Postoperative stabilization of the strabismic angle in intermittent exotropia

Clinical factors affecting the rate of exodrift after surgery in patients with basic intermittent exotropia

We investigated the period of postoperative exodrift during follow-up and clinical factors that affect the rate of exodrift after surgery in the patients with intermittent exotropia (IXT). A retrospective review of medical records of patients with exodrift who underwent bilateral rectus recession for IXT was performed. Exodrift was defined as angle of deviation greater than 10 prism diopters (PD) at distance and near. The median survival period of postoperative exodrift was analyzed using Kaplan Meier survival analysis. The patients were divided into two groups according to the median period of postoperative exodrift (early and late group). The weighted Cox’s proportional hazards regression analysis to investigate the risk factors that affect rate of postoperative exodrift was performed. A total of 108 patients was included. The preoperative angle of deviation at distance and near were 30.3 ± 7.2 PD and 29.5 ± 8.6 PD, respectively. The median survival period of postoperative exodrift was 24 months (range, 6–48 months).The angle of deviation at postoperative day 1 in early and late group were − 3.8 ± 5.5 PD (range, − 16–8 PD) and − 7.7 ± 4.6 PD (range, − 16–4 PD) (p < 0.01). Minus value means esodeviation. In regression analysis, the angle of deviation at postoperative day 1 was the significantly related with rate of exodrift (p < 0.01). The median period of exodrift after surgery was 24 months, angle of deviation at postoperative day 1 could affect the rate of exodrift in patients with IXT.

Can Clinical Measures of Postoperative Binocular Function Predict the Long-Term Stability of Postoperative Alignment in Intermittent Exotropia?

Purpose

To evaluate whether clinical measures of postoperative binocular functions could predict the long-term stability of postoperative ocular alignment in children with intermittent exotropia.

Methods

A retrospective study was performed in thirty-nine children (median: 7 years) who have been surgically treated from intermittent exotropia without overcorrection (less than 10 prism diopters [pd] of exodeviation at 1 month postoperatively). Angles of deviation and binocular functions were measured preoperatively and at 1 month, 6 months, and the final follow-up visit (≥24 months) postoperatively. We examined the relationships between postoperative drift (change of ocular alignment) and binocular functions (sensory fusion, fusional convergence amplitude, and stereoacuity).

Results

The surgical success rate (esophoria/tropia ≤5 pd to exophoria/tropia ≤10 pd) dropped to 76.9% at 6 months after surgery and to 53.8% at individuals' last visit (mean: 37 months). The mean exodrift was 7.7 ± 9.2 pd from the postoperative month 1 to the final visit (p < 0.001) on distance fixation. Distance stereoacuity, central fusion, and fusional convergence amplitude significantly improved following surgery (p < 0.05). However, no significant correlation was found between their binocular functions measured at the beginning of each follow-up period and the postoperative drift (all p > 0.13).

Conclusion

Our findings suggest that the clinical measures of sensory fusion, fusional convergence amplitude, and stereoacuity cannot serve as a robust predictor for the long-term stability of postoperative ocular alignment in patients who underwent successful surgery without overcorrection at 1 month postoperatively.

The fast exodrift after the first surgical treatment of exotropia and its correlation with surgical outcome of second surgery

Background

To compare the rate of exodrift after a second surgery for recurrent exotropia, in patients grouped to fast versus slow exodrift after their first surgery. To determine whether there is a correlation with surgical outcome, and to evaluate the factors associated with fast exodrift.

Methods

Patients with recurrent intermittent exotropia, who underwent contralateral lateral rectus recession and medial rectus resection as the second surgery and were followed up for 24 months postoperatively between January 1991 and January 2013, were reviewed retrospectively. The patients were divided into two groups according to the rate of exodrift after the first surgery: Group F, patients exhibiting fast exodrift after the first surgery (> 10 prism diopters [PD] before postoperative month 6); and Group S, patients exhibiting slow exodrift after the first surgery (≤10 PD before postoperative month 6). The difference in the clinical course over the 24 months after the second surgery between the two groups and factors associated with fast exodrift were analyzed.

Results

In total, 106 patients with recurrent exotropia were enrolled in this study. Of these, 68 (64.2%) and 38 (35.8%) patients were included in group F and S, respectively. Group F showed more exodrift compared with groups S over the 24-month postoperative period; however, there was no significant difference in the clinical course between the two groups during that time (p = 0.54, repeated-measure ANOVA). In logistic analysis, immediate postoperative deviation after the first surgery was associated with fast exodrift (p <  0.001).

Conclusion

Although patients with recurrent exotropia had shown fast exodrift after the first surgery, no significant difference in the surgical outcome was observed after the second surgery according to the rate of exodrift after the first surgery.

The Stabilization of Postoperative Exo-drift in Intermittent Exotropia after Surgical Treatment

PURPOSE

To investigate the long-term clinical course of intermittent exotropia after surgical treatment to determine whether and when postoperative exo-drift stabilizes, and the required postsurgery follow-up duration in cases of intermittent exotropia.

METHODS

We retrospectively reviewed the medical records of patients diagnosed with intermittent exotropia who underwent surgical treatment between January 1992 and January 2006 at Yeungnam University Hospital and postoperatively performed regular follow-up examinations for up to 7 years. We also analyzed the difference in exo-drift stabilization, according to surgical procedure.

RESULTS

A total of 101 patients were enrolled in the study. Thirty-one patients underwent lateral rectus recession and medial rectus resection (R&R) and 70 patients underwent bilateral lateral rectus recession (BLR). The postoperative angles of deviation increased significantly during the initial 36 months, but no subsequent significant changes were observed for up to 84 months. Follow-ups for 7 years revealed that more than 50% of the total amount of exo-drift was observed within the first postoperative year. In addition, the angles of deviation at 1 year correlated with those at 7 years postoperatively (Pearson correlation coefficient r = 0.517, p < 0.001). No significant exo-drift was observed after 36 months in patients who underwent BLR, whereas after 18 months in patients who underwent R&R.

CONCLUSIONS

The minimum postoperative follow-up required after surgical treatment to ensure stable results is 36 months. In particular, careful follow-up is necessary during the first postoperative year to detect rapid exo-drift. Patients who underwent BLR required a longer follow-up than those who underwent R&R to ensure stable postoperative alignment.

Contact topical anesthesia versus general anaesthesia in strabismus surgery

OBJECTIVE

To evaluate the anesthetic block provided by contact topical anesthesia (CTA) in strabismus surgery in adult patients. To analyze postoperative pain and surgical outcome obtained by CTA compared with general anesthesia (GA).

METHODOLOGY

Prospective longitudinal cohort study of adult patients undergoing strabismus surgery by CTA or GA. The intensity of pain perceived by patients during the course of surgery and in the postoperative period was measured using Numerical Pain Scale. The success of the surgical outcome, considered as a residual ocular deviation<10 prism diopters, was evaluated.

RESULTS

Twenty-three patients were operated using CTA and 26 using AG. During the course of surgery, pain intensity experienced by patients in ATC group was 3.17±2.44. There were no differences between CTA group and AG group in the intensity of pain in the immediate postoperative period (2.13±2.39 vs. 2.77±2.18, respectively; P=.510) and during the first postoperative day (3.22±2.84 vs. 3.17±2.73; P=.923). Surgical success was significantly higher in the CTA group than in the GA group (78.3 vs. 73.1%; P=.019).

CONCLUSIONS

CTA provides adequate sensory block to perform strabismus surgery. The control of postoperative pain is similar to that obtained with AG. Conservation of ocular motility providing CTA enables better surgical outcome.

Improvement in fusion and stereopsis following surgery for intermittent exotropia

PURPOSE

To evaluate fusion stereopsis in patients with intermittent exotropia before and after strabismus surgery.

METHODS

Fifty-three patients (mean age: 11.8 years, range: 5 to 25 years) with intermittent exotropia were enrolled. Fusion was measured with the Worth 4-dot test. Near stereopsis was examined with Titmus and stereoscopic test charts (created in China by Shao-Ming Yan). Distance stereopsis was tested with random-dot stereograms produced by Tianjin Eye Hospital. All patients completed the tests preoperatively and 2 and 6 weeks postoperatively.

RESULTS

There were no statistically significant differences in stereoscopic test charts among groups preoperatively (P > .05) and postoperatively (P > .05) or on Titmus tests preoperatively (P > .05) and postoperatively (P > .05). Among 53 patients, the percentage of distance stereoscopic improvement was 49% after 2 weeks and 77% after 6 weeks compared to 13% preoperatively. Six weeks postoperatively, random-dot stereograms were significantly different in those younger than 7 years and older than 13 years (P < .05), as well as those 7 to 13 years and older than 13 years (P < .05). Fifty (94%) demonstrated peripheral fusion and only 21 (40%) demonstrated central fusion preoperatively. Six weeks postoperatively, all patients exhibited peripheral fusion and 52 (98%) demonstrated central fusion. Central fusion in patients with intermittent exotropia significantly increased after 6 weeks (chi-square = 42.29, P < .01).

CONCLUSIONS

Patients with intermittent exotropia have good near stereoacuity preoperatively and postoperatively. Even if surgery is postponed until adolescence, distance stereopsis can still be recovered. Surgical intervention can restore central fusion and stereoacuity in patients with intermittent exotropia.

Early postoperative alignment as a predictor of 6-month alignment after intermittent exotropia surgery

PURPOSE

The angle of postoperative deviation changes over time in patients undergoing surgery for intermittent exotropia. The aim of the current study was to assess the relationship between the motor alignment at 1 week and 6 months after exotropia surgery.

METHODS

The records of 81 patients who underwent surgery for intermittent exotropia from 2002 to 2012 at Imam Hussein Medical Center and had at least 6 months of postoperative follow-up were retrospectively reviewed. Each patient underwent complete eye examination and had surgery for orthophoria. Patients were divided into three groups according to their 1-week postoperative alignment (undercorrection [exotropia > 10 prism diopters (PD)], orthophoria [exotropia ≤ 10 PD and esotropia ≤ 5 PD], and overcorrection [esotropia > 5 PD]).

RESULTS

The postoperative success rates for 1 week and 6 months were 75.3% and 76.5% respectively. Of 61 orthophoric, 13 undercorrected, and 7 overcorrected patients at 1 week postoperatively, 51 (83.6%), 7 (53.8%), and 2 (28.6%) patients, respectively, preserved their initial alignment at 6 months (P = .024 for orthophoria). The type of surgery had no effect on the results at 6 months. Reoperation was needed in 10 (12.3%) of our patients at the 6-month follow-up (7 undercorrected and 3 orthophoric patients).

CONCLUSIONS

Early postoperative alignment of intermittent exotropia at 1 week can be considered a predictor of orthophoria at 6 months, whereas fewer cases in other groups made predicting their alignment at 6 months statistically difficult. Reoperation was needed in 12.3% of cases at the 6-month follow-up.

Factors associated with the angle of exodeviation in patients with recurrent exotropia

AIMS

To compare preoperative and postoperative distance deviation angle in recurrent exotropes, and to determine factors associated with large-angle recurrent exotropia.

METHODS

In recurrent exotropes who were followed-up more than 2 years postoperatively, the largest angle after recurrence (LAAR) was compared with the preoperative deviation angle (PA). Patients were classified into those who had LAAR<PA and LAAR≥PA. Differences in clinical factors between groups were examined.

RESULTS

Among 242 exotropes who underwent surgery, and followed-up for more than 2 years postoperatively, 83 showed recurrent exotropia. Mean age at surgery was 5.7 ± 2.4 years, and mean postoperative follow-up was 36.2 ± 11.3 months. The bigger the preoperative angle, the bigger the angle of recurrence is. However, the smaller the preoperative angle, the angle of recurrence grows closer to the preoperative one. Only six showed bigger recurrence (LAAR≥PA), and these patients had a smaller mean preoperative angle (p=0.01) compared to patients whose angle of recurrence was smaller than the preoperative one. Among the patients with LAAR<PA, type of exotropia (p=0.03) and preoperative constant deviation (p=0.02) was associated with PA-LAAR≤5(Δ).

CONCLUSIONS

Although the overall incidence of recurrent exotropia with a relatively large angle (LAAR≥PA) is low among patients who underwent surgery for exotropia (2.5%), the possibility of this phenomenon should be noted. The ratio of relatively large angle recurrence was higher in patients with a small preoperative exodeviation and basic type exotropia.