In this study, we explored the neural mechanism underlying impaired stereopsis and possible functional plasticity after strabismus surgery. We enrolled 18 stereo-deficient patients with intermittent exotropia before and after surgery, along with 18 healthy controls. Functional magnetic resonance imaging data were collected when participants viewed three-dimensional stimuli. Compared with controls, preoperative patients showed hypoactivation in higher-level dorsal (visual and parietal) areas and ventral visual areas. Pre- and postoperative activation did not significantly differ in patients overall; patients with improved stereopsis showed stronger postoperative activation than preoperative activation in the right V3A and left intraparietal sulcus. Worse stereopsis and fusional control were correlated with preoperative hypoactivation, suggesting that cortical deficits along the two streams might reflect impaired stereopsis in intermittent exotropia. The correlation between improved stereopsis and activation in the right V3A after surgery indicates that functional plasticity may underlie the improvement of stereopsis. Thus, additional postoperative strategies are needed to promote functional plasticity and enhance the recovery of stereopsis.
Humans ; Exotropia/surgery* ; Depth Perception/physiology* ; Strabismus/surgery* ; Oculomotor Muscles/surgery*

No abstract available.
Child ; Eye Movements/*physiology ; Humans ; Male ; Oculomotor Muscles/physiopathology/*surgery ; Ophthalmologic Surgical Procedures/*methods ; Strabismus/physiopathology/*surgery ; Syndrome

PURPOSE: The purpose of this study is to compare the surgical outcomes and near stereoacuities after unilateral medial rectus (MR) muscle resection and lateral rectus (LR) recession according to deviation angle in basic intermittent exotropia, X(T). METHODS: Ninety patients with basic type X(T) were included in this study. They underwent unilateral recession of the LR and resection of the MR and were followed postoperatively for at least 12 months. Patients were divided into three groups according to their preoperative deviation angle: group 1 < or =20 prism diopter (PD), 20 PD< group 2 <40 PD, and group 3 > or =40 PD. Surgical outcomes and near stereoacuities one year after surgery were evaluated. Surgical success was defined as having a deviation angle range within +/-10 PD for both near and distance fixation. RESULTS: Among 90 patients, groups 1, 2, and 3 included 30 patients each. The mean age in groups 1, 2, and 3 was 9.4 years, 9.4 years, and 11.0 years, respectively. The surgical success rates one year after surgery for groups 1, 2, and 3 were 80.0%, 73.3%, and 73.3% (chi-square test, p = 0.769), respectively. The undercorrection rates for groups 1, 2, and 3 were 16.7%, 23.3%, and 26.7%, and the overcorrection rates were 3.3%, 3.3%, and 0%, respectively. The mean preoperative near stereoacuities for groups 1, 2, and 3 were 224.3 arcsec, 302.0 arcsec, and 1,107.3 arcsec, and the mean postoperative near stereoacuities were 218.3 arcsec, 214.7 arcsec, and 743.0 arcsec (paired t-test; p = 0.858, p = 0.379, p = 0.083), respectively. CONCLUSIONS: In basic X(T) patients, the amount of angle deviation has no influence on surgical outcomes in unilateral LR recession and MR resection. The near stereoacuities by one year after LR recession and MR resection for intermittent X(T) were not different among patient groups separated by preoperative deviation angle.
Child ; Exotropia/physiopathology/*surgery ; Female ; Follow-Up Studies ; Humans ; Male ; Oculomotor Muscles/physiopathology/*surgery ; *Ophthalmologic Surgical Procedures ; Retrospective Studies ; Treatment Outcome ; Vision, Binocular/physiology ; Visual Acuity/physiology

PURPOSE: The purpose of this study was to investigate the clinical course of esodeviation after exotropia surgery in older patients (older than 15 years) and to compare it with that in younger patients (15 years or younger). METHODS: The medical records of all surgeries for exodeviation from December 2004 to February 2007 were reviewed and 82 patients were found with consecutive esodeviation. The patients were divided into two groups according to their age: Group A (patients older than 15 years) and Group B (patients age 15 or younger). The clinical course of esodeviation in Group A was compared to that in Group B by means of survival analysis. RESULTS: The median survival times of the esodeviation were 2.0+/-0.1 months in Group A and 1.0+/-0.1 months in Group B (p=0.40). The prevalence of consecutive esotropia at six months was 0% in Group A and 6.1% in Group B (p=0.32). The myopic refractive error, worse sensory condition, and a larger preoperative exodeviation in Group A did not affect the clinical course of the two groups differently. CONCLUSIONS: The postoperative esodeviation of patients older than 15 years after exotropia surgery tended to persist longer during the early postoperative period than that of patients 15 years or younger, however, the difference did not persist at postoperative six months.
Adult ; Age Factors ; Child ; Esotropia/*etiology/physiopathology ; Exotropia/*surgery ; Female ; Humans ; Kaplan-Meiers Estimate ; Male ; Oculomotor Muscles/*surgery ; *Postoperative Complications ; Vision, Binocular/physiology ; Visual Acuity/physiology

PURPOSE: The purpose of this study was to establish a set of normative data values for saccade movements using videonystagmography and to evaluate the effects of manual correction on this data. METHODS: We examined 25 healthy subjects (9 men and 16 women). All tests were carried out by one well-instructed physician. Errors such as the wrong detection of the inflection point, missing movement, and prediction occurred during some tests. Thus, the same physician manually corrected the data by deleting error data from row results. RESULTS: We established a set of normative data for horizontal saccade movements (amplitude size 15 and 30 degrees) for mean peak velocity, latency, and accuracy. Manual correction only impacted latency and accuracy at 30 degrees horizontal, which is likely related to possible errors during the test. CONCLUSIONS: The present study provides clinically useful videonystagmography-based normative data for clinicians regarding saccade movements in Korean individuals.
Adult ; Female ; Healthy Volunteers ; Humans ; Male ; Oculomotor Muscles/*physiology ; Photic Stimulation ; Reference Values ; Reproducibility of Results ; Saccades/*physiology ; Video Recording/*methods ; Young Adult

PURPOSE: We wanted to examine the effect of graded recession and anteriorization of the inferior oblique muscle on patients suffering from unilateral superior oblique palsy. METHODS: Inferior oblique muscle graded recession and anteriorization were performed on twenty-two patients (22 eyes) with unilateral superior oblique palsy. The recession and anteriorization were matched to the degree of inferior oblique overaction and hypertropia. The inferior oblique muscle was attached 4 mm posterior to the temporal border of the inferior rectus muscle in six eyes, 3 mm posterior in five eyes, 2 mm posterior in five eyes, 1 mm posterior in five eyes, and parallel to the temporal border in one eye. RESULTS: The average angle of vertical deviation prior to surgery was 11.3+/-3.9 prism diopters (PD). The total average correction in the angle of vertical deviation after surgery was 10.8+/-3.8 PD. In the parallel group, the average reduction was 14 PD. After surgery, normal inferior oblique muscle action was seen in eighteen of twenty-two eyes (81.8%). CONCLUSIONS: Graded recession and anteriorization of the inferior oblique muscle is thought to be an effective surgical method to treat unilateral superior oblique palsy of less than 15 PD.
Treatment Outcome ; Retrospective Studies ; Ophthalmologic Surgical Procedures/*methods ; Oculomotor Nerve Diseases/physiopathology/*surgery ; Oculomotor Muscles/physiopathology/*surgery ; Male ; Humans ; Follow-Up Studies ; Female ; Eye Movements/*physiology ; Child, Preschool ; Child ; Adult ; Adolescent

PURPOSE: To analyze innervated myotendinous cylinders (IMCs) in the extraocular muscles (EOMs) of normal subjects and strabismic patients. METHODS: The rectus muscles of 37 subjects were analyzed. Distal myotendinous specimens were obtained from 3 normal subjects, 20 patients with acquired strabismus, 11 with infantile strabismus, and from 3 with congenital nystagmus, and were studied by using light microscopy. Some specimens (6 rectus muscles) were also examined by transmission electron microscopy. RESULTS: IMCs were found in the distal myotendinous regions of EOMs. The IMCs of patients with acquired strabismus showed no significant morphological alterations. However, significant IMCs alterations were observed at the distal myotendinous junction of patients with congenital strabismus and congenital nystagmus. CONCLUSIONS: This study supports the notion that IMCs in human EOMs function mainly as proprioceptors, along with effector properties, and a disturbance of ocular proprioceptors plays an important role in the pathogenesis of oculomotor disorder. We suggest that a proprioceptive feedback system should be stimulated and calibrated early in life for the development of binocular vision.
Adolescent ; Adult ; Child ; Child, Preschool ; Female ; Humans ; Infant ; Male ; Microscopy, Electron, Transmission ; Middle Aged ; Oculomotor Muscles/*innervation/physiopathology/ultrastructure ; Proprioception/physiology ; Strabismus/*pathology/physiopathology ; Young Adult

PURPOSE: To evaluate differences in self-identity in patients diagnosed with strabismus, patients who underwent strabismus surgery, and healthy control individuals. METHODS: Self-identity testing was done during a military service physical examination. There were three subject groups: subjects with strabismus (group 1), subjects who had undergone corrective strabismus surgery (group 2), and subjects free of strabismus (group 3). The self-identity test was comprised of six sub-sections (subjectivity, self-acceptance, future confidence, goal orientation, initiative, and familiarity). Statistical significance of the sub-sections was compared across the three groups. Correlations in age at the time of surgery and across the six sub-sections were investigated in group 2. RESULTS: A total of 351 subjects were enrolled in the study; 96 subjects were in group 1, 108 subjects were in group 2, and 147 subjects were in group 3. Significant differences were evident in subjectivity, self-acceptance, initiative and familiarity between groups 1 and 3. No significant differences were found between groups 2 and 3. In group 2, statistical significance was evident between age at surgery and initiative and familiarity (r = −0.333, p < 0.001; r = −0.433, p < 0.001, respectively). CONCLUSIONS: Self-identity is greater in non-strabismus subjects than strabismus subjects. Correction of strabismus may increase self-identity levels.
Adolescent ; Adult ; Eye Movements/*physiology ; *Facial Expression ; Female ; Humans ; Male ; Oculomotor Muscles/*physiopathology/surgery ; Ophthalmologic Surgical Procedures ; Retrospective Studies ; *Self Concept ; Strabismus/physiopathology/*psychology/surgery

PURPOSE: To compare the outcomes of unilateral lateral rectus recession between the first operation and second operation for exotropia. METHODS: Thirty-two patients who underwent unilateral lateral rectus recession for exotropia of 15 to 20 prism diopters (PD) were investigated. The follow-up period was at least 6 months. We classified 17 patients without a surgical history for exotropia (first operation group) and 15 patients with a previous procedure (second operation group). Surgical success was defined as an exodeviation or esodeviation of less than 10 PD at the primary position. Postoperative deviation angles and success rates were compared between the two groups. RESULTS: There were no significant differences in the age, gender, visual acuity (logarithm of the minimal angle of resolution), preoperative deviation, and amount of recession between the two groups. Postoperative deviations were -1.7 +/- 5.5:1.3 +/- 5.1 PD at one day, 4.3 +/- 3.8:5.6 +/- 5.1 PD at 1 month, 4.3 +/- 4.3:3.0 +/- 8.1 PD at 3 months, and 5.0 +/- 4.3:4.5 +/- 7.2 PD at 6 months post-operation, and there was no statistically significant difference between the two study groups. Surgical success rate were 95.2:100% at one day, 95.2:92.9% at 1 month, 90.5:85.7% at 3 months, and 90.0:92.9% a 6 months post-operation. CONCLUSIONS: In patients with exotropia of 15 to 20 PD, no significant difference was found in terms of the postoperative deviation angle and the surgical success rate between the first operation and the second operation groups. Unilateral lateral rectus recession can lead to similar results in 15 to 20 PD exotropia for the first operation or recurrent exotropia.
Adolescent ; Child ; Child, Preschool ; Exotropia/physiopathology/*surgery ; Eye Movements/*physiology ; Female ; Follow-Up Studies ; Humans ; Male ; Oculomotor Muscles/physiopathology/*surgery ; Ophthalmologic Surgical Procedures/*methods ; Retrospective Studies ; Treatment Outcome

PURPOSE: To compare the outcomes of unilateral lateral rectus recession between the first operation and second operation for exotropia. METHODS: Thirty-two patients who underwent unilateral lateral rectus recession for exotropia of 15 to 20 prism diopters (PD) were investigated. The follow-up period was at least 6 months. We classified 17 patients without a surgical history for exotropia (first operation group) and 15 patients with a previous procedure (second operation group). Surgical success was defined as an exodeviation or esodeviation of less than 10 PD at the primary position. Postoperative deviation angles and success rates were compared between the two groups. RESULTS: There were no significant differences in the age, gender, visual acuity (logarithm of the minimal angle of resolution), preoperative deviation, and amount of recession between the two groups. Postoperative deviations were -1.7 +/- 5.5:1.3 +/- 5.1 PD at one day, 4.3 +/- 3.8:5.6 +/- 5.1 PD at 1 month, 4.3 +/- 4.3:3.0 +/- 8.1 PD at 3 months, and 5.0 +/- 4.3:4.5 +/- 7.2 PD at 6 months post-operation, and there was no statistically significant difference between the two study groups. Surgical success rate were 95.2:100% at one day, 95.2:92.9% at 1 month, 90.5:85.7% at 3 months, and 90.0:92.9% a 6 months post-operation. CONCLUSIONS: In patients with exotropia of 15 to 20 PD, no significant difference was found in terms of the postoperative deviation angle and the surgical success rate between the first operation and the second operation groups. Unilateral lateral rectus recession can lead to similar results in 15 to 20 PD exotropia for the first operation or recurrent exotropia.
Adolescent ; Child ; Child, Preschool ; Exotropia/physiopathology/*surgery ; Eye Movements/*physiology ; Female ; Follow-Up Studies ; Humans ; Male ; Oculomotor Muscles/physiopathology/*surgery ; Ophthalmologic Surgical Procedures/*methods ; Retrospective Studies ; Treatment Outcome