to occur after initial postoperative esotropia of 11–20Δ than after smaller esodeviations. When monofixation syndrome occurs, secure peripheral fusion, at least partial stereopsis and visual comfort replace frequent divergence with visual annoyance and a noticeable cosmetic defect.