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PubMed2004

Factors influencing the outcome of strabismus surgery in patients with exotropia.

PURPOSE: To determine the factors associated with favorable and less favorable outcomes in strabismus surgery for treatment of exotropia and to show the factors influencing the efficacy of the surgical procedure. METHODS: Case files of 225 patients with a diagnosis of primary exotropia were evaluated. Information about patient age at onset of deviation, patient age at surgery, interval between onset and surgery, preoperative deviation, refractive errors, degree of anisometropia, visual acuity, presence of amblyopia, presence of an A- or a V-pattern, amount of surgery performed, type of exotropia (intermittent or constant), and existence of binocular single vision before surgery were obtained and evaluated using multiple regression analysis. RESULTS: Preoperative deviation and refractive errors were proved to be significant factors influencing a favorable outcome in patients with surgically treated exotropia (r(2) = 0.12, P <.001, and r(2) = 0.07, P <.001 respectively). Preoperative deviation, amount of surgery performed, and refractive errors shifting toward myopia significantly influenced the efficacy of the surgery performed (r(2) = 0.31, 0.06, and 0.025, respectively). CONCLUSION: Special care should be paid to refractive errors in patients with exotropia before determining the amount of surgical intervention.

Child, Preschool↗
PubMed2004

Identification and developmental expression pattern of van gogh-like 1, a second zebrafish strabismus homologue.

Cell movement plays a central role in both normal embryogenesis and the development of diseases such as cancer. Therefore, identification and analysis of proteins controlling cell movement is of special importance. The zebrafish trilobite locus encodes a Van Gogh/Strabismus homologue, which regulates diverse cell migratory behaviors during embryogenesis. Trilobite is most similar to human Van Gogh-like 2 (VANGL2)/Strabismus 1 and mouse Loop-tail associated protein/Lpp1. Both human and mouse genomes encode a second Strabismus homologue referred to as VANGL1/Strabismus 2 and Lpp2, respectively. This prompted us to ask whether another van gogh/strabismus gene, one more closely related to human VANGL1, exists in the zebrafish genome. This paper describes the identification of zebrafish vangl1 and provides the first spatiotemporal expression and functional analysis of a vertebrate vangl1 homologue. Our data indicate that vangl1 and trilobite/vangl2 are expressed in largely non-overlapping domains during embryogenesis. Injection of synthetic vangl1 RNA partially suppressed the gastrulation defect in trilobite mutant embryos, suggesting that Vangl1 and Trilobite/Vangl2 have similar biochemical activities.

Amino Acid Sequence↗
PubMed2006

Bilateral convergent strabismus with exophthalmus (BCSE) in cattle: an overview of clinical signs and genetic traits.

Bilateral convergent strabismus with exophthalmus (BCSE) is a heritable eye defect prevalent in many cattle breeds and known worldwide. BCSE shows a progressive course often terminating in complete blindness. The onset of the defect can sometimes be slowly progressing (late in life) and, as the first signs of the defect are frequently not noticed prior to first breeding, prevention cannot be achieved only by exclusion of affected animals from the breeding program. This paper provides an overview of the clinical signs, histopathology and genetics of BCSE, its distribution in different cattle breeds and analyses the association between milk production traits and US Brown Swiss. There were different modes of inheritance proposed for BCSE, but although an autosomal dominant major gene is considered most likely in German Brown cattle, an association with milk production traits could not be found. Comparative molecular genetic approaches could help to characterize the responsible genes for this ocular disease in cattle.

Animals↗
PubMed1990

A comparative study of grating and recognition visual acuity testing in children with anisometropic amblyopia without strabismus.

Bailey-Lovie-Ferris visual acuity charts and Teller visual acuity cards were used to compare recognition and grating visual acuity at near testing distances in 32 children with anisometropic amblyopia without strabismus. Appropriate optical corrections were worn. Test-retest intraobserver reliability was higher for letters (r =.95) than for gratings (r = .68). Using 20/30 visual acuity or better as the criterion for normal visual acuity, eight eyes with letter visual acuities ranging from 20/42 to 20/138 would have been inaccurately found to be normal by using the Teller visual acuity cards alone. Grating visual acuity measurements tended to be better than letter visual acuity; and, in general, they did not worsen proportionately with poorer letter visual acuity.

Adolescent↗
PubMed1999

Assessment of central and peripheral fusion and near and distance stereoacuity in intermittent exotropic patients before and after strabismus surgery.

PURPOSE: To determine whether central fusion and distance stereoacuity are useful as objective measures in assessing the need for and success of surgery for intermittent exotropia (X[T]). METHODS: A prospective, institutional, clinical trial was conducted of 26 consecutive patients with X(T) who were undergoing strabismus surgery in whom fusion (central and peripheral) and stereoacuity (at near and distance) were assessed preoperatively and postoperatively, as well as in 112 normal subjects. To obtain accurate measurements with sensory tests, the lower age was limited to 5 years for inclusion. A successful surgical alignment was defined as an exotropia of 10 prism diopters or less at 6 m. Sensory and motor outcome measures were determined 1 year after surgery. RESULTS: The successful surgical alignment rate was 69%. All patients with X(T) demonstrated peripheral fusion, whereas 35% demonstrated central suppression preoperatively and postoperatively. Central fusion was not predictive of surgical outcome (P = .078); however, there was a trend toward less surgical success in patients with central suppression. Patients with X(T) exhibited good near stereoacuity before and after surgery. Distance stereoacuity in patients with X(T) preoperatively was significantly diminished compared with normal subjects (P < .001) and was improved in 58% postoperatively. Patients who achieved successful surgical alignment had a greater likelihood of demonstrating distance stereoacuity improvement postoperatively than patients who failed to achieve successful surgical alignment (P = .003). Patients with central suppression were unlikely to improve their distance stereoacuity postoperatively (P = .014). CONCLUSIONS: Successful surgery may improve distance stereoacuity. Better distance stereoacuity and central fusion are frequently associated with better surgical success in X(T).

Adolescent↗
PubMed1993

Timing of amblyopia therapy relative to strabismus surgery.

BACKGROUND: It is taught that amblyopia must be fully reversed before surgery for esotropia is undertaken to achieve the best surgical outcome. In some cases, this means delaying surgery for many months. The alternative of operating early, before the completion of amblyopia therapy, and continuing to treat the amblyopia postoperatively has not been evaluated previously. METHODS: Forty-seven children younger than 8 years of age were identified with a history of both amblyopia and esotropia. They had no other ocular, medical, or neurologic abnormalities. They had no prior strabismus surgery. Of these 47 patients, 26 had their amblyopia fully treated before surgery, and 21 underwent surgery before completing amblyopia therapy. Five of the latter group did not require amblyopia therapy after surgery even though they were still amblyopic before operation. The motor outcome was assessed by comparing the motor alignment at 6 and 0.33 m using accommodative targets in primary position before surgery, at 6 months after surgery, and at the child's most recent visit. Motor success was defined in this study as a postoperative deviation at distance fixation of 8 prism diopters or less. The sensory result was assessed by comparing the frequency of detectable stereoacuity. RESULTS: The treatment groups did not differ significantly in age, depth of amblyopia, refractive error, or preoperative angle. There was no significant difference detected in motor or sensory outcome whether amblyopia was fully or only partially treated before surgery. CONCLUSION: Performing corrective surgery in children with esotropia before full resolution of amblyopia is safe and efficient if the amblyopia therapy is continued after surgery. This strategy permits earlier surgery without postponing the operation until full resolution of amblyopia. The finding that five patients did not require amblyopia therapy after surgery suggests that eye re-alignment itself can help reverse amblyopia in some cases.

Accommodation, Ocular↗
PubMedDate not supplied

Optical imaging of orientation and ocular dominance maps in area 17 of cats with convergent strabismus.

Strabismus (or squint) is both a well-established model for developmental plasticity of the brain and a frequent clinical symptom. While the layout and topographic relationship of functional domains in area 17 of divergently squinting cats has been analyzed extensively in recent years (e.g. Löwel et al., 1998), functional maps in convergently squinting animals have so far not been visualized with comparable detail. We have therefore investigated the functional organization of area 17 in adult cats with a surgically induced convergent squint angle. In these animals, visual acuity was determined by both behavioral tests and recordings of visual evoked potentials, and animals with comparable acuities in both eyes were selected for further experiments. The functional layout of area 17 was visualized using optical imaging of intrinsic signals. Monocular iso-orientation domains had a patchy appearance and their layout was different for left and right eye stimulation, so that segregated ocular dominance domains could be visualized. Iso-orientation domains exhibited a pinwheel-like organization, as previously described for normal and divergently squinting cats. Mean pinwheel density was the same in the experimental and control animals (3.4 pinwheel centers per mm2 cortical surface), but significantly (P < 0.00001) higher than that reported previously for normal and divergently squinting cats (2.7/mm2). A comparison of orientation with ocular dominance maps revealed that iso-orientation domains were continuous across the borders of ocular dominance domains and tended to intersect these borders at steep angles. However, in contrast to previous reports in normally raised cats, orientation pinwheel centers showed no consistent topographical relationship to the peaks of ocular dominance domains. Taken together, these observations indicate an overall similarity between the functional layout of orientation and ocular dominance maps in area 17 of convergently and divergently squinting cats. The higher pinwheel densities compared with previous reports suggest that animals from different gene pools might generally differ in this parameter and therefore also in the space constants of their cortical orientation maps.

Animals↗
PubMed2000

Efficacy and complications of dose increments of botulinum toxin-A in the treatment of horizontal comitant strabismus.

PURPOSE: To investigate the efficacy and complications associated with dose increments of botulinum toxin-A (BTA) for comitant horizontal strabismus patients. METHODS: Twenty-five esotropic (ET) and 45 exotropic (XT) patients received 2.5-20 U of BTA injection. Parameters for achieving less than 10 prism dioptres (pd) of horizontal deviation and percentage correction of the pretreatment deviation were assessed for injections of less than 10 U and more than 10 U of BTA. Induced ptosis and vertical deviation were examined within and after 6 months of follow-up. RESULTS: The mean pretreatment deviations were 38.6 +/- 2.5 pd and 37.6 +/- 1.9 pd for the ET and XT groups, respectively. After receiving 1.6 and 1.5 injections on average, improvement to less than 10 pd at the primary position occurred in 32% of ET and 22% of XT patients; the difference was not statistically significant. The percentage corrections of the ET patients were 41.4 +/- 9.3% and 36.9 +/- 5.6% in those treated with less than 10 U and more than 10 U of BTA respectively; the difference between the two groups was insignificant. For the XT patients the values were 42.1 +/- 7.4% and 28.9 +/- 3.5% respectively, which also were not statistically significantly different. Frequency of induced ptosis was more common in ET than XT patients (p = 0.01) and this difference was more pronounced with increased doses of BTA (7.7% in ET and 5.3% in XT patients with less than 10 U of BTA, and 24.0% in ET and 4.3% in XT patients with more than 10 U of BTA). Ptosis resolved completely within 6 weeks in all cases. Induced vertical deviation with less than 10 U of BTA was encountered in one case of ET (11.1%, 9 pd) and in another case of XT (8.3%, 4 pd), increasing to 60.0% (2-20 pd) and 38.8% (4-16 pd) respectively with more than 10 U of BTA injection. In about a year, induced vertical deviation resolved in approximately 40%, and decreased in 30% of the cases. CONCLUSION: Increasing the dose of BTA is clinically effective in larger deviations, although statistically indifferent, especially in ET compared with XT. However, an increased dose is accompanied by increased incidence of induced ptosis and vertical deviation. Ptosis is temporary, but vertical deviation may persist for a long time and may present a cosmetic problem for some patients when more than 10 U of BTA is used.

Adolescent↗
PubMed2003

Discs-Large and Strabismus are functionally linked to plasma membrane formation.

During early embryogenesis in Drosophila melanogaster, extensive vesicle transport occurs to build cell boundaries for 6,000 nuclei. Here we show that this important process depends on a functional complex formed between the tumour suppressor and adaptor protein Discs-Large (Dlg) and the integral membrane protein Strabismus (Stbm)/Van Gogh (Vang). In support of this idea, embryos with mutations in either dlg or stbm displayed severe defects in plasma membrane formation. Conversely, overexpression of Dlg and Stbm synergistically induced excessive plasma membrane formation. In addition, ectopic co-expression of Stbm (which associated with post-Golgi vesicles) and the mammalian Dlg homologue SAP97/hDlg promoted translocation of SAP97 from the cytoplasm to both post-Golgi vesicles and the plasma membrane. This effect was dependent on the interaction between Stbm and SAP97. These findings suggest that the Dlg-Stbm complex recruits membrane-associated proteins and lipids from internal membranes to sites of new plasma membrane formation.

Animals↗
PubMed2002

Zebrafish trilobite identifies new roles for Strabismus in gastrulation and neuronal movements.

Embryonic morphogenesis is driven by a suite of cell behaviours, including coordinated shape changes, cellular rearrangements and individual cell migrations, whose molecular determinants are largely unknown. In the zebrafish, Dani rerio, trilobite mutant embryos have defects in gastrulation movements and posterior migration of hindbrain neurons. Here, we have used positional cloning to demonstrate that trilobite mutations disrupt the transmembrane protein Strabismus (Stbm)/Van Gogh (Vang), previously associated with planar cell polarity (PCP) in Drosophila melanogaster, and PCP and canonical Wnt/beta-catenin signalling in vertebrates. Our genetic and molecular analyses argue that during gastrulation, trilobite interacts with the PCP pathway without affecting canonical Wnt signalling. Furthermore, trilobite may regulate neuronal migration independently of PCP molecules. We show that trilobite mediates polarization of distinct movement behaviours. During gastrulation convergence and extension movements, trilobite regulates mediolateral cell polarity underlying effective intercalation and directed dorsal migration at increasing velocities. In the hindbrain, trilobite controls effective migration of branchiomotor neurons towards posterior rhombomeres. Mosaic analyses show trilobite functions cell-autonomously and non-autonomously in gastrulae and the hindbrain. We propose Trilobite/Stbm mediates cellular interactions that confer directionality on distinct movements during vertebrate embryogenesis.

Animals↗
PubMed2000

Association analysis between bilateral convergent strabismus with exophthalmus and milk production traits in dairy cattle.

Bilateral convergent strabismus with exophthalmus (BCSE) is characterized in cattle by a symmetrical antero-medial rotation and protrusion of the eyeballs. This eye defect is caused by an inherited, centrally insufficient function of the eye muscles recti laterales and retractores. In German Brown cattle a monogenic, autosomal dominant inheritance proved to be most probable in complex segregation analysis. In our study running between October 1993 and May 1995 a total of 200 affected German Brown cows was studied. The investigation of the association between milk production traits and BCSE was based on 10,960 German Brown cows. The analysis revealed no significant differences between affected and non-affected cows, nor between cow families with and without affected members. There was no indication of an association between milk production traits and occurrence of BCSE within cow families. Linkage or pleiotropy of the BCSE locus with quantitative trait loci for milk production traits may be rather unlikely.

Animals↗
PubMed2002

Garlic and the strabismus surgeon.

Potential side-effects caused by complementary medicines are often not anticipated. A case is reported of bilateral retro-bulbar haemorrhages with elevated intraocular pressure during strabismus surgery that occurred as a result of odourless garlic tablet ingestion prescribed by a naturopath. A near-catastrophic event was averted with rapid recognition and medical treatment. This is believed to be the first such report of haemorrhaging in ophthalmic surgery induced by garlic. It is concluded that unregulated naturopathic prescribing is potentially dangerous; doctors need to ask specifically about naturopathic potions.

Complementary Therapies↗
PubMed2000

Extraocular muscle myositis and restrictive strabismus in 10 dogs.

Ten cases of uni- or bilateral restrictive ventromedial strabismus in young dogs of different breeds are reported. Clinically, abnormalities were restricted to the extraocular muscles with sparing of the masticatory muscles and limb muscles. This was supported in some cases by imaging studies, electrophysiology, and immunocytochemical assay for antibodies against type 2M fibers. Histologically, there was variable lymphocytic plasmacytic mononuclear cell infiltration and fibrosis. This disorder is similar in many aspects to chronic masticatory myositis with focal myositis and subsequent fibrosis. Surgical correction may restore eye position and vision.

Journal Article↗
PubMed1996

[Partly accommodative convergent strabismus with and without excess convergence. Surgical treatment].

BACKGROUND: Partly accommodative esotropia typically shows a persistent convergent angle after correction of hypermetropia. This condition can-or cannot-be accompanied by an accommodative convergence excess. PATIENTS AND METHODS: Fifty patients were examined, operated on and followed up by the same team, and were separated into 2 groups: Group 1: partly accommodative esotropia without convergence excess (N = 20); Group 2: partly accommodative esotropia with convergence excess (N = 30). The operations of the first group consisted of 11 posterior fixations (Fadenoperations) on both internal recti (IR), and 9 combined horizontal operations or recessions of both IR. The operations of group 2 consisted of 23 Fadenoperations and 7 classic procedures. RESULTS: Comparison of angle reductions after a 6-month follow-up showed that posterior fixation was more effective in reducing esotropia when measured without glasses (p = 0.003), whereas both techniques produced similar effects when angles were considered with correction of hypermetropia. In group 2, the effects of posterior fixation on residual angles at near were significantly higher than on angles measured at distance fixation (p < 0.001). Objective refraction (median) was S + 3.60 for group 1 and S + 1.75 for group 2. CONCLUSION: Fadenoperation appeared to satisfactorily reduce convergence excess in our group of 30 patients with partly accommodative esotropia. In our series of 20 patients with accommodative strabismus without convergence excess, Fadenoperation was more effective only when angles were considered without glasses.

Accommodation, Ocular↗
PubMed1994

[Early surgery of convergent strabismus. Preliminary results of a series of 45 cases].

BACKGROUND: The age for strabismus surgery remains controversial and the various studies differ whether the results of residual angle and binocular vision may be better with early or late surgery. Different operating techniques for infantile esotropia have been proposed: recession of both medial recti, combined surgery on horizontal muscles, posterior fixation on one or both eyes, posterior fixation with simultaneous recession, botulin injection. PATIENTS: Our study presents 45 children with congenital esotropia operated at a mean age of 18.5 months. The surgical technique consisted of posterior fixation of both medial recti with or without simultaneous recession.

Age Factors↗
PubMed1998

Congenital fibrosis of the extraocular muscles type 2, an inherited exotropic strabismus fixus, maps to distal 11q13.

The extraocular fibrosis syndromes are congenital ocular-motility disorders that arise from dysfunction of the oculomotor, trochlear, and abducens nerves and/or the muscles that they innervate. Each is marked by a specific form of restrictive paralytic ophthalmoplegia with or without ptosis. Individuals with the classic form of congenital fibrosis of the extraocular muscles (CFEOM1) are born with bilateral ptosis and a restrictive infraductive external ophthalmoplegia. We previously demonstrated that CFEOM1 is caused by an autosomal dominant locus on chromosome 12 and results from a developmental absence of the superior division of the oculomotor nerve. We now have mapped a variant of CFEOM, exotropic strabismus fixus ("CFEOM2"). Affected individuals are born with bilateral ptosis and restrictive ophthalmoplegia with the globes "frozen" in extreme abduction. This autosomal recessive disorder is present in members of three consanguineous Saudi Arabian families. Genetic analysis of 70 individuals (20 affected individuals) reveals linkage to markers on chromosome 11q13, with a combined LOD score of 12.3 at the single nonrecombinant marker, D11S1314. The 2.5-cM CFEOM2 critical region is flanked by D11S4196/D11S4162 and D11S4184/1369. Two of the three families share a common disease-associated haplotype, suggesting a founder effect for CFEOM2. We hypothesize that CFEOM2 results from an analogous developmental defect to CFEOM1, one that affects both the superior and inferior divisions of the oculomotor nerve and their corresponding alpha motoneurons and extraocular muscles.

Blepharoptosis↗
PubMed2002

The planar polarity gene strabismus regulates convergent extension movements in Xenopus.

The signaling mechanisms that specify, guide and coordinate cell behavior during embryonic morphogenesis are poorly understood. We report that a Xenopus homolog of the Drosophila planar cell polarity gene strabismus (stbm) participates in the regulation of convergent extension, a critical morphogenetic process required for the elongation of dorsal structures in vertebrate embryos. Overexpression of Xstbm, which is expressed broadly in early development and subsequently in the nervous system, causes severely shortened trunk structures; a similar phenotype results from inhibiting Xstbm translation using a morpholino antisense oligo. Experiments with Keller explants further demonstrate that Xstbm can regulate convergent extension in both dorsal mesoderm and neural tissue. The specification of dorsal tissues is not affected. The Xstbm phenotype resembles those obtained with several other molecules with roles in planar polarity signaling, including Dishevelled and Frizzled-7 and -8. Unlike these proteins, however, Stbm has little effect on conventional Wnt/beta-catenin signaling in either frog or fly assays. Thus our results strongly support the emerging hypothesis that a vertebrate analog of the planar polarity pathway governs convergent extension movements.

Adaptor Proteins, Signal Transducing↗
PubMed2003

Prickle and Strabismus form a functional complex to generate a correct axis during planar cell polarity signaling.

Frizzled (Fz) signaling regulates the establishment of planar cell polarity (PCP). The PCP genes prickle (pk) and strabismus (stbm) are thought to antagonize Fz signaling. We show that they act in the same cell, R4, adjacent to that in which the Fz/PCP pathway is required in the Drosophila eye. We demonstrate that Stbm and Pk interact physically and that Stbm recruits Pk to the cell membrane. Through this interaction, Pk affects Stbm membrane localization and can cause clustering of Stbm. Pk is also known to interact with Dsh and is thought to antagonize Dsh by affecting its membrane localization. Thus our data suggest that the Stbm/Pk complex modulates Fz/Dsh activity, resulting in a symmetry-breaking step during polarity signaling.

Amino Acid Sequence↗