Superior oblique palsy （SOP） is a common ocular torticollis disease， and the surgical treatment should be performed early to avoid affecting the patient′s facial and skeletal development. In the clinical development process， SOP can gradually become common strabismus. The clinical classifications of SOP can be divided into congenital and acquired， unilateral and bilateral. According to different clinical manifestations， SOP can further be subdivided into 7 types. Therefore， the surgical treatment for SOP is not only to strengthen the superior oblique muscle， but also to choose the best individualized therapeutic plan to improve the patient's strabismus and head position， based on the clinical development process， classification， and clinical type of SOP.

Objective To evaluate the long term effect of corrective surgery in adult strabismic patients with visual impairment； to study the stability of postoperative alignment and factors that influence it. Methods This was a retrospective clinically controlled study of the alignment， binocular vision， ocular movement and quality of life in 72 adult strabismic patients with visual impairment （BCVA less than 0.3 in one or both eyes）. These patients were compared to 79 patients without visual impairment. Data were analyzed using an independent samples t test， χ² test， rank sum test and logisitic regression analysis. Results There was no significant difference in the success rate between the two groups within 2 years after surgery （χ2=1.97， P>0.05）. Forty-eight （67%， 48/72） and sixty-six （84%， 66/79） were defined as ″successful″ at the last follow-up in the visually impaired group and control group， respectively. The difference was significant（χ2=6.14， P<0.05）. Of the 24 patients defined as ″not successful″ in the visually impaired group， 22 cases were under-corrected and 2 cases were over-corrected. Three patients and 34 patients achieved normal or partial stereoacuity in the visually impaired and control groups， respectively. The difference in stereoacuity between the two groups was significant （χ2=31.34， P＜0.01）. The scores from the quality of life questionnaire were lower in the visually impaired group than in the control group （t=-3.30， -3.72， -3.77， P＜0.01）. Conclusion Approximately two in three patients with visual impairment can achieve long-term successful outcomes with corrective surgery. However， alignment stability， binocular vision and quality of life were worse in patients with visual impairment than in those without visual impairment.

Objective To use superior rectus transposition （SRT） with adjustable medial rectus muscle recession for the treatment of sixth nerve palsy. Methods This was a retrospective clinical study. Eleven patients with sixth nerve palsy who underwent SRT in Tianjin Eye Hospital or the First People′s Hospital of Xuzhou were reviewed. The pre- and postoperative outcomes were compared and included the deviation angle of esotropia in the primary position， the head turn angle， and the limit of abduction. In the 11 cases， 8 patients had a medial rectus recession. Adjustable suture medial rectus recession was used to identify the proper positions. The average follow-up time was more than 6 months. Preoperative and postoperative first angle， angle of the compensatory head turn， limited extent of inside and outside duction were compared with a paired t test. Results Postoperatively， 10 patients showed orthophoria in the primary position and improved compensatory head turn. The patients were satisfied that there was no diplopia. One patient required a second surgery for under-correction. Compensatory head turn and diplopia were corrected after inferior rectus temporal transposition. In the 11 patients， esotropia improved from 31.2°±13.7° to 3.4°±1.7° （t=7.28， P<0.01）； compensatory head turn improved from 26.1°±7.7° to 0.9°±3.0° （t=10.75， P<0.01）； the abduction limit decreased from -4.8±0.9 to -2.0±0.9 （t=8.84， P<0.01） while the adduction limit increased from -0.2±0.4 to -1.0±0.4 （t=4.62， P<0.05）. No new vertical or torsional deviation was observed in any of the 11 patients. Conclusion Superior rectus transposition with medial rectus recession can be performed during the same surgery， avoiding the risk of anterior segment ischemia. SRT does not induce new vertical or torsional strabismus. Therefore， SRT with medial rectus recession is an effective approach to treat sixth nerve palsy.

Objective To evaluate the effect of strabismus surgery on the quality of life in strabismus patients. Methods From November 2013 to September 2014， 89 strabismus patients at West China Hospital were evaluated with an Adult Strabismus （AS-20） test and were followed up for （83.6±34.0）days. The difference between pre- and postoperative scores was analyzed using the AS-20 test and its subscales （psychosocial and functional）. The influence of age， gender， deviation type， and the existence or non-existence of binocular vision were compared using independent samples t test， rank sum test， Spearman test. Results The preoperative AS-20 total score was 50.3±18.5 and was significantly higher at 80.8±20.6 postoperatively （t=9.975， P<0.01）. Females had a lower preoperative AS-20 total score but had greater improvement compared to males （tpre=2.050， tchange=-2.593， P<0.05）. Patients with esotropia and exotropia （tpre=-0.480， tpost=0.237， tchange=1.495， P>0.05） and the existence of binocular vision （tpre=0.446， tpost=0.498， P>0.05） did not show a statistically significant difference in the AS-20 total scores or a change in AS-20 scores. There was no correlation between age and the change in AS-20 scores （r=0.021， P>0.05）. Conclusion Strabismus surgery resulted in a highly significant improvement in quality-of-life scores. Females had a lower quality-of-life preoperatively but had a greater benefit. There was no relationship between the deviation type， age， or the existence or non-existence of binocular vision and the AS-20 scores.

Objective To investigate the effect of a modified Yokoyama′s technique in the treatment of fixus strabismus with high myopia. Methods A retrospective analysis was conducted on the medical records of 8 eyes of 6 patients with myopic fixus esotropia who underwent the modified Yokoyama′s surgery between 2011 and 2014. The location of the extraocular muscles was investigated with CT scan. Ocular alignment and motility in the nine diagnostic gaze positions were evaluated pre- and postoperatively. A forced duction test was also performed during the operation. Modified Yokoyama′s surgery and the medial rectus muscle recession were performed to correct eye position. Results The scans showed that the position of the extraocular muscles had changed， and restricted abduction and elevation were detected by the forced duction test in the affected eye before surgery. The modified Yokoyama′s surgery was successfully performed on eight eyes of six patients with fixus myopic esotropia. Orthotropia in the primary gaze position was achieved in all operative eyes after 6 months of follow-up. Complications of anterior segment ischemia did not occur. Conclusion The modification of Yokoyama′s technique is a good surgical choice for treatment of myopic fixus esotropia.

Objective To investigate the optimal timing for surgery in early-onset exotropia （XT） and the long-term postoperative effect. Methods One hundred eleven cases diagnosed with XT before 3 years old who were followed up for at least 2 years after surgery were retrospectively analyzed. Logistic regression was used to study the possible factors of the postoperative orthotropia rate and postoperative synoptophore/Titmus stereopsis， such as the age of onset， age at surgery， the type of strabismus， preoperative synoptophore/Titmus stereopsis and postoperative eye position. Results Based on a chi-square test and Spearman correlation analysis， classification of intermittent and constant XT had a statistically significant correlation with the rate of long-term orthotropia （χ²=4.125， P<0.05）. Classification of intermittent and constant XT （χ²=3.951， P<0.05） and the postoperative orthotropia （χ²=4.269， P<0.05） had a statistically significant correlation to postoperative synoptophore stereopsis. Classification of intermittent and constant XT had a statistically significant correlation to postoperative Titmus stereopsis （χ²=6.988， P<0.01）. Logistic regression analysis showed that the classification of intermittent and constant XT was the main factor affecting the long-term orthotropia rate （OR=0.445， P<0.05）. Preoperative synoptophore stereopsis was the main factor affecting postoperative synoptophore stereopsis （OR=10.500， P<0.01）. Preoperative Titmus stereopsis and the classification of intermittent and constant XT were the factors affecting postoperative Titmus stereopsis （OR=11.480， 0.175， P<0.05）. Conclusion It is suggested that patients with early-onset XT undergo surgery before the loss of binocular vision function. The loss of stereopsis function and the loss of the ability to control deviation were indications for exotropia surgery.

Objective To compare the outcomes of surgery for exotropia and surgery for exotropia combined with an inferior oblique muscle weakening procedure in children and adolescents. Methods In a retrospective study， 179 cases of the children underwent conventional horizontal muscle surgery for exotropia from August 2009 to September 2011 were included. All children were divided into two groups based on whether or not they underwent an inferior oblique weakening procedure： group A included 48 patients who underwent surgery for exotropia combined with an inferior oblique weakening procedure， and group B included 131 patients who were only treated with surgery for exotropia. The success rates of alignment， overcorrection， and under-correction were compared between the 2 groups at postoperative days 1 to 3 and then at the final follow-up （a minimum of 6 months）. Enumeration data were analyzed with a χ2 test， measurement data were analyzed with an independent samples t test. Results At postoperative days 1 to 3， the success rates of alignment were 73% and 72%， the over-correction rates were 23% and 21%， and the under-correction rates were 4% and 6% in groups A and B， respectively （χ2=0.276， P＞0.05）. At the final follow-up， the success rates of alignment were 62% and 69%， the over-correction rates were 6% and 5%， and the under-correction rates were 31% and 26% in groups A and B， respectively （χ2=0.807， P＞0.05）. There was no significant difference in surgical outcomes between groups A and B at postoperative days 1 to 3 and at the final follow-up. Conclusion The inferior oblique muscle weakening procedure might have no significant effect on surgical alignment in children with exotropia. Eye surgeons may not need to change the conventional parameters of muscle strabismus surgery for horizontal exodeviations when inferior oblique muscle weakening procedures are simultaneously performed.

Objective To further refine the Chinese Adult Strabismus-20 （CAS-20） health-related quality of life（HRQOL） questionnaire using Rasch analysis. Methods In this cross-sectional study， the CAS-20 questionnaire was independently completed by 246 adult strabismus patients. Based on the score for each item， Rasch analysis was performed on the original CAS-20 using the following aspects： dimensionality， response order， local dependence， infit and outfit analysis， differential item function， subject targeting and confirmatory dimensionality. Results The original CAS-20 was divided into 4 subscales， which were labeled ″self-perception″， ″interaction″， ″reading function″， and ″general function″. Response ordering was appropriate for all of the 4 subscales. As a result of infit and outfit analysis， 3 items were removed， one each from ″self-perception″， ″reading function″， and ″general function″. No significant differential item function was found for sex or age. Compared with the ability of the patients and item difficulty， the 3 subscales matched well except for ″reading function″. Conclusion The original CAS-20 was reduced to 17 items， and divided into 4 subscales， which were ″self-perception″， ″interaction″， ″reading function″， and ″general function″. Subject response choices saved 5 test options. The refined CAS-20 may prove to be more responsive to HRQOL changes in adult strabismus patients.

Objective To explore the influence of head tilt on fovea-disc angle （FDA）. Methods This was a self-controlled study. 3D OCT-1000 was used to take fundus photos for 26 non-strabismus subjects （52 eyes） at entopic position， head to the right at 30° and head to the left at 30° respectively. CorelDRAW X4 drawing software was used to measure the FDA values in these photos. The data were analyzed using t test， analysis of variance and linear regression. Results FDA values： the differences in right eye among head to the right （13.53°±3.36°）， entopic position （6.56°±2.28°） and head to the left （-0.53°±3.88°） had statistical significance （F=115.866， P<0.05）. The FDA value of head to the right was significantly higher than that of the entopic position （P<0.05）， while the FDA value of the entopic position was significantly higher than head to the left （P<0.05）. The differences in left eye between head to the right （1.08°±3.31°）， entopic position （7.31°±2.80°） and head to the left （13.45°±3.44°） had statistical significance （F=98.437， P<0.05）. The FDA value of head to the right was significantly lower than that of the entopic position （P<0.05）， while the FDA value of the entopic position was significantly lower than head to the left （P<0.05）. There were no significant differences between the FDA values of different genders （t=0.906， P>0.05）. The FDA values were not correlated with age （r=0.001， P>0.05）. Conclusion Head tilt has a significant influence on fovea-disc angle. In clinical practice， when fundus photography is used to evaluate the fundus rotation of patients， attention should be paid to the placement of head.

Objective To observe cortial activation areas in comitant strabismus patients in response to different disparity stereogram stimuli and to compare average activation voxels in comitant strabismus patients and normal subjects. Methods This was a case series study. Twelve subjects （mean age 16.9±3.9 years） with comitant strabismus and 10 healthy volunteers （mean age 21.2±2.7 years） were enrolled. The experiment was a block design. Three uncrossed disparity （1 200″， 2 400″ and 3 600″） random-dot stereograms （RDS） were presented during the on-stimulus phase， and a black cross line fixed in the center of a white screen was displayed during the off- stimulus phase. Functional MRI data were processed with the statistical parametric mapping 5 software and t test. Results During the disparity of 1 200″ RDS stimulus， the right inferior occipital gyrus and left middle occipital gyrus （BA18） showed activation in the healthy group， and the left middle occipital gyrus （BA18） showed activation in the strabismus group. During the disparity of 2 400″ RDS stimulus， and bilateral middle occipital gyruses （BA18） and the right inferior temporal gyrus （BA37） showed activation in the healthy group， and bilateral middle occipital gyruses （BA18） showed activation in the strabismus group. During the disparity of 3 600″ RDS stimulus， bilateral middle occipital gyruses （BA18） showed activation in the healthy group， but no significant activation area was observed in the strabismus group. Under three different disparity stimuli， the average activation voxels in the comitant strabismus group were significantly lower than in the healthy group （t=-3.16， -3.38， -2.47， P<0.05）. Conclusion During RDS stimuli， bilateral occipital lobes showed activation in comitant strabismus and normal subjects. In addition， the right temporal lobe showed activation in the healthy subjects. Under different disparity stimuli， average activation voxels in comitant strabismus patients are lower than in healthy subjects.

Objective To investigate the changes in the characteristics of anisometropia and stereopsis recovery in patients with refractive accommodative esotropia after receiving a refractive correction. Methods In this retrospective study， all patients with refractive accommodative esotropia with complete medical records were divided into groups based on the initial power of anisometropia [low （anisometropia≤1.0 D）， moderate （1.0 D<anisometropia<2.5 D） or high （anisometropia≥2.5 D）] and initial visual acuity （binocular vision balance or the amblyopic eye）. An independent samples t test， mixed linear model analysis and chi-square test was used for statistical analysis. Results After 6.8±2.8 years follow-up， 87（82.1%） patients had a lower degree of anisometropia， 14（13.2%） patients had a moderate degree of anisometropia， and 5（4.7%） patients had a high degree of anisometropia. ①The effect of the refractive correction on the initial binocular visual acuity showed a statistically significant improvement （t=9.787， P<0.05）； ②The influence of the initial degree of anisometropia on stereopsis recovery was statistically significant （χ2=18.785， P<0.01）； ③After wearing glasses， a decrease in the trend of the spherical equivalent was observed in the three anisometropia groups（F=142.913， P<0.01）. Conclusion In this study， a higher initial degree of anisometropia is correlated with a lower initial visual acuity and a poorer subsequent stereopsis. With an increase in the amount of time glasses are worn， the initial states of anisometropia tend to change toward a more balanced refraction.