Calibration of saccades in infants.

Prism induced shift of fixation was measured in 12 cooperative patients utilizing electro-oculography. These recordings were compared with a voluntary shift in fixation of the same eye. No differences were noted when comparing voluntary movements with prism induced movements. Trial of the prism induced eye movement for calibration in a group of 10 infants has shown it can be used successfully.

Double elevator palsy.

Of 15 patients with monocular limitation of elevation, six had no deviation in primary gaze while the remaining nine had hypotropia of the involved eye. Twelve of 15 patients had restriction to upgaze on forced duction testing. Eleven of these 12 had normal upward saccadic velocity, which suggested normal elevator function. Four patients had reduced saccadic velocity, which indicated true elevator weakness. Superior rectus muscle paresis alone could account for limited elevation and would reduce upward saccadic speed. Patients with a diagnosis of "double elevator palsy" only infrequently (about one quarter of cases) have palsy of an elevator muscle and may have only a single elevator palsy. The identification of a true elevator weakness is most important in planning management.

Saccadic velocity studies in superior oblique palsy.

Eighteen patients (21 eyes) with superior oblique palsy had vertical saccadic velocity measurements in primary gaze, adduction, and abduction. No noticeable difference was found when upward saccades were compared with downward saccades in all fields of gaze. Thus, saccadic velocity studies would not be helpful in the diagnosis of superior oblique palsy.

Saccades with limited downward gaze.

Fourteen patients with monocular limitation of downward gaze had vertical saccadic velocity measurements. Patients with orbital floor fracture and endocrine ophthalmopathy were excluded from the group. In four cases (29%), the difference between upward downward saccadic velocities was 20% or less. These patients were not thought to have any evidence of inferior rectus muscle paresis. In ten cases (71%), the difference between upward and downward saccades varied between 46% to 275% (average, 115%), upward saccades being more rapid in each case. These cases were all believed to have moderate to great inferior rectus muscle palsy. In one subject with a lidocaine hydrochloride-induced inferior rectus muscle palsy, upward saccades were 135% faster than downward saccades. These findings were compared with those in patients with monocular limitation of elevation, and the surgical management was reviewed.

The adjustable Harada-Ito procedure.

In four patients with superior oblique palsy, symptomatic excyclotorsion was present without a substantial vertical deviation. Surgery of anteriorizing and lateralizing the anterior fibers of the superior oblique tendon on an adjustable suture was performed (adjustable Harada-Ito procedure). the morning after surgery, adjustment of the suture was made to eliminate the torsional deviation. The suture was loosened when an overcorrection was present and was tightened when an undercorrection was present. Follow-up varied from two to 20 months. All patients remained free of torsional symptoms and no vertical deviation was induced. In addition, the eyes operated on had no limitation of elevation in adduction. The technique allows the surgeon to more exactly adjust the advanced fibers of the superior oblique tendon so as to minimize or eliminate the excyclotorsion and eliminate symptomatic complaints.

The treatment of A and V patterns by monocular surgery.

Eleven patients with "A" or "V" pattern strabismus and the absence of notable oblique muscles overactions, were operated on, using the technique of monocular vertical displacement of the horizontal rectus muscles. The average correction of the A or V pattern was 16.5 delta. Subjective torsional complaints were not reported by any of the patients. Torsion was measured postoperatively with the Maddox rod, Maddox wing, and amblyoscope. The average torsional measurement, at least one month postoperatively, was 1.6 degrees with a range of 0 degrees to 7 degrees. It was concluded that monocular vertical displacement of the horizontal rectus muscles can result in satisfactory correction of the A or V pattern and produces no substantial postoperative torsional symptoms or substantial measured torsion at both distance and near fixation.

A model for eye muscle surgery.

An inexpensive model for demonstrating and practicing strabismus surgery is described here. The figure-of-8 technique, adjustable rectus recession and resection surgery, and various types of conjunctival closure have been performed on the model. The model can also be helpful in demonstrating and practicing typical recession, resection, advancement, tucking, and marginal myotomy procedures to residents in ophthalmology.

Adjustable rectus muscle recession surgery. A follow-up study.

Fifty-six patients underwent an adjustable rectus muscle recession procedure. This procedure permits the surgeon to enhance or diminish the amount of muscle recession on the evening after surgery or the first postoperative day if cover-testing indicates an inappropriate amount of undercorrection or overcorrection. The adjustable rectus muscle recession technique seems to be a practical and effective means to change the strabismic deviation postoperatively. The procedure requires patient cooperation and is most suitable for patients age 15 years and older. The procedure has been effective in altering the angle of deviation, and this alteration has been stable during the follow-up period in most cases. In this initial series, the reoperation rate was low, postoperative alignment was excellent, and complications were minimal.

Restrictive factors in strabismus.

Either muscle weakness (paresis) or mechanical restrictions can account for diminished ocular rotation. In practice, restrictions are more commonly seen. The forced duction test, differential intraocular pressure measurement and saccadic velocity studies can all assist in documenting the presence of restriction. Restrictions frequently occur with orbital floor fracture, endocrine ophthalmopathy and Brown's syndrome, and following multiple stabismus procedures, orbital or retinal detachment surgery, or muscle transposition surgery. They also occur as a result of antagonist muscle contracture after rectus muscle palsy or they may be due to orbital tumor or inflammation.

Saccadic velocity measurements in internuclear ophthalmoplegia.

Five patients with internuclear ophthalmoplegia had horizontal saccades measured by electro-oculography. In all patients, abduction saccadic velocities were normal while adduction saccades were slowed either binocularly or monocularly. In one patient, adduction saccades were reduced in velocity, even though full adduction was present. Saccadic velocity measurements may be helpful in diagnosing internuclear ophthalmoplegia, especially in the early or subclinical case. As bilateral internuclear ophthalmoplegia frequently suggests multiple sclerosis, prolonged examination with more sophisticated and difficult diagnostic tests is avoided.

Treatment of unilateral acute sixth-nerve palsy with botulinum toxin.

We studied 29 consecutive patients with acute unilateral sixth-nerve palsy, who received botulinum toxin injection to the antagonist medial rectus muscle. The average interval between onset of palsy and treatment was 40 days and the mean follow-up from the last injection was 14 months. Before treatment, esotropia in the primary position ranged from 12 to 45 prism diopters and limitation to abduction in the affected eye ranged from -2 (approximately 15 degrees lateral to midline) to -6 (15 degrees nasal to midline). After treatment, 22 of 29 patients (76%) had complete recovery of motility as determined by version testing. Of the seven patients with a residual abduction deficit, two had fusion in the primary position, three had fusion with prismatic correction, and two patients required subsequent surgery. Botulinum toxin injection seems to be an effective treatment option in cases of acute unilateral sixth-nerve palsy.

Change in the cycle of circadian strabismus.

PURPOSE/METHODS: We observed a change in the typical circadian, 24-hour pattern of strabismus (esotropia) in a 2-year-old patient. Methods used include study of the history of the deviation pattern, observation, and measurement of the deviation on the day after travel and six weeks later. RESULTS/CONCLUSIONS: The patient responded to standard recession-resection surgery with a straight eye position daily, through three months of follow-up. Rapid travel over six time zones probably caused the change in the circadian pattern of strabismus.

Strabismus and pseudostrabismus with retrolental fibroplasia.

Three patients with temporal displacement of the macular secondary to retrolental fibroplasia had true strabismus in associations with amblyopia and pseudostrabismus related to a large, positive angle kappa. In one case, a headturn associated with the neutral point of nystagmus was also a presenting problem. Ocular deviation was measured by the light reflex test and the prism cover test, with particular attention paid to adequate cosmetic alignment. Large amounts of prism placed before the fixating eye resulted in loss of visual acuity, while eyes placed in a parallel position by surgical means may not appear to be straight. Thus, surgery can result in parallel ocular alignment while prismatic therapy may be required to center the pupillary light reflex and to provide satisfactory cosmetic appearance.

Horizontal saccadic velocities in Duane's syndrome.

Horizontal ocular saccadic velocities were measured by electro-oculography in 33 patients with Duane's syndrome. In 28 patients with limited abduction associated with retraction on adduction (Type 1), abduction saccadic velocity was markedly reduced while adduct-on saccades were moderately slow. In three patients with exotropia and good abduction but associated limited adduction and retraction on adduction (Type 2), abduction velocity was good, while adduction saccadic speed was slow. In two patients with limited abduction and adduction with retraction on adduction (Type 3), abduction and adduction saccadic velocity was appreciably slow. Ocular electromyographic testing selected patients indicated that slow abduction saccades could be explained by absence of lateral rectus muscle recruitment, while slow adduction saccadic speed could be explained by paradoxical innervation of the lateral rectus muscle.

The O'Connor cinch revisited.

The modified O'Connor cinch operation is a useful, but little used, adjustable resection operation. For increased understanding of its shortening and adjustment characteristics, a standard cinch was performed in animals and patients with strabismus. Animal studies showed that, as each strand of the cinch was removed, a small, relatively equal release of the cinch effect occurred. Measurement of the shortening obtained in patients with strabismus showed a consistent resection effect of about 4 mm. Review of 17 cases in which the cinch was used as part of the surgical treatment showed the technique to be adjustable by reducing the overcorrection in 6 cases. Ten to 20 prism dioptres of reduction in the deviation was obtained with adjustment of the cinch on the first postoperative day. All 17 cases had satisfactory adjustment. The largest residual deviation was 12 prism dioptres.

Adolescent cystinosis: a clinical and specular microscopic study of an unusual sibship.

Six members of a sibship originally consisting of 8 offspring lived to teenage. Five of these developed the adolescent form of cystinosis. Since adolescent cystinosis is autosomal recessive, such a high incidence of affected members is of uncommon occurrence. Depending on whether the sibship size (n) is known as 6 to 8, it should occur only in approximately 1.5% or 5.8% of sibships of corresponding size. Specular microscopy was used to study the corneal stroma of all 3 of the living, affected members of this sibship and the conjunctiva of one of the siblings. Vivid, needle-shaped crystals were observed in the corneal stroma. Smaller, variably shaped crystals were observed in the conjunctiva. The crystals seen with specular microscopy fit the description of those studied with light and electron microscopy.

Giant orbital cyst after strabismus surgery.

We describe the clinical, histopathologic, and radiologic findings and management of a patient who had a giant orbital cyst after reoperative strabismus surgery. In the case report, we describe, in detail, a giant orbital cyst developing on the medial side of the globe after the third operation for repair of strabismus. Imaging studies, including computed tomographic (CT) scan and orbital ultrasound, demonstrate the findings. The observations at surgery and the surgical pathologic condition of the cyst are described. The orbital cyst was successfully removed, advancing the remaining medial rectus muscle and recessing the lateral rectus muscle, which resulted in reduction of a large-angle exotropia to a small exodeviation. Adduction was improved but not normalized. The pathologic examination indicated a benign inclusion cyst of the conjunctiva with fibrosis and chronic inflammation. A possible cause of this type of cyst is an epithelial remnant inadvertently placed with the muscle substance during previous surgery.

Forced duction, active force generation, and saccadic velocity tests.

The forced duction test reveals information about mechanical limitations to full ocular rotation. When voluntary ocular rotation is limited, and the forced duction test is completely free, paresis of an extraocular muscle is suggested. The active force generation test and saccadic velocity measurements both provide information about the active forces available to move the globe. Active force can be felt with the forceps in the force generation test. These forces can be measured quantitatively with the calibrated Scott forceps. The saccadic velocity test measures the work an extraocular muscle performs (the eye movement) but does not measure active force directly. The force available is inferred by comparing saccadic velocity measurements to normal control values. This test is especially useful in infants and children, in whom the force duction test cannot be done without general anesthesia, and whose cooperation is insufficient to allow force generation measurements to be performed. It is likely that future improvements in instrumentation and further knowledge of basic oculomotor mechanisms will increase the value of these techniques in clinical strabismus.

Quantitative evaluation of the strabismus patient.

Quantitative techniques of measuring ocular motor function have proven extremely useful in evaluating the strabismus patient. The forced duction test has been valuable in determining the extent of mechanical restrictions and, in some instances, indirectly provides information about muscle strength. The active force generation test is a direct measure of active muscle force, while the differential intraocular pressure test (which may be easier to perform) provides data on active force indirectly. Saccadic velocity studies reveal the presence of muscle paresis or paralysis as contrasted with restrictions. Several neuro-ophthalmic conditions have typical eye movement patterns that are helpful in identifying them correctly. Saccadic velocity tests can also be helpful in diagnosing a disinserted extraocular muscle. Quantitative studies assist in more accurate diagnosis and are helpful in therapeutic decision making in terms of the timing and type of therapy indicated.

Think superior oblique palsy.

Superior oblique palsy is thought to be the most frequent cause of acquired vertical diplopia. It is often the result of blunt head trauma but may also be caused by brain tumor, meningitis, diabetes, lesions of the cavernous sinus, and superior orbital fissure as well as arteriosclerosis. The characteristics frequently include a small vertical strabismus in primary gaze, ipsilateral inferior oblique overaction with an increased hypertropia to the contralateral side, a "V" pattern, excyclotorsion, and a positive Bielschowsky head tilt test to the ipsilateral side. In a typical case, it is not difficult to make the proper diagnosis. Several patients will be described whose superior oblique palsy was marked by an association with another motility disturbance.