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Egocentric localization changes following unilateral strabismus surgery.

We measured spatial localization (using an open-loop pointing task) monocularly in each eye of eight patients undergoing unilateral strabismus surgery. Most of these patients had some degree of binocular vision. We found that, in most cases, changes in spatial localization produced by surgery on the operated eye paralleled those found in the other eye, both in magnitude and duration. Unilateral surgery can have central effects on egocentric localization.

Adolescent↗

Topical anesthesia for strabismus surgery.

Twenty-two adults underwent strabismus surgery under topical anesthesia over the past 4 years. Benefits of this technique include avoidance of certain hazards of general and retrobulbar anesthesia, the ability to adjust eye position to the patient's satisfaction on the operative table, and expanded options for patients unwilling to undergo general anesthesia. The major disadvantages are the possibility of increased patient discomfort. Patient selection is important.

Administration, Topical↗

A diagnostic ruler for strabismus and amblyopia.

We designed a diagnostic slide ruler for easier detection of strabismus and amblyopia, both of which begin in childhood. This new instrument makes the Parks three-step test easier to use and faster than other methods in diagnosing isolated cyclovertical muscle paralysis. Furthermore, the slide ruler tests visual acuity with both series letters and single letters. Incorporated into the instrument are Laurence's strabismometer, Haab's pupillometer, occluder, pinhole, and millimeter ruler. A laboratory model is now available, and this slide ruler can assist the ophthalmological practitioner in analyzing three-step test data more rapidly than graphs and computer programs can. This instrument can also diagnose pediatric patients in the early stages of microstrabismus and amblyopia to obtain the best therapeutic results.

Amblyopia↗

Results of combined surgery on the superior oblique and horizontal rectus muscles for A-pattern horizontal strabismus.

Results obtained in 32 patients with A-pattern horizontal strabismus and overacting superior oblique muscles treated with combined bilateral superior oblique tenotomies and bilateral symmetric surgery on the horizontal rectus muscles were analyzed retrospectively. The magnitude of reduction of the A-pattern correlated positively (r = 0.69) with the size of the preoperative A-pattern. Overall, 27 of the 32 patients (84%) had a satisfactory reduction in their A-pattern. Esodeviated patients received less correction in the primary position than exodeviated patients. Postoperative complications were minimal if the superior oblique tendon was hooked under direct visualization, and minimal dissection was performed on the surrounding tissue prior to transecting it near the nasal side of the superior rectus muscle.

Child↗

Synthetic polypeptide sleeve for strabismus surgery.

A synthetic polypentapeptide sleeve was placed around the superior rectus muscle of five New Zealand white rabbits in hopes of preventing postoperative fibrous scarring. Two forms of the polypentapeptide were used. No significant inflammation or scarring occurred with either form of the polypentapeptide when compared to controls. One form elicited a fibrous membrane surrounding the sleeve within 2 weeks. The other elicited no such reaction after 2 months. The latter form of the polypentapeptide may be useful in preventing scarring following strabismus surgery.

Amino Acid Sequence↗

Periocular infection after strabismus surgery. The Periocular Infection Study Group.

Fewer than 15 cases of cellulitis and subconjunctival abscess after extraocular muscle surgery have been reported in detail. In an effort to provide greater information about this serious complication, the members of the American Association for Pediatric Ophthalmology and Strabismus (AAPO&S) were surveyed and contributed cases were analyzed. Among the 25 cases of cellulitis, there was a predominance of preschool age patients and Staphylococcus aureus cultures. Many cases presented after a normal initial postoperative visit. The most common symptoms were marked swelling and pain. Possible predisposing factors included unsuspected sinusitis, eye rubbing, and poor hygiene. Two patients had documented bacteremia, but no patient developed endophthalmitis. All cases resolved on antibiotics, but only five patients were successfully treated with oral antibiotics alone. Periocular infections after extraocular muscle surgery can present after a normal initial postoperative visit. Symptoms of marked swelling and pain are cause for closer inspection. S. aureus is the most common organism and oral antibiotics alone can fail to halt the infection.

Abscess↗

Should early strabismus surgery be performed for ocular torticollis to prevent facial asymmetry?

To help determine whether ocular torticollis causes facial asymmetry, we analyzed photographs of patients with long-standing head tilts for amounts of tilt and facial asymmetry. Significant facial asymmetry that correlated with the side of the head tilt was found in patients with congenital superior oblique muscle paresis, but not in patients with traumatic superior oblique muscle paresis nor in patients with dissociated vertical deviation. The mechanism explaining the development of facial asymmetry in these patients may be deformational molding of the face and skull from the infant's sleeping with its head turned predominantly to one side during the first 6 to 12 months of life. Early strabismus surgery to correct the head tilt may help prevent facial asymmetry, but ensuring that the infant sleeps with alternating head positions may be more important.

Adolescent↗

Hydroxypropylmethylcellulose and sodium hyaluronate in adjustable strabismus surgery.

The efficacy of hydroxypropylmethylcellulose and sodium hyaluronate as adjuncts during adjustable strabismus surgery was evaluated experimentally. Fifteen randomized NZA rabbits underwent a bilateral 4-mm recession of the superior rectus followed by a 0.05 mL injection of submuscular hydroxypropylmethylcellulose 2% (HPMC) in one eye and sodium hyaluronate 1% (Healon) in the other eye. Five additional rabbits (10 eyes), used as controls, underwent the same procedure, but no viscoelastic was injected after surgery. The force needed to move the muscle 4 mm toward its original insertion was measured immediately and 24 hours after the operation, using a force gauge. The force needed to adjust the muscles increased 326.0%, 98%, and 124.7%, respectively in the control, Healon and HPMC groups (p < 0.001). No significant difference was found between the two viscoelastic substances. Histologic evaluation of the operation sites disclosed similar inflammation in both controls and viscoelastic groups (p = .5960).

Animals↗

Distance stereo acuity improvement in intermittent exotropic patients following strabismus surgery.

To determine whether distance stereo acuity improved following strabismus surgery in patients with intermittent exotropia, we tested 20 patients (5 to 87 years old) preoperatively and postoperatively using the Mentor BVAT II Video acuity tester (Santa Barbara, Calif) and binocular visual system. Acuity improved in 75% as assessed by contour circles and in 45% as assessed by random dot E tests at distance. Our results suggest that surgical realignment of intermittent exotropia restores distance stereo acuity. We conclude that measuring distance stereo acuity offers valuable information in the evaluation of the intermittent exotropic patient.

Adolescent↗

The adjustable globe: a technique for adjustable strabismus surgery.

BACKGROUND: Conventional adjustable strabismus surgery involves postoperative repositioning of individual muscles anchored to the sclera via adjustable sutures. Greaves has described anchoring opposing rectus muscles to one another, via sutures passing on either side of the limbus. With the muscles disinserted, the "freed" globe can be adjusted to the desired position within the resulting suture cradle. Friction of the sutures against the sclera holds the muscles in place until healing occurs. METHODS: Using a cul-de-sac approach, we performed 23 horizontal and three vertical adjustable globe procedures, with median follow-up of 7 weeks. Four procedures were performed on nonhuman primates, monitored with iris fluorescein angiography. RESULTS: Esodeviations were well corrected, but exodeviations were often grossly undercorrected. Prolonged postoperative discomfort and photophobia were experienced. Possible evidence for mild anterior segment ischemia was noted. CONCLUSION: Concern about poor results with exodeviations, discomfort, and possible anterior segment ischemia led us to abandon this procedure.

Adolescent↗

Posterior superior oblique tenectomy at the scleral insertion for collapse of A-pattern strabismus.

PURPOSE: To evaluate the efficacy of tenectomy of the posterior fibers of the superior oblique tendon at the scleral insertion to reduce A-pattern deviations with mild-to-moderate superior oblique overaction. METHODS: We retrospectively reviewed 22 consecutive patients with A-pattern strabismus and mild-to-moderate superior oblique overaction on whom posterior tenectomy of the superior oblique at the scleral insertion was performed between January 1988 and August 1994. Nine females and 13 males were included, with an age range of 3 to 36 years (mean 13.0 years). RESULTS: The average preoperative A-pattern for all patients was 18.0 prism diopters (delta) (10 to 33 delta), and a collapse of 16.1 delta was achieved (P < .000001). The average preoperative A-pattern for esotropic patients was 21.0 delta with an average correction of 18.6 delta. The average preoperative A-pattern for exotropic patients was 16.2 delta with a mean improvement of 14.5 delta. Twenty patients (91%) were postoperatively measured to have 6 delta or less difference between up and downgaze. Follow up ranged from 5.0 to 41.0 months (average, 14.0 months). CONCLUSIONS: This technique provides the surgeon with a predictable partial superior oblique weakening operation that carries a low risk of induced superior oblique palsy, unwanted cyclotorsion, or head tilt.

Adolescent↗

Evaluation of hemodynamic changes in the ophthalmic artery with color Doppler ultrasonography after strabismus surgery.

PURPOSE: To investigate the blood flow changes in ophthalmic artery with color Doppler ultrasonography after strabismus surgery. METHODS: Twenty eyes of 19 patients who underwent recession or resection surgery on two horizontal rectus muscles in 1 eye were examined using color Doppler ultrasonography preoperatively and 1 week and 1 month postoperatively. Measurements from both eyes of 16 age- and sex-matched normal subjects served as control data. The systolic maximum velocity, mean velocity, end-diastolic velocity, pulsatility index, and resistance index of the ophthalmic artery were determined. The Mann-Whitney U test was performed for comparison of the control and study group preoperatively for any hemodynamic parameter. Statistical comparison of the preoperative and postoperative measures in the study group was performed with Friedman's two-way analysis of variance. RESULTS: No difference (P>.05) was observed preoperatively between the study and control groups for any hemodynamic parameter in the ophthalmic artery. Although the ophthalmic artery showed a slight increase in systolic maximum velocity 1 month postoperatively, there were no statistically significant differences (P>.05) in velocities or resistance in the ophthalmic artery at any interval. CONCLUSION: Two horizontal rectus muscle operations in a previously unoperated eye do not cause significant hemodynamic changes in the ophthalmic artery. However, further studies are needed to obtain more information about the effect of multiple vertical rectus muscle operations on the blood flow parameters of the ophthalmic artery.

Adolescent↗

Strabismus measurements using the alternating and simultaneous prism cover tests: a comparative study.

PURPOSE: To determine the most accurate method of strabismus measurement in patients with constant manifest esotropia. METHODS: Patients underwent routine cover test assessment with the cover-uncover test and the alternating cover test with any increase in the angle of deviation being noted between the two methods. The simultaneous and alternating prism cover test was then performed to see if a qualitative increase in angle deviation was represented by a quantitative measurement. Patients also were assessed for the presence of binocular vision in free space using Bagolini striated lenses and motor fusion responses to base out prisms. RESULTS: There was a significant difference between the alternating and simultaneous prism cover test measurements for all patients (mean difference for near fixation: 4.72 prism diopters [delta]; 95% confidence interval [CI], 1.68-7.75 delta; df=51; P<.001). For patients who showed a qualitative change in angle based on observational judgement using the cover tests, the mean difference in angle measured by simultaneous and alternating prism cover test for near fixation was 7.42 delta (95% CI, 5.75-10.30 delta; df=25; P<.001). CONCLUSION: To obtain an accurate interpretation of the size of manifest esotropia, the angle of deviation needs to be measured by the simultaneous and alternating prism cover test when an observable difference is noted on the cover test. The presence of a latent component to a manifest deviation should prompt the investigation of binocular reflexes even if the manifest angle is too large to be commensurate with binocular vision.

Adolescent↗

Study of the psychosocial aspects of strabismus.

PURPOSE: To systematically evaluate the perception of psychosocial difficulties due to strabismus and the impact of corrective surgery in adolescents and young adults in India. METHODS: Patients 15 to 25 years of age with childhood onset (< or = 5 years of age) of constant concomitant squint (> or = 30 prism diopters of deviation for distance) were included in the study. After a detailed orthoptic evaluation, demographic data of the patients and their parents were recorded. Postgraduate Institute Health Questionnaire N-2 (standardized in India) was administered to rule out neuroticism in the patients. Psychosocial problems faced by the patients were evaluated with a semistructured interview schedule. Patients were evaluated 3 months after surgery using a similar interview schedule to assess the psychological impact of surgery. RESULTS: Eighty percent of both male and female patients had problems in their social life; 85% of the males and 75% of the females had personal problems due to squint. After surgery, a positive change in appearance was noticed by 97.5% and 95% noticed a change in self-esteem and self-confidence. CONCLUSION: These patients had difficulties with self-image and interpersonal relationships, faced ridicule at school and work, and generally avoided activities that brought attention to their defect. Substantial changes were noticed in them after corrective surgery, and the differences in their scores before and after surgery were statistically significant.

Adolescent↗

Infant strabismus: a 25-year review of 750 cases.

The review demonstrates that there is no justification for delay in treating babies who present with strabismus. A survey of 750 infants aged from 0 to 36 months among 5497 cases seen by an individual orthoptist over 25 years shows a decreasing use of surgery and an increasing proportion of fully functional results over this time. It emphasizes that no infant is too young for assessment and treatment.

Age Factors↗

Strabismus in children with cerebral palsy.

A group of 238 patients with cerebral palsy were identified of whom 108 could be studied through their charts. Only 20 of these patients had strabismus. Of this group, 10 received no surgical therapy. In these patients followed up to a period of four years, no evidence of significant change in the strabismic deviation was found. Patients who were treated by medical and optical means alone did not show evidence of improvement. Surgical therapy was effective in providing a cosmetically acceptable result. Surgery was performed between two and one-half and 13 years of age in eight patients, with an average age of surgery of 6.5 years. The results which we obtained are comparable to those obtained by others at an earlier age. It does not appear that the age of surgery affects the ultimate cosmetic nor functional outcome in children with cerebral palsy.

Age Factors↗

"Tissue-drag" with polyglycolic acid (Dexon) and polyglactin 910 (Vicryl) sutures in strabismus surgery.

The new absorbable synthetic sutures, polyglycolic and (Dexon) and Polyglactin 910 (Vicryl), are excellent sutures for strabismus surgery, but they have a bothersome tendency to attract adjacent tissue (tissue-drag). This difficulty is found especially with the 5-0 size suture, less so with the 6-0 size suture, and minimally with the 7-0 size suture. The presence and number of short, stubbly, protuberant strands (hooklets) seen on the surface of these sutures under high magnification correlates with the lack of ease with which the sutures pass through tissue. Other factors involved in tissue-drag include the crevices between braids in these sutures and the fiber-tissue friction due to the innate nature of the suture materials. Sutures which pass with ease through tissue, such as catgut and nonabsorbable sutures, are seen to have smooth surfaces under high magnification. Coating the 5-0 and 6-0 Dexon and Vicryl sutures to smooth their surfaces and reduce tissue-drag was ineffective with isotonic saline solution, minimally to moderately effective with glycerine and with methylcellulose and polyvinyl alcohol solutions, but highly effective with peanut and sesame oils. Though tissue-passage of Dexon and Vicryl sutures was much improved by coating with oil and entirely satisfactory, it still was not quite as good as with catgut. Clinically, the oil did not compromise the knot security or ease of handling of the sutures. No unusual postoperative reaction was seen with the use of the oiled sutures. Although oiling the synthetic absorbable sutures at time of surgery is effective, we recommend that suture manufacturers reduce the tissue-drag of synthetic absorbable sutures either by smoothing the surface in the manufacturing process or by developing an absorbable coating applied to the sutures during manufacture.

Lubrication↗

Adverse response to prism therapy in strabismus.

The recent literature on prism therapy in strabismus is reviewed. A case is reported in which an esotrope, treated by means of prism neutralization to effect sensory orthotropia, responded with a marked increase in the angle of squint. Guidelines are suggested to minimize risk of such adverse effect when prism therapy is attempted.

Child↗