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Deficiency of adaptive control of the binocular coordination of saccades in strabismus.

Disconjugate (different in the two eyes) oculomotor adaptation is driven by the need to maintain binocular vision. Since binocular vision is deficient in strabismus, we wondered whether oculomotor disconjugate adaptive capabilities are deficient in such subjects. We studied eight adult subjects with constant, long-standing convergent strabismus of variable angles (4-30 prism D). No subject had severe amblyopia. Binocular vision was evaluated with stereoacuity tests. Two subjects had peripheral binocular vision and gross stereopsis; two other subjects had abnormal retinal correspondence and abnormal or pseudo gross stereopsis. In the other subjects binocular vision and stereopsis were absent. To stimulate disconjugate changes of saccades, subjects viewed for 20 min an image that was magnified in one eye (aniseikonia). Subjects with residual peripheral binocular vision and even subjects with pseudo or abnormal binocular vision showed disconjugate changes of the binocular coordination of their saccades; these changes reduced the disparity resulting from the aniseikonia. In contrast, for subjects without binocular vision the changes were not correlated with the disparity induced by the aniseikonia. Rather, these changes served to improve fixation of one or the other eye individually.

Adaptation, Physiological↗

Efficacy of diclofenac versus dexamethasone for treatment after strabismus surgery.

OBJECTIVE: To compare the efficacy of topical diclofenac sodium 0.1% versus dexamethasone 0.1% on the conjunctival healing process and on intraocular pressure (IOP) after strabismus surgery. DESIGN: A randomized clinical trial. PARTICIPANTS: Forty consecutive pediatric patients who underwent strabismus surgery. INTERVENTION: The patients were assigned before surgery to receive topical diclofenac 0.1% (study group, 20 patients) or dexamethasone 0.1% (control group, 20 patients) from immediately after surgery to up to 4 weeks after surgery (both combined with chloramphenicol 0.2%, polymyxin B sulfate 2500 U). MAIN OUTCOME MEASURES: Between-group comparison of five parameters: patient discomfort, conjunctival chemosis, inflammation, gap, and intraocular pressure (IOP) at 1, 2, and 4 weeks after surgery. RESULTS: At postoperative week 2, the diclofenac-treated group showed significantly less patient discomfort and less conjunctival inflammation, edema, and gap than the dexamethasone group (P: = 0.003, P: = 0.04, P: = 0.02, P: = 0. 001, respectively). At week 4, the study patients continued to show less discomfort and conjunctival gap (P: = 0.02). The dexamethasone group showed a significant change in IOP between the preoperative and the fourth postoperative week (P: = 0.001 in the right eye, P: = 0.0005 in the left eye) and an increased prevalence of higher IOP during the fourth postoperative week (P: = 0.01 in the right eye, P: = 0.02 in the left eye). Thirty-eight percent of the dexamethasone group showed an increase in IOP to more than 21 mmHg during the four postoperative weeks. No increase in IOP was noted in the diclofenac group. CONCLUSIONS: Topical diclofenac is superior to dexamethasone for each of the five postoperative parameters examined. Its maximal effect occurred at 2 weeks after surgery, without an increase in IOP or in local subconjunctival hemorrhage.

Adolescent↗

Correction of restricted extraocular muscle motility in surgical management of strabismus in graves' ophthalmopathy.

OBJECTIVE: To compare the success rates for strabismus surgery designed to correct limitation of duction with surgery designed to correct deviation in patients with Graves' ophthalmopathy. DESIGN: Retrospective nonrandomized comparative trial. PARTICIPANTS: One hundred thirty-seven patients with Graves' ophthalmopathy who had undergone at least one extraocular muscle surgery were divided into two groups: those whose first surgery occurred before June 1997 (control group) and those whose first surgery occurred in June 1997 or thereafter (case group). INTERVENTIONS: Extraocular muscle surgery primarily directed at either correcting deviation (control group) or correcting limitation of ductions (case group). MAIN OUTCOME MEASURES: Postoperative deviations in the primary position were measured in prism diopters 30 to 180 days after surgery. A postoperative deviation of less than 5 diopters was considered a successful surgical outcome. RESULTS: Patients undergoing strabismus surgery specifically designed to correct limitation of duction achieved a 74% success rate compared with a 44% success rate in the control group (P < 0.01). Furthermore, the rate of reoperation in this group was only 27% compared with 44% in the control group (P < 0.04). CONCLUSIONS: Compared with surgery aimed primarily at the correction of deviation, extraocular muscle surgery tailored to address restriction of ductions in patients with Graves' ophthalmopathy is associated with improved surgical success of initial realignment and with a lower rate of reoperation

Eye Movements↗

Reoperations in strabismus.

Reoperations in strabismus are done for overcorrection, undercorrections, and new strabismus problems such as dissociated vertical deviation and ptosis. Each patient requiring reoperation should be thoroughly evaluated on the basis of current findings with the understanding that some alteration in anatomy will be found. Restrictions must be freed and muscle force balanced to first provide straight eyes in the primary position and secondly the best vision possible. With persistence, 80% to 90% of patients requiring reoperation can expect a satisfactory end result.

Adult↗

Botulinum toxin injection into extraocular muscles as an alternative to strabismus surgery.

Sixty-seven injections of botulinum. A toxin were given to patients for correction of strabismus. No systemic complications of any kind have occurred. The maximum time of paralysis occurs four to five days following the injection, and then gradually diminishes, depending on the dose. The maximum correction of strabismus has been 40 prism diopters. The maximum follow-up following injection is six months. Injection of botulinum A toxin into extraocular muscle to weaken the muscle appears to be a practical adjunct or alternative to surgical correction.

Acetylcholine↗

Differential intraocular pressure in strabismus diagnosis.

An evaluation of the differential intraocular pressure test in the diagnosis of non-comitant strabismus is described and the results compared with findings in ten normal subjects. Increased intraocular pressure occurring when an eye cannot complete a full duction indicates both the existence of a restriction and the presence of underlying muscle force generation. The differential intraocular pressure test is easily performed, non-invasive, generally reliable, and can be performed on children who are unlikely to cooperate with other types of diagnostic procedures. Although false-negative results may occur, this test nevertheless provides useful additional information to that normally obtained in a motility examination. When combined with passive forced ductions, an accurate picture of both active and passive components of the strabismus may be determined.

Adolescent↗

Delayed conjunctival closure in adjustable strabismus surgery.

Adjustable suture strabismus surgery has proved to be a significant aid in handling difficult strabismus cases, and various methods of conjunctival closure have been discussed. A new method of conjunctival closure, enabling direct visualization and manipulation of the muscle with minimal tissue drag during adjustment, is described. The conjunctiva can be fully closed over the knot after adjustment, providing increased patient comfort and a better cosmetic result.

Conjunctiva↗

Persistent strabismus presenting after cataract surgery.

To determine causative factors of persistent strabismus presenting after cataract surgery, the surgical techniques and subsequent motility findings of eight patients who had persistent postoperative strabismus were studied. In two of the eight patients, complications related to the placement of the bridle suture were believed causative based on subsequent surgical findings. A similar etiology could be speculated in an additional three patients. An isolated vascular accident coincident to the cataract operation could account for a sixth case. The final two patients were believed to have a decompensated congenital fourth nerve palsy. In no patients could the myotoxic effect of a local anesthetic or the hypoxic effect of an ocular pressure-reduction device plausibly account for the deviation.

Aged↗

Teller acuity cards versus clinical judgment in the diagnosis of amblyopia with strabismus.

Teller acuity card testing, which is a form of the preferential-looking procedure, is a popular way of assessing visual acuity in preverbal patients. The authors suspected that the clinical judgment of a pediatric ophthalmologist is superior to the Teller acuity cards in diagnosing amblyopia when strabismus is present. Acuity card and fixation preference measurements on each eye were compared at the same clinical visit in a group of 108 strabismic patients. The authors found that the acuity cards could be used to detect amblyopia. However, the pediatric ophthalmologist was more sensitive in diagnosing amblyopia than the Teller acuity cards in the presence of strabismus.

Amblyopia↗

Errors in the three-step test in the diagnosis of vertical strabismus.

The Parks three-step test is the standard for diagnosing which isolated cyclovertical muscle is palsied. It does not, however, tell the examiner if in fact one is dealing with a palsy of one cyclovertical muscle. Numerous other causes of vertical strabismus may have a positive Bielschowsky head tilt test. The use of the three-step test in these clinical situations may lead to incorrect diagnosis and treatment. These clinical conditions include contracture of the vertical recti, paresis of more than one vertical muscle, dissociated vertical divergence, previous vertical muscle surgery, skew deviation, myasthenia gravis, and small nonparalytic vertical deviations associated with horizontal strabismus. Several diagnostic steps in addition to the three-step test are necessary to tell if one is in fact dealing with a palsy of a single cyclovertical muscle.

Adult↗

Botulinum treatment of childhood strabismus.

Four hundred thirteen children ranging in age from 2 months to 12 years were treated for strabismus by botulinum injection of extraocular muscles. An average of 1.7 injections per patient was given. Follow-up at an average of 26 months after the last injection (minimum, 6 months) was available on 362 children (88%). The frequency of correction of 10 prism diopters (PD) or less in various groups of strabismus cases was: all 362 cases, 61%; all esotropia, 66%; infantile esotropia, 65%; and exotropia, 45%. Smaller deviations (10-20 PD) were more frequently corrected (73%) than were larger deviations (20-110 PD, 54%). The frequency of correction to 10 PD or less of previously operated cases was not different from that of unoperated cases. There was no globe perforation, amblyopia, or visual loss produced by the injection treatment in this series.

Botulinum Toxins↗

Improvement of compensatory head postures after strabismus surgery.

PURPOSE: To determine the incidence and relative frequencies of orientations of compensatory head postures (CHP) and success in surgically treating the CHP seen in patients with pure lateral rectus paresis (group I), superior oblique paresis (group II), Duane syndrome (group III), Brown syndrome (group IV), and congenital motor nystagmus (group V). METHODS: The authors retrospectively reviewed all patients assessed and treated between 1985 and 1991 with these five conditions. Frequencies and orientations of the CHP were determined in all patients in each group. The success of surgery in eliminating the CHP in the subgroups of patients who underwent surgery to treat the CHP also was determined. RESULTS: The frequencies of CHP were 29.0% of 93 group I cases, 71.2% of 139 group II cases, 68.1% of 91 group III cases, 17.4% of 35 group IV cases, and all 23 group V cases, for an overall incidence of 56.7% of 381 patients. For patients who underwent surgery to eliminate a CHP, success rates were 85.7% of 21 group I cases, 75.6% of 41 group II cases, 87.2% of 47 group III cases, 100% of 5 group IV cases, and 78.3% of 23 group V patients, for an overall success rate of 82.5% of 137 surgical cases. CONCLUSION: Because CHP is seen frequently in strabismus and nystagmus disorders, ocular causes must be ruled out in any case of an anomalous head posture. Appropriately planned surgery for CHP caused by incomitant strabismus or eccentric nystagmus null zones has a high rate of success in eliminating CHP.

Adolescent↗

Postoperative binocularity in adults with longstanding strabismus.

The authors tested preoperatively and postoperatively for binocularity with the Bagolini lenses in a series of 359 adults who underwent surgery for long-standing constant strabismus. Eighty-six percent of patients showed a binocular response with the Bagolini lens test almost immediately after surgery. Regardless of the type of deviation present preoperatively, the duration of strabismus, or the depth of amblyopia in the deviating eye (if present), the vast majority of patients developed binocularity. The development of binocularity with the Bagolini lenses after surgery appears to be related to the stability of the postoperative ocular alignment.

Adult↗

The association of strabismus, amblyopia, and refractive errors in spasmus nutans.

PURPOSE: Spasmus nutans is a condition that includes asymmetric nystagmus and occurs during the amblyogenic period. Because specific alterations in early visual experience are known to be associated with changes in visual development, relations between spasmus nutans and abnormal visual sequelae were examined. METHODS: The records of 18 patients with spasmus nutans were reviewed retrospectively. The incidence of strabismus, amblyopia, anisometropia, and astigmatism was compared with published age-matched control subjects. RESULTS: There was a significantly higher incidence of strabismus (10 of 18) and amblyopia (8 of 18) of the eye with the greater amplitude of nystagmus. No correlation of refractive error with lateralization of nystagmus could be established. Twelve of 18 patients required spectacles for improvement in visual acuity and for treatment of amblyopia. Best-corrected visual acuity averaged 1.20 Snellen lines poorer than age-adjusted normative values; however, loss of visual acuity was, in most cases, symmetric and not related to lateralization of nystagmus. CONCLUSION: Early detection and treatment of anticipated abnormal visual issues in patients with spasmus nutans will optimize visual outcomes.

Age of Onset↗

A randomized, double-blind, placebo controlled comparison of droperidol, ondansetron, and metoclopramide for the prevention of vomiting following outpatient strabismus surgery in children.

STUDY OBJECTIVE: To compare the efficacy of ondansetron, droperidol, or metoclopramide with placebo in preventing postoperative vomiting following strabismus surgery. STUDY DESIGN: Randomized, double-blind, placebo-controlled clinical trial. SETTING: University outpatient surgery center. PATIENTS: 160 ASA physical status I and II children ages 1 to 12 years who were scheduled for strabismus surgery. INTERVENTIONS: Administration of either ondansetron 100 mcg/kg, metoclopramide 250 mcg/kg, droperidol 75 mcg/kg, or placebo intravenously after induction of anesthesia. MEASUREMENTS AND MAIN RESULTS: Both ondansetron and droperidol were superior to metoclopramide and placebo in preventing predischarge vomiting, with incidences of 5%, 5%, 32%, and 25%, respectively. However, there was no difference in the incidence of postdischarge vomiting among the groups (ondansetron 25%, droperidol 25%, metoclopramide 20%, and placebo 25%). CONCLUSIONS: While both ondansetron and droperidol are more effective than metoclopramide when compared with placebo in decreasing the incidence of predischarge vomiting, none of these drugs was more effective than placebo in decreasing the incidence of postdischarge vomiting. Recovery from anesthesia was not significantly different among the groups as assessed by time to awakening, initial Steward score, and time to discharge.

Ambulatory Surgical Procedures↗

Intraoperative sponge 5-fluorouracil to reduce postoperative scarring in strabismus surgery.

INTRODUCTION: To determine whether 5-fluorouracil is effective in reducing scarring after strabismus surgery we used rectus muscle surgery in experimental animals to compare a single intraoperative dose of 5-fluorouracil with mitomycin C and to compare results in similarly treated controls not receiving these antimetabolites. METHODS: Muscle resections were performed on eight rabbits (16 eyes). Four eyes had 5-fluorouracil (50 mg/ml), and four eyes received mitomycin C (0.2 mg/ml), each of which was applied during surgery on an ophthalmic sponge for 5 minutes. Eight eyes served as controls. Six weeks after surgery conjunctival vascularity, muscle length-tension curves, muscle disinsertion force, and the histologic degree of scarring were assessed. RESULTS: The mitomycin C-treated eyes clearly had more conjunctival avascularity and a lower disinsertion force. Both treated groups had flatter length-tension curves and less scarring on histologic examination than the control eyes. CONCLUSIONS: Antifibroproliferative therapy with intraoperative sponge 5-fluorouracil appears as effective as, and is possibly safer than, mitomycin C. It may be a useful adjunct in recurrent strabismus surgery or in other situations where a risk of excessive postoperative scarring exists.

Administration, Topical↗

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.

Adult↗

Instrument-induced measurement errors during strabismus surgery.

PURPOSE: The purpose of this study was to determine the clinical setting where errors in measurements of muscle position during strabismus surgery made by the Scott curved ruler or by calipers become important and to characterize the magnitude of those errors. METHODS: Geometric analysis was used to determine the measurement error between true arc lengths of 3.0 to 20.0 mm versus Scott curved ruler measurements and caliper measurements for axial lengths ranging from 18 to 30 mm. RESULTS: For measurements less than 9.0 mm, neither the Scott curved ruler nor calipers had any clinically important measurement error for any axial length. For axial lengths substantially smaller than 21 mm or larger than 24 mm, the Scott curved ruler, although more accurate than calipers, caused clinically important measurement errors with arc length measurements as small as 12 mm in very small eyes and 14 mm in large eyes. For axial lengths of 30 mm or more, both calipers and the Scott curved ruler had similar accuracy for measuring long arc lengths. CONCLUSIONS: Both the Scott curved ruler and calipers are accurate in measuring arc lengths 9.0 mm or less. For longer arc length measurements, accuracy becomes dependent on axial length. The Scott curved ruler, although substantially more accurate than calipers for most common axial lengths, can introduce clinically important measurement errors when measuring arc lengths as small as 12 mm. Axial length should be considered when measuring muscle position during strabismus surgery.

Anthropometry↗