Acquired esotropia fixus is associated with high myopia.1 It is caused by non-uniform ocular elongation, which herniates superotemporally and retroequatorially through the muscle cone, in patients with high myopia.2 The spherical refraction in patients with esotropia fixus and high myopia is generally greater than −15.00 diopters (D). The disorder typically affects middle-aged and elderly people and tends to aggravate gradually, resulting in eyeball fixation in the extreme inferomedial position. Eventually, there is obstruction of ocular motility in all positions,3 which severely affects the appearance and visual function.
Currently, the Jensen procedure for superior rectus and lateral rectus muscles is the main surgical approach for strabismus in patients with esotropia fixus. The procedure classically entails union of the superior rectus and lateral rectus muscles using one pair of sutures applied 14 to 16 mm posterior to their respective insertions. However, the difficulty to expose the surgical site with a strabismus hook and the increased chance of injury to orbital tissues are some of its limitations. We modified the surgical procedure to improve its effectiveness.
Patients and Methods
We performed a retrospective analysis of 13 cases (15 eyes) of esotropia fixus with high myopia treated at our hospital between February 2014 and December 2015. This experimental research on human subjects was approved by the Institutional Review Board at Southwest Hospital, Chongqing, China. Written informed consent was obtained from all participants prior to their inclusion in the study.
Patients included 4 men (5 eyes) and 9 women (14 eyes). The mean age (± standard deviation) of patients was 50.0 ± 10.4 years (range: 30 to 70 years). All patients underwent an orthoptic examination. The mean spherical equivalent refraction was −22.53 ± 6.06 diopters (D) (range: −12.50 to −29.00 D). The mean axial length was 30.03 ± 5.65 mm (range: 26.50 to 32.47 mm). Preoperatively, the angle of deviation was determined in all patients.
The prism cover test could not be performed in all patients due to restricted ocular motility. Instead, the angle of deviation was assessed by means of corneal reflection optical inspection at 33 cm: the corneal reflection point situated from the middle of the pupillary margin and the limbus to outside the limbus (the angle of deviation was 30° to 45° esotropia and 15° to 45° hypotropia). Limitation of ocular motility was estimated and recorded on a scale of −1 to −6.
Ocular Motility of the Operated Eye
Thirteen eyes were unable to reach midline (−5), and 2 eyes exhibited marked limitation of abduction (−4). None of the 15 eyes showed supraduction. Forced duction testing was positive in 13 eyes and negative in 2 eyes. All 13 patients (15 eyes) underwent orbital magnetic resonance imaging (MRI) (Figure 1). Axial elongation was detected in 15 globes (13 patients), eyes were fixed inferomedially, the superior rectus muscle showed a nasal shift, and the lateral rectus muscle showed an inferior shift. Postoperative examinations were performed at 1 day, 2 weeks, 3 months, and 6 months after the operation.
Preoperative orbital magnetic resonance imaging. (A) Coronal scan showing a nasal shift of the superior rectus muscle and an inferior shift of the lateral rectus muscle (red circle). (B) Horizontal scan showing axial elongation of the eyeball and prolapse of the posterior part of the equator from the muscle cone temporally (red arrow).
All 13 patients (15 eyes) received general anesthesia. A medial rectus large recession or rectus tenotomy was performed according to the degree of fibrosis of the medial rectus muscle. If possible, a preset suture was adopted on the medial rectus muscle to recess the muscle for 7 mm in the operation. If impossible, the tendon of the medial rectus muscle was cut off.
Medial rectus muscle surgery was not performed in 2 eyes because of a fair abduction function. In the remaining 13 eyes, medial rectus muscle surgery was performed first during the operation. A limbal ladder incision was employed for the medial rectus.
Nine eyes (7 patients) underwent large muscle recession, approximately 7 mm posterior to the respective original insertion. A rectus tenotomy was performed in 4 eyes (4 patients). A Parks incision was employed superotemporally approximately 8 mm posterior to the limbus. During intraoperative exploration, the superior rectus muscle was found to have shifted nasally, and the lateral rectus muscle had shifted inferiorly; these results were consistent with the MRI findings.
The superior rectus and lateral rectus muscles were separated up to 12 to 14 mm from their respective point of insertion. The temporal half of the superior rectus muscle and the superior half of the lateral rectus muscle were looped and tied together by two pairs of 5-0 polyethylene terephthlate non-absorbable sutures, without splitting into two beams before the union (Figure 2, Video 1, available in the online version of this article).
Intraoperative photographs during the Jensen procedure for superior rectus and lateral rectus muscles. (A) Parks incision (superotemporal) approximately 8 mm posterior to the limbus. (B) Traction exerted on the lateral rectus muscle, which had shifted inferiorly. (C) Two pairs of sutures, 12 and 14 mm posterior to the lateral rectus insertion, were applied without splitting the lateral rectus muscle into two beams. (D) Traction exerted on the superior rectus muscle, which had shifted nasally. (E) Two pairs of sutures, 12 and 14 mm posterior to the superior rectus insertion, were applied, without splitting into two beams. (F) Looping of the two pairs of sutures.
On the first postoperative day, 12 eyes (10 patients) were found to be in the primary position, with no residual esotropia (80.0%); 2 eyes (2 patients) exhibited 5° to 10° esotropia and less than 5° hypotropia (13.3%); and 1 eye (1 patient) exhibited 15° esotropia and 5° hypotropia (6.7%).
One eye (1 patient) was lost to follow-up by the 3-month follow-up (follow-up rate: 92.3%). At 3 months, 9 eyes (7 patients) were aligned in the primary position (64.3%), 1 eye (1 patient) showed 10° esotropia (7.2%), 2 eyes (2 patients) showed 10° esotropia and 5° hypotropia (14.3%), and 2 eyes (2 patients) showed 15° to 20° esotropia and 5° hypotropia (14.3%). One patient whose ocular alignment was 20° esotropia in the second week progressed to 30° esotropia; no change in alignment was seen in the rest of the patients.
At 3 months, the operated eye of the above patients showed normal ocular motility in all directions and underwent a prism cover test (+60 prism diopters). The reason for ocular alignment development may be due to loose suturing of the union or severe medial rectus muscle fibrosis. The patients underwent medial rectus muscle exploration followed by its recession in the operated eye, and medial rectus muscle recession with lateral rectus muscle shortening in the other eye. Postoperatively, the patients had normal ocular alignment and motility. At the 6-month follow-up visit, 10 eyes (9 patients) were observed (follow-up rate: 69.2%). Among the remaining eyes, 6 eyes (5 patients) were in the primary position (60.0%), 1 eye (1 patient) showed 10° esotropia and 5° hypotropia (10.0%), 1 eye (1 patient) showed 15° esotropia (10.0%), and 2 eyes (2 patients) showed 15° esotropia and 5° hypotropia (20.0%). The degree of medial rectus muscle fibrosis affected the efficacy. The harder the fibrosed muscle, the worse was the treatment efficacy. Ocular motility improved remarkably postoperatively. Three eyes were evaluated as normal. Therefore, our modified surgical procedure showed a good efficacy (Figure 3, Table 1).
(A) Preoperative photographs showing more than 45° deviation of the left eye and extremely limited superior and lateral ocular motility. (B) Photographs of the same patient at the 3-month follow-up after surgery. The photographs show the primary position and normal ocular motility.
Ocular Motility and Alignment of the Operated Eye at Different Time Points
The etiology of acquired esotropia fixus with high myopia was considered attributable to medial rectus muscle fibrosis and lateral rectus muscle paralysis.4 Several surgical methods for stabilization of the globe in patients with high myopia have been described. These include the recession–resection procedure and large recession of the medial rectus muscle, complete disinsertion of the medial rectus muscle, lateral rotation of the eye using scleral stay sutures, and the Jensen procedure for superior rectus and inferior rectus muscles.1 The traditional recession–resection surgery aims to alter the muscle strength, but it is only effective in patients with small-angle esotropia or those in the early stages5; moreover, these patients are associated with high relapse rates. Relapses were probably the result of redislocation of the globe after temporary placement back within the muscle cone.6 Normalization of muscle kinematics was not satisfactory.
Poor efficacy of the conventional surgical methods for esotropia fixus with high myopia prompted a search for potential causes of acquired strabismus other than medial rectus fibrosis and lateral rectus paralysis. MRI studies revealed an inferotemporal shift of the lateral rectus muscle and an inferior shift of the medial rectus muscle in patients with esotropia fixus.2,7 By MRI, Yokoyama et al.8 further found that the axial elongation of the eyeball in these patients caused the posterior part of the equator to prolapse from the muscle cone superotemporally. Thus, it was deduced that the rapid posterior expansion due to high myopia resulted in medial rectus muscle tension, a change in force vectors caused by the change in location of the lateral rectus and superior rectus muscles, a superotemporal shift of the enlarged posterior pole, mechanical adduction due to nasal shift of the superior rectus muscle, limited abduction, mechanical infraduction due to inferior shift of the lateral rectus muscle, limited supraduction, inferomedial fixation, and severely restricted abduction and supraduction.2,3
The surgical technique has changed as the pathophysiological mechanisms have become better understood. Yokoyama et al.9 first adopted a loop myopexy of the temporal head of the superior rectus muscle and the superior head of the lateral rectus muscle without muscle splitting, with or without concomitant surgery of the medial rectus muscle. However, adopting this procedure, the gap in the muscle cone in the superotemporal globe was too wide to be closed by a single suture.3 In addition, Wong et al.10 and Basmak et al.11 employed a loop myopexy without muscle splitting in patients with esotropia fixus with high myopia. This procedure minimized compromise of the anterior ciliary circulation because the muscles are not cut or split. Furthermore, the procedure was easily reversed by cutting and removal of the band.11 The aim of the loop myopexy was to correct the displaced extraocular muscle path and reverse the dislocation of the globe.6 The surgical procedure was performed to correct the deviated muscle paths.12
More recently, studies have documented improved outcomes in patients with esotropia fixus with this surgical method.13,14 Although generally good results have been reported in most cases, there are considerable limitations in abduction and elevation postoperatively.1 All of these surgical methods entailed the union of the temporal half of the superior rectus muscle and the superior half of the lateral rectus muscle with one pair of 5-0 nonabsorbable sutures at 14 to 16 mm posterior to the superior rectus or lateral rectus muscle insertion, after separation of the superior rectus and lateral rectus muscles. This approach reduced the risk of scleral perforation and ocular ischemic syndrome because the suture was fixed to the sclera. Ocular motility is significantly improved because of the recovery of the superotemporal prolapse of the posterior eyeball of the equator from the muscle cone postoperatively. Farid et al.3 reported an improved union of the superior rectus and lateral rectus muscles with the use of three pairs of sutures for the superior rectus and lateral rectus muscles, at 12, 14, and 16 mm posterior to the respective insertions; medial rectus recession to 10 mm posterior to the insertion is likely to increase tissue injury and the associated postoperative complications. Muscle union surgery has been shown to be effective for restoration of the dislocated globe back into the muscle cone.6 In this study, we applied two sutures to connect the superior rectus and lateral rectus muscles more tightly, which facilitates the recovery of the vector force of the superior and lateral rectus muscles. Moreover, it makes the operation easier, which can achieve the same effect by connecting at 12 and 14 mm posterior to the lateral and superior rectus insertions.
In 2013, we adopted the classic Jensen procedure for lateral rectus and superior rectus muscles to correct esotropia fixus with high myopia. However, it was difficult to separate the superior rectus and lateral rectus muscles up to 14 to 16 mm posterior to their respective insertions. Since 2014, we modified the traditional surgical procedure in two respects: the union of the superior rectus and lateral rectus muscles was performed without splitting into two beams and the union of two pairs of sutures at approximately 12 and 14 mm posterior to the lateral and superior rectus after the insertion was performed. This kind of surgical approach has two advantages. First, by using two pairs of sutures, the union of the superior rectus and lateral rectus muscles is rendered closer to the posterior pole, and more muscle fibers are secured as compared to that with one pair of sutures, which promotes the recovery of the force vectors of the superior rectus and lateral rectus muscles. The superotemporal prolapsed eyeball is restored to its normal location, which allows free movement of the globe within the muscle cone. This procedure eliminates the adducting effect caused due to crowding of the superior rectus and lateral rectus muscles in the nasal orbit. The two-suture procedure effectively closes the gap in the muscle cone superotemporally. Second, the surgical procedure is relatively simple compared to the use of three pairs of sutures, and the union achieved 12 and 14 mm posterior to the insertions ensures comparable efficacy to that with use of three pairs of sutures and the Jensen procedure of the lateral rectus and superior rectus muscles 14 to 16 mm posterior to the insertion. The position of the sutures approximates the equator, which facilitates recovery of the muscle path and kinematics. The surgical procedure improved ocular motility and alignment significantly, without obvious complications, during either surgery or follow-up. Adjustable union of the superior rectus and lateral rectus muscles yielded even better results.
The 13 patients (15 eyes) treated by the modified surgical procedure were followed up to 6 months postoperatively. All patients showed significant improvement in ocular motility and alignment. They were all satisfied with the results. Our modified surgical procedure is convenient to perform and helps achieve superior outcomes.
- Ho TH, Lin MC, Sheu SJ. Surgical treatment of acquired esotropia in patients with high myopia. J Chin Med Assoc. 2012;75:416–419. doi:10.1016/j.jcma.2012.06.003 [CrossRef]
- Aoki Y, Nishida Y, Hayashi O, et al. Magnetic resonance imaging measurements of extraocular muscle path shift and posterior eyeball prolapse from the muscle cone in acquired esotropia with high myopia. Am J Ophthalmol. 2003;136:482–489. doi:10.1016/S0002-9394(03)00276-9 [CrossRef]
- Farid MF, Elbarky AM, Saeed AM. Superior rectus and lateral rectus muscle union surgery in the treatment of myopic strabismus fixus: three sutures versus a single suture. J AAPOS. 2016;20:100–105. doi:10.1016/j.jaapos.2015.11.015 [CrossRef]
- Ohta M, Iwashige H, Hayashi T, Maruo T. Computed tomography findings in convergent strabismus fixus [article in Japanese]. Nippon Ganka Gakkai Zasshi. 1995;99:980–985.
- Hayashi T, Iwashige H, Maruo T. Clinical features and surgery for acquired progressive esotropia associated with severe myopia. Acta Ophthalmol Scand. 1999;77:66–71. doi:10.1034/j.1600-0420.1999.770115.x [CrossRef]
- Yamaguchi M, Yokoyama T, Shiraki K. Surgical procedure for correcting globe dislocation in highly myopic strabismus. Am J Ophthalmol. 2010;149:341–346. doi:10.1016/j.ajo.2009.08.035 [CrossRef]
- Krzizoh TH, Kaufmann H, Traupe H. Elucidation of restrictive motility in high myopia by magnetic resonance imaging. Arch Ophthalmol. 1997;115:1019–1027. doi:10.1001/archopht.1997.01100160189008 [CrossRef]
- Yokoyama T, Tabuchi H, Ataka S, Shiraki K, Miki T, Mochizuki K. The mechanism of development in progressive esotropia with high myopia. In: Faber JT, ed. Transactions: 26th Meeting, European Strabismological Association. Boca Raton, FL: CRC Press; 2000.
- Yokoyama T, Ataka S, Tabuchi H, et al. Treatment of progressive esotropia caused by high myopia: a new surgical procedure based on its pathogenesis. In: Faber JT, ed. Transactions: 27th Meeting, European Strabismological Association. Boca Raton, FL: CRC Press; 2002.
- Wong I, Leo SW, Khoo BK. Loop myopexy for treatment of myopic strabismus fixus. J AAPOS. 2005;9:589–591. doi:10.1016/j.jaapos.2005.09.003 [CrossRef]
- Basmak H, Sahin A, Yildirim N. Surgical treatment of strabismus fixus associated with high myopia. Ophthalmic Surg Lasers Imaging. 2008;39:397–398. doi:10.3928/15428877-20080901-02 [CrossRef]
- Sturm V, Menke MN, Chaloupka K, Landau K. Surgical treatment of myopic strabismus fixus: a graded approach. Graefes Arch Clin Exp Ophthalmol. 2008;246:1323–1329. doi:10.1007/s00417-008-0885-5 [CrossRef]
- Durnian JM, Maddula S, Marsh IB. Treatment of “heavy eye syndrome” using simple loop myopexy. J AAPOS. 2010;14:39–41. doi:10.1016/j.jaapos.2009.11.018 [CrossRef]
- Akar S, Gokyigit B, Aribal E, Demir A, Göker YS, Demirok A. Surgical procedure joining the lateral rectus and superior rectus muscles with or without medial rectus recession for the treatment of strabismus associated with high myopia. J Pediatr Ophthalmol Strabismus. 2014;51:53–58.
Ocular Motility and Alignment of the Operated Eye at Different Time Points
|Cases||Eye||CROI at 33 cm Postoperative||Ocular Alignment||1 Day Postoperative||2 Weeks Postoperative||3 Months Postoperative||6 Months Postoperative||Ocular Motility|
|1||Left||> 45° ET, > 45° hypotropia||−5||Primary position||Primary position||Primary position||Primary position||Normal|
|2||Left||> 45° ET, > 45° hypotropia||−5||Primary position||10° ET, < 5° hypotropia||10° ET, 5° hypotropia||Lost to follow-up||Abduction -3|
|3||Right||> 45° ET, > 45° hypotropia||−5||Primary position||Primary position||10° ET, 5° hypotropia||10° ET, 5° hypotropia||Abduction -2|
|4||Left||> 45° ET, > 45° hypotropia||−5||Primary position||Primary position||Primary position||Primary position||Abduction -2|
|5||Right||30° ET, 30° hypotropia||−4||10° ET, < 5° hypotropia||10° ET, < 5° hypotropia||10° ET, < 5° hypotropia||15° ET, 5° hypotropia||Abduction -3|
|6||Right||> 45° ET, > 45° hypotropia||−5||15° ET, 5° hypotropia||20° ET, 5° hypotropia||30° ET, 5° hypotropia, 60ΔR/L7ΔET||Another surgery, primary position||Normal|
|7||Right||> 45° ET, > 45° hypotropia||−5||10° ET, < 5° hypotropia||15° ET, 5° hypotropia||15° ET, 5° hypotropia||15° ET, 5° hypotropia||Abduction -2|
|8||Left||> 45° ET, > 45° hypotropia||−4||Primary position||Primary position||Primary position||Lost to follow-up||Normal|
|9||Left||> 45° ET, > 45° hypotropia||−5||Primary position||Primary position||Primary position||Primary position||Abduction -2|
|10||Left||45° ET, 30° hypotropia||−5||Primary position||10° ET||15° ET||15° ET||Abduction -3|
|11||Both||> 45° ET, 30° hypotropia||−5||Primary position||Primary position||Primary position||Primary position||Abduction -3|
|12||Both||45° ET, 30° hypotropia||−5||Primary position||Primary position||Primary position||Lost to follow-up||Abduction -2|
|13||Left||30° ET, > 15° hypotropia||−5||Primary position||Lost to follow-up||Lost to follow-up||Lost to follow-up||Lost to follow-up|