Complex Strabismus Research Articles

Technique for MRI of ocular motility.

Our goal was to improve existing MR methods used in the assessment of ocular motility in the horizontal gaze direction, by using high resolution 20 s images and an experimental setup that prevents physiologically induced head motion in patients and eye convergence to the fixation point, thus improving the analysis of the relationships between the eyeball and the right muscle bellies in horizontal gaze exploration. The method has potential clinical applications for the diagnosis and/or follow-up of complex strabismus.

Grave complications after superior oblique tenotomy or tenectomy for brown syndrome

Introduction: Superior oblique tenotomy or tenectomy was the preferred procedure for Brown syndrome for decades. Superior oblique palsy was reported as a complication, but the complex nature of this palsy and the difficulty in treating it was not emphasized. We documented cases with distressing symptoms of unilateral and bilateral superior oblique palsy after a free tenotomy or tenectomy of the superior oblique tendon for Brown syndrome. Methods: Four cases referred for management of complex strabismus after superior oblique surgeryfor Brown syndrome were identified. Case histories, complications, and corresponding management are described in detail. Results: All cases presented with bothersome symptomatic superior oblique palsy—incomitant vertical deviation with significanttorsion, diplopia worse in functional down gaze, and anomalous head postures. Although reanastomoses of the superior obliquetendon was attempted in all cases,the procedure was modestly successful in only one case. Superior oblique palsy could not be reversed. After three procedures, Case 1 was orthotropic in primary, right, and left gaze but had a small intermittenttropia in down gaze. Case 2 underwent bilateral superior oblique operations. Despite a unilateral reanastomosed superior oblique tendon, hypertropia in down and left gaze and 15 degrees chin down position persisted. Case 3 showed correction of head tilt and a negative covertest 1 week after the second operation for iatrogenic superior oblique palsy, but stability of the procedure could not be ascertained. Case 4 had a successful attempt at reanastomosis and regained control of the vertical deviation as a hyperphoria. Both anomalous head posture and torsion improved. Conclusion: Superior oblique surgeryfor Brown syndrome may cause irreversible serious strabismus problems. Patients are left with distressing cyclovertical deviation worse in the functional position of gaze with significant torsional component that was resistant to therapy. Although adaptive mechanisms, such as an anomalous head posture, may develop, patients are leftwith a permanent disabilitythat could not be reversed. One should scrupulously adhere to the indications for surgery in Brown syndrome. Preoperative assessment of superior oblique function is stressed. An alternative surgical procedure that is potentially reversible should be considered.This should include a reliable method to recover both ends of the tenotomized superior oblique tendon in case the procedure needs to be modified at a later date.

Robinson's Computerized Strabismus Model Comes of Age

In this article we review our further development of D.A. Robinson's computerized strabismus model. First, an extensive literature study has been carried out to get more accurate data on the anatomy of the average eye and the eye muscles, and about how these vary with age and with refraction. Secondly, the force-length relations that represent the mechanical characteristics of the eye muscles in the model have been determined more accurately in vivo recently, and the model was changed accordingly. Thirdly, many parameters that were free in the original model and not derived from in vivo measurements were replaced by derivatives from in vivo measurements or made redundant. Fourthly, the ease of operation was improved greatly and the algorithms were made so much faster that a calculation for nine positions of gaze now takes ten seconds on a handheld HP 200LX Palmtop. The predictions of the model compared well with clinical results in horizontal muscle surgery, oblique muscle surgery, forced duction tests and abducens, oculomotor or trochlear palsies. Consequently, complex strabismus surgery in our clinic is now guided by the predictions of the computerized model.

Case Report Esotropia Following Bilateral Lateral Orbital Decompressions for Gravesʼ Disease

A 48-year-old woman with mild Graves' orbitopathy underwent bilateral lateral orbital decompressions through preauricular hairline incisions by a general plastic surgeon. Immediately postoperatively she developed marked left orbital and eyelid edema and incapacitating diplopia due to a large angle esotropia and severe bilateral abduction deficits. Examination 13 months later revealed normal visual acuities and a 90 prism diopter esotropia. She underwent complex strabismus surgery with resultant orthophoria in primary and down gaze. Four years later, a thin section computed tomographic scan revealed severe attenuation of both lateral rectus muscles with incarceration of the muscle bellies into the lateral osteotomy sites. This case demonstrates a rare, but avoidable, complication of orbital surgery for Graves' disease.

Adjustable Suture Strabismus Surgery

We examined 333 patients between the ages of 11 and 70 years who underwent strabismus surgery with adjustable sutures over a ten-year period. The type of strabismus, the number and amount of adjustments, the postoperative drift, and complications were evaluated. A large percentage of patients required adjustment to obtain the desired postoperative position. The postoperative drift patterns were characteristic for each type of preoperative deviation and were similar to that reported for nonadjustable procedures. Adjustable suture techniques were especially helpful in selected horizontal deviations, vertical deviations, and the more complex strabismus problems. The complications from adjustable suture operations in this series were minimal.