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PubMed1985

Treatment of strabismus in adults with botulinum toxin A.

Eighty-five adults with horizontal concomitant strabismus were treated with an injection of a low dose of botulinum toxin A (BTXA) into the lateral or medial rectus muscle. The ocular deviation was reduced by an average of 60% independently of its size and whether or not surgery had previously been performed. The change was temporary, however, except in those cases with binocular functions, when fusion was re-established. Repeated low dose injections can maintain the improvement, but at higher doses, although larger reductions are produced, temporary local side effects--ptosis and vertical strabismus--are common. The technique is simple, well tolerated, and has no systemic side effects.

Adolescent↗

PubMed2003

Conjugate adaptation of saccadic gain in non-human primates with strabismus.

In this study, we have used the double-step paradigm to test saccadic gain adaptation during monocular viewing in one normal monkey, two monkeys with exotropia, and one monkey with esotropia. In this paradigm, the target for the saccade is displaced during the saccade, resulting in a consistent visual error. Studies in normal humans and monkeys have shown that the brain responds to this consistent visual error by gradually changing saccade gain. Using this technique, we were able to elicit adaptation in both the viewing eye and the nonviewing eye in the normal monkey and in monkeys with strabismus. The rate of adaptation was not significantly different in the viewing and nonviewing eyes in the normal and strabismic monkeys. The magnitude of adaptation as calculated by a percentage change in gain was also not significantly different in the viewing and the nonviewing eyes in the normal and strabismic monkeys. Our data show that animals with strabismus retain the ability to elicit a conjugate adaptation of saccades using this mechanism. We also suggest that the double-step paradigm elicits a conjugate adaptation of saccades whether the animal is viewing monocularly (our studies) or binocularly (data published in literature).

Adaptation, Physiological↗

PubMed1984

Response properties of striate cortex neurons in cats raised with divergent or convergent strabismus.

Recordings were made from striate cortex in five groups of cats that had been raised with strabismus produced by sectioning the extraocular muscles. These groups included animals reared with exotropia, unilateral or bilateral esotropia, and esotropia combined with lid suture of the unoperated eye. In addition, a group of esotropes was studied in which the unoperated eye was removed a few hours prior to recording. For comparison, five normal adult cats were also studied. In each of the above groups, cells were sampled in the representations of the central and peripheral visual fields in area 17 ipsilateral and contralateral to the deviated eye. We mapped the receptive field of each responsive cell, determined its ocularity, and tested it for selectivity. Confirming previous work, we found a marked loss of cortical binocularity in cats raised with strabismus. On average only 7% of the neurons that we recorded could be driven by both eyes. This percentage was relatively constant at all cortical locations that were studied and was not influenced by whether cats had been reared with exotropia, unilateral esotropia, or bilateral esotropia. The percentage of selective cells driven by the deviated eye in exotropes or esotropes did not appear to be different from normal at most cortical locations (but see 5, below). In addition, we did not observe any bias in the axial preference of selective cells in strabismic cats when compared with normal adult cats. In both exotropes and esotropes the deviated eye drove fewer cells when compared with the proportion that are driven by one eye in normal cats. In exotropes this deficit did not vary at different cortical representations of the visual field. In esotropes, however, this deficit was graded, being least in the representation of the peripheral visual field in area 17 contralateral to the deviated eye, intermediate in the representations of the central visual field in the contralateral and ipsilateral hemispheres, and greatest in the representation of the peripheral visual field in ipsilateral area 17. Furthermore, only when recording from the peripheral field representation in the ipsilateral hemisphere did we encounter significant numbers of cells driven by the deviated eye that lacked normal selectivity. Since it is possible that deprivation of the converged eye during development might account for the deficits noted above, we attempted to evaluate this factor using several independent lines of evidence. First, we could find no correlation between the angle of esotropia and the ability of the deviated eye to drive ipsilateral cortical cells representing the peripheral visual field.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMedDate not supplied

Treatment of vomiting after paediatric strabismus surgery with granisetron, droperidol, and metoclopramide.

We have compared the efficacy and safety of granisetron, droperidol, and metoclopramide in the treatment of postoperative vomiting (POV) in children scheduled for strabismus surgery. After experiencing POV during the first 3 h after recovery from anaesthesia, 120 patients received intravenously, in a randomized, double-blind manner, granisetron 40 microg/kg, droperidol 50 microg/kg, or metoclopramide 0.25 mg/kg (n = 40 in each group). The patients were then observed for 24 h after administering the study drugs. Emesis-free episodes were more often observed in patients who had received granisetron (88%) than in those who had received droperidol (63%) or metoclopramide (58%; p < 0.05). No clinically serious adverse events were observed in any group. In conclusion, granisetron is more effective than droperidol or metoclopramide in the treatment of POV after paediatric strabismus surgery.

Antiemetics↗

PubMed1994

Oculomotor and nystagmus tests in subjects with strabismus.

Smooth pursuit (SP) and saccades (SC) as well as nystagmus were recorded with electro-oculography in 21 healthy subjects with manifest non-paralytic strabismus. A normal SP function under binocular conditions could be recorded in 67% of the subjects and complementary monocular recordings increased the figure to 81%. The corresponding figure for the SC test was 38 and 67%, respectively. However, a minority of the subjects presented a normal test result under both binocular and monocular conditions. Spontaneous nystagmus and/or nystagmus after headshaking was present in 67%. These findings may indicate that subjects with strabismus have a combination of a 'subclinical' vestibular and oculomotor dysfunction.

Ear Diseases↗

PubMed1987

Ocular complications in strabismus fixus convergens.

Two cases of strabismus fixus are described. Histopathological examination of the eyeballs from both patients revealed the following complications of this rare disorder: ocular ischemia, atrophy of the optic nerve, and old central retinal artery occlusion. These complications are likely to be secondary to the mechanical stretching and torsion of the optic nerve with subsequent strangulation of its blood supply. Early surgical correction of strabismus fixus is recommended.

Arterial Occlusive Diseases↗

PubMed1990

Morphological study of extraocular muscle proprioceptor alterations in congenital strabismus.

The sensorial structures located at the myotendinous junction of the extraocular muscles of patients suffering from congenital strabismus have been studied. Important alterations of these receptors have been observed, both at light and electron microscopy. The receptors appear smaller, with an inner capsule dividing the tendinous component into irregularly shaped compartments. At electron microscopy it is possible to identify: (1) receptors still possessing their architecture and nerve component but with modified nerve ending features and relationship with the Schwann cell covering; (2) receptors maintaining their general architecture but completely lacking the nerve component; (3) receptors where also the general architecture is completely disorganized. All these alterations seem to indicate that in strabismics the reception and transmission of proprioceptive information are abnormal and support the hypothesis that a disturbance of ocular proprioception can play an important role in the pathogenesis of congenital strabismus.

Adolescent↗

PubMed1995

Direct sub-Tenon's ocular anesthesia for strabismus surgery.

We assessed the safety and effectiveness of sub-Tenon's anesthesia, a local anesthesia, for strabismus surgery. For 15 surgeries, we used anesthesia by sub-Tenon's infusion, followed by direct infusion through a transconjunctival route with a local anesthetic agent. We found the procedure was simple, it minimized complications compared with other techniques and was effective in achieving rapid anesthesia. With the ocular movement remaining, we checked eye position by the alternative cover-uncover test at the end of surgery. We obtained good eye position for all patients. This method leads to good results for strabismus surgery.

Adolescent↗

PubMed2000

Effect of timing of ondansetron administration on incidence of postoperative vomiting in paediatric strabismus surgery.

This prospective, randomized, double-blinded study evaluated the effect of the timing of ondansetron administration on its antiemetic efficacy in children undergoing elective strabismus surgery. One hundred and twenty children aged one to 15 years, ASA physical status 1 or 2, were randomly allocated to receive intravenous ondansetron 100 micrograms/kg either at induction (Group 1) or at the end of the surgery (Group 2). All patients had general anaesthesia induced and maintained with nitrous oxide and halothane, muscle relaxation with vecuronium, endotracheal intubation, reversal with neostigmine and glycopyrrolate, and pethidine 0.5 mg/kg analgesia. Episodes of nausea and vomiting were evaluated at 0 to 2, 2 to 6 and 6 to 24 hour intervals by a blinded observer. Demographic data, duration of anaesthesia, type of surgery, incidence of previous postoperative nausea or vomiting and motion sickness and number of patients who developed oculocardiac reflex requiring atropine treatment were similar in both groups. The incidence of emesis in the first 24 hours following surgery was similar in both groups (35% Group 1, 33.3% Group 2, P = 1.00). Severity of emesis (median number of emetic episodes, rescue antiemetic requirement and mean time to the onset of first episode of emesis) and mean time to discharge from the post anaesthesia care unit were also similar in the two groups. We conclude that the timing of ondansetron administration either before or after the surgical manipulation of extraocular muscles had similar antiemetic efficacy following strabismus surgery in children.

Adolescent↗

PubMed1993

Propofol infusion and the incidence of emesis in pediatric outpatient strabismus surgery.

A prospective, randomized, double-blind study was conducted to examine the effect of a propofol infusion on the incidence of postoperative emesis in children undergoing outpatient strabismus surgery. Seventy-eight children, aged 3-12 yr, were allocated randomly to receive either nitrous oxide and halothane or nitrous oxide and a propofol infusion for the maintenance of anesthesia. The overall incidence of vomiting during the first 24 h was 64% in those receiving halothane and 41% in those receiving the propofol infusion; this difference was statistically significant (P < 0.05). In children who received no opioids postoperatively, the incidence of vomiting in the first 24 h was 71% in the halothane group and 24% in the propofol group; this difference was also significant (P = 0.001). We conclude that propofol was effective in reducing the incidence of postoperative emesis in pediatric outpatient strabismus surgery.

Anesthesia↗

PubMed2005

Prophylactic dexamethasone for postoperative nausea and vomiting in pediatric strabismus surgery: a dose ranging and safety evaluation study.

In this double-blind, randomized, placebo-controlled study, we evaluated the efficacy and safety of different doses of prophylactic IV dexamethasone for postoperative nausea and vomiting (PONV) in 168 children (aged 2-15 yr) scheduled for strabismus surgery. Patients received IV dexamethasone 0.25 mg/kg (D 0.25), 0.5 mg/kg (D 0.5), 1.0 mg/kg (D 1), or saline (S) immediately after induction of general anesthesia. Patients were discharged 24 h after surgery. Nausea and vomiting were assessed at 0-2, 2-6, and 6-24 h after surgery. Blood glucose was measured preoperatively and at 4 h after study drug administration. Wound healing and infection were assessed after 1 wk. More patients in group S had vomiting at 0-2, 2-6, and 6-24 h (P = 0.001, P = 0.003, and P = 0.04, respectively) and required larger doses of rescue antiemetics compared with the dexamethasone groups. Fewer patients in the dexamethasone groups (6, 3, and 6 in D 0.25, D 0.5, and D 1, respectively) had severe PONV compared with group S (P = 0.001). No significant increase in postoperative blood glucose levels was observed and wound healing was satisfactory in all four groups. The results suggest that dexamethasone 0.25 mg/kg is more effective than saline and equally effective compared with larger doses for preventing PONV for pediatric strabismus surgery.

Adolescent↗

PubMed2006

[Sensorial strabismus: a study of 191 cases].

PURPOSE: To evaluate the charts of patients with sensorial strabismus regarding range of different aspects, such as etiology, the type and the amount of deviation, relationship between the type of deviation and the patient's age when the disease occurred and the surgical outcome. METHODS: A retrospective analysis of data charts of 191 patients seen at the section of Ophthalmology at the University of São Paulo, from September 1990 to July 2002. RESULTS: There were 84 male and 107 female patients. The most frequent diagnosis responsible for low vision in the squinted eye was atrophic chorioretinitis in 49 patients. Eighty-seven were exotropes and 97 were esotropes. Fifty patients were operated on, but 8 of them were lost to follow-up. In 90.5% the surgical outcome was successful: less than 15 prismatic diopters of hyper or undercorrection after surgery. CONCLUSIONS: The good surgical outcome seen in this and other studies enhances and justifies the need for surgical correction of this type of strabismus.

Adolescent↗

PubMedDate not supplied

[Botulinum toxin treatment for horizontal strabismus in children with cerebral palsy].

UNLABELLED: To evaluate the efficacy of botulinum toxin injection in the treatment of horizontal strabismus in children with cerebral palsy. METHODS: A group of 24 patients, age 6 - 156 months, with cerebral palsy and horizontal strabismus (17 esotropias ranging from 25 to 45 PD and 7 exotropias ranging from 20 to 45 PD) were treated with botulinum toxin (34 medial rectus and 14 lateral rectus muscles). The children underwent full ophthalmic examination. The injection treatment was performed after sedation using Mendonça's forceps. The follow-up was done after 7 days, 15 days and monthly. Deviation less or equal of 10 PD after 6 months of follow-up was considered successful. However, if patients did not achieve this result a second application could be performed. RESULTS: In the group of esotropia (n=17) 47.1% had successful results with only one application after two years of follow-up. All of these patients had previous deviation less than or equal to 35 PD. In the exotropia group a single injection was not sufficient to achieve successful result. The side effects included: subconjutival hemorrhage in 4 (16.7%) patients, transient vertical deviation in 4 (16.7%) and transient ptosis in 22 (91.7%). CONCLUSION: The use of botulinum toxin was a good alternative in the treatment of children with cerebral palsy and esotropia.

Botulinum Toxins, Type A↗

PubMed2005

Persistent strabismus after cataract extraction.

BACKGROUND: Transient ocular misalignment as a complication of parabulbar and peribulbar anesthesia has already been reported in the literature. The aim of our study was to present a case of irreversible iatrogenic vertical strabismus after cataract surgery, which had to be operated on. METHODS: Clinical and orthoptic evaluation of a female patient with vertical diplopia after phacoemulsification cataract surgery. RESULTS: One week after the uneventful surgery, a 68-year-old patient complained of a sudden vertical deviation in the operated eye. The patient had not had a history of previous motility disorders. On examination, the patient showed hypertropia in the left eye of 15-20 degrees in primary position. Three and 6 months postoperatively, there was no a spontaneous improvement, while the persistent vertical deviation was 40 prism dioptres. Strabismus surgery was required 1 year after the cataract surgery. CONCLUSION: Diplopia is a complication of peribulbar anesthesia which could be persistent. The superior and inferior rectus muscle are especially vulnerable. Its occurrence may be technique--related and the incidence increases when hyaluronidase is not available.

Aged↗

PubMed1995

Strabismus after retinal detachment surgery: etiology, diagnosis, and treatment.

Between 5% and 25% of patients may experience persistent diplopia after surgery for retinal detachment. The complexity of the presentation poses a distinct challenge to both the retinal and the strabismus surgeon. Careful evaluation to determine factors contributing to the strabismus and assessment of fusional capabilities are essential before treatment. A combination of the appropriate surgical approach with nonsurgical adjuncts such as prisms or botulinum toxin is often successful in relieving symptoms.

Diplopia↗

PubMed1992

Reduction of postoperative adhesions in strabismus surgery.

An animal experiment was done to evaluate the efficacy of tissue coating with sodium hyaluronic acid and subconjunctival injection of triamcinolone acetate in reducing the severity of postoperative adhesions following strabismus surgery. Experimental animals underwent a mild traumatic surgical procedure in one superior rectus muscle and a severe traumatic surgical procedure in the other superior rectus muscle. Each group was divided into control group, sodium hyaluronate coating group and triamcinolone acetonide injection group. Grading the severity of adhesions through surgical exploration of operative sites and histological comparison after 4 weeks revealed a significant reduction of postoperative adhesions in sodium hyaluronate group compared with control group under conditions of severe surgical trauma. But triamcinolone groups have no significant differences compared with control groups by statistical analysis. Tissue protection afforded by sodium hyaluronate may lead to an effective method which minimizes the surgical trauma to the tissues and reduces the postsurgical adhesions following strabismus surgery.

Animals↗

PubMed2001

Extraocular muscle changes after cryotherapy for retinopathy of prematurity and the development of strabismus in premature infants.

To find out whether the cryotherapy for the treatment of the retinopathy of prematurity (ROP) causes structural changes of the extraocular muscle (EOM), and also whether the changes are related with the occurrence of strabismus. To examine the acute stage change, we conducted a transconjunctival cryotherapy around the superior rectus muscle of a rabbit and resected it 0, 3, 7, 14, and 28 days after the cryotherapy. In observing chronic changes, we first categorized patients who had an esotropia surgery into groups, one of which combined prematurity and cryotherapy and one group affected by prematurity but without having had cryotherapy. Then we compared the change of EOM with that of a fullterm infant group. In a rabbit, edema, acute inflammatory cells and a large amount of degenerated muscle fibers were observed immediately after the cryotherapy and on the 3rd day. On the 7th day, regenerated muscle fibers were observed and on the 14th day, the inflammatory cells decreased and the amount of regenerated muscle fiber increased. On the 28th day, abnormal findings were not observed any more and the muscle was found to be normal. When chronic changes of EOM in human on 1 1/2 to 8 1/2 years after cryotherapy, there were no abnormal findings observed in three groups. From the study, we can infer that cryotherapy can cause acute inflammation and necrosis of muscle fiber but such an acute change will improve and does not result in structural change in the long term. Therefore, the occurrence of strabismus in patients with ROP is considered to be attributable to reasons other than injury of EOM.

Animals↗

PubMed2004

A case of surgical repair in strabismus fixus with ptosis.

Strabismus fixus is very rare and the convergent form is rarely accompanied by blepharoptosis. We successfully treated one patient with high myopia whose convergent strabismus fixus, accompanied by blepharoptosis, became severe after cataract surgery. We report the case with a discussion of its pathology. We performed levator advancement operation, bilateral lateral rectus 11 mm resection, and bilateral medial rectus 8 mm recession. The suture was removed after maintaining temporary traction suture for 6 days. Blepharoptosis was completely corrected by postoperative 2 months. Esodeviation was 15PD, which was not increased compared with immediately after surgery. Satisfactory cosmetic outcome was obtained.

Aged↗