Unilateral recession and resection in Duane syndrome

Unilateral recession and resection in Duane syndrome

Unilateral Recession and Resection in Duane Syndrome Yair Morad, MD,a Stephen P. Kraft, MD,a and James L. Mims III, MDb Purpose: To assess the efficac...

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Unilateral Recession and Resection in Duane Syndrome Yair Morad, MD,a Stephen P. Kraft, MD,a and James L. Mims III, MDb Purpose: To assess the efficacy of lateral rectus resection with medial rectus recession in the affected eye of patients with Duane retraction syndrome (DRS) with esotropia and limited abduction, compared with bilateral medial rectus recessions. Methods: The charts of 9 patients with DRS who underwent a recession-resection procedure and 10 patients with DRS who underwent bilateral medial rectus recessions were reviewed. Ocular ductions (graded from 0 = full duction to –4 = total deficit), severity of retraction, alignment, head position, and binocular single vision field (for study group only) were recorded before and after surgery. Results: Before surgery, the study and control groups did not differ in mean primary position esotropia (16.9 and 18.8 PD, respectively), face turn (16.5° and 15.0°, respectively), average limitation of abduction (–3.9 and –3.7, respectively), or adduction (-0.1 and –0.3, respectively). After surgery, both groups had similar mean face turns (3.9° and 1.0°), esotropia (3.3 PD and 1.0 PD), and abduction limitation in the affected eye (–2.4 and –2.6). However, mean adduction was significantly worse in the control group than in the study group (–1.5 vs –0.6, P = .02). Globe retraction improved in all control subjects. It worsened in 5 study subjects and did not improve in the other 4. In the study group, 1 patient required reoperation for undercorrection and another was overcorrected. Conclusion: Seven of 9 patients with DRS, selected on the basis of esotropia, limited abduction, and mild retraction, benefited from a recession-resection procedure. Abduction improved to the same degree as seen after bilateral medial rectus recessions, with less tendency to limit adduction. (J AAPOS 2001;5:158-62)

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uane retraction syndrome (DRS) is a spectrum of eye motility disorders in which the common features are retraction of the globe and narrowing of the lid fissure, both occurring on attempted adduction of the involved eye.1,2 These result from anomalous cocontraction of the lateral rectus and medial rectus muscles on adduction of the involved eye, probably caused by simultaneous innervation of the lateral rectus muscle by a branch of the third nerve.3-7 Electromyographic studies have shown that other muscles innervated by the third nerve can also cocontract with the lateral rectus muscle.3-5 Patients with DRS characterized by limited abduction and esotropia often use a significant compensatory face turn toward the affected eye to maintain binocular single vision (BSV). Various surgical approaches can be effective in treatFrom the Department of Ophthalmology, The Hospital for Sick Children and The University of Toronto,a Toronto, Ontario, Canada, and the Department of Ophthalmology, University of Texas Health Science Center and the Christus Santa Rosa Children’s Hospital, San Antonio, Texas.b Dr Morad was supported in part by a grant from the American Physicians Fellowship for Medicine in Israel. Submitted June 30, 2000. Revisions accepted January 9, 2001. Reprint requests: Stephen P. Kraft, MD, Department of Ophthalmology, The Hospital for Sick Children, 555 University Ave, Toronto, ON, Canada M5G 1X8 (e-mail: [email protected]). Copyright © 2001 by the American Association for Pediatric Ophthalmology and Strabismus. 1091-8531/2001/$35.00 + 0 75/1/114187 doi:10.1067/mpa.2001.114187

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ing this common form of DRS. Medial rectus recession as a sole procedure in the involved eye can eliminate the compensatory head posture.8,9 Adding a large recession or a posterior fixation suture to the contralateral medial rectus muscle may enhance the range of BSV field to the affected side by partially matching rotation deficits to that side.2,9-12 Transposition of the vertical rectus muscles has been advocated to improve abduction in this form of DRS.13-15 In general, resection of the lateral rectus muscle of the affected eye in patients with DRS with esotropia and limited adduction is not recommended because of the risk of severely limiting adduction and worsening globe retraction on adduction. However, in selected cases, we have combined resection of the lateral rectus muscle with recession of the medial rectus muscle of the affected eye in patients with DRS. These patients had esotropia with limited abduction and mild to moderate globe retraction. We compared our results with those of patients with DRS and limited abduction in whom we have performed bilateral medial rectus recessions, which has been a much more common option for this form of DRS. We are unaware of any previous studies reporting results of recession-resection procedures in treating patients with DRS with limited abduction.

METHODS We reviewed the charts of 9 patients from the practices of 2 coauthors (S.P.K., J.L.M.) who performed lateral rectus resection and medial rectus recession on the affected eye in Journal of AAPOS

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patients with unilateral DRS syndrome with esotropia and limited abduction. All the patients with DRS who underwent this procedure were included. Before their operations, all patients had complete ophthalmologic assessments. Hyperopia over +2.00 D was corrected with spectacles. Measurements were taken in primary position and the secondary positions of gaze by using the prism and cover test while the patient fixated with the unaffected eye on a target at 6 m and in primary position at 1/3 m. Face turns were measured by using an orthopedic protractor. Ductions were recorded for both eyes, and limitations were graded on a scale from 0 (full movement) to –4 (no movement past the midline), as noted by Pittar.16 Rotation of the eye to 50% of the full excursion was rated as -2; rotations of -1 (mild limitation, with sliver of sclera visible on maximal voluntary rotation) and -3 (only slight movement into field of action) were interpolated between these values.16 The severity of globe retraction was assessed by using signs developed by one of the coauthors11: (1) exodeviation of more than 3 PD on gaze to the nonaffected side, (2) noticeable enophthalmos and palpebral fissure narrowing more than 2 mm (as measured with a ruler placed vertically at the lateral canthus) in full adduction compared with primary position, (3) defective adduction as indicated by a corneal light reflection 1 mm or more inside the lateral limbus on adduction, (4) near point of convergence greater than 6 cm, and (5) upshoot or downshoot when affected eye moves to adduction. We recorded the number of these signs in each patient. With one exception, all patients considered for a recession-resection procedure had 3 signs or fewer. Preoperative and postoperative fields of BSV of the study group patients were measured by a Goldmann perimeter or an arc perimeter in patients old enough to cooperate and in younger patients by the range within which they showed motor fusion (phorias). Surgery in the study group involved recession of the medial rectus muscle of no more than 5.0 mm and resection of the lateral rectus muscle of no more than 4.0 mm. These limits were chosen to minimize chances of significantly worsening the globe retraction. The control group included 10 consecutive patients with DRS with esotropia and limitation in abduction who underwent bilateral medial rectus recessions by the second author (S.P.K.) between 1995 and 1998. All patients had the same preoperative assessment as the study group; however, BSV field tests were not done. The amount of recession in the eye with DRS was geared to free the forced duction at surgery. The medial rectus muscle of the fellow eye was also recessed to try to increase the range of BSV field to the side of the limited abduction. One of the authors (S.P.K.) operated using a limbal approach, the other (J.L.M.) used a fornix approach. Follow-up time after surgery was at least 6 months. Statistical analysis for nonparametric data was done by using the Mann-Whitney test for unpaired data or the

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Wilcoxon matched paired test for paired data. For comparison of parametric data, we used the paired t test for paired data and Student t test for nonpaired data.

RESULTS Study Group The study group patients ranged in ages from 3 to 33 years (mean, 8.3 years). In 8 cases, the DRS affected the left eye. Visual acuity was between 20/20 to 20/40 in all patients, with no more than 1 Snellen line difference between eyes. Table 1 presents their clinical data before and after surgery. The average medial rectus recession was 4.15 mm (range, 4.0-5.0 mm), and the average lateral rectus resection was 3.4 mm (range, 3.0-4.0 mm). Before surgery the mean face turn was 16.5°; after surgery the turn was 5° or less in 7 patients (78%), unchanged in 1 patient, and to the reverse side in another. On average, the turn was reduced to 3.4° (P = .005). The angle of esotropia in primary position averaged 16.9 PD before surgery and 3.4 PD (P = .015) after surgery. The esotropia was reduced to 4 PD or less in 7 patients (78%), had converted to 6 PD of exotropia in 1 patient, and did not change in another. The latter patient (patient 5) underwent additional medial rectus recession in the affected eye combined with posterior fixation suture placement on the contralateral medial rectus muscle that resulted in orthophoria in primary position. Another patient (patient 7) had posterior fixation sutures placed on both horizontal rectus muscles of the affected eye during initial surgery in an attempt to eliminate upshoots in adduction. Preoperative and postoperative photographs in 9 positions of gaze of one of the patients (patient 2) are shown in the Figure. Abduction in the affected eye was severely limited in all patients before surgery (mean, –3.9; range, –3 to -4). Adduction was normal or minimally restricted (mean, -0.1; range, 0 to -2). After surgery, abduction in the affected eye improved in all patients to a mean of –2.4 (range, –1 to –3, P = .0078). Adduction, however, worsened in 3 patients (up to –2 limitation). Adduction limitations after surgery averaged –0.6, a figure not significantly different from the average before surgery. On average, patients had 2.1 signs of retraction before their operations. Surgery worsened the retraction of the affected eye in adduction in 5 patients but did not affect it in the other 4. Patients had an average number of 3.2 signs of retraction after surgery, significantly more than before it (P = .0078). Among the 5 patients who had 3.5-mm or 4.0mm resections, the retraction signs increased in all but 1. However, the signs worsened in only 1 of 4 patients who had 3.0-mm resections. The width of the horizontal BSV fields before surgery averaged 24.2°, with the center point an average of 16.3° off center. After surgery, the width of the fields increased to an average of 36.6° (P = .16), and the center point of the field moved to an average of 4.1° off center (P = .0048).

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A

B FIGURE. Preoperative (A) and postoperative (B) photographs of patient 2 of the study group in 9 positions of gaze. Compared with before surgery, the abduction limitation improved from –4 to –1. Adduction was reduced from 0 to –1, while retraction was not worsened by surgery.

Control Group The control group patients ranged in ages from 3 to 34 years (mean, 14.1 years), 9 of whom had left-sided DRS. Visual acuity was between 20/20 to 20/30 in all patients. Table 2 presents clinical data, as well as measurements of ocular ductions, before and after surgery. Before surgery, all patients had a face turn (average, 15°; range, 10°-20°), with an average esotropia of 18.8 PD (range, 10-25 PD). Recession of the medial rectus muscles averaged 6.2 mm in the affected eye and 6.3 mm in the nonaffected eye. It eliminated the face turn and esotropia in all patients except 2, reducing the average head posture to 1° (P < .001) and the average esotropia in primary position to 1 PD (P < .001). Abduction was limited to an average of –3.7 before surgery but improved to an average of -2.6 (P = .0034) after it. In contrast, adduction was mildly limited before surgery (average, –0.3; range, –1 to 0) but was significantly more limited afterwards (average, -1.5; range, -0.5 to –2; P = .002). Eye retraction improved significantly from an average of 2.1 signs before surgery to 0.81 signs after correction (P < .001). BSV field testing was not performed in the control group. Comparison of Both Groups Before surgery, both groups did not differ in the average amount of esotropia in primary position, face turn, limita-

tion in abduction or adduction, and eye retraction signs. Surgery led to improved face turns in both groups to a similar degree (P = .07). Esotropia angles in primary position were comparable. No significant difference was found in the postoperative grading of abduction limitation between the groups. However, the average limitation of adduction was significantly worse after surgery in the control group (P = .02). Retraction grading of the affected eye in adduction after surgery was less severe in the control group (P = .01). Although globe retraction improved in all patients in the control group, none of the study patients showed improvement, and 5 (55%) patients experienced worsening of the retraction.

DISCUSSION In unilateral DRS with esotropia and limited abduction, surgical treatment is aimed at achieving orthotropia in primary position and eliminating a compensatory head posture and, where possible, disfiguring globe retraction. In addition, it should try to maximize the range of BSV field, which ideally should be centered around the primary position. The field can be enlarged by matching the range of ductions in the 2 eyes.2,9-12 Bilateral medial rectus recessions has been the most common procedure used by the authors for patients with DRS with esotropia; for this reason, we chose a control group from among patients who underwent this surgery.

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TABLE 1. Ocular deviations and ductions in study group patients before and after recess-resect procedure on the affected eye Operation (mm) No. 1 2 3 4 5 6 7 8 9 Mean

Age (y) MR Rec. LR Res 3.0 3.0 33.0 3.5 4.6 7.2 4.5 6.0 10.0 8.3

5.0 5.0 5.0 5.0 5.0 4.0 5.0 4.0 5.0 4.8

3.0 3.0 3.5 4.0 4.0 4.0 3.0 3.0 3.5 3.4

Deviation in primary (PD)

Head turn (°)

Adduction

Abduction

Retraction Follow-up (No. of signs) (mo)

Pre

Post

Pre

Post

Pre

Post

Pre

Post

Pre

Post

20 17 30 12 11 15 16 12 15 16.5

0 0 0 10* 11 9 0 0 5 3.9

20 ET 25 ET 30 ET 10 ET 16 ET 10 ET 12 ET 14 ET 15 ET 16.9

Flick XT Ortho Ortho 6 XT 16 ET 4 ET Flick ET Ortho Ortho 3.3

0.0 0.0 –0.5 0.0 0.0 –0.5 0.0 0.0 0.0 –0.1

–1.0 –1.0 –1.0 0.0 0.0 0.0 –0.5 0.0 –2.0 –0.6

–4.0 –3.0 –4.0 –4.0 –4.0 –4.0 –4.0 –4.0 –4.0 –3.9

–1.0 –1.0 –2.5 –2.0 –3.0 –3.0 –3.0 –3.0 –3.0 –2.4

2 2 2 1 2 2 4 1 3 2.1

2 2 2 4 4 4 4 3 4 3.2

12 6 10 40 8 11 40 43 60 25.4

*Head turn was converted to the opposite side. ET, Esotropia; LR, lateral rectus; MR, medial rectus; Ortho, orthophoria; PD, prism diopters; Post, after surgery; Pre, before surgery; Rec, recession; Res, resection; XT, exotropia.

TABLE 2. Ocular deviations and ductions in control group patients before and after bilateral medial rectus recessions

No.

Age (y)

1 2 3 4 5 6 7 8 9 10 Mean

34.0 2.5 27.0 3.0 9.0 31.0 9.0 6.0 14.0 5.5 14.1

MR recession (mm) Affected Non-affected Head turn (°) eye eye Pre Post 8.0 7.0 6.0 7.0 5.0 8.0 5.0 5.0 6.0 4.5 6.2

5.0 6.0 6.0 9.0 6.0 6.0 6.0 7.0 6.0 6.0 6.3

20.0 10.0 10.0 20.0 10.0 17.5 17.5 17.5 10.0 17.5 15.0

5.0 0.0 0.0 0.0 5.0 0.0 0.0 0.0 0.0 0.0 1.0

Esotropia in primary (PD) Pre Post 25.0 15.0 10.0 22.5 14.0 16.0 25.0 20.0 15.0 25.0 18.7

4.0 0.0 0.0 0.0 6.0 0.0 0.0 0.0 0.0 0.0 1.0

Adduction Pre Post 0.0 1.0 –0.5 –0.5 0.0 0.0 0.0 0.0 –0.5 –0.5 –0.3

–2.0 –1.5 –2.0 –2.0 –1.5 –2.0 –1.0 –0.5 –1.0 –1.0 –1.4

Abduction Pre Post –4.0 –4.0 –4.0 –4.0 –4.0 –4.0 –3.0 –4.0 –3.5 –2.5 –3.7

–4.0 –2.0 –2.0 –2.0 –3.5 –3.0 –2.0 –2.5 –3.5 –1.5 –2.6

Retraction (No. of signs) Follow-up Pre Post (mo) 2 2 2 3 2 2 2 2 2 1 2

1 1 1 2 1 0 0 1 0 0 0.8

9 8 9 6 13 9 5 7 12 6 8.4

ET, Esotropia; LR, lateral rectus; MR, medial rectus; Ortho, orthophoria; PD, prism diopters; Post, after surgery; Pre, before surgery; Rec, recession; Res, resection; XT, exotropia.

Resecting the affected lateral rectus muscle in DRS patients is generally not advocated because of concerns that it may worsen globe retraction.10 However, it has been carried out successfully in selected patients since the 1930s (Phillip Knapp, oral communication, 1978). To the best of our knowledge, this study is the first to report the results of recession-resection procedure in the affected eye of patients with DRS and esotropia. Our results suggest that the surgeon should limit the recession of the medial rectus muscle to no more than 5.0 mm when a lateral rectus resection is added to the plan. This amount is less than the amounts of recession we generally perform when the lateral rectus muscle is not resected. The medial rectus muscle recession is required to release restricted forced ductions to abduction and thus facilitate improvements in abduction. The trade-off in some of our patients was a worsening of the signs of globe retraction. This problem was most severe after lateral rectus resections of 4.0 mm, as seen in patients 4, 5, and 6. This finding suggests that lateral rectus resections of 4.0

mm, while modest, may still be excessive in attempting to achieve the twin goals of good alignment and centering the BSV field around primary position. To minimize the chances of worsening the retraction, we recommend limiting the resection to no more than 3.0 or 3.5 mm. While this amount would be considered inadequate for esotropia surgery in patients without DRS, our experience shows that it can form an effective part of a surgical plan for patients with DRS with esotropia and limited abduction. Small resections of the lateral rectus muscle can be effective in this form of Duane syndrome because of the abnormal muscle structure noted in these cases. The lateral rectus muscle in Duane syndrome is stiffer and, as a result, has a higher length-tension curve than a normal lateral rectus muscle.17,18 Thus, the muscle would be tightened more per millimeter of resection than would a normal lateral rectus muscle. The size of the esotropia in primary position is another factor that must be considered before undertaking a recession-resection procedure. From our experience, the angle

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of the esotropia should be at least 14 or 15 PD to avoid the risk of an overcorrection. We had 3 patients with angles of 10 to 12 PD, one of whom (patient 4) had the only overcorrection seen in the study. This patient underwent a medial rectus recession of 5.0 mm and lateral rectus resection of 4.0 mm and showed worsening of retraction, as well as an exotropia in primary position, after surgery. We believe that only patients with minimal signs of globe retraction (3 or fewer by our criteria) would benefit from a recession-resection procedure on the affected eye. We would not recommend using this procedure on patients with DRS with marked upshoots or downshoots, eyelid narrowing of more than 50% on adduction, or unusually stiff, fibrotic lateral rectus muscles. This method does offer advantages, however, when used on the appropriate patients: it is a straightforward procedure that does not put the normal eye at any surgical risk. A small resection is easily reversible should signs of globe retraction worsen or an overcorrection occur. Undercorrections can be solved by further weakening the ipsilateral medial rectus muscle or weakening the contralateral medial rectus muscle. Sole recession of the ipsilateral medial rectus muscle can eliminate abnormal face turn but generally produces only minimal improvement in abduction, thus limiting the range of BSV to the ipsilateral side.8 For this reason, surgeons often add a recession or posterior fixation of the contralateral medial rectus muscle to match duction deficits and improve the range of abduction in the affected eye, thus expanding the range of BSV to the ipsilateral side.9-12 Pressman and Scott12 showed that relatively large recessions (up to 8 mm) of both medial rectus muscles can increase the field of BSV to both a right and left gaze to an average total field width of 30°. However, they reported postoperative worsening of adduction limitations, similar to our experience with this approach. The average ipsilateral medial rectus muscle recession performed in the control group was 6.15 mm as opposed to 4.75 mm in the study group (P = .006). We believe that this difference accounted for the increased limitation in adduction in our control group, which was the trade-off for the enlarged BSV field they achieved. This finding is similar to the results reported by Pressman and Scott.12 Lateral transposition of the vertical rectus muscles has been shown to improve the abduction of the affected eye and improve the range of BSV field into the ipsilateral field of gaze.14,15 In their study of vertical muscle transposition, Molarte and Rosenbaum14 showed that this approach can improve abduction ability and increase the horizontal BSV field size. Although they did not report the average width of their patients’ BSV fields, they stated that some patients gained 60° of diplopia-free field. However, 46% of their patients required additional medial rectus weakening surgery and 15% developed a vertical deviation. Foster15 reported good expansion of the BSV field to the ipsilateral side in patients with DRS on whom he performed full-tendon transpositions with posterior fixation sutures. However, this

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procedure also runs the risk of inducing vertical tropias. Undercorrections following vertical muscle transpositions could necessitate weakening of the ipsilateral medial rectus muscle, with the attendant risk of anterior segment ischemia. The recession-resection procedure in our study patients and bilateral medial rectus recessions in the control patients achieved similar improvements in abduction. However, in the control group, this improvement was no better than a –2 limitation in any patient, whereas in the study group, 2 patients showed marked improvement following surgery to a –1 limitation (Figure). Moreover, in the control group, improvement in abduction was achieved at the cost of further limiting adduction of the affected eye in all cases, with 4 of 10 patients showing a –2 limitation. In contrast, adduction in the affected eye in the study group was worsened in only 4 patients, and in only 1 was it more limited than a grade of –1. Our study had methodological limitations: the examiners who evaluated the results of surgery were not blind to the type of surgery performed, and all patients were not examined by the same surgeon. We tried to overcome these difficulties by establishing strict outcome criteria. In summary, we found that ipsilateral recessionresection procedures in patients with DRS with esotropia can lead to improvements in abduction and elimination of compensatory face turns comparable with those achieved by the more traditional approach of bilateral medial rectus recessions. However, the choice of a recession-resection procedure should be limited to patients with mild retraction of the globe and good preoperative adduction. In addition, we recommend limiting the resection of the lateral rectus muscle to no more than 3.5 mm to minimize the risks of compromising adduction and worsening retraction. Finally, the esotropia in primary position should be at least 15 PD to reduce the risk of overcorrection. Further research on a larger cohort of patients is needed to confirm our results. This paper was prepared with the assistance of Editorial Services, The Hospital for Sick Children, Toronto, Ontario, Canada.

References 1. Duane A. Congenital deficiency of abduction, associated with impairment of adduction, retraction movements, contraction of the palpebral fissure and oblique movements of the eye. Arch Ophthalmol 1905;34:133-59. 2. Kraft SP. A surgical approach to Duane syndrome. J Pediatr Ophthalmol Strabismus 1988;25:119-30. 3. Scott AB, Wong G. Duane’s syndrome. An electromyographic study. Arch Ophthalmol 1972;87:140-7. 4. Sato AB. Electromyographic study on retraction syndrome. Jpn J Ophthalmol 1960;4:57-66. 5. Huber A. Electrophysiology of the retraction syndromes. Br J Ophthalmol 1974;58:293-300. 6. Metz HS. Duane’s retraction syndrome. Arch Ophthalmol 1982; 100:843-4. 7. Raab EL. Clinical features of Duane’s syndrome. J Pediatr Ophthalmol Strabismus 1986;33:64-8.

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8. Kaban TJ, Smith K, Day C, Orton R, Kraft S, Cadera W. Single medial rectus recession in unilateral Duane syndrome type I. Am Orthoptic J 1995;45:108-14. 9. Kraft SP, Clarke MP. Surgical treatment of Duane’s retraction syndrome. Ophthalmol Clin North Am 1992;5:79-92. 10. Saunders AS, Wilson ME, Bluestein EC, Sinatra BS. Surgery on the normal eye in Duane retraction syndrome. J Pediatr Ophthalmol Strabismus 1994;31:162-9. 11. Mims JL. Choice of surgery for Duane’s retraction syndrome. In: Van Heuven WAJ, Zwaan J, editors. Decision making in Ophthalmology. St Louis: Mosby; 1992. p. 162-3. 12. Pressman S, Scott WE. Surgical treatment for Duane’s syndrome. Ophthalmology 1986;93:29-38.

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13. Feretis D, Papastratigakis B, Tsamparlakis J. Planning surgery in Duane’s syndrome. Ophthalmologica 1981;183:148-53. 14. Molarte AB, Rosenbaum AL. Vertical rectus muscle transposition surgery for Duane’s syndrome. J Pediatr Ophthalmol Strabismus 1990; 27:171-7. 15. Foster RS. Vertical muscle transposition augmented with lateral fixation. J AAPOS 1997;1:20-30. 16. Pittar G. Practical management of squint. New South Wales: Turton and Armstrong; 1990. p. 58-63. 17. Miller NR, Kiel SM, Green WR, Clark AW. Unilateral Duane’s retraction syndrome. Arch Ophthalmol 1982;100:1468-72. 18. von Noordern GK. Binocular vision and ocular motility. 5th ed. St Louis: Mosby; 1996. p. 430-7.

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