SEARCH · PubMed Health

Results for “Strabismus”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 199 records · Page 11Linked to original sources

PubMed2001

[Histological and ultrastructural studies of extraocular muscle proprioceptor in concomitant strabismus].

OBJECTIVE: To investigate the morphological change of extraocular muscle proprioceptor (EMP) in concomitant strabismus and study its pathogenesis. METHODS: The samples were obtained from the extraocular muscles of patients with concomitant strabismus and enucleated eyeballs. After being stained, the samples were examined under light microscopy (LM) and transmission electron microscopy (TEM) to count the number of the mitochondria in each sample in an area of 4,000 mm(2) of the axon under the same amplification. RESULTS: Under light microscopy, at the myotendinous junction of the extraocular muscle, the EMP nerve fibers were ended at the initial site or the bilateral sides of a nearby single extrafusal fiber. Under electron microscopy, the general architecture of the receptors in concomitant strabismus was completely disorganized. The nerve component in them had disappeared. The number of the mitochondria in 4,000 mm(2) of the axon in the experimental group was significantly lower than that in the control group (P < 0.05). CONCLUSION: The results indicate that in concomitant strabismus, the reception and transmission of proprioceptive information are abnormal, and the morphological EMP disturbance plays an important role in the pathogenesis of concomitant strabismus.

Adolescent↗

PubMed2002

Incomitant strabismus associated with instability of rectus pulleys.

PURPOSE: Connective tissue pulleys serve as functional mechanical origins of the extraocular muscles (EOMs) and are normally stable relative to the orbit during gaze shifts. This study evaluated pulley stability in incomitant strabismus. METHODS: Contiguous 2- or 3-mm thick magnetic resonance images (MRIs) perpendicular to the orbital axis spanned the anteroposterior extents of 12 orbits of six patients with incomitant strabismus. Imaging was performed in central gaze, supraduction, infraduction, abduction, and adduction. Rectus EOM paths were defined by their area centroids and plotted in a normalized, oculocentric coordinate system. Paths of EOMs ran toward the pulleys. Sharp EOM path inflections in secondary gaze indicated pulley locations in three dimensions. RESULTS: MRI revealed substantial inferior shift of the lateral rectus (LR) pulley of up to 1 mm during vertical gaze shifts in patients with axial high myopia and a posterior shift from abduction to adduction in simulated Brown syndrome. There was substantial LR pulley shift opposite the direction of vertical gaze in a subject with X-pattern exotropia who had undergone repeated LR surgery. The medial rectus (MR) pulley shifted inferiorly with gaze elevation in Marfan syndrome. Pulley instability was associated with significantly increased globe translation during gaze shifts. CONCLUSIONS: Pulley instability, resulting in EOM sideslip during ductions, occurs in some cases of incomitant strabismus. Resultant patterns of strabismus may depend on static pulley positions, pulley instability, and coexisting globe translation that alters pulley locations relative to the globe. Translational instability of pulleys and the globe could produce abnormalities in actions of otherwise normal EOMs, and connective tissue disorders causing these instabilities should be considered as potential causes of strabismus.

Adult↗

PubMed1999

Corneal topographical changes following strabismus surgery.

PURPOSE: To study corneal topographical changes after strabismus surgery. METHODS: Computer-aided corneal topography was used in 43 strabismus patients (45 eyes) one or two days prior to and six or seven days after strabismus surgery. The spherical and cylindrical equivalents were calculated based on the simulated keratometry. RESULTS: After the surgery, only the changes at 3 mm in the inferior quadrant were statistically significant. The changes at 3 mm in the rest quadrants and the changes at 7 mm were not significant. Significant changes in spherical equivalent were found post-operatively. Neither the horizontal nor the vertical meridional equivalent showed significant changes after surgery. CONCLUSIONS: The results of corneal topographical changes following strabismus surgery in our preliminary study indicated the little effect of strabismus surgery on corneal curvature and corneal astigmatism.

Adolescent↗

PubMed2005

An unusual case of congenital convergent convergent strabismus fixus.

BACKGROUND: Convergent strabismus fixus is classified into congenital and acquired types; however, there are only a few detailed case reports of congenital convergent strabismus fixus. Here, we report a rare case of this condition in which the eyeball was shown by imaging diagnosis to be fixed with a hard cord-like material in the orbit. To our knowledge, there have been no previous reports of congenital convergent strabismus fixus caused by an abnormal cord-like material that was clearly identifiable by imaging. CASE REPORT: The patient was a 16 year old female who visited our department for consultation regarding restoration of normal appearance of her strabismus. She had undergone strabismus surgery at the age of 3 years, but a forced duction test was strongly positive in all directions, and the eyeball was not mobile at the time. The initial surgery performed was a tenotomy of the medial rectus muscle and inferior rectus muscle and resection of the lateral rectus muscle of the right eye. The eye position and eye movement remained unchanged after surgery. At this time, MRI of the orbital region was performed, and an abnormal cord-like material connecting the posterior eyeball to the orbital wall was detected in the orbit. The cord-like material was pulling strongly on the posterior eyeball, congenitally fixing the eye position internally. CONCLUSION: We experienced a rare case in which a hard cord-like material in the orbit congenitally fixed the position of the eyeball. On MRI, the intensity of the cord-like material was clearly different from those of the muscle and nerve tissues. Considering the linearity of the cord-like material and the results of a forced duction test, the cord-like material probably consisted of fairly hard tissue, similar to bone.

Adolescent↗

PubMedDate not supplied

Extraocular muscle imaging in complex strabismus.

BACKGROUND AND OBJECTIVE: Abnormalities of extraocular muscle are an unusual cause of complex strabismus. The traditional evaluation based on clinical examinations is insufficient for the interpretation of incomitant motility disorders resulting from extraocular muscle anomalies. Extraocular muscle imaging by computed x-ray tomography (CT) or magnetic resonance imaging (MRI) can provide useful information for diagnosis, pathophysiology, and treatment of complex strabismus. PATIENTS AND METHODS: Five cases of complex strabismus resulting from congenital anomalies of the extraocular muscles and their successful evaluation using extraocular muscle imaging are described. RESULTS: Orbital CT or MRI scan was obtained in five patients who had unusual incomitant strabismus. It confirmed the diagnosis of the absence of the medial rectus muscle, accessory lateral rectus muscle, atrophy of the inferior or both superior and medial rectus muscles, and abnormal thickening of the levator palpebrae superioris and superior rectus muscle. CONCLUSIONS: Extraocular muscle imaging is a useful technique for evaluating anatomic abnormalities. It should be considered when evaluating patients with atypical strabismus.

Adolescent↗

PubMed2006

Corneal astigmatic effects of conventional recession vs suspension recession ("hang-back") strabismus surgery: a pilot study.

INTRODUCTION: Changes in refractive error after strabismus surgery occur secondary to changes in corneal curvature. The change in refractive error is usually transient but may lead to a temporary decrease in vision. We compared the change in corneal curvature following strabismus surgery in eyes utilizing a suspension (so-called "hang-back") recession technique to eyes undergoing conventional recession surgery. METHODS: Sixteen patients undergoing bilateral medial or lateral rectus recessions were prospectively entered into the study. One eye was randomly selected to undergo conventional strabismus surgery and the other eye underwent strabismus surgery using the suspension technique. Keratometry measurements were taken in the operating room immediately prior to and immediately after surgery. The change in corneal curvature was calculated and analyzed for each technique. RESULTS: The mean change in corneal curvature was -0.06 diopters (D) for the suspension group and +0.18 D for the conventional group, confirming prior reports. However, all eyes undergoing suspension surgery had a change within 1 D whereas only 75% of those eyes undergoing conventional surgery fell within the same range. Overall there was twice the variation in the degree of astigmatism in the conventional group when compared with the suspension group. CONCLUSIONS: No eye undergoing suspension surgery experienced a change in corneal curvature greater than 1 D while 25% of those undergoing conventional surgery did. Therefore, possible benefits to the suspension recession technique might include less overall variability of astigmatism change and decreased amounts of induced astigmatism. Patients undergoing strabismus surgery using a suspension technique may be less likely to notice a change in their vision in the immediate postoperative period.

Astigmatism↗

PubMedDate not supplied

[Strabismus and pseudostrabismus in premature infants].

Prematurity is a factor that predisposes to strabismus. Three hundred of the 1785 children with strabismus in out patient care during the latter five years were preterm babies, showing that prematurity intervenes in 16.7% of cases in the onset of strabismus. The onset age of strabismus deviation was also earlier before the age of two in 30% of cases. Visual acuity, refraction, strabismus deviation and fixation in terms of the degree of prematurity are analyzed. Neuropsychological examination revealed neurologic disturbances in 28.2% of these children, of which 5% encephalopathy. The neurologic disturbances, frequently of polycentric origin also represent an obstacle in reestablishing binocular vision. Seven premature infants presented pseudostrabismus with abnormal kappa angle and small deviation angle due to macula ectopia.

Child↗

PubMed1987

Injection of type A botulinum toxin into extraocular muscles for correction of strabismus.

Between July 1984 and March 1985, 51 injections of type A botulinum toxin were given to 39 patients aged 11 to 81 years with various types of strabismus, including paralytic strabismus, sensory exotropia, consecutive and residual postsurgical deviations and partially accommodative esotropia. All deviations were documented by orthoptic assessment and photography. After treatment the patients were followed for up to 3 years. The beneficial effects of a single injection were modest, and a second injection was often necessary to achieve satisfactory ocular alignment. Thirteen of the 26 patients (50%) with nonparalytic strabismus and 10 of the 13 patients (77%) with paralytic strabismus had a good outcome (final deviation 12 prism dioptres or less). Adverse side effects included transient ptosis and diplopia and inadvertent vertical deviation. Twenty-one consecutive cases of nonparalytic horizontal strabismus treated with adjustable sutures were also reviewed. The results in these patients were more predictable and longer lasting than those in the patients who received botulinum toxin.

Adolescent↗

PubMed1979

Fixational eye movements in amblyopia and strabismus.

Horizontal eye position was monitored using a photoelectric method during monocular and binocular fixation in four patients having amblyopia without strabismus, thirteen patients having constant strabismus with amblyopia, and five patients having intermittent strabismus. Four abnormalities of fixation were found: increased drift, saccadic intrusions, manifest nystagmus, and latent nystagmus. Increased drift was related to the presence of amblyopia, while saccadic intrusions and nystagmus were related to the presence of strabismus. Understanding dynamic aspects of oculomotor control can provide insight into clinical assessment of fixation in amblyopia and strabismus.

Adolescent↗

PubMed1983

Cyclic strabismus.

An unusual age of presentation of cyclic strabismus, which became constant in a relatively short period of time without a previous history of surgery, trauma, or strabismus, is reported. The mechanism of cyclic strabismus is still unknown; however, most cases are treated successfully with strabismus surgery. Cyclic strabismus is distinct from other rhythmic diseases in that peripheral manipulation of the target organ results in resolution of the deviation.

Adolescent↗

PubMed1980

Dynamic vergence eye movements in strabismus and amblyopia: symmetric vergence.

Dynamic vergence eye movements in response to step target displacements along the midline were measured by an infrared reflection technique in 11 patients having either intermittent strabismus, constants-strabismus amblyopia, or amblyopia without strabismus. We found the absence of normal disparity (fusional) vergence in all patients having strabismus and in some patients having amblyopia without strabismus. A characteristic response consisting of a binocular accommodative vergence component and an early binocular saccadic component was used to foveate the target of interest with the dominant eye. Vergence responses in our control subjects and patients with the nondominant eye occluded were similar to those recorded in our patients during binocular viewing. These results suggest that disparity information is not utilized by patients, probably as a result of long-term, ongoing suppression in the deviated or amblyopic eye. Accommodative vergence with the aid of an early foveating saccade was the primary mechanism for tracking targets in three-dimensional space.

Accommodation, Ocular↗

PubMed1994

[An investigation of 4,125 cases of Kazak childhood strabismus and amblyopia].

An investigation was made on 4,125 Kazak pupils (aged from 4 to 14 years) with strabismus and amblyopia in 9 schools of 5 countries. Among the subjects examined, 48 cases (1.1%) were strabismus including 32 (66.67%) external and 16 (33.33%) internal strabismus; 15 cases (31.25%) suffered from both strabismus and amblyopia and 33 (68.75%) were strabismus but had normal visual acuity; 139 cases (209 eyes) were amblyopia (morbidity rate: 3.37%) including 70 binocular and 69 monocular amblyopia, 73 males and 66 females. Out of the 209 amblyopia eyes, 84 (40.19%) were slight, 104 (49.76%) medium and 21 (10.05%) serious. Ametropia was also found to be in the majority in Kazak childhood amblyope. Only 106 of 209 eyes were simple farsighted. To prevent the occurrence of amblyopia the writer suggests that efforts of finding and correcting ametropia at early stage should be made.

Adolescent↗

PubMed1994

Interocular transfer of the movement aftereffect in central and peripheral vision of people with strabismus.

PURPOSE: To compare binocularity in central and peripheral vision of people with early-onset strabismus and people with normal binocular vision. METHODS: Ten subjects with early-onset strabismus, and nine subjects with normal binocular vision were tested. To assess binocularity, interocular transfer (IOT) of a rotary movement aftereffect (MAE) was measured. The MAE stimuli were either confined to the central 2.8 degrees of the visual field or were presented 10 degrees into peripheral vision. RESULTS: In peripheral vision, there was no significant difference in IOT for the two groups of subjects. In central vision, there was a significant decrease of IOT in subjects with early-onset strabismus. Their IOT was, however, significantly greater than zero. CONCLUSIONS: Early-onset strabismus appears to spare binocularity in peripheral vision but reduces it in central vision. It does not abolish binocularity assessed by IOT of MAE, suggesting that some binocular connections survive early-onset strabismus, even in central vision.

Adolescent↗

PubMed1998

Screening for childhood strabismus by primary care physicians.

OBJECTIVE: To review the clinical classification of strabismus, to describe the timing and method of strabismus screening examinations, and to discuss the principles of treatment. QUALITY OF EVIDENCE: Current literature (1983 to 1995) was searched via MEDLINE using the MeSH headings strabismus, ocular motility disorders, and amblyopia. Articles were selected based on their date of publication, clinical relevance, and availability. Preference was given to more recent articles, articles with large numbers of subjects, and well-designed cohort studies. Official recommendations from academic groups were analyzed. Descriptions of clinical tests and their illustrations are based on classic texts. MAIN FINDINGS: Primary care physicians should screen all low-risk children. High-risk children (low birth weight, family history of strabismus, congenital ocular abnormality, or systemic conditions with vision-threatening ocular manifestations) should be referred to an ophthalmologist for screening. Screening should be performed in the neonatal period, at 6 months, and at 3 years (Grade A recommendation), as well as at 5 to 6 years (Grade B recommendation). Screening examination includes inspection, examining visual acuity, determining pupillary reactions, checking ocular alignment, testing eye movements, and ophthalmoscopy. CONCLUSIONS: Primary care physicians are essential to early detection of strabismus and amblyopia. Early detection can help minimize visual dysfunction, allow for normal development of binocular vision and depth perception, and prevent psychosocial dysfunction.

Age Factors↗

PubMed1998

Combined intraocular and strabismus surgery.

BACKGROUND AND OBJECTIVE: To study the results of combined intraocular and strabismus surgery. PATIENTS AND METHODS: Combined surgery was done in 14 patients. In 10 of these patients, cataract and strabismus surgery were combined. One had a penetrating keratoplasty, and another required placement of a glaucoma valve implant. In one patient trabeculectomy, pupilloplasty, and lensectomy were done, and one patient needed repair of a leaking bleb. RESULTS: The strabismus of most patients was significantly improved. Eleven patients (79%) were orthophoric +/- 10 prism diopters (PD). Visual outcome was good in patients with no structural abnormalities who were compliant with occlusion therapy, if applicable. CONCLUSIONS: Combined intraocular and strabismus surgery has a success rate comparable with that of standard strabismus surgery.

Adolescent↗

PubMed1998

[The surgical treatment of strabismus and diplopia in Graves-Basedow ophthalmopathy].

PURPOSE: The aim of the study is to evaluate results of surgical treatment of strabismus and diplopia in Graves-Basedow ophthalmopathy. MATERIAL AND METHODS: The surgical procedure was performed in 40 patients with horizontal strabismus, horizontal strabismus with vertical deviation or isolated vertical strabismus. There were performed 86 surgical procedures on the eye muscles (in 20 cases adjustable sutures were used). RESULTS: Recovery or recovery without binocular single vision was observed in 27 cases (67.5%) and improvement in 11 cases (27.5%). CONCLUSIONS: The necessary conditions of surgical treatment are stabile euthyreoid state, the stabilization of the angle of strabismus and diplopia. The best results of operation are in the prefibrosis period of the muscle directly. The surgical procedures of weakening the function of muscles and adjustable sutures are recommended. The operations of several stages and atraumatic should be performed.

Adult↗

PubMed1999

Quantitative visual fields under binocular viewing conditions in primary and consecutive divergent strabismus.

BACKGROUND: Although there have been a number of studies on the size of the suppression scotoma in divergent strabismus, there have been no reports on the full extent (i.e. size as well as depth) of this scotoma. METHODS: Binocular static perimetry was used to measure suppression scotomas in five patients with primary divergent strabismus and ten patients with consecutive divergent strabismus. Four control subjects were also included in the study. With two modified Friedmann visual field analysers, we measured the visual field of both eyes under monocular and binocular viewing conditions. The objective angle of squint ranged from 3 degrees to 25 degrees. Best corrected visual acuity was at least 0.4, but mostly 1.0 in both eyes. RESULTS: All subjects had normal visual fields for each eye under monocular viewing conditions. In 12 of the 15 subjects, we found a large area of suppression encompassing the projection of the fixation point as well as that of the fovea in the non-fixating eye under binocular viewing conditions. In 2 of these 12 patients, one with primary and one with consecutive divergent strabismus, the area of suppression was located nasally to the position of the fovea in the field of the non-fixating eye (nasal hemisuppression). In another two patients with divergent squint combined with vertical deviation, a small fixation-point suppression scotoma was found. The depth of suppression ranged from 3 dB to 16 dB. In one subject only, no suppression was found. CONCLUSIONS: Our findings indicate that the shape of the suppression scotoma is not related to the origin of divergent strabismus or to the angle of squint. Our results also indicate that the critical age for the development of suppression in divergent squint might be up to 14 years.

Adolescent↗

PubMed1992

Refraction changes in children developing convergent or divergent strabismus.

Strabismus and amblyopia were studied in a cohort of children born in 1979 or 1980 in the area of Västerås, Sweden. Forty percent of the children had participated in a voluntary eye examination at 1 year of age. All children diagnosed as strabismic and/or amblyopic between 1979 and 1988 at any of the three eye clinics in the area were included in this study. Strabismic cases were mostly detected by the parents while microstrabismus and straight eye amblyopia were found at the general 4 years of age screening at children's health centres. In 57 cases with (n = 31) and without amblyopia (n = 41) it was possible to obtain several refraction values between 1 and 6 years of age. In this study we concentrated on manifest esotropia and exotropia. The aim of the study was to describe changes of refraction before and after onset of strabismus and to establish risk indicators that identified populations at risk of developing strabismus. We found that patients with esotropia show a more pronounced hypermetropia than exotropic cases at the time of detection of strabismus. This difference becomes more definite over time, since hypermetropia increased in the deviating eye in the esotropic cases while refractive errors remained stationary in most of the exotropic eyes. It was also apparent that anisometropia frequently developed after onset of strabismus in esotropic cases in contrast to exotropic cases. An increasing refractive error in the deviating esotropic eye could be combined with an emmetropisation of the fixating eye.

Anisometropia↗