Meta-analysis of unilateral resection-recession versus plication-recession for exotropia / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To compare the effectiveness of unilateral lateral rectus recession-medial rectus resection(RR))and lateral rectus recession-medial rectus plication(RP)in the treatment of exotropia. METHODS: Evidence-based medicine research. A systematic database search was conducted Medline, Embase, Web of Science, the Cochrane Register of Controlled Trials and so on from August 2011 to August 2021. Related studies meeting the inclusion criteria were included in our study. The main outcome measures were as follows: success rate and postoperative deviation. Mean difference(MD)and odds ratio(OR)with 95% confidence interval(CI)were statistical analyzed as measurement data and continuous variables statistics. RESULTS: A total of two randomized controlled studies and five retrospective studies were included. The Meta-analysis results showed that the success rate of surgery was similar for RP group compared with RR group(OR=0.65, 95%CI:0.39-1.07, P=0.09). There was no difference in the incidence of poor postoperative prognosis of the two groups(the undercorrection and overcorrection rates)(OR=1.59; 95%CI: 0.92-2.74, P=0.10; OR=4.43; 95%CI: 0.69-28.18, P=0.12). There were no significant differences in postoperative deviation and the amount of external oblique drift(MD=0.75, 95%CI: -0.27-1.76, P=0.15; MD=-0.34, 95%CI: -1.30-0.63, P=0.50). CONCLUSION: The success rate of RP and RR surgery is close to the incidence of poor postoperative prognosis, moreover, there was no significant difference between the deviation and the amount of external oblique drift after the two surgeries, RP is an effective surgical procedure for the treatment of exotropia.

Surgical Outcomes of Modified Medial Rectus Resections in Recurrent Intermittent Exotropia

PURPOSE: To evaluate the outcomes of modified medial rectus (MR) resection using a lowered amount of MR resection for recurrent exotropia after bilateral lateral rectus (LR) recessions. METHODS: Fifty-six patients, who underwent MR resection from 2003 to 2017 for recurrent exotropia after bilateral LR recessions, were included. MR resection was performed using modified MR resection with a smaller amount of resection than the standard of 4 mm resection at 20 prism diopters (PD) of exotropia. Postoperative surgical results at 1 month, 6 months, 1 year and 2 years were classified as a success (5 PD esotropia [ET]-10 PD exotropia [XT]), overcorrection (>5 PD ET), and undercorrection (>10 PD XT). The clinical factors affecting surgical results at postoperative 6 month and 2 years were also evaluated. RESULTS: The success rate was 78.2% at postoperative 1 month and 87.5% at postoperative 6 months. The overcorrection rate was 21.8% and the undercorrection rate was 0% at postoperative 1 month. At postoperative 6 months, the overcorrection rate decreased to 0% and the undercorrection rate was 12.5%. The success rate was 85.7% at postoperative 1 year and 66.6% at postoperative 2 years. There was no clinical factor affecting the surgical outcomes except the ocular alignment at postoperative 1 month. The deviation at postoperative 1 month was more esotropic in patients with success at postoperative 6 months and 2 years than that in patients with undercorrection (p < 0.05). CONCLUSIONS: The modified MR resection showed favorable results of 87.5% at postoperative 6 months and 85.7% at 1 year. The angle of deviation at postoperative 1 month was an indicator of subsequent surgical outcomes.

The Effect of Bilateral Medial Rectus Resection for Recurrent Intermittent Exotropia

PURPOSE: The purpose of this study was to investigate the effect of bilateral medial rectus muscle resection on the treatment of recurrent intermittent exotropia. METHODS: A retrospective chart analysis was conducted for 25 patients who underwent bilateral medial rectus resection for recurrent exotropia over 20 prism diopters (PD) between January 2009 and August 2015. The medial rectus was resected from 4.0 to 6.5 mm by 0.5 mm according to the deviation angle. The postoperative angle of deviation was checked at 1 day, 1 week, 3 months, 6 months, and 1 year postoperatively to investigate the amount of corrected deviation per resected muscle. RESULTS: The average preoperative deviation angle was 27.20 ± 5.02 PD exodeviation and the mean resection was 5.10 ± 0.79 mm of the medial rectus. The postoperative angle deviation was 10.68 ± 5.50 PD esodeviation at 1 day. The incidence of esodeviation tended to decrease over time. At 1 year, the postoperative angle deviation was 1.16 ± 7.54 PD esodeviation. The overcorrection rate was 84% at 1 day postoperatively but decreased to 24% at 1 year with a success rate of 68%. The corrected deviation angle per millimeter was 7.53 ± 1.22, 7.75 ± 2.16, 6.27 ± 1.74, 5.50 ± 1.54, and 5.56 ± 1.58 PD/mm at 1 day, 1 week, 3 months, 6 months, and 1 year after surgery, respectively. The dose effect per millimeter decreased over time. The corrected deviated angle per millimeter remained constant regardless of the amount of medial rectus muscle resection at 1 year postoperatively(p=0.939). CONCLUSIONS: Bilateral medial rectus resection for recurrent exotropia over 20 PD tended to overcorrect at first; however, after 1 year, the mean angle of deviation was 1.16 ± 7.54 PD esodeviation. Bilateral medial rectus resection is an effective surgical method for the treatment of recurrent exotropia over 20 PD.

Efficacy of unilateral medial rectus resection in children with residual and recurrent exotropia / 国际眼科杂志(Guoji Yanke Zazhi)

AIM:To investigate the efficacy of unilateral medial rectus resection in children with residual and recurrent exotropia and analyze the influence of difference types of strabismus and methods of primary surgery on the surgical outcome.METHODS:This investigation was a retrospective case series study that examined data from 48 pediatric patients (48 eyes) who underwent unilateral medial rectus resection between January 2009 and February 2013 for residual and recurrent exotropia.We surveyed the outcome of eye alignment,lateral incomitance,fusion function,stereoacuity in children at 1d,6wk and at last follow-up of 6-32 (mean 11.99± 7.06) mo after the surgery.RESULTS:At 1d after the surgery,the rate of surgical success was 83％ (40/48),and the rate of undercorrection and overcorrection was 4％ (2/48) and 13％(6/48),respectively.At 6wk after the surgery,the rate of surgical success was 81％ (39/48),and the rate of undercorrection and overcorrection was 13％ (6/48) and 6％ (3/48),respectively.At the final follow-up of 6-32 (mean 11.99±7.06) mo,the surgical success rate was 75％ (36/48),and the rate of undercorrection was 25％ (12/48).No patient exhibited overcorrection.There were no significant differences in the surgical success rate either among pediatric patients who had previously undergone different types of surgery or among patients who had been diagnosed with different types of exotropia (P=0.168 and P=0.50,respectively).No patients presented with lateral incomitance or limited ocular motility.CONCLUSION:Unilateral medial rectus resection is a safe and effective surgical approach for treating in children with residual and recurrent exotropia.In addition,it may achieve the same surgical effectiveness regardless of the patients' previous surgical procedures or types of exotropia.

Surgical Outcome of Sensory Exotropia with Distant-Near Disparity

PURPOSE: To assess clinical features of sensory exotropia with distant-near disparity, surgical outcome, and compare according to amount of medical rectus resection. METHODS: Authors retrospectively reviewed medical records of patients of sensory exotropia with follow-up over 6 months. We defined patients with over 10 prism diopter (PD) disparity as distant-near disparity sensory exotropia (DND-XT) and without disparity as basic sensory exotropia (B-XT). First, we analyzed and compared data of visual acuity, cause and age of visual loss, amount of deviation. Second, Surgical failure was analyzed with dividing DND-XT into conventional surgery group as Parks' formula and reduced medial rectus resection group in accordance with disparity. Surgical success was defined as less than 10 PD deviation in distant, near fixation. RESULTS: B-XT consisted of 58 patients (40 males) and DND-XT of 33 patient (13 males). There was no significant difference between 2 groups in onset and cause of visual loss, deviation at distant fixation. But, log MAR visual acuity of worse eye was better in DND-XT than B-XT (1.74 +/- 0.78, vs. 2.10 +/- 0.74, p = 0.039). Average deviation in distant fixation in DND-XT was 46.55 +/- 16.59 PD in distant and 14.93 +/- 8.91 PD in near fixation. All patients underwent surgery of medial rectus resection and lateral rectus recession and average deviation was 6.83 +/- 7.71 PD at distant fixation, 3.02 +/- 0.69 PD at near fixation at last follow-up. Among 33 patients, 16 patients underwent conventional amount of surgery and 17 patients with reduced medial rectus resection. In patient with conventional surgery, 9 patients were surgical failure (8 patients of over-, 1 patient of under-correction) but in patient with reduced amount of resection, only 1 patient was under-correction. CONCLUSIONS: As a result of medial rectus resection and lateral rectus recession in DND-XT, more surgical failures due to over-correction were observed with conventional resection and higher surgical success was attained in consideration of disparity.

Dose-Effect Relationship of Unilateral Medial Rectus Resection for Recurrent Exotropia

PURPOSE: To investigate the dose-effect relationship of unilateral medial rectus resection for recurrent exotropia after bilateral lateral rectus recession. METHODS: This study comprised 39 patients who underwent unilateral medial rectus resection for recurrent exotropia under 25 PD and bilateral rectus recession for prior surgery of exotropia. The medial rectus was resected from 5.0 to 7.0 mm according to angle deviation at a distance. The postoperative deviated angle was checked at one week, 3 months and 6 months postoperatively to investigate the amount of corrected deviation per resected muscle. RESULTS: The average preoperative deviation was 21.33 +/- 2.96 PD. We resected mean 6.26 +/- 0.57 mm of the medial rectus muscle. The postoperative deviated angle was 0.82 +/- 3.47, 1.87 +/- 3.10 and 5.40 +/- 4.79 PD at 1 week, 3 months and 6 months after surgery, respectively. The corrected deviated angle per millimeter (mm) was 3.29 +/- 0.68, 3.17 +/- 0.58 and 2.75 +/- 0.89 PD at 1 week, 3 months and 6 months after surgery. There were no significant differences among the changes of postoperative deviation per millimeter according to the amount of medial rectus (MR) resection (p-value = 0.423, 0.382) The success rate was 89.75%, 92.31% and 87.18% at 1 week, 3 months and 6 months after surgery, respectively. The expected corrected angle according to the amount of resection remained constant and was 3.04-3.22 PD/mm at 3 months after surgery and 2.79-2.82 PD/mm at 6 months after surgery. CONCLUSIONS: The dose-effect per millimeter was decreased as time passed. There was no statistical difference among the corrected deviation angles per millimeter according to the amount of MR resection. We expect that the calculated dose-effect relationship may be a useful guideline for unilateral medial rectus resection for recurrent exotropia.

Result Comparison after Reoperation in Recurrent Exotropia According to the Type of First Operation

PURPOSE: To investigate and compare the clinical courses and surgical success rates of secondary operations in recurrent exotropia according to the type of first operation for correction of exotropia. METHODS: A retrospective chart review was performed for all patients with recurrent exotropia of the basic or pseudodivergence excess types. In group A (36 patients), bilateral lateral rectus (LR) recession was performed as the first operation and uni- or bilateral medial rectus (MR) resection was performed as the second operation. In group B (19 patients), unilateral LR recession-MR resection (R&R) was performed as the first operation and LR recession or R&R in contralateral eye as the second operation. RESULTS: There were no significant differences between the 2 groups when considering age at each operation, frequency of the amblyopia, prescription of prism, time interval for recurrence and reoperation and the final and cumulative success rates. No postoperative complications were observed in either group. The mean number of used muscles for the first and second operation was 3.9 +/- 0.4 in group A, and 3.4 +/- 0.5 in group B (p = 0.001). Mean time interval for occurrence of postoperative orthophoria was 3.7 +/- 6.2 months in group A and 6.5 +/- 16.2 in group B (p = 0.047). In group B, the incidence of esodeviation tended to increase after postoperative 1 month. CONCLUSIONS: The final success rates of reoperation between the 2 types of the first operation in recurrent exotropia were similar. Mean time between postoperative overcorrection of orthophoria was shorter in the group with bilateral LR recession followed by secondary MR resection than in the other group. Unilateral R&R followed by LR recession or R&R in contralateral eye may be more helpful to decrease the number of used muscles than in the bilateral LR recession followed by secondary MR resection.

Result Comparison after Reoperation in Recurrent Exotropia According to the Type of First Operation

PURPOSE: To investigate and compare the clinical courses and surgical success rates of secondary operations in recurrent exotropia according to the type of first operation for correction of exotropia. METHODS: A retrospective chart review was performed for all patients with recurrent exotropia of the basic or pseudodivergence excess types. In group A (36 patients), bilateral lateral rectus (LR) recession was performed as the first operation and uni- or bilateral medial rectus (MR) resection was performed as the second operation. In group B (19 patients), unilateral LR recession-MR resection (R&R) was performed as the first operation and LR recession or R&R in contralateral eye as the second operation. RESULTS: There were no significant differences between the 2 groups when considering age at each operation, frequency of the amblyopia, prescription of prism, time interval for recurrence and reoperation and the final and cumulative success rates. No postoperative complications were observed in either group. The mean number of used muscles for the first and second operation was 3.9 +/- 0.4 in group A, and 3.4 +/- 0.5 in group B (p = 0.001). Mean time interval for occurrence of postoperative orthophoria was 3.7 +/- 6.2 months in group A and 6.5 +/- 16.2 in group B (p = 0.047). In group B, the incidence of esodeviation tended to increase after postoperative 1 month. CONCLUSIONS: The final success rates of reoperation between the 2 types of the first operation in recurrent exotropia were similar. Mean time between postoperative overcorrection of orthophoria was shorter in the group with bilateral LR recession followed by secondary MR resection than in the other group. Unilateral R&R followed by LR recession or R&R in contralateral eye may be more helpful to decrease the number of used muscles than in the bilateral LR recession followed by secondary MR resection.

The Effect of Unilateral Medial Rectus Resection for Recurrent Intermittent Exotropia

PURPOSE: The purpose of this study is to investigate the effect of unilateral medial rectus muscle resection (UMR) for the treatment of recurrent intermittent exotropia after bilateral lateral rectus muscle recession (BLR). METHODS: Medical records of 121 subjects who underwent UMR for the treatment of recurrent intermittent exotropia after BLR with more than six months of follow-up were reviewed. Patients were classified into two groups, the 4-mm group who underwent 4-mm UMR and the 5-mm group who underwent 5-mm UMR. Successful postoperative motor alignment was defined as within 10 prism diopters (PD) of exotropia and four PD of esotropia. RESULTS: The mean time interval between the primary surgery and recurrence was 13.55 +/- 20.78 months (1-120 months). Average follow-up period after secondary surgery was 27.42 +/- 15.98 months (6-48 months). Cumulative success rate at six months after UMR was 87.1% in the 4-mm group and 88.2% in the 5-mm group, respectively, and that at 24 months was 72.7% in the 4-mm group and 50.0% in the 5-mm group (p = 0.132). The average effect of resection was 4.87 +/- 0.91 PD/mm in the 4-mm group and 4.73 +/- 0.84 PD/mm in the 5-mm group (p = 0.374). CONCLUSIONS: Because of recurrent intermittent exotropia, less time is required for surgery in UMR after BLR, and patients and parents are more likely to accept a secondary surgery because of single muscle surgery. Therefore, UMR may be an effective surgical method for patients with 16-30 PD of recurrent intermittent exotropia.

The Changes of Corneal Astigmatism and Refraction After Horizontal Rectus Muscle Surgery in Intermittent Exotropia

PURPOSE: To investigate changes in corneal astigmatism and refractive power in intermittent exotropia after lateral rectus recession with or without medial rectus resection. METHODS: We compared visual acuity, spherical equivalent, refractive power, astigmatism from cycloplegic refraction, and Orbscan corneal topography in two groups consisting of 40 eyes from 20 patients who underwent bilateral lateral rectus recession (Group 1) and 33 eyes from 33 patients who underwent monocular medial rectus resection with lateral rectus recession (Group 2) immediately preoperatively and at 1 and 4 weeks postoperatively. RESULTS: In Group 1, the refractive power changed +0.12 D on average in the horizontal median and -0.08 D on average in the vertical median at 1 week postoperatively. The refractive power changed +0.07 D on average in the horizontal median and -0.04 D on average in the vertical median at 4 weeks postoperatively. No significant change in the corneal astigmatic axis was detected. In Group 2, the refractive power changed +0.4 D on average in the horizontal median and -0.19D on average in the vertical median, and the corneal astigmatic axis significantly shifted by +0.51 D in the 'with-the-rule astigmatism' direction at 1 week postoperatively (p=0.02). However, the refractive power changed +0.2 D on average in the horizontal median and -0.09 D on average in the vertical median, and the corneal astigmatic axis changed +0.2 D at 4 weeks postoperatively, although these values were not statistically significant. CONCLUSIONS: Postoperative refractive power and corneal astigmatism did not change significantly, as compared to preoperative values, at 4 weeks postoperatively in the lateral rectus recession-only or medial-and-lateral rectus recession group.

The Effect of Medial Rectus Resection in Reccurent Exotropia After Lateral Rectus Recession

PURPOSE: To investigate the effect of unilateral medial rectus resection in recurrent exotropia under 25 Prism Diopter after unilateral or bilateral lateral rectus recession. METHODS: A retrospective chart analysis was conducted for 21 patients who underwent unilateral medial rectus resection for recurrent exotropia under 25PD and uni- or bilateral lateral rectus recession for prior surgery of exotropia. The medial rectus was resected from 5.0 to 7.0 mm by 0.5 mm according to angle deviation at a distance. The postoperative deviated angle was checked at one week, three months and six months postoperatively to investigate the amount of corrected deviation per resected muscle. RESULTS: The average preoperative deviation was 20.57+/-3.37PD. We resected mean 6.1+/-0.62 mm of the medial rectus. At one week after the surgery, the postoperative deviated angle was 2.00+/-4.32PD, After six months it was 6.57+/-7.40PD, and there appeared to be an increase of deviation. Ten patients (48%) fused before surgery and 12 (57%) after surgery. The corrected deviation per resected muscle was 2.88+/-1.08PD. CONCLUSIONS: Unilateral medial rectus resection is an effective surgical method for the treatment of recurrent exotropia under 25 PD after lateral rectus recession.

Comparison of the Stability of Postoperative Alignment in Sensory Exotropia: Adjustable Versus Non-Adjustable Surgery

PURPOSE: To compare the success rates and stabilities of postoperative alignment between adjustable and the non-adjustable surgeries in the treatment of sensory exotropia. METHODS: A retrospective analysis was performed on all patients with sensory exotropia who had undergone unilateral lateral rectus recession and medial rectus resection (R&R) between January 1998 and August 2005. Thirty-four patients underwent conventional R&R, and 20 patients underwent R&R with adjustable suture of the lateral rectus. The surgical results between the two groups were analyzed with regard to the preoperative and post-operative deviation angles and the postoperative drift. The postoperative deviation angle was measured on postoperative day 1 as well as at two weeks, three months, six months and the final visit after surgery. RESULTS: There were no statistically significant differences in the mean preoperative and postoperative deviation angles between the two groups. In 30 (88%) patients in the non-adjustable group and 15 (75%) patients in the adjustable group, postoperative deviation was less than 15 prism diopters (PD) at the three month follow-up. There was no significant difference in the mean postoperative drift between the two groups. CONCLUSIONS: Strabismus surgery with adjustable sutures did not show a significantly better result than surgery without adjustable sutures in the treatment of sensory exotropia. Considering the amount of postoperative exodrift in both groups, we postulate that the immediate ocular alignment after surgery for sensory exotropia should be orthophoric or 5-6 PD of esodeviation.

Comparison of Surgical Results Between Unilateral Recession-Resection and Bilateral Resections in Recurrent Exotropia

PURPOSE: The purpose of this study was to compare the surgical results between unilateral lateral rectus recession-medial rectus resection (R and R) and bilateral medial rectus resections in recurrent exotropia. METHODS: In this retrospective study, 22 patients with recurrent exotropia of the basic or pseudodivergence excess types were enrolled. In group A (14 patients), unilateral R and R was performed during the first operation, and R and R was performed in contralateral eyes during the second operation. In group B (8 patients), bilateral lateral rectus recessions were performed during the first operation and bilateral medial rectus resections during the second operation. RESULTS: The mean time interval between the first and second operations was 28.9 months (range, 5 to 64 months) in Group A and 59.9 months (range, 35 to 75 months) in Group B, which was a significant difference between the two groups (p=0.006). The success rates at last follow-up after the second operation were 85.7% in Group A and 87.5% in Group B, which was not statistically different between the two groups (p<1.000). CONCLUSIONS: There was no difference in success rate after the second operation between the two groups. Therefore, the operation method for recurrent exotropia can be chosen according to the operator's preference.

Unilateral Resection-Recession Based on Near/Distance Deviation in Children with Exotropia of the Convergence Insufficiency Type

PURPOSE: The purpose of this study was to evaluate prospectively the long-term surgical results of unilateral lateral rectus (LR) muscle recession and medial rectus (MR) muscle resection in children with convergence insufficiency exotropia (XT). METHODS: This prospective study included 14 children with an angle of XT greater at near than at distance by 10 prism diopters (PD) or more. The amounts of resection and recession were based on near and distance deviation, respectively. Minimum follow-up was one year (mean, 26.6+/-19.4 months) after surgery. RESULTS: Significant postoperative reduction was achieved in mean distance exodeviation from 22.5 PD to 9.1 PD (p=0.000), and in mean near exodeviation from 33.8 PD to 13.6 PD (p=0.000). The mean near-distance difference decreased from 11.3 PD preoperatively to 4.6 PD postoperatively (p=0.000). A Fresnel prism was used temporarily to treat postoperative esotropia in only one patient for 6 months postoperatively. CONCLUSIONS: Unilateral surgery biased more to MR strengthening than to LR weakening in children with convergence insufficiency XT, was found to successfully reduce both distance and near deviation and to collapse near-distance differences with a low risk of long-term postoperative esotropia.

Comparison of Surgical Results Between Bilateral Recession and Unilateral Resection-Recession in Intermittent Exotropia

PURPOSE: The purpose of this study is to compare the postoperative results of surgery for 60 patients with intermittent exotropia (20-30PD). METHODS: They were classified into two groups: one group with bilateral lateral rectus recession (n=34) and another group with unilateral medial rectus resection and lateral rectus recession (n=26). We assessed the postoperative results by comparing the deviation at postoperative 1 year to those at 1day, 1week, 1month, and 6months after surgery. RESULTS: The stisfactory result defined as orthophoria and deviation between 10PD esodeviation and 10PD exodeviation. The postoperative success rates are as follows: 65% in the bilateral rectus recession group and 62% in the unilateral lateral rectus muscle recession and medial rectus resection group. In the bilateral lateral rectus recession group, postoperative 1 day alignment of 11-15PD esodeviation showed the success rate of 83%. In the unilateral medial rectus resection and lateral rectus recession group, postoperative 1 day alignment of 1-5PD esodeviation resulted in the success rate of 80%. CONCLUSIONS: The initial postoperative esodevation of 11-15PD in bilateral lateral rectus recession and esodeviation of 1-5PD in unilateral medial rectus resection and lateral rectus recession can lead to good results. Postoperative 1 year surgical results for exotropia of moderate degree could be predicted from angle of deviation at postoperative 6 months, regardless of the type of surgery.

Consecutive Esotropia after Surgical Correction of Intermittent Exotropia

Intentional overcorrection is recommended immediately after surgery of intermittent exotropia for its superior long-term prognosis. However, esotropia can develop in 6~15%, especially in children less than 4 years of age, and bring about the problems such as diplopia, suppression, decreased vision and impaired binocular single vision. The purpose of this study is to evaluate the factors possibly associated with its occurrence. A retrospective study was conducted on the 22 patients with consecutive esotropia, which had developed after surgical correction of intermittent exotropia. They underwent unilateral or bilateral medial rectus muscle recession for correction of esotropia. The mean angle of exodeviation before intermittent exotropia surgery was 30.0+/-5.2 PD(prism diopters)(23~40 PD). The mean angle of esodeviation at surgery for consecutive esotropia was 24.1+/-10.3 PD(10~55 PD). Before surgery of intermittent exotropia, 13 of the 16 patients(81.3%)had showed lateral incomitancy. No significant difference was found between age at surgery and consecutive esotropia. High AC/A ratio had been present preoperatively in only one patient. No patient showed A-V pattern preoperatively. Out of the 17 patients who had undergone bilateral lateral rectus recessions for intermittent exotropia, 10(58.8%) patients had either lateral rectus muscle recessed by 7.5 mm or more. Four of the 5 patients(80%)had a medial rectus resected by 5 mm or more. This study suggests that consecutive esotropia after intermittent exotropia surgery can develop more likely in the patients who have had lateral incomitancy, excessive recession of lateral rectus muscle by 7.5 mm or more, or excessive resection of medial rectus muscle by 5 mm or more.

Surgical Results in Basic Exotropia of Moderate Degree

The purpose of this study is to assess the postoperative stability for exotropia by comparing the deviation at postoperative 2 years to those at 1 day, 1 week, 1 month, 3 months, 6 months, and 1 year after surgery in children with basic exotropia of between 25 and 30 prism diopters. They were classified into two groups:one group[n=20]with unilateral lateral rectus recession and medial rectus resection, and another group[n=15] with bilateral lateral rectus recession. There was no difference in age at the time of surgery or preoperative angle of deviation between the two groups. Exodrift occurred according to an increase in follow-up and maximal correlation between postoperative 6 months and 2 years in both groups[r=0.85, r=0.81, respectively, p>0.05]was noted. Success rates at postoperative 2 years were 65%and 60%, respectively[p>0.05]. In conclusion, long-term surgical results for exotropia of moderate degree and basic type could be predicted from angle of deviation at postoperative 6 months, regardless of the type of surgery.

Comparison of Surgical Results by Initial Postoperative Alignment Following Bilateral Lateral Rectus Recession and Unilateral Lateral Rectus Recession-Medial Rectus Resection in Intermittent Exotropes

We attempted to predict the success, undercorrection, overcorrection rate at postoperative 1 year by examining alignment at postoperative 1 day and find out the relationship between alignment of postoperative 1 day and 1year. Forty-six patients with intermittent exotropia underwent bilateral lateral rectus recession at Keimyung university, Dongsan medical center and fifty-seven patients underwent unilateral medial rectus resection and lateral rectus recession at Catholic university, St.Mary`s hospital. The alignment at postoperative 1 day was classified as the overcorrected with 11-20PD, the overcorrected with 1-10PD,the orthotropia, and the undercorrected with residual exotropia of 1-10PD. There was a statistically significant relationship between alignment at postoperative 1 day and 1 year in unilateral medial rectus resection and lateral rectus recession and bilateral lateral rectus recession (r=0.74, r=0.51, p<0.05). Those patients who were overcorrected 1-20PD had a significantly higher success rate than those undercorrected 1-10PD at postoperative 1 day (p<0.05). In the unilateral medial rectus resection and lateral rectus recession group,postoperative 1 day alignment of 1-10PD resulted in the highest success rate of 73.7%. In the bilateral lateral rectus recession group,postoperative 1 day alignment of 11-20PD showed the highest success rate of 76.9%. There were no significant differences in the success rate,undercorrection rate, and overcorrection rate between the two kinds of surgery at postoperative 1 year. As a result, the alignment at postoperative 1 day can be one of the predictive factors of future surgical outcome. The initial postoperative overcorrection of 11-20PD in bilateral lateral rectus recession and overcorrection of 1-10PD in unilateral medial rectus resection and lateral rectus recession can lead to good results.