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PubMed2001

Second cluster of strabismus cases after periocular anesthesia without hyaluronidase.

We describe a second cluster of cases of iatrogenic strabismus that occurred in clinical practices following cataract surgeries that occurred in 2000 when hyaluronidase was once again unavailable for use in periocular anesthetic regimens. Twelve cases of transient or permanent strabismus were referred by 4 anterior segment surgeons who had no previous cases of postcataract strabismus when performing periocular injections with hyaluronidase. The charts of the patients were reviewed retrospectively. Recurrence of an increase in postoperative strabismus when hyaluronidase became unavailable for a second time supports the concept that this enzyme may be more important than previously suspected in preventing damage to the extraocular muscles after periocular anesthetic injections.

Aged↗

PubMed2000

Oculographic and clinical characterization of thirty-seven children with anomalous head postures, nystagmus, and strabismus: the basis of a clinical algorithm.

BACKGROUND AND PURPOSE: We studied children with nystagmus who also had anomalous head postures and strabismus to determine the etiology of the conditions and present a diagnostic clinical algorithm. METHODS: The patients for this study were among the 560 patients evaluated in the ocular motor neurophysiology laboratory between the years 1991 and 1997. Clinical characteristics, infrared oculography data, and medical and surgical treatments were entered into a database for analysis. Oculography was performed on all patients according to a standard protocol, and data were stored and analyzed off-line. Etiology of anomalous head posture was determined with both clinical and oculography information. RESULTS: Thirty-seven children are the subjects of this report. The etiology of anomalous head posture was a "gaze null" due to congenital nystagmus in 23 (62%) patients, an "adduction null" due to manifest latent nystagmus in 12 (32%) patients, spasmus nutans in 1 (3%) patient, and strabismus in 1 (3%) patient. The patients' ages ranged from 9 months to 12 years and averaged 4.4 years. Sixty-nine percent were male patients. Nineteen (63%) of 30 patients had abnormal recognition (linear optotype) acuity in at least 1 eye on monocular cover; the recognition remained abnormal in 5 (17%) of 30 patients under binocular conditions. Thirty percent of patients had amblyopia, 16% had some structural disease of the eyes, 22% had some systemic syndrome or abnormality, 57% had a significant refractive error, and 27% had some ability to fuse. CONCLUSIONS: The major etiology for anomalous head posture in these patients was to adopt a gaze null due to congenital nystagmus (62% of patients) regardless of the direction of their anomalous head posture or type of strabismus. Moving the fixing eye as the first step for the anomalous head posture, combined with moving the nonfixing eye for the resulting strabismus may help treat these patients.

Algorithms↗

PubMed1997

The prevalence of strabismus in congenital nystagmus: the influence of anterior visual pathway disease.

PURPOSE: To determine the influence of underlying visual system disorders on the risk of developing strabismus in children with congenital nystagmus. METHODS: We retrospectively reviewed 82 cases of congenital nystagmus from a pediatric ophthalmology referral practice. RESULTS: Strabismus was found in 50% of children with congenital nystagmus. The prevalence of strabismus was 82% in children with bilateral optic nerve hypoplasia, 53% in patients with albinism, 36% in children with congenital retinal dystrophies, and 17% in children with idiopathic congenital nystagmus. CONCLUSION: The risk that a child with congenital nystagmus will have strabismus develop can be predicted from the nature of the underlying visual disorder.

Adolescent↗

PubMed1998

Asymmetric motion visually evoked potentials in infantile strabismus are not an artifact of latent nystagmus.

BACKGROUND: Patients who have infantile strabismus exhibit a directional asymmetry of motion visually evoked potentials (MVEPs) recorded under conditions of monocular viewing. The majority of these patients also have latent nystagmus, raising the possibility that the MVEP asymmetry is an artifact of the nystagmus. To explore this issue, we correlated MVEPs and eye movements under conditions that eliminated or increased latent nystagmus. METHODS: MVEPs and eye movements were recorded under conditions of monocular viewing in three adults who had combined infantile-onset strabismus and latent nystagmus. The subjects viewed vertically oriented grating stimuli that oscillated horizontally at temporal frequencies of 6.6 to 11.0 Hz by use of spatial frequencies of 1 to 3 cycles/degree. Quantitative eye movement recordings of latent nystagmus and horizontal pursuit/optokinetic nystagmus were also obtained. RESULTS: Eye movement recordings showed that the latent nystagmus was absent or markedly diminished when the viewing eye was in a 45-degree adducted position, whereas nystagmus velocity increased 10 to 40 times (to 2.2 to 4.5 degrees/second) when the viewing eye was in an abducted position (p < 0.05). MVEPs were abnormal (asymmetry indices > 0.40) when the viewing eye was in an adducted or abducted position of gaze. No correlation was found between the MVEP asymmetry index and the velocity of latent nystagmus. CONCLUSIONS: MVEP asymmetries in infantile strabismus remain robust under conditions that eliminate or greatly reduce the oscillations of latent nystagmus. MVEP asymmetries and ocular motor abnormalities both characterize infantile strabismus, but the ocular motor defects do not cause the MVEP asymmetries. The nasotemporal asymmetry of MVEPs and the nasotemporal asymmetry of pursuit and latent nystagmus are likely caused by deficits in related but separate binocular visual cortical circuits.

Adult↗

PubMed1996

What happens to binocularity in primate strabismus?

Normal humans for whom the positions and movements of the two eyes are constrained to be yoked together are able to extract rich binocular sensory information from the environment. Humans with strabismus are deficient in extracting some of this information. Studies of strabismus in non-human primates can augment what has been learned from humans about relationships between strabismus and sensory binocular function. For example, speculation about the role of binocular vision in primate evolution can help us understand why it is that the advantages of sensory binocular function outweigh the disadvantages of having the positions of the two eyes yoked together. Physiological optics assessments of fixation patterns and accommodative responses in monkeys provide information about how the brain accomplishes and coordinates motor and sensory binocular functions, and sets the stage for determining underlying neural mechanisms responsible for this coordination. Finally, a developmental perspective, concerned with events that occur during an early sensitive period in the life span of an infant primate, can help us understand how nature and nurture interact to set up this complex neural system in normal individuals, and how this process is disrupted in conditions such as strabismus.

Accommodation, Ocular↗

PubMed1998

The association between the oculocardiac reflex and post-operative vomiting in children undergoing strabismus surgery.

The oculocardiac reflex (OCR) is a potentially serious complication of ophthalmic surgery which is most commonly elicited during paediatric strabismus surgery. Post-operative vomiting (POV) is also extremely common after such procedures and may result in admission following planned day-case surgery. Although many factors play a part in the occurrence of POV, stimulation of the trigemino-vagal reflex arc is thought to explain the particularly high rate of vomiting after strabismus surgery. The OCR and the vaso-vagal response share this neuronal pathway, the bradycardia of the OCR often being the only objective feature of the vaso-vagal response while the patient is anaesthetised. The aim of this study was to investigate the possible association between the occurrence of the OCR and subsequent POV in children undergoing strabismus surgery. We have studied this relationship in 79 children, aged between 1 and 13 years, undergoing strabismus surgery under standardised anaesthetic conditions. A positive OCR was regarded as a drop in heart rate of 10% or more, or the onset of a dysrhythmia. An intraoperative OCR was elicited in 51 (64.6%) of the 79 children, whilst 29 (36.7%) developed POV in the subsequent 24 h period. There was a significant association between a positive intraoperative OCR and POV (p = 0.01): children with a positive OCR were 2.6 times more likely to vomit than those without the reflex. We conclude that there is an association between the occurrence of the OCR and POV and discuss possible preventive strategies.

Adolescent↗

PubMed2002

A retrospective pilot study to assess the impact of strabismus surgery on the corneal endothelium in children.

PURPOSE: To investigate if strabismus surgery has an impact on the corneal endothelium in children. METHODS: Fourteen children who had undergone uncomplicated strabismus surgery an average of 41 months previously (range 24-73 months) were compared with a group of age-matched (range 5-12 years) and refractive error (RE)-matched (range -4.74 to +4.25 D) children. Following noncontact specular microscopy, areas of at least 100 cells were measured, the number of sides for each cell recorded, and endothelial cell density (ECD) calculated from the area measures. Corneal diameter was measured with a clinical rule, corneal curvature with a manual keratometer, central corneal thickness (CCT) by ultrasound pachometry, and IOP by non-contact tonometry. RESULTS: The average ECD (+/-S.D.) in the post-surgery group was 4467+/-627 cells mm(-2), which was significantly higher (p < 0.02) than in the control group (3781+/-452 cells mm(-2)). This was because the average endothelial cell area in the surgery group was significantly smaller than in the control group (p < 0.005; 252+/-25 microm2 vs 296+/-29 microm2). Differences in cell areas were slightly greater for smaller cells (-15.7% for five-sided cells, -15.6% for six-sided cells, -14.3% for seven-sided cells and -13.8% for eight-sided cells). The cell differences appear to be related to both a slightly smaller corneal diameter (11.00+/-0.52 mm vs. 11.21+/-0.58 mm) and a slightly higher CCT (0.528+/-0.033 mm vs. 0.515+/-0.032 mm) in the post-operative group. CONCLUSION: The endothelial mosaic in children after strabismus surgery can show a higher than expected ECD value and slight cell pleomorphism. These signs indicate that there might be differences in eye growth and endothelial inflammatory stress associated with uneventful strabismus surgery.

Age Distribution↗

PubMed2001

[Localized argyrosis 58 years after strabismus operation--an ophthalmological rarity].

BACKGROUND: A pigmented episcleral lesion may have several etiologies. We describe the rare occurrence of a localized argyrosis secondary to former strabismus treatment. HISTORY: A 70-year old female patient was referred to our clinic for diagnosis and treatment of a pigmented episcleral process near the insertion of the left lateral rectus muscle which was noticed on a routine control by her ophthalmologist. The patient was free from ocular symptoms. There was a history of strabismus surgery on the left eye at the age of twelve. Due to the suspicious appearance of the lesion the possibility of a conjunctival malignant melanoma was considered. A ultrasound exam could not exclude this suspicion and therefore a biopsy was performed. Silver deposits and rests of a suture could be found. CONCLUSION: Silver deposits are a rare cause of a pigmented localized episcleral lesion. Several possibilities of silver contamination in our patient are discussed. The most likely explanation is the use of silver containing suture material in strabismus surgery performed 58 years ago. A localized argyrosis secondary to past strabismus surgery should therefore be included in the differential diagnosis of a pigmented episcleral lesion.

Aged↗

PubMed2004

[Decompensated strabismus surso-adductorius].

Strabismus surso-adductorius is a frequent unilateral or bilateral eye movement disorder. Its clinical features include eye elevation with concomitant vertical deviation in adduction, an abnormal head posture from which the patient is unaware (head turned and tilted towards the healthy side), a moderate subjective excyclotorsion, and a positive Bielschowsky head tilt test. Despite its anglo-saxon denomination as "congenital fourth nerve palsy", it is not a paretic disorder. Strabismus surso-adductorius differs from fourth nerve palsy both by etiology and by symptoms. A proper diagnosis is important as neuroradiological examination is mandatory in cases of acquired non-traumatic fourth nerve palsy, whereas decompensated strabismus surso-adductorius can be operated on without any further investigations. Early on, the oculomotor disorder is often well compensated and it does manifest at the adult age. Asthenopia and intermittent vertical diplopia appear as the fusional mechanisms fade out. The best surgical technique for strabismus surso-adductorius is an inferior oblique weakening procedure. In severe cases a combined shortening of the superior oblique tendon may be necessary.

Adult↗

PubMed2006

[Landolt C and snellen e acuity: differences in strabismus amblyopia?].

BACKGROUND: Assessment of visual acuity depends on the optotypes used for measurement. The ability to recognize different optotypes differs even if their critical details appear under the same visual angle. Since optotypes are evaluated on individuals with good visual acuity and without eye disorders, differences in the lower visual acuity range cannot be excluded. In this study, visual acuity measured with the Snellen E was compared to the Landolt C acuity. PATIENTS AND METHODS: 100 patients (age 8 - 90 years, median 60.5 years) with various eye disorders, among them 39 with amblyopia due to strabismus, and 13 healthy volunteers were tested. Charts with the Snellen E and the Landolt C (Precision Vision) which mimic the ETDRS charts were used to assess visual acuity. Three out of 5 optotypes per line had to be correctly identified, while wrong answers were monitored. In the group of patients, the eyes with the lower visual acuity, and the right eyes of the healthy subjects, were evaluated. RESULTS: Differences between Landolt C acuity (LR) and Snellen E acuity (SE) were small. The mean decimal values for LR and SE were 0.25 and 0.29 in the entire group and 0.14 and 0.16 for the eyes with strabismus amblyopia. The mean difference between LR and SE was 0.55 lines in the entire group and 0.55 lines for the eyes with strabismus amblyopia, with higher values of SE in both groups. The results of the other groups were similar with only small differences between LR and SE. CONCLUSION: Using the charts described, there was only a slight overestimation of visual acuity by the Snellen E compared to the Landolt C, even in strabismus amblyopia. Small differences in the lower visual acuity range have to be considered.

Adolescent↗

PubMed1998

[Surgery of strabismus and rupture of the blood-aqueous barrier (ischemia of the anterior segment)].

BACKGROUND: First described in 1957, anterior segment ischemia (ASI) following extraocular muscle surgery for non paralytic or paralytic strabismus is a rare but serious complication. Systemic and anatomical risk factors can be identified and vesselsparing surgical techniques used. The aim of this study is to evaluate those changes in the anterior chamber that may indicate the presence of post-operative subclinical ASI. METHODS: Pre- and 1 day post-operative anterior chamber flare measurements with the Laser flare cell meter (Kowa FC-1000) were made in 107 patients (109 operations) undergoing strabismus surgery. Surgery was carried out by the same surgeon in all cases and under general anaesthesia. Patients were divided into different groups according to the muscles operated (horizontal recti, vertical recti, obliques, or combinations thereof). RESULTS: Global and selective analysis showed no significant statistical difference between pre- and post-operative flare measurements in patients undergoing strabismus surgery. CONCLUSION: No subclinical ASI was found in this study of 109 strabismus operations (107 patients).

Adolescent↗

PubMed2000

Effect of prior orbital decompression on outcome of strabismus surgery in patients with thyroid ophthalmopathy.

PURPOSE: To compare strabismus surgery outcomes of patients who have had prior orbital decompression for thyroid ophthalmopathy with those of patients who have not had decompression. METHODS: The records of all patients operated on by the author for strabismus related to thyroid ophthalmopathy were retrospectively reviewed. RESULTS: Fifty patients were included in this study. Seventeen patients had previously undergone orbital decompression, and 33 patients had not. Seventy-six percent of patients who had had orbital decompression had a good or excellent outcome compared with 91% of those who had not had orbital decompression. Patients in the orbital decompression group had an average of 1.4 operations compared with 1.2 in the no-decompression group. The average numbers of muscles operated on were 3.1 in the decompression group and 1.9 in the no-decompression group. Patients who had been decompressed were more than 4 times as likely to require surgery for both a horizontal and vertical deviation than patients who had not been decompressed. CONCLUSIONS: Patients with thyroid ophthalmopathy who have had orbital decompression have a lower success rate of surgery for strabismus, more frequently need correction for both horizontal and vertical deviations, and have more muscles operated on than patients who have not had orbital decompression. The need for orbital decompression in patients with Graves' disease is reflective of a worse degree of orbitopathy. In addition, ocular changes from decompression surgery may interfere with a successful result from strabismus surgery.

Decompression, Surgical↗

PubMed2000

Scar remodeling after strabismus surgery.

PURPOSE: We sought to investigate abnormal scar lengthening after strabismus surgery. METHODS: Patients with overcorrection after strabismus surgery or undercorrection after extraocular muscle resection underwent exploration of previously operated muscles. Abnormal findings were documented by inspection and photography, and repair was undertaken at first with absorbable sutures and later with nonabsorbable sutures. RESULTS: Lengthened scars, consisting of amorphous connective tissue, were repaired on 198 muscles in 134 procedures by excision of the scar and reattachment of the muscle to sclera; absorbable sutures were used in 64 procedures, and nonabsorbable sutures were used in 70 procedures. Thirty-one procedures were followed by partial recurrence of the original overcorrection; 7 of these had documented restretching. The use of nonabsorbable sutures decreased the recurrence of strabismus from 42% to 6%. Factors that distinguished patients with stretched scars from patients with classic slipped muscles included minimal or no limitation of versions, less separation of the tendons from sclera, and thicker appearance of the scar segments. CONCLUSIONS: A lengthened or stretched remodeled scar between an operated muscle tendon and sclera may contribute to variability of outcome after strabismus repair, even years later. Definitive repair requires firm reattachment of tendon to sclera with nonabsorbable suture support.

Adolescent↗

PubMed2000

Surgical management of V-pattern strabismus and oblique dysfunction in craniofacial dysostosis.

INTRODUCTION: Strabismus affects as many as 60% to 70% of patients with craniofacial dysostosis. V-pattern strabismus with severe oblique muscle dysfunction is the most common ocular motility problem seen and can be difficult to manage. Few studies have reported on the results of strabismus surgery in this condition. METHODS: We retrospectively reviewed the surgical management and outcomes of 14 patients with craniofacial dysostosis who underwent 16 operations to determine the optimal surgical procedure and to report on extraocular muscle anomalies noted at the time of surgery. Operations performed included medial rectus muscle infraplacement (n = 2), inferior oblique (IO) recession (n = 3), IO myectomy (n = 3), IO anterior transposition (n = 3), and IO denervation/extirpation (n = 5). RESULTS: All patients had significant residual ocular motility dysfunction postoperatively. No beneficial effect was noted after IO anterior transposition or after medial rectus muscle infraplacement. Modest improvement of the V-pattern and oblique muscle dysfunction was noted after denervation/extirpation and myectomy of the IO muscle. Bilateral absent or anomalous superior oblique tendons were noted in 8 of 9 patients in whom the superior oblique tendon was examined at surgery. CONCLUSIONS: Strabismus in craniofacial dysostosis is complex and difficult to cure with surgery. Denervation/extirpation and myectomy of the IO muscle offered modest benefits, though neither procedure resulted in normalization of ocular motility. Agenesis of the superior oblique tendon may be causally related in a large proportion of affected patients.

Adolescent↗

PubMed2001

Timing of postoperative adjustment in adjustable suture strabismus surgery.

PURPOSE: The use of adjustable sutures in strabismus surgery has increased the rate of surgical success. Little data are available on the optimum timing for postoperative adjustment after strabismus surgery. We wanted to compare 2 common practices of adjustable suture technique after strabismus surgery. METHODS: Two comparable groups of 40 patients each, who had strabismus surgery with adjustable suture technique, were prospectively studied. Group A had early adjustment the same day of the surgery about 6 hours after the operation, and group B had late adjustment the next day about 24 hours after the operation. Subjective scoring tables were used to evaluate the pain felt by the patient before, during, and after the adjustment and any difficulties of the adjustment process. Requirements of postoperative pain medications and final alignment 6 weeks after surgery were also compared. RESULTS: Despite adequate statistical power, no significant differences were found between the groups regarding pain before, during, and after adjustment, difficulties performing the adjustment, and final alignment after 6 weeks (P > .05). Both adjustment schedules were equally associated with mild to moderate pain before, during, and after the adjustment. In the first 24 hours after surgery, no overall difference in the use of pain medications was found. Nausea and vomiting in the first 24 postoperative hours were more common in the early adjustment group (P = .02). CONCLUSION: The surgeon can feel free to choose the timing for postoperative adjustment. However, when performing an early adjustment, the surgeon should be especially prepared to control nausea and vomiting.

Adult↗

PubMed2002

The value of adult strabismus correction to the patient.

OBJECTIVES: To look at the value of adult strabismus correction to the patient, to consider what is known, and to define the challenges and opportunities for helping these patients. METHOD: The benefits of adult strabismus correction leading to the establishment of binocularity, expansion of visual field, and improved psychosocial health are presented and supported by published studies. RESULTS: Adults with strabismus can benefit from its correction. CONCLUSION: There is a tremendous need to educate the medical community and the lay public that adults with strabismus can be helped with restoration of their eyes to a position of alignment for normal function.

Adult↗

PubMed2002

A 12-year, prospective study of extraocular muscle imaging in complex strabismus.

INTRODUCTION: Diagnostic imaging by magnetic resonance imaging (MRI) or computed x-ray tomography (CT) has become the standard of care in many medical fields. Clinical imaging of the extraocular muscles (EOMs) can now provide insight into some causes of strabismus, in some cases challenging traditional concepts of etiology and suggesting alternative treatments. METHODS: Between 1990 and 2001, 62 orthotropic volunteers and 261 strabismic patients underwent orbital imaging under a prospective protocol. Surface coil MRI was performed with fixation control with slice thickness of 1.5 to 3 mm; CT was performed with 1-mm slice thickness. Images were correlated with ophthalmological examinations. RESULTS: MRI was performed in 267 and CT in 56 subjects. Comparison with normal orbits commonly demonstrated abnormalities of EOM size or location in strabismic patients. These included absence (5 patients) or atrophy (33 patients) of the superior oblique (SO) muscle in SO palsy; abnormalities of the trochlea or SO tendon in Brown's syndrome (8 patients); heterotopy of the rectus pulleys associated with incomitant strabismus (46 patients), including instability of pulleys (9 patients); trauma to rectus EOMs (16 patients); atrophy of the lateral rectus (10 patients), inferior rectus (4 patients), medial rectus (4 patients), superior rectus (4 patients), and inferior oblique (1 patient) muscles; and EOMs disinserted by scleral buckles (3 patients). EOM abnormalities correlated closely with clinically abnormal patterns of ocular motility. CONCLUSIONS: With the appropriate technique, EOM imaging is a valuable adjunct in clinical evaluation of complex strabismus. Because imaging can provide unique information unavailable from the clinical examination alone, it should be performed when indicated to evaluate patients with strabismus more complex than concomitant esotropia and exotropia.

Adult↗

PubMed2003

Intensity and complexity index of disease for strabismus surgery.

BACKGROUND: The value of health care must be calculated by weighing quality of care with cost of care, and quality of care must be measured not only by objective clinical outcomes but also by resulting health-related quality of life and patient satisfaction. To date, no validated method allows this determination. In this article, we present results of a survey to determine an intensity and complexity index (ICI) for strabismus surgery and discuss how this information can be used in a larger system of determining treatment outcomes and value. METHODS: We surveyed the membership of the American Association for Pediatric Ophthalmology and Strabismus to determine the ICI for 20 specific surgical procedures on the extraocular muscles and for 17 add-on factors that correct for circumstances altering the difficulty of the surgical procedure. RESULTS: Of the 620 surveys that were sent, 222 (36%) were returned and analyzed. Median ICI ranged from 1.00 for lateral rectus recession and for medial rectus recession to 2.00 for Harada-Ito and for superior oblique lengthening with silicone expander. Median ICI for add-on factors ranged from 0.50 for lateral incomitance, concurrent neurological syndrome, age 70 years or older, and ASA rating III or higher to 2.00 for complicated strabismus operation, eg, lost muscle. CONCLUSIONS: The ICI is a new method of risk-adjusting a patient population undergoing strabismus surgery, thus allowing further evaluation of the outcome and the value of treatment of disease in that patient population.

Data Collection↗