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Results for “Strabismus”

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At least 289 records · Page 16Linked to original sources

PubMed2003

Ultrasound of the horizontal rectus muscle insertion sites: implications in preoperative assessment of strabismus.

PURPOSE: To determine the reproducibility and accuracy of ultrasonographic (US) measurements of distances between the corneoscleral limbus and the insertion site of the medial (MR) or lateral rectus (LR) muscle compared with intraoperative measurements in patients with strabismus. METHODS: One eye in each of 17 patients with postoperative secondary strabismus caused by over- or undercorrected eso- and exotropia and one eye of each of 19 patients with previously untreated strabismus underwent five repeated measurements by high-resolution ultrasonography of the distance from the corneoscleral limbus to the muscle insertion and three actual intraoperative measurements. Reproducibility, expressed as the coefficient of variation, accuracy (relative error) of US measurements, and the agreement with intraoperative measurements were assessed. RESULTS: The coefficients of variation for US data were 2.02% and 3.18% for the MR and 7.33% and 11.77% for the LR, in the surgical and untreated groups, respectively. The relative error was 6.15% +/- 8.14% (mean +/- SD) and 3.66% +/- 12.83% for the MR muscle, and 12.21% +/- 10.66% and -7.69% +/- 7.83% for the LR muscle, in the surgical and untreated groups, respectively. The 95% limits of agreement (mean +/- 2 SD) between the US and intraoperative measurements were 0.65 +/- 1.82 and 0.15 +/- 1.42 mm for the MR muscle, and 1.12 +/- 2.01 and -0.49 +/- 0.98 mm for the LR muscle, in the surgical and untreated groups, respectively. CONCLUSIONS: The results indicate good reliability and accuracy of US readings and suggest a potential usefulness in preoperative assessment of patients with strabismus with surgical failure and missing preoperative clinical data.

Adolescent↗

PubMed2004

Efficacy of low-dose dexamethasone for preventing postoperative nausea and vomiting following strabismus repair in children.

We studied the efficacy of a range of doses of dexamethasone for prevention of postoperative nausea and vomiting following strabismus repair in children in a hospital-based, prospective, double-blinded, randomized, placebo-controlled trial. Two hundred and ten children were randomized to receive either dexamethasone in one of four dosages: 50 microg/kg (Group 1), 100 microg/kg (Group 2), 200 microg/kg (Group 3) and 250 microg/kg (Group 4) or normal saline (Group 5) prior to corrective surgery for strabismus. Anaesthesia was standardized and included nitrous oxide, pethidine, intubation and the use of muscle relaxant and reversal with neostigmine. Postoperative nausea and vomiting were evaluated in epochs of 0-2 hours, 2-6 hours and 6-24 hours after surgery. Parent satisfaction was assessed 24 hours after surgery and the operated eye was examined for wound infection and delayed healing one week later Dexamethasone was effective in preventing nausea and vomiting after strabismus repair: 57.1% children in Group 1, 42.9% in Group 2, 52.4% in Group 3, and 59.5% in Group 4 were free from postoperative nausea and vomiting compared with 7.1% in placebo group. The lowest dose of 50 microg/kg was as efficacious as the higher dosages of dexamethasone during the 24 hours studied. Of the children who developed postoperative nausea and vomiting those who received dexamethasone had significantly fewer episodes than those in the placebo group. We conclude that dexamethasone 50 microg/kg is effective for the prevention of postoperative nausea and vomiting following strabismus repair in children.

Adolescent↗

PubMed2006

The genetic basis of complex strabismus.

Members of my research laboratory combine clinical, genetic, and molecular biologic approaches to the study of congenital strabismus. Strabismus, which is misalignment of the eyes, affects 2-4% of the population and causes loss of binocular vision and amblyopia (vision loss in a structurally normal eye). The cause of strabismus when it occurs in the absence of structural brain abnormalities is generally unknown. In the last decade, we have focused our research studies on understanding the genetic etiology of a series of complex strabismus syndromes in which eye movement in at least one direction is limited or paralyzed. We are discovering that these disorders result from mutations in genes necessary for the normal development and connectivity of brainstem ocular motoneurons, including PHOX2A, SALL4, KIF21A, ROBO3, and HOXA1, and we now refer to these syndromes as the "congenital cranial dysinnervation disorders," or CCDD.

Brain Stem↗

PubMed2002

The role of telemedicine in the assessment of strabismus.

Thirty patients with strabismus were seen face to face by an ophthalmologist and an orthoptist. The patients were then presented by the same orthoptist to a second ophthalmologist via a telemedicine link. Twenty-six patients were seen using a bandwidth of 384 kbit/s and four using 128 kbit/s. There was agreement between the two ophthalmologists about diagnosis and management in 24 cases, partial agreement in one and no agreement in five (17%). Manifest strabismus was safely diagnosed and managed using telemedicine at 128 kbit/s, although 384 kbit/s was preferred because it obviated the need for repeated examination. Latent strabismus and micro-movements were difficult to diagnose using telemedicine even at 384 kbit/s. Young patients who are unable to sit still would not be suitable for strabismus assessment via telemedicine.

Adult↗

PubMed1984

Psychological and educational correlates of strabismus in school children.

The results of a study investigating the relationship of psychiatric and cognitive disorder with strabismus and its treatment in primary school aged children are reported. Results suggest that children with strabismus have a higher prevalence of psychiatric disorder, particularly an emotional disorder or psychosis. Subjects also had an increased risk of having educational problems and of exhibiting difficulties with tasks involving visual perception. Variables related to the nature and treatment of the strabismus did not appear influential in the development of the psychiatric disorder. Family disruption was significantly associated with both the presence of strabismus and emotional and behavioural problems in the children reported by parents and teachers.

Achievement↗

PubMed1995

Effects of mitomycin C on delayed adjustment in experimental strabismus surgery.

In adjustable strabismus surgery, a satisfactory final result would be achieved with delayed adjustment. However, the postoperative adhesions following strabismus surgery make delayed adjustment impossible. We evaluated the efficacy of mitomycin C in reducing the severity of postoperative adhesions following strabismus surgery and in delaying the time adjustment after surgery. Experimental rabbits underwent a hang-back recession procedure in the superior rectus muscle. A topical application of mitomycin C was made between the conjunctiva and the sclera for 5 minutes during the operation. We then studied the possible time of delayed adjustment and estimated the minimal forces required for the adjustment. The topical application of 0.1 mg/ml mitomycin C between the conjunctiva and sclera allowed for a 2-week delayed adjustment after surgery, and 0.2 mg/ml mitomycin C prevented the adhesions between these tissues and the muscle 5 weeks after surgery. These results suggest that topical mitomycin C may enhance the success rate of strabismus surgery with delayed adjustment and reduce postoperative adhesions.

Administration, Topical↗

PubMedDate not supplied

The association of strabismus and aphakia in children.

Strabismus was present in 40% of patients with cataracts/dislocated lenses at the time of initial diagnosis and continued to present an obstacle to complete rehabilitation with 86% of the congenital patients and 61% of the acquired patients found to have strabismus at their latest post therapy visits. The type of horizontal deviation found at the initial examinations was distributed equally between esotropia and exotropia in the unilateral congenital cataracts patients. However, all of our patients with strabismus and bilateral congenital cataracts were esotropic. The acquired group was heavily weighted toward the exodeviations at the time of the initial examination and during treatment showed an even greater percentage of exotropia. Visual acuity results in the various groups followed perhaps the expected trends with the poorest results in the unilateral congenital cataract patients. Those patients in the acquired groups have better visual results with 56% of the traumatic and 83% of the non-traumatic eyes achieving vision of 20/70 or better. Despite the high incidence of strabismus present in these patients, we feel this should in no way be a deterent to the decision to initiate therapy as it does not seem to relate to visual acuity results. The overall good visual results in these patients justifies the approach of early surgery, adequate correction, and vigorous occlusion.

Adolescent↗

PubMedDate not supplied

Frequency of naturally occurring strabismus in monkeys.

A colony of Macaca nemestrina monkeys was screened for naturally occurring strabismus. Thirteen cases of naturally occurring strabismus were documented, 12 esotropes and one exotrope. The characteristics of the strabismus in these monkeys were similar to those of human clinical cases. Four of the affected monkeys showed interocular differences in grating acuity. We estimated the incidence of strabismus in the monkey colony to be 4%.

Animals↗

PubMedDate not supplied

PVEP evidence of true suppression in adult onset strabismus.

Customarily, it is taught that strabismus acquired in childhood results in suppression of the diplopic image, whereas strabismus acquired in adulthood causes diplopia or conscious image ignoring, but not true cortical suppression. The pattern visual evoked potential (PVEP) was recorded from strabismic patients, three with childhood onset, two adult onset with diplopia, and three with longstanding adult onset strabismus "ignored" diplopia. Patients with childhood onset and adult onset "ignored" diplopia similarly showed essentially no response under haploscopic stimulation, whereas patients with diplopia and normal control subjects showed a 50% decrease (rivalry). These results suggest that adults with acquired strabismus who "ignore" the diplopic image actually have a suppressed cortical visual activity, as evidenced by the pattern visual evoked potential.

Adolescent↗

PubMedDate not supplied

Retinal perforation in strabismus surgery.

PURPOSE: Perforation of the retina is a major complication of strabismus surgery. The reported incidence of perforation varies from 0.13% to 12%. This study was undertaken to determine, from a large collaborative database, the incidence of suspected and unsuspected retinal and choroidal injury in pediatric horizontal muscle surgery. METHOD: All children with horizontal strabismus surgery seen between September 1992 and October 1995 were examined with Indirect ophthalmoscopy immediately following their procedure. Surgery was performed by both resident and attending physicians. Cases involving muscle reoperation, high myopia, or patients with connective tissue disorders were excluded. RESULTS: Strabismus surgery was performed on 765 patients, who underwent 1129 muscle recessions and 349 muscle resections. These children also had 161 vertical or oblique muscle procedures performed. Intraocular trauma resulting from horizontal muscle surgery was noted in 14 patient, including three retinal perforations. One of these patients was treated with cryotherapy; the other two received no therapy other than intraoperative and postoperative antibiotics. DISCUSSION: The incidence of retinal perforation was 0.4% and the incidence of choroidal injury without perforation was 1.4% in this large series of children undergoing horizontal strabismus surgery. Retinal detachment or endophthalmitis did not develop during the 6-week follow-up period.

Adolescent↗

PubMedDate not supplied

Tolerance of patients and postoperative results: topical anesthesia for strabismus surgery.

PURPOSE: To assess patient tolerance and the postoperative results of intraoperative adjustment of strabismus surgery under topical anesthesia. METHODS: Twenty-four patients with strabismus underwent rectus muscle recession under topical anesthesia without the use of additional systemic analgesics and sedatives. Patient tolerance was estimated according to the sites of procedure. In addition, the angle of strabismus was measured 1 day, 6 weeks, and 1 year postoperatively. RESULTS: Of the 24 patients identified (11 men and 13 women; mean age: 24 years), 16 had exotropia, 7 were esotropic, and 1 was hypertropic. During the operation, 17 patients never expressed any pain, and 7 patients complained of discomfort on muscle manipulation. Postoperatively, the success rate was 95.8% (23 patients) the first day after surgery, 79.2% (19 patients) after 6 weeks, and 70.8% (17 patients) after 1 year. CONCLUSION: Intraoperative adjustment performed with the patient under topical anesthesia is recommended in all cooperative cases of strabismus surgery and is comfortable for patients.

Adolescent↗

PubMedDate not supplied

Comparison of ondansetron with ondansetron plus dexamethasone for antiemetic prophylaxis in children undergoing strabismus surgery.

BACKGROUND: Children undergoing strabismus surgery have a high incidence of postoperative nausea and vomiting. Ondansetron plus dexamethasone is effective in reducing its incidence in many surgical procedures. PURPOSE: To examine the efficacy of ondansetron plus dexamethasone in children undergoing strabismus surgery. PATIENTS AND METHODS: A randomized, placebo-controlled, double blind study of 100 children 2 to 12 years old, in American Society of Anesthesiologists classes I and II, and undergoing strabismus surgery with the use of general anesthesia was conducted. Children received normal saline (n = 31), an injection of 0.15 mg/kg of ondansetron (n = 39), or an injection of 0.15 mg/kg of ondansetron and 0.2 mg/kg of dexamethasone (n = 30). Postoperatively, children were monitored for the number of emetic episodes, Steward recovery score, and need for a rescue antiemetic. RESULTS: The incidence of vomiting was 64.5% in the group receiving saline, 33.3% in the group receiving ondansetron, and 10% in the group receiving ondansetron plus dexamethasone (P < .001). The incidence of early vomiting (0 to 4 hours) and the need for a rescue antiemetic were significantly lower in the groups receiving ondansetron (P < .01) and ondansetron plus dexamethasone (P < .001) compared with the group receiving saline; however, the former two groups were comparable in this regard. In the late postoperative period (4 to 24 hours), the incidence of vomiting and the need for a rescue antiemetic were not significantly different among the groups. Vomiting was significantly more severe in the group receiving saline compared with the groups receiving ondansetron and ondansetron plus dexamethasone at all times (P < .01 and P < .001, respectively). However, the latter two groups were comparable in this regard. CONCLUSION: Ondansetron and ondansetron plus dexamethasone were equally effective in preventing early nausea and vomiting in children following strabismus surgery. However, the efficacy of dexamethasone in late postoperative nausea and vomiting could not be demonstrated. Further studies with a large population and different doses of dexamethasone may be warranted.

Antiemetics↗

PubMedDate not supplied

Evaluation of intranasal midazolam in refraction and fundus examination of young children with strabismus.

PURPOSE: To determine the clinical sedative effect and dosage of intranasal midazolam in refraction and fundus examination of children with strabismus. PATIENTS AND METHODS: Refraction and fundus examination with (n = 28) and without (n = 24) sedation were performed in 52 children with strabismus whose ages ranged from 7 to 26 months. We delivered a 5-mg/mL solution of midazolam via a syringe for 60 seconds to provide a dose of 0.2 mg/kg. We repeated the dose to a maximum of 0.3 mg/kg if there was no clinical sedative response after 10 to 15 minutes. The ease of examination and sedation for each patient was scored by a blinded observer. The groups were evaluated for ease of examination and the time needed to complete it. RESULTS: We obtained clinically adequate sedation at a mean (+/- standard deviation) of 15 minutes (+/- 2.69 minutes). Sedation was achieved with a mean dose of 2.64 mg/kg (+/- 0.66 mg/kg). Children receiving midazolam had significantly calmer examination scores. The time needed to complete the examination was statistically significantly shorter for these children than for children not receiving sedation (P < .05). CONCLUSIONS: Intranasal midazolam is a beneficial drug and method of delivery for the sedation of anxious children with strabismus undergoing refraction and fundus examination. Sedation prior to examination is effective in reducing the anxiety and time associated with ophthalmologic examination of children with strabismus.

Administration, Intranasal↗

PubMedDate not supplied

Prevalence and development of strabismus in 10-year-old premature children: a population-based study.

PURPOSE: To evaluate the prevalence and development of strabismus, at 10 years, in children born prematurely. METHODS: This population-based study included 216 premature and 217 full-term children from the same geographic area. RESULTS: Strabismus was noted in 16.2% (35 of 216) premature and in 3.2% (7 of 217) full-term children. The most important risk factors for strabismus at 10 years were anisometropia at 6 months, spherical equivalent refractive errors (i.e., > +3 D or < -3 D) at 2.5 years, and various neurologic conditions. CONCLUSION: At 10 years, children born prematurely have a greater risk of strabismus than children born at term.

Child↗

PubMed2000

Listing's law in strabismus and amblyopia: a preliminary report.

We investigated whether Listing's law applies in patients with diminished or no stereopsis due to strabismus or amblyopia. Eye movements of normal subjects and patients with strabismus and/or amblyopia were recorded during monocular and binocular fixation; from these data the shape and relative orientation of displacement planes were calculated. In normal subjects, monocular or binocular fixation did not influence the thickness and relative orientation of displacement planes. No differences were found between normals and the patient with amblyopia due to anisometropia. In one patient with strabismus but without amblyopia, the orientation of displacement planes depended on the fixation conditions; a coupling between horizontal vergence effort and plane orientation was observed. Patients with amblyopia and strabismus showed abnormally shaped and/or abnormally orientated displacement planes, which depended on the fixation conditions. Differences between both eyes in the shape of the planes were also observed. These results show that normal Listing behavior can be present in subjects with diminished stereopsis. They also show that normal stereopsis does not necessarily mean normal Listing behavior, suggesting that Listing's law is mainly a result of motor strategy.

Adult↗

PubMedDate not supplied

[Hereditary factors in strabismus].

This retrospective study took place in the Ophthalmology Department of Douala General Hospital. The aim was to determine the importance of hereditary factors in a group of strabismic Cameroonians. In a series of 275 patients with strabismus, we found 79 familial cases (28.72%). Among them, 22.78% had more than one relative with squint and 75% had the same type of strabismus as their relative. There was no significant difference in the percentage of familial cases with regard to the type of strabismus, the sex, the mode of fixation and the impairment of ductions. As far as ametropias are concerned, only myopia showed a hereditary tendency in our series. The authors agree with the literature in that there is a significant hereditary component in the cause of strabismus, but its genetic sites are yet to be identified. There is strong hope in this direction with the decoding of the human genom and the advances in molecular biology. However, the study of familial cases is important since it allows high risk groups to be defined and screened. It thus makes it possible to successfully fight amblyopia through early detection and treatment.

Adult↗

PubMed2002

Strabismus (STB)/Vang-like (VANGL) gene family (Review).

Strabismus 1 (STB1/VANGL2) and Strabismus 2 (STB2/VANGL1), which have been cloned and characterized using bioinformatics and cDNA-PCR, are human homologues of Drosophila tissue polarity gene strabismus (stbm)/Van Gogh (Vang). STB1 and STB2 are tetra-membrane-spanning proteins with 73.1% total-amino-acid identity. Serine-rich domain and Strabismus-homology (STH1 and STH2) domains are conserved among human STB1, STB2, Xenopus Stbm, and Drosophila Stbm. STH2 domain with the C-terminal Ser/Thr-X-Val motif is implicated in binding with Dishevelled (DVL) proteins. STB1 gene is clustered with CASQ1 gene on human chromosome 1q21-q23, while STB2 gene is clustered with CASQ2 gene on human chromosome 1p13. STB1 and STB2 genes are located around cancer susceptibility loci or recombination hot spots in the human genome. STB1 is moderately expressed in K-562 (leukemia), G-361 (melanoma), and MKN7 (gastric cancer) cells. STB2 is highly expressed in MKN28, MKN74 (gastric cancer), BxPC-3, PSN-1, and Hs766T (pancreatic cancer) cells. On the other hand, STB1 and STB2 are significantly down-regulated in several cancer cell lines and primary tumors. Xenopus homologue of human STB1 and STB2 regulates negatively the WNT - beta-catenin signaling pathway. Loss-of-function mutations of genes encoding negative regulators of WNT - beta-catenin signaling pathway lead to carcinogenesis. Based on functional aspects and human chromosomal loci, STB1 gene and STB2 gene are predicted to be potent tumor suppressor gene candidates. STB1 and STB2 might be suitable targets for tissue engineering in the field of re-generative medicine and for chemoprevention and treatment in the field of clinical oncology.

Amino Acid Sequence↗

PubMed2003

Quantification of incidental needle and suture contamination during strabismus surgery.

PURPOSE: To quantify the level of bacterial contamination of needles and sutures immediately after use in strabismus surgery. METHODS: Strabismus surgery was performed on 56 eyes from 31 pediatric strabismus surgical cases. Preoperative site preparation included instillation of 5% povidone-iodine in the conjunctival fornices in all cases. A total of 124 needles and 127 sutures were cultured immediately after final scleral passage. RESULTS: Seventeen of the 31 cases (54.8%) produced at least one positive specimen. Nineteen per cent of the needles and 25.2% of the sutures were culture positive. The bulk of positive specimens (96.7% of needles, 91.3% of sutures) produced 3 or less colony forming units, corresponding to 7 or less total viable organisms per needle or sutures in accordance with the dilution scheme. Coagulase-negative staphylococci overwhelmingly predominated. CONCLUSIONS: Needles and sutures used in strabismus surgery can become contaminated during surgery despite preoperative povidone-iodine preparation. The number of viable bacterial contaminants is usually below the level known to consistently produce experimental endophthalmitis. However, a few needles and sutures carried a high contaminant load, suggesting the possibility that contaminated needles and sutures could potentially cause postoperative intraocular infection.

Adolescent↗