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At least 883 records · Page 49Linked to original sources

PubMed1991

Strabismus presenting after cataract surgery.

Strabismus presenting after cataract surgery is etiologically related to a heterogenous group of disorders. Clinical data from 63 patients so affected revealed four broad etiologic categories: 1) pre-existing disorders that preceded the cataract surgery, but were rendered asymptomatic by the occluding cataract (e.g., thyroid eye disease, cranial nerve palsy, myasthenia); 2) disorders precipitated by prolonged occlusion by a cataract (e.g., sensory deviations, decompensation of heterophorias, and central disruption of binocular vision); 3) disorders resulting from surgical trauma to extraocular muscles and orbital soft tissues. Traumatic injury to the inferior rectus muscle secondary to retrobulbar anesthesia injection, a specific subset, is postulated to result from a Volkmann's type ischemic contracture, a well-known osseofascial compartment syndrome occurring in peripheral skeletal muscles. 4) Disorders related to resulting aphakia/pseudophakia and associated optical aberrations (e.g.; anisophoria, ocular dominance reversal, and color/brightness disparity). The diagnostic and therapeutic implications of these findings are discussed.

Adult↗

PubMed1992

Objective measurement of small angles of strabismus in infants and children with photographic reflection pattern evaluation.

A new photographic method for the precise measurement of the angle of squint in children and infants is presented. The apparatus consists of a reflex camera with three horizontally aligned flashes and a small fixation light. The subjects are photographed while fixating binocularly or monocularly in the primary or secondary position. Six reflections can be seen on the photograph of each pupil. These are the first and fourth Purkinje images of each light source. From the reflection patterns, the squint angle or the angle kappa or alpha can be computed using a simple formula. A vertical angle of strabismus may be calculated from the same photograph using the same principle. Results from orthotropic and strabismic adults and from children are evaluated to establish reference values. Cooperation from the children is generally very good. The accuracy of the new method is between between 2 and 4.5 prism diopters (between 1 degree and 2.5 degrees), depending on the measuring strategy.

Adult↗

PubMed2000

[Familial sick sinus syndrome associated to strabismus and persistent left superior vena cava].

We report a family in which the mother and her three sons suffered sick sinus syndrome and strabismus. Two members had a persistent left superior vena cava with drainage into coronary sinus. The illness in all members of this family was oligosymptomatic, and well tolerated with mild symptoms like dizziness, fatigue and exercise dyspnea associated with nodal rhythm. Three of them, had episodes of paroxysmal atrial fibrillation. All patients remain asymptomatic after pacemaker implantation.

Adult↗

PubMed2000

Anterior segment ischemia after strabismus surgery with microvascular dissection.

Anterior segment ischemia is a rare but well-known complication of extraocular muscle surgery.(1) Several surgical techniques have been used to prevent this complication in high-risk patients. A number of studies have suggested that microvascular dissection and preservation of the anterior ciliary vessels during strabismus surgery may reduce the risk of ischemic complications. (2-4) We present a case in which anterior segment ischemia occurred despite the use of this vessel-sparing technique.

Anterior Eye Segment↗

PubMed1998

Bilateral recession of superior rectus muscles: its influence on A and V pattern strabismus.

PURPOSE: To determine whether bilateral superior rectus recession modifies A and V pattern strabismus. PATIENTS AND METHODS: Three patients with V patterns and eight patients with A patterns underwent bilateral superior rectus recession with neither oblique muscle surgery nor vertical displacement of the horizontal rectus muscles. Another three patients with A patterns underwent simultaneous superior oblique tenotomy and superior oblique recession. RESULTS: Two of the patients with V patterns demonstrated an increase in the V pattern after surgery; one was unchanged. Five of the patients with A patterns converted to V patterns after surgery. In the remaining three patients the pattern was eliminated. The three patients who underwent superior oblique tenotomy along with superior rectus recession had large shifts toward V pattern (mean shift, 40 delta). CONCLUSION: Bilateral superior rectus recession tends to increase V patterns and reduce A patterns. Superior rectus recession may be synergistic with superior oblique tenotomy in collapsing an A pattern.

Accommodation, Ocular↗

PubMed1998

The anesthetic management of the pediatric strabismus patient.

Postoperative nausea and vomiting continues to be a common perioperative complication for pediatric strabismus patients. Postoperative pain management and the choice of general anesthetic can increase the incidence of perioperative nausea. Current techniques for induction of general anesthesia and selection of agents, prevention and treatment of postoperative pain, and options for antiemetic therapy will be reviewed.

Anesthesia↗

PubMed1998

Vertical strabismus resulting from an anomalous extraocular muscle.

Unusual ocular motility abnormalities have been rarely reported to result from anomalous extraocular structures. These structures, which may be either muscular or fibrotic, attach to the globe and produce a mechanical restriction resulting in incomitant strabismus. To our knowledge, we report the first patient with an anomalous extraocular muscle in whom the clinical, radiologic, surgical, and histopathologic findings are described.

Child, Preschool↗

PubMed1999

A comparison of sutures for adjustable strabismus surgery.

BACKGROUND: The adjustable suture technique after strabismus surgery may be more easily performed if the sutures offered minimal resistance during the procedure as desired by the surgeon. METHODS: In a rabbit model, 3 different types of 6-0 absorbable sutures-Biosorb-C (polyglycolic acid with polycaprolate coating, Alcon Surgical), coated Vicryl (polyglactin 910 coated with polyglactin 370 and calcium stearate, Ethicon), and Dexon-"S" (polyglycolic acid, Davis and Geck)-were advanced through scleral tunnels when attached and not attached to extraocular muscles. Resistance was measured with a precise strain gauge accurate to 0.1 g with an intrinsic microprocessor. RESULTS: For unattached advancements, Biosorb-C offered significantly less resistance than Vicryl at 6 and 24 hours after operation (P < .02), whereas Dexon-"S" offered less resistance than Vicryl only at 24 hours (P = .001). At 6 hours, Biosorb-C sutures were marginally more slipperythan Dexon-"S" (P= .07). For sutures attached to extraocular muscles at 6 hours after surgery, the 3 sutures offered similar resistance. By 24 hours after the initial procedure, Vicryl presented significantly more resistance than either Biosorb-C or Dexon-"S" (P< .01 for both). For all comparisons of 6 versus 24 hours after surgery, the only significant increase in resistance were Vicryl sutures attached to muscles (P= .02). CONCLUSIONS: These data support the use of Biosorb-C and Dexon-"S" for the adjustable suture technique whether adjusted at 6 or 24 hours after the initial procedure, although Biosorb-C may be slightly easier to adjust at 6 hours. If Vicryl is used, it would be easier to adjust the muscle 6 hours after surgery rather than after 24 hours.

Animals↗

PubMed1989

Strabismus does not prevent recovery from monocular deprivation: a challenge for simple Hebbian models of synaptic modification.

It has been suggested that development of central connections in the mammalian visual system is governed by a simple Hebbian rule of synaptic modifiability. Under such a rule, simultaneity of presynaptic and postsynaptic action potentials is a prerequisite for enhanced synaptic efficacy. The present paper reports the results of a study designed to test whether this hypothesis is applicable to the development of the thalamo-cortical visual pathway. In four-week-old kittens, exposure to a 2-d period of monocular deprivation was used to render the vast majority of cortical cells capable of being activated only by the nondeprived eye. During a subsequent 3-5 month recovery period, both eyes were open but surgically misaligned. This combination of conditions was chosen so that during the recovery period presynaptic activity originating from the initially deprived eye would be decorrelated from postsynaptic action potentials in cortical neurons. If synaptic modification is regulated by a simple Hebbian mechanism, then in this situation the deprived eye should be unable to recover control of cortical cells. In fact, the present results indicate that during the recovery period the proportion of cortical neurons dominated by the deprived eye rose to a level equal to that of the nondeprived eye--a result contrary to that predicted by a simple Hebbian rule of development. Histological analysis indicated that a similar level of recovery was present both within and outside of cortical layer IV, the main thalamo-recipient layer. As expected, the induced strabismus resulted in a failure of cortical binocularity to recover in these kittens. Although these results argue against a simple Hebbian mechanism of development, they are compatible with the hypothesis that synaptic modifiability is dependent upon correlations between presynaptic activity and local, subthreshold, postsynaptic changes. This alternative hypothesis has the advantage of allowing modification of local synaptic circuits within the dendritic arbors of a single neuron.

Action Potentials↗

PubMedDate not supplied

Effect of strabismus on the development of vernier acuity and grating acuity in monkeys.

The effect of experimental strabismus on the development of vernier acuity and grating acuity was studied in Macaca nemestrina monkeys. Six monkeys were studied longitudinally beginning near 10 days after birth. Four of the six monkeys developed amblyopia. As is true for human strabismic amblyopes, the deficit in vernier acuity was larger than the deficit in grating acuity in the amblyopic monkeys. The developmental data reveal that this differential disruption of vernier acuity can be understood as a result of a slowed developmental process associated with amblyopia.

Amblyopia↗

PubMed1999

Comparative effects of intravenous ketorolac and pethidine on perioperative analgesia and postoperative nausea and vomiting (PONV) for paediatric strabismus surgery.

BACKGROUND: Corrective strabismus surgery is associated with moderate pain and a very high incidence of postoperative nausea and vomiting (PONV). Ketorolac tromethamine, a nonsteroidal anti-inflammatory drug, is a popular analgesic in adults. There are only limited published data on the use of intravenous ketorolac for paediatric analgesia perioperatively. This study evaluated and compared the emetic and analgesic effect of ketorolac with pethidine and its suitability for this kind of surgery. METHODS: Following institutional ethics committee approval and parental consent, 52 ASA class I children of age 2.5 to 15 yr were randomised to receive either ketorolac 0.9 mg kg-1 or pethidine 0.5 mg kg-1 given intravenously (i.v.). A blinded observer assessed recovery by Steward's method immediately after arrival at the post anaesthesia care unit (PACU), pain by validated Objective Pain Score (OPS) at 0 h, 1/2 h and 1 h after arrival at the PACU and PONV by Numeric Rank Score at specified time intervals. RESULTS: There were no differences in demographic data, anaesthesia time or surgery duration. Recovery scores, OPS and postoperative analgesic requirement were similar in both groups. PONV at various time intervals for the first 24 h, occurred more frequently in the pethidine group as compared to the ketorolac group (P < 0.001) There were no side effects observed with either drug. CONCLUSION: Ketorolac in a dose of 0.9 mg kg-1 i.v. at the induction of anaesthesia is as effective as pethidine 0.5 mg kg-1 i.v. as an analgesic and is associated with significantly less PONV.

Adolescent↗

PubMed1987

Day case strabismus surgery without post-operative ocular medication. A masked randomised study.

A masked, randomised study was designed to test the hypothesis that day case strabismus surgery and the absence of post-operative topical medication is a plan of management that does not compare unfavourably with discharge from hospital on the day after surgery with topical antibiotic and anti-inflammatory therapy for 14 days. The results indicate that patients who have day case surgery do not have more complications than overnight stay patients and that their inflammation and discomfort settle just as quickly without topical therapy. Medical, social and financial benefits of day case surgery are noted.

Ambulatory Surgical Procedures↗

PubMed1988

Transposition surgery in childhood strabismus.

Transposition surgery involves an alteration in the mechanical properties of muscle action, such that the direction of movement of the eye following contraction of the muscle is modified. Though often used in the management of more complex motility disorders we have investigated the role of such surgery in concomitant childhood strabismus, and report the results of a computer model prediction and a retrospective review of cases.

Adolescent↗

PubMed1990

Botulinum toxin therapy in dysthyroid strabismus.

We report our experience with the use of Botulinum toxin injection in 38 patients (64 injections) with severe dysthyroid strabismus. Three quarters of the injections led to a decrease in the angle of the squint by a mean 75% of the initial deviation. The average duration of effect was two months. Twenty six patients went on to surgery after stabilisation of their squint and endocrine status. Six patients achieved a stable long-term result with Botulinum toxin only. We suggest these results of treatment of early dysthyroid myopathy are more consistent with the characteristics of inflammatory spasm than contracture. The value of Botulinum toxin as a temporary means of maintaining binocularity in these young patients is discussed.

Adult↗

PubMed1991

Strabismus surgery in children: the prospects for binocular single vision.

The restoration or maintenance of useful binocular single vision (BSV) represents the ideal outcome in the management of a squinting child. However, in planning such management it is essential to have a clear appreciation of the likelihood of attaining that goal, and what factors will help in its attainment. Using both a literature review and some preliminary information from our own patient database we examine the prospects for BSV in different strabismus groups. We also discuss the techniques available to allow prediction of which children are candidates for the development of BSV following squint correction.

Child↗

PubMed1991

Treatment of strabismus after retinal detachment surgery with botulinum neurotoxin A.

Thirty-one consecutive patients were treated with injections of Botulinum Neurotoxin A to rectus muscles for strabismus following retinal detachment surgery. In 14 cases the presenting problem was diplopia and in 17 cases the presenting problem was cosmetic appearance. A total of 67 injections was given. Twenty-seven cases had nine months or more follow-up. Of these, four of 11 cases with diplopia had fusion restored, four were shown to have no fusion potential, and three had temporary improvement only. In 16 cases with a primary cosmetic problem there was no useful effect in two, three had surgery as an alternative, three were realigned long-term, and eight had continuing maintenance therapy with toxin. Over half the series had undergone multiple detachment surgery, often for giant tears and other complex pathology.

Adult↗

PubMed1993

New materials for rectus muscle tendon extension in strabismus surgery.

Conventional strabismus surgery has both limitations and complications. Some of these have been overcome by the use of 'hang-back' sutures. Here we describe a new technique using Mersilene and Teflon as extraocular muscle implants for large muscle recessions. Results of initial studies in rabbits are presented and discussed. Mersilene implants evoked a marked fibroblastic reaction which limits their usefulness. Results with Teflon were more encouraging and suggest that it would be a useful spacer material in tendon extensions.

Animals↗

PubMed1995

Management of strabismus due to orbital myositis.

We report on 5 consecutive patients seen at the botulinum toxin clinic at Moorfields Eye Hospital with an ocular motility disorder secondary to orbital myositis. CT scans demonstrated involvement of one or both of the medial recti in the inflammatory process in all 5 patients. In addition 1 patient had involvement of both the lateral recti and the right superior rectus. Two patients had been treated with oral steroids, 3 with non-steroidal anti-inflammatory agents, and 1 with orbital radiotherapy. Prior to toxin injection 3 patients had an esotropia (ranging from 4 delta to 30 delta) and two an exotropia (52 delta and 85 delta). A vertical imbalance was present in 3, and all 5 patients had symptomatic diplopia. A total of six injections were given to 5 patients, 2 of whom later went on to have surgery. Toxin injection reduced the angle of the deviation to less than 10 delta in 4 patients, all of whom are now asymptomatic. The fifth patient has persistent diplopia despite two operations to correct a large exotropia. We discuss the role of botulinum toxin and surgery in the management of strabismus due to orbital myositis.

Adolescent↗