Predictive factors affecting the short term and long term exodrift in patients with intermittent exotropia after bilateral rectus muscle recession and its effect on surgical outcome.

PURPOSE: To determine the predictive factors that affect short term and long term postoperative drift in intermittent exotropia after bilateral lateral rectus recession and to evaluate its effect on surgical outcome. METHODS: Retrospective review of 203 patients with diagnosis of intermittent exotropia, who had surgical corrections with more than 3 years of followup. Different preoperative parameters were obtained and evaluated using Pearson's correlation analysis. RESULTS: The proportion of exodrift increased from 62% at 6 weeks to 84% at 3 years postoperatively. The postoperative drift was 4.3 ± 8.1 PD at 6 weeks, 5.8 ± 8.4 PD at 6 months, 7.2 ± 8.3 PD at 1 year, 7.4 ± 8.4 PD at 2 years, and 7.7 ± 8.5 PD at 3 years. Preoperative deviation and initial overcorrection were significant factors affecting the postoperative drift at 3 years (r = 0.177, P = 0.011, r = -0.349, and P < 0.001, resp.). CONCLUSIONS: Postoperative exodrift along three years occurs in a majority of patients after bilateral lateral rectus recession for intermittent exotropia. The long term surgical success is significantly affected by this postoperative exodrift. A larger preoperative deviation and a larger initial overcorrection are associated with a larger early and late postoperative exodrift.

A prospective study of fusional convergence parameters in Chinese patients with intermittent exotropia.

PURPOSE: To evaluate the correlation between different fusional convergence parameters and the Newcastle Control Score (NCS) in children with intermittent exotropia. METHODS: In this consecutive prospective observational series, 101 Chinese children with intermittent exotropia were examined by a single observer, who assessed the level of control using the revised NCS and measured the angle of deviation and fusional convergence. Levels of control were defined according to the NCS as good (0-3), moderate (4-6), or poor (7-9). The correlation between the different fusional convergence parameters and the NCS was evaluated. RESULTS: The total convergence amplitude was similar among the different control groups (P = 0.288 and P = 0.628 at near and at distance, respectively). The convergence reserve was higher in the good control group compared with the moderate and poor control groups, both at near (P = 0.001) and at distance (P = 0.001). Among all fusional convergence parameters, we determined that the fusional reserve ratio had strongest correlation with control (near ratio: r = -0.66, P = 0.001; distant ratio: r = -0.59, P = 0.001). Among patients with a fusional reserve ratio ≥ 2 at distance, 100% (5 of 5 patients) of these patients demonstrated good control (NCS ≤ 3). CONCLUSIONS: In children with intermittent exotropia, the total convergence amplitude was similar among different levels of control. The convergence reserve was lower in the poor control group. Fusional reserve ratio ≥ 2 was an indicator of good control in patients.

Prognostic factors predicting the surgical outcome of bilateral lateral rectus recession surgery for patients with infantile exotropia.

PURPOSE: To determine the presurgery factors affecting early and long-term favorable outcomes of bilateral lateral rectus recession surgery for infantile exotropia. PATIENTS AND METHODS: A retrospective study of 50 patients with infantile exotropia (both constant-type and intermittent-type exotropia with onset before 1 year of age) who had bilateral lateral rectus recession surgery correction with more than 1 year follow up. Presurgery data were obtained and evaluated by use of multiple regression analysis. RESULTS: Smaller presurgery distance deviation (p = 0.042), older age at surgery (p = 0.025), longer interval between onset and surgery (p = 0.020), and more myopic refractive error (p = 0.007) were associated with successful outcome at 6 weeks, but none was correlated with successful outcome at 1 year. Among all data, presurgery distance deviation was the only significant determinant (multiple regression analysis, p = 0.021) for successful outcome at 6 weeks. Presurgery distance deviation (ß = 0.952, p < 0.001) was correlated with the distant angle of deviation 6 weeks (ß = 0.952, p < 0.001) and 1 year (ß = 0.394, p = 0.006) postsurgery. CONCLUSIONS: Smaller presurgery deviation was found to be associated with more favorable surgical outcome.

Preoperative factors predicting the surgical response of bilateral lateral rectus recession surgery in patients with infantile exotropia.

PURPOSE: To determine the preoperative factors affecting the efficacy in bilateral lateral rectus recession surgery for infantile exotropia. METHODS: This was a retrospective study of 50 patients with infantile exotropia who had bilateral lateral rectus recession surgery correction with more than 1 year of follow-up. Preoperative parameters influencing the response of the surgery were obtained and evaluated using multiple regression analysis including age at onset, age at surgery, interval between onset and surgery, preoperative deviation, refractive error, anisometropia, amount of surgery performed, presence of A- or V-pattern, and preoperative phase of exotropia. The response to surgery was defined as the change in deviation divided by the amount of the surgery. RESULTS: Thirty-two (64%) and 24 (48%) patients had successful outcome at 6 weeks and 1 year postoperatively, respectively. The mean response to surgery was 1.79 ± 0.63 prism diopters (PD)/mm recession at 6 weeks and 1.58 ± 0.75 PD/mm recession at 1 year postoperatively. Exotropic drift was 5.12 ± 7.27 PD at 6 weeks and 8.02 ± 6.81 PD at 1 year postoperatively. Pre-operative deviation was correlated with the response of surgery at 6 weeks (ß = 0.342, P = .020) and 1 year (ß = 0.391, P = .007) postoperatively. CONCLUSIONS: Surgical response decreases over time due to the exotropic drift. Larger preoperative distance deviation was associated with larger surgical response. Both the exotropic drift and the preoperative deviation should be considered in applying the surgical dose in infantile exotropia.

Long-term ocular alignment after bilateral lateral rectus recession in children with infantile and intermittent exotropia.

PURPOSE: To compare postoperative drift after bilateral lateral rectus recession for infantile exotropia (XT) and for intermittent XT and to compare initial postoperative alignment with long-term motor outcome. METHODS: Medical records of all patients with infantile exotropia or intermittent exotropia who had undergone bilateral lateral rectus muscle recession surgery with a follow-up longer than 3 years were reviewed. The pre- and postoperative angles of deviation at distance and at near and postoperative drift at distance were compared. Surgical outcome was categorized as "success" (esotropia <6(Δ) or exotropia <11(Δ)), "recurrence" (>10(Δ) exotropia), or "overcorrection" (>5(Δ) of esotropia). RESULTS: The overall mean postoperative exotropic drift at 3 years was 10.4(Δ) in the infantile XT group and 7.2(Δ) in the intermittent XT group (P = 0.05). Both groups had a low success rate at 3 years: 41% in the infantile XT group and 51% in the intermittent XT group (P = 0.270). For patients with an initial esotropia of 0(Δ) to 10(Δ), the success rate at 3 years was 86% in the infantile XT group (12 of 14) and 65% in the intermittent XT group (28 of 43). CONCLUSIONS: Postoperative exotropic drift is clinically similar in patients with intermittent versus infantile exotropia. Esotropia of 0(Δ) to 10(Δ) during the early postoperative period may be associated with the best long-term ocular alignment.

Refractive changes after pediatric intraocular lens implantation in Hong Kong children.

PURPOSE: To report the refractive changes after cataract surgery and intraocular lens (IOL) implantation in Hong Kong Chinese children. METHODS: The clinical records of all patients who had cataract extraction and IOL implantation before age 18 years and with more than 2 years of follow-up were studied retrospectively. The refractive errors of all patients determined by cycloplegic refraction at 6 weeks, 3 months, 6 months, and 1 year postoperatively and then annually thereafter were included for analysis. Patients were stratified into groups according to their age at IOL implantation for analysis. RESULTS: Twenty-six eyes (81.3%) had developmental cataracts, 3 eyes (9.4%) had traumatic cataracts, and 3 eyes (9.4%) were iatrogenic (from surgical or medical treatment). Patients demonstrated a mean myopic shift (diopters) of -5.53 (0 to 2 years old) -4.68 (3 to 5 years old), -2.60 (6 to 8 years old), -0.42 (9 to 11 years), and -0.09 (> 11 years). There was no significant difference in myopic shift between eyes that were operated on and those that were not. No statistically significant differences in refractive change were found in comparing males to females, unilateral to bilateral cases, traumatic to non-traumatic cases, amblyopic to nonamblyopic eyes, primary to secondary intraocular lenses, or polymethylmethacrylate to acrylic IOLs. CONCLUSION: The postoperative myopic shift in pediatric patients undergoing IOL implantation is greatest in the younger age groups and persists until at least 8 years of age. The mean rate of myopic shift also decreases with age. The refractive development of the pseudophakic eyes was not significantly different from the fellow phakic eyes.

Exotropic drift and ocular alignment after surgical correction for intermittent exotropia.

PURPOSE: To evaluate changes in the angle of deviation over time and compare the motor success rate with different initial postoperative deviation in patients undergoing surgical correction for intermittent exotropia. METHODS: Forty-eight patients aged between 1 and 10 years who underwent bilateral lateral rectus recession for intermittent exotropia were retrospectively evaluated. Preoperative and postoperative ocular deviations at 1 week, 1 month, and 6 months were analyzed. Full surgical correction was attempted in all patients. Motor success was defined as ocular deviation within 10 prism diopters of orthophoria at 6 months postoperatively. RESULTS: The follow-up period ranged from 6 months to 3 years. Although most patients had exotropic drift, this drift was greater in patients with initial esotropia (86.7%) and orthophoria (70.0%) compared to patients with exotropia (26.1%). Motor success was achieved in 29 (60.4%) patients. There was no statistical difference between ocular alignment at 1 week postoperatively and final motor success (P = .782). There was good correlation between ocular alignment at 1 week and 6 months postoperatively (rho = 0.585, P < .001). Age and preoperative deviation were not found to be associated with motor success. CONCLUSIONS: The success rate appears to be unaffected by initial ocular alignment, suggesting that deliberate initial overcorrection may be unnecessary. Future studies are warranted to evaluate the long-term stability of this alignment.