Computed tomography findings in convergent strabismus fixus

X-ray computed tomography (CT) of the eyeball and orbit revealed the cause of eye movement disorder in convergent strabismus fixus. The findings suggest that the disease can be diagnosed and treated at an early stage. Twelve cases of progressive esotropia with high myopia and 20 cases with normal visual acuity served as subjects in this study. The CT slice was parallel to the German horizontal plane, and the lens and medial and lateral rectus muscles were scanned. The average axial length of the affected eyes was significantly longer than in normal eyes. In progressive esotropia, the characteristic CT findings are an elongated eyeball, mechanical contact between the eyeball and lateral wall of the orbit, and a downward displacement of the lateral rectus muscle. Thus, it is reasonable to conclude that eye movement disorder in convergent strabismus fixus results from weakness of the lateral rectus muscle which has been displaced downward due to compression of the eyeball against the orbital wall.     

Nystagmus reduction by horizontal rectus retroplacements

Seven patients with nystagmus underwent large retroplacements of the four horizontal rectus muscles. Nystagmus was horizontal in all seven patients, but three had a vertical component. The horizontal nystagmus improved in all seven patients. All improved at least one line for distance and from three to five lines for near. Retroplacement of the four horizontal rectus muscles is a safe and effective procedure for the reduction of nystagmus and the improvement of vision, particularly for near vision, producing little or no induced strabismus or limitation of motility.     

MR imaging in patients with strabismus

The patients with strabismus, including 8 with superior oblique paresis, 1 with inferior rectus paresis, and 1 with congenital constant exotropia, were examined with MR imaging at 1.5 tesla (T) or 0.5T with a surface coil. Abnormal findings of extraocular muscles were identified in 8 of the 10 patients and most of them were consistent with the clinical findings. Deviation of the optic nerves was noted in 5 patients. Coronal short repetition time (RT) and echo time (ET) images were used to measure the concerned extraocular muscles and the optic nerves. The differences in diameters between the concerned extraocular muscles of both the diseased and normal eyes were calculated. MR imaging is considered to be advantageous and can be favorably used to observe and measure the extraocular muscles and other intraorbital structures in patients with strabismus.     

The oculocardiac reflex as a surgical aid in identifying a slipped or 'lost' extraocular muscle

The oculocardiac reflex during strabismus surgery has generally been regarded as a hazard capable of causing death. Six cases are presented which show a beneficial use of the oculocardiac reflex. Isolation of a previously slipped or 'lost' extraocular muscle can be difficult. In this series identification of the tissue as muscle was substantiated by observing a positive oculocardiac reflex when traction was placed on the suspected tissue. Each of the 6 dislodged extraocular muscles was the medial rectus muscle. Three of the muscles had been resected and 3 either recessed or tenotomised. In one patient, despite 6 previous strabismus operations, including 2 strabotomies on a muscle that slipped, and in another patient, who had a lapse of 6 years since the last strabotomy, when the slipped muscle was isolated, the oculocardiac reflex could still be elicited. To avoid abolishing the oculocardiac reflex during surgery the anaesthetist should be instructed to avoid the use of an intravenous parasympatholytic agent, such as atropine, at the time of induction and during the operation.     

Experimental strabismus in the kitten

1. We have examined the relative roles of visual and nonvisual input to striate cortex cells in causing the breakdown of binocularity produced by brief periods of visual-axis misalignment in kittens. 2. In the first study, the binocularity of single neurons recorded from the striate cortex was assessed in kittens reared with either surgical or optical strabismus. Surgical strabismus was induced by performing a unilateral medial rectus tenotomy, and optical strabismus by means of goggles that held prisms of equal power before the two eyes with their bases oriented in opposite directions. The loss of functional binocular connections was of comparable severity in these two groups of kittens. Control kittens, reared wearing goggles containing prisms whose bases were oriented in the same direction, showed normal levels of binocularity. 3. In the second experiment, normal kittens were given a surgical strabismus at around 1 mo of age and kept in total darkness for 2 days, 2 wk, or 4 wk. Cortical binocularity was normal in these kittens. 4. Finally, a group of kittens was reared in the illuminated colony with a symmetric surgical strabismus (bilateral medial rectus tenotomy). These kittens suffered a severe loss in cortical binocularity that was comparable to that seen in control kittens reared with asymmetric (unilateral) strabismus. 5. We conclude that altered visual input caused by misregister of the images falling in the two eyes is necessary and almost certainly sufficient to cause breakdown of cortical binocularity in kittens exposed to brief periods of divergent strabismus and that, when strabismus is induced surgically, this loss of binocularity is not dependent on the symmetry of the surgical manipulation; we thus find no evidence for a special role of afferents from the extraocular muscles in producing this effect.     

Diagnosis and surgical management of strabismus associated with thyroid-related orbitopathy

BACKGROUND: In the healing phase of thyroid-related orbitopathy, fibrosis and contracture of the extraocular muscles may result in restrictive ocular motility. Ocular misalignment may occur in both eyes and along three different axes of rotation. Successful surgical treatment depends on precise identification of the muscles that are restricting motility and producing the misalignment. METHODS: Between 1980 and 1994, 22 patients were surgically treated for restrictive strabismus caused by thyroid-related orbitopathy. Preoperatively, all patients underwent complete neuroophthalmic, oculoplastic, and orthoptic examinations. Analysis of ductions, measurement of torsion, and the use of monocular neutralization techniques were essential additions to the usual motility exam. Patients were placed into diagnostic categories based on the clinical pattern of extraocular muscle restriction. Adjustable recessions were done for all initial surgeries. RESULTS: Patients with unilateral inferior rectus involvement or with ipsilateral inferior rectus-contralateral superior rectus involvement had large vertical deviations (equal to or > 20 prism diopters [delta]). Patients with bilateral inferior rectus involvement had small vertical deviations (< 20 delta). Excyclotorsion correlated strongly with the presence of tight inferior recti. Vertical comitance (upgaze versus downgaze measurement of equal to or < 15 delta) correlated with the ipsilateral inferior rectus-contralateral superior rectus pattern of involvement. Vertical incomitance (upgaze versus downgaze measurement of > 15 delta) correlated with unilateral inferior rectus involvement. Eighteen of 22 patients had excellent postoperative alignment and elimination of diplopia in functional positions of gaze. Those with less favorable results developed reversal of the hypertropia and exotropia in downgaze. Sixteen out of 19 patients who underwent inferior rectus recession had induced inferior eyelid retraction. CONCLUSION: Different combinations of extraocular muscle restriction in this series of patients produced characteristic patterns of misalignment. Appropriate, adjustable, strabismus surgery was successful in restoring binocular vision in 21 out of 22 patients with a minimum of complications.     

Separation of several free polyamines and their acetylated derivatives by ion-pair reversed-phase high performance liquid chromatography

BACKGROUND: Convergence excess esotropia (EC) can be an additional component in all forms of strabismus. The most favourable prognosis is found in those cases where EC is associated with microtropia or bifoveal fusion, due to a better binocular potential. METHODS: 50 non selected cases were entered into the study and divided into two groups (Group A: EC with microtropia; Group B: EC with bifoveal fusion). All the patients were followed at the Lausanne Strabismus Unit and all cases underwent a bilateral medial rectus posterior fixation (Cüppers' Faden operation) placed at 13 mm from the original insertion. RESULTS: In Group A, the average reduction of angle of strabismus was 25 delta for near fixation, 20 delta in Group B. In both groups, the average decrease in angle for distance fixation was 6 delta. In Group A, 75% of cases gained some binocularity post-operatively, not only for distance but also for near fixation. In Group B, all the patients showed a normal response on the Lang stereotest post-operatively. CONCLUSIONS: In both groups of this study, a bilateral medial rectus retroequatorial myopexy was a satisfactory alternative for those patients who refused to wear bifocal glasses.     

Modifications of and special operating tricks in the classical technique of surgery against strabismus

Even nowadays the idea of most of the operations against strabismus is based on myectomy and reposition of the rectus muscles. At the Department of Ophthalmology of the University Medical School of Debrecen we use mainly these two methods of operation. At our Department we performed 1605 operations against strabismus during the last 10 years. 1269 of our patients had convergent, 336 had divergent strabismus. The majority of the operations were performed on patients less than 6 years of age, under general anesthesia. The outcome of the operation is successful if it results in a situation, in which torque affecting the eyeball stabilizes it in the normal position. The advantage of the combined surgical procedure is that the former muscular balance remains intact, and by relatively small intervention good results can be achieved. In the rectus muscles of squint patients anatomical and histopathological changes could be found, especially if they did not receive pleoptic treatment preoperatively. Depending on the direction of the strabismus one of the muscles is thicker, while the other is thinner, due to hyper- and hypofunction. Our surgical experience of many years showed that by modifying the classical technique of the operations with some fine technical tricks it was possible to increase the success rate. In our film we presented the right way of incising and handling the subconjunctival connective tissue (Tenon capsule) thus making it possible to lay it back to its original place at the end of the operation. This way the chance of postoperative scarring is reduced. We demonstrated how to test the contractility of the muscles by using muscle-hooks, that replaces the forceps test. In case of myectomy we demonstrated the tricks of how to handle the easiest and the finest way. In case of retroposition we can achieve perfect reconstruction and wound healing by using the shown simple technique. We also take much care of suturing the conjunctiva during operations performed on infants that is important because of their undisciplined behavior.     

Diagnostic assays in cytomegalovirus retinitis

The aim of the work is to inspect the influence of the treatment by using hyper-correcting prisms on the vertical deviations of the eyes and on the head's position in persons with nystagmus. We observed 4 persons with nystagmus without strabismus and 3 persons with convergent squint. In persons without strabismus the prismatic correction placed with an edge in the direction of the "calm's zone" (quiet's zone) to obtain the straight position of the head when looking forwards was applied. Twice a day during 10 minutes the patients were making the movement's exercises in the vertical and horizontal direction looking by the prism separately by each eye. This prism (often 35 D prism) was placed with the edge in the direction of greater deviation of the oblique inferior muscles and the left rectus inferior muscle. Patients with convergent strabismus were treated according to the principles of localization method with consideration of the localize exercises by using hyper-correcting prisms in the vertical and horizontal directions. Two patients had a surgery in order to eliminate not aesthetic and strong prisms which were applied because of large horizontal squint. One patient with convergent alternate squint with hyperactivity of both inferior oblique muscles and inferior rectus muscle of the left eye was treated without surgery, only by the conservative treatment with prisms. In all patients we obtained a straight position of the head despite of the nystagmus still existing during the eyes movements in some directions. The treatment by using hyper-correcting prisms can completely replace the surgical treatment or is able to supplement it and prevent relapses.     

Treatment of strabismus and nystagmus with botulinum toxin type A. An evaluation of effects and complications

PURPOSE: Injection of botulinum toxin type A into eye muscles leads to a temporary paralysis and the effects have been evaluated in strabismus or nystagmus. METHOD: A total of 112 patients with different types of concomitant and paralytic strabismus and acquired nystagmus were treated with botulinum toxin, according to well-established indications. RESULTS: The lasting effects of the injections on strabismic angle were largest in esotropia, consecutive exotropia and abducens palsy, and amounted to, on an average, 12 prism diopters or 6 degrees. The larger the strabismus the better was the effect. Repeated injections reduced the angle further. In complex nystagmus forms retrobulbar injections could be used. The side effects were mostly due to spread of botulinum toxin to the levator, producing ptosis (8%), or the inferior rectus muscle, causing vertical strabismus (10%). On an average 42% of the patients were later operated for strabismus and nystagmus. CONCLUSION: Injection of botulinum toxin A into eye muscles is a valuable adjunct to surgery in the treatment of strabismus and nystagmus.     

Transnasal endoscopic approach to expose the medial rectus from the annulus of Zinn to the penetration of Tenon''s capsule

Conventional strabismus surgery employs a conjunctival incision to gain access to Tenon's space where a wide variety of procedures are routinely performed on the tendon and anterior aspect of the extraocular muscles. Recently, transnasal endoscopic surgical techniques have gained acceptance as effective means of decompressing the medial wall and floor of the orbit in patients with thyroid-related orbitopathy. The orbital surface of the medial rectus and inferior rectus are exposed from the annulus of Zinn to a position close to where the muscles penetrate Tenon's capsule. In theory, this technique also provides the exposure necessary to locate and retrieve a "lost" medial rectus when the usual sub-Tenon's approach fails to recover the muscle. Cadaver studies demonstrate the feasibility of exposure and suture placement in the stump of a lost medial rectus with passage of the suture through Tenon's capsule to transmit the force of the muscle to the globe, provided that the lost muscle is retrieved before severe contracture develops.     

LTP, NMDA, genes and learning

PURPOSE: To describe the results of strabismus surgery on three patients with chronic progressive external ophthalmoplegia, a group of rare disorders characterized by ptosis and slowly progressive ophthalmoparesis that has been shown to result from defects in mitochondrial DNA. METHODS: Strabismus surgery using the adjustable suture technique was performed in three patients with strabismus and chronic progressive external ophthalmoplegia confirmed by clinical, biochemical, histopathologic, and genetic criteria. All three patients had mitochondrial DNA deletions. Two patients were exotropic; one patient was esotropic. RESULTS: Rectus muscle recessions were initially unsuccessful in correcting strabismus in one patient, although a subsequent procedure employing rectus muscle resections was successful in alleviating a significant head turn and improved ocular alignment. In the two other patients, a single procedure consisting of rectus muscle recessions combined with large rectus muscle resections successfully achieved good postoperative alignment. The amount of surgery performed in these three patients exceeded that predicted in standard strabismus tables. CONCLUSIONS: The myopathic process that results in chronic progressive external ophthalmoplegia renders rectus muscle recessions less effective compared with resections for correcting the associated strabismus seen in these patients. Rectus muscle resections therefore should be an integral procedure in the surgical management of the strabismus associated with chronic progressive external ophthalmoplegia.     

Long-term observation of ablatio-prophylaxis with kryopexy (author''s transl)

Five cases of laceration of an extraocular muscle without involvement of the globe or significant involvement of the adnexa occurred after injury with a pencil, mower blade, screen door, and building nail, and at surgery when the surgeon operated on the wrong muscle. The inferior rectus muscle was involved in three cases, the lateral rectus muscle in one, and the medial rectus muscle in one, Traumatic muscle laceration involves the inferior or medial rectus muscles more often than the other muscles. This may occur for two reasons: these muscles are closer to the corneoscleral limbus, and they are more visible during the protective blink with associated upward and usually outward movement of the globe (Bell's phenomenon). When the lacerated muscle could be found, it was repaired either by reinsertion to the sclera or reunion of the severed muscle segments. When the muscle could not be found, a muscle transfer procedure was carried out. Patients with fusion before injury regained fusion in part of the visual field after muscle repair.     

The diagnosis and treatment of abduction deficiencies

Deficient abduction can be due to both innervational deficiencies and/or mechanical restrictions. Innervational deficiencies include lateral rectus weakness or paralysis, myasthenia gravis, progressive external ophthalmoplegia nd Duane's syndrome with aberrant innervation to the lateral rectus muscle. Mechanical causes include restrictions on the medial side of the globe (a tight medical rectus due to endocrine ophthalmopathy, a contractured medial rectus muscle as a result of a lateral rectus paralysis, excessive resection of the medial rectus muscle, scarring and hemorrhage due to multiple previous operations upon the medial rectus), as well as a posteriorly inserted lateral rectus. This latter condition may result from a traumatically disinserted lateral rectus muscle, an excessively recessed lateral rectus muscle or a lateral rectus that has slipped from its attachment following strabismus surgery. Insufficient force for full abduction is caused by posterior insertion of the lateral rectus. The diagnosis of these various conditions is considered with reference to the forced duction, force generation and saccadic velocity tests. The treatment of these different causes of abduction deficiency is discussed noting that the approach to treatment depends upon the etiology of the abduction deficiency.     

Animal models of strabismic amblyopia: comparative behavioral studies

Visual acuity and visuo-motor behavior were assessed in various models of experimental amblyopia in cats (n = 15). Three models of strabismic amblyopia were studied: surgical esotropia by sectioning one lateral rectus muscle; comitant optical strabismus by rearing cats with goggles which placed a stationary wedge prism before one eye; and incomitant optical strabismus by rearing cats with goggles which placed a rotatable wedge prism before one eye. These cats were compared with normal and monocularly deprived cats. Clear amblyopic deficits were found in monocularly deprived, esotropic and rotating prism cats. The amblyopic deficits were graded among these preparations, being most severe in monocularly deprived cats and least severe in esotropic cats. The degree of behavioral amblyopia in these preparations was correlated with the extent of physiological abnormalities in visual cortex and the lateral geniculate nucleus. Fixed optical strabismus did not result in behavioral deficits and does not appear to be a good model of strabismic amblyopia. Variable optical strabismus, on the other hand, produced clear deficits in one eye, both behaviorally and physiologically, without impaired ocular motility.     

Sliding door technique for the repair of midline incisional hernias

We describe a technique that enables the autologous repair of large midline incisional hernias by restoring the functional musculoaponeurotic support of the abdominal wall. Unlike other methods of hernia repair, the essential step of the sliding door technique is the complete release of the rectus abdominis muscles from the anterior and posterior layers of their sheaths. The released muscles are thus overlapped and sutured together without tension. Another step of the technique is the release of both rectus sheaths by incising the aponeuroses of the external oblique muscles. We report on the use of this technique in 10 patients with midline incisional hernias (mean size of the abdominal musculofascial defect 14 x 11 cm). The patients were examined 14 months to 5.5 years after hernia repair. Two postoperative complications occurred: one marginal skin necrosis and one subcutaneous seroma. Recurrences were not observed. Ultrasound examination showed that the rectus muscles maintained their overlapped position postoperatively. Clinical muscle testing indicated that the strength of the released rectus muscles provides functional support to the reconstructed anterior abdominal wall.     

Childhood burns in south eastern Nigeria

A case has been presented in this article of congenital absence of bilateral inferior rectus muscles combined with restriction of the lateral rectus muscle and malinsertion of the inferior oblique muscle to the lateral rectus muscle. The surgical procedures for correction of the absence of the inferior rectus muscle and embryogenesis of extraocular muscles were also reviewed.     

Functioning muscle transplantation after wide excision of sarcomas in the extremity

Free functioning muscle transplantation was performed after resection of 23 sarcomas in the extremity. There were 21 soft tissue sarcomas and two malignant bone tumors. The tumor resection was performed with a wide margin in all except two patients who had a marginal margin in a limited area. The consequent extensive soft tissue defect received free musculocutaneous flaps, the motor nerve of which was repaired in the recipient site. The most frequent procedure was latissimus dorsi transplantation to replace thigh muscles in 17 cases. The other donors included gracilis, tensor fascia lata, and rectus femoris, which were selected according to the site of defects. Patients were followed up for a mean of 60 months (range, 13-119 months). The grafted muscles showed reinnervation at a mean of 6 months postoperatively in all patients except for a 75-year-old patient. Obtained contraction of the muscles was powerful in 18 patients and fair in four patients. Performance of the salvaged limb significantly improved after recovery of the muscles. Although there were five distant recurrences, local recurrence was seen in one patient with systemic metastases. Because muscle loss could be compensated functionally for by the innervated free muscle transfer, the method encouraged surgeons to perform more radical tumor excisions and this may have contributed to the excellent local tumor control that was achieved. Thus, functioning muscle transplantation was extremely useful in limb salvage surgery from the functional and oncologic viewpoints.     

High resolution, dynamic, magnetic resonance imaging in complicated strabismus

Strabismus cases, especially after previous surgery or trauma to extraocular muscles, often present diagnostic challenges. Conventional clinical tests are helpful in some cases but may be inconclusive. High resolution, dynamic, orbital magnetic resonance imaging (MRI) may yield additional critical information about orbital and extraocular muscle anatomy and function. We report four complicated strabismus cases for which dynamic surface coil MRI helped formulate a precise diagnosis and the most appropriate surgical plan.     

Study of the olfactory effects of citronellal in the environmental air

The study was performed using four cadavers of adult persons with the method of preparation. The access to the ligament was obtained by the removal of the inferior orbital wall and inferior orbital adiposal layer. Topographical anatomy of Lockwood ligament, its interrelations with inferior rectus and oblique muscles and attachment to lateral and medial orbital walls were studied. Lockwood ligament, the transverse fascial structure that supports the eyeball, stabilizes it, providing the framework for inferior rectus and oblique muscles of the eye.