The Effect of Preoperative Occlusion Therapy on Long-term Outcome after Surgery for Early-onset Exotropia

PURPOSE: To investigate the effect of preoperative part-time occlusion therapy on long-term surgical success in early-onset exotropia. METHODS: The medical records of patients who underwent surgery for exotropia with onset before the first year of age and who were followed for ≥3 years were reviewed. Patients were divided into two groups according to the degree of compliance with part-time occlusion therapy: the good compliance group (>50% adherence rate) and the poor compliance group (≤50% adherence rate). Surgical success was defined as orthophoria to exodeviation less than 10 prism diopters both at distance and near. The level of postoperative stereopsis was compared between the two study groups among total enrolled patients and among those with constant exotropia. RESULTS: Of the 51 patients, 26 were assigned to the good compliance group and the remaining 25 patients to the poor compliance group. The surgical success rate was significantly higher in the good compliance group than in the poor compliance group (80.8% vs. 52.0%, p = 0.040). Among 24 constant exotropia patients (12 patients for each group), the success rate was insignificantly higher in the good compliance group than in the poor compliance group (75.0% vs. 58.3%, p = 0.448). The good compliance group had a better level of stereopsis than the poor compliance group (p = 0.045 for all 44 patients, p = 0.020 for 19 patients with constant exotropia). CONCLUSIONS: Preoperative part-time occlusion therapy was useful for improving the surgical outcome of early-onset exotropia and postoperative stereopsis.

Comparison of Sensory and Motor Functions in Patients with Constant and Intermittent Infantile Exotropia

PURPOSE: The aim of this study was to compare sensory and motor functions in patients with constant and intermittent primary infantile exotropia. METHODS: From March 2010 to November 2015, 58 patients with primary infantile exotropia were divided into a constant group (21 patients) and an intermittent group (37 patients) according to frequency of exodeviation at the first visit. Sex, family history of strabismus, age at diagnosis, spherical equivalent, and presence of amblyopia were compared. Angle of deviation, ocular motor function, and stereopsis were measured. RESULTS: Females were more prevalent (p = 0.027) and the spherical equivalent of the right eye was more myopic (-0.99 D) (p = 0.023) in the constant infantile exotropia group. However, there was no significant difference in family history of strabismus, age at diagnosis, amblyopia, latent nystagmus, or stereopsis between the two groups. There were no significant differences between the two groups in angle of deviation at near or distance (p = 0.598, p = 0.518). Dissociated vertical deviation was accompanied in 2 patients in the constant group and 3 in the intermittent group. Inferior oblique overaction was accompanied in 8 patients in the constant group and 16 in the intermittent group, while vertical deviation was accompanied in 1 patient in the constant group and 3 in the intermittent group. However, there were no significant differences between the groups for any of these findings. CONCLUSIONS: Constancy of exodeviation is insufficient to diagnose primary infantile exotropia. Compared to those in whom exodeviation was intermittent, the patients with constant infantile exotropia showed similar clinical features. Therefore, close observation is recommended in patients with intermittent and constant infantile exotropia.

Clinical Manifestations of Constant Infantile Exotropia

PURPOSE: The purpose of this study is to evaluate the clinical course and surgical outcomes of constant infantile exotopia developed in the first year of life. METHODS: Eighteen patients diagnosed with constant infantile exotropia who underwent surgery between June 1993 and July 2003 were reviewed retrospectively. Age at diagnosis and surgery, refractive error, and preoperative and postoperative prism diopters were evaluated for all patients. RESULTS: The mean age at diagnosis was 7.3+/-2.2 months (2~11 months) and mean deviation was 47.2+/-16.6 prism diopters (PD) (25~90 PD). Inferior oblique muscle overaction was found in 3 (17%) patients. Bilateral lateral rectus muscle recession was performed in all patients and mean amount of recession was 8.0+/-0.9 mm (7.0~9.0 mm). The mean age at surgery was 16.7+/-4.1 months (7~24 months) and the mean postoperative follow-up period was 34.3+/-23.0 months (7~83 months). Thirteen patients (76%) showed stable alignments after the first operation and 3 patients (18%) required reoperation due to undercorrection and recurrence. Among them, one patient (6%) required a third operation. CONCLUSIONS: Early surgical intervention in constant infantile exotropia resulted in good postoperative outcome and stable alignments after the first operation.

Clinical Course and Outcome of Infantile Exotropia

PURPOSE: To evaluate the clinical course and surgical outcome of infantile exotropia with large and constant angle, as defined by the onset of exotropia before 6 months. METHODS: We reviewed the records of 11 patients who were diagnosed with infantile exotropia and received surgery between July 1987 and December 2003. Age at onset and surgery, visual acuity, refractive error, pre- and post-operative angle of strabismus, and binocular sensory status after surgery were evaluated for each patient. RESULTS: The mean age at onset, diagnosis, and first surgery was 2.3 months (range, birth to 5 months), 14.9 months (range, 4 to 33 months), and 36.3 months (range, 11 to 45 months), respectively. The mean size of preoperative exodeviation was 57.3 prism diopters (PD) (range, 40 to 100 PD). Six patients (54.5%) required reoperation to correct residual or recurred exotropia, oblique dysfunction, and/or DVD. Two (18.2%) of the six required a third operation. Sensory tests including Lang test were performed in seven patients but all failed in Lang test and showed no fusion even with successful surgical treatment. CONCLUSIONS: Infantile exotropia should be observed for a long period and needs proper reoperation because it may be frequently associated with residual or recurred exotropia, oblique dysfunction, and/or DVD after initial operation. However, improvement of binocular function can rarely be expected even with successful surgical alignment.

The Clinical Feature and Surgical Outcome of Infantile Exotropia

PURPOSE: To investigate the clinical features and treatment of infantile exotropia which developed in the first year of life. METHODS: The medical records of infantile exotropia operated on in our hospital were reviewed for preoperative and postoperative deviation, cycloplegic refraction, Worth 4-dot test and Titmus stereo acuity test. RESULTS: Preoperative mean deviation was 37 prism diopters. The average post-operative follow-up period was 26.5 months (12~86 months). Twelve patients (71%) had successful horizontal alignment with final horizontal deviations of less than 8 prism diopters, and five patients were undercorrected between 10 and 20 prism diopters. None were overcorrected. Six patients (35%) had fusion at distance and near as well as stereoacuity of 200 seconds of arc or less. Both preoperative and postoperative associated anomalies were inferior oblique muscle overaction (35%), dissociated vertical deviation (18%), both inferior oblique muscle overaction and dissociated vertical deviation (18%), nystagmus (12%) and V-pattern (6%). CONCLUSION: Although infantile exotropia is rare, it has similarities to infantile esotropia. Infantile exotropia features a large-angle deviation, accompanied with inferior oblique muscle overaction and dissociated vertical deviation. After operation, no cases were overcorrected, while high levels of binocular function, and stereoacuity developed in some cases.

Clinical effect of early surgery in infantile exotropia

To evaluate the effects of early surgical intervention in infantile exotropia on the motor and sensory functions, we reviewed the records of 17 subjects diagnosed with exotropia before the age of 12 months, receiving surgery before the age of 24 months, with a follow-up period greater than one year, between 1996 and 2000. Of the 17 subjects (6 intermittent, 11 constant), 14 (82%) (6 intermittent, 8 constant) had a final horizontal deviation of <10 PD, with 3 (18%) needing a re-operation. Fusion and gross binocularity were developed in 7 (4 intermittent, 3 constant), and 11 (6 intermittent, 5 constant) subjects, respectively. Seven subjects developed stereopsis of 200 seconds or better, and 5 of the 6 with intermittent exotropia (83%) being involved. In conclusion, over 80% of the successful alignments were obtained with surgery before the age of 24 months in infantile exotropia, which was similar to previous studies. Furthermore, early surgical intervention, particularly in the intermittent phase, resulted in more effective sensory function.