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PubMed1988

Strabismus surgery on the nonamblyopic eye.

To date most surgeons operate only on the nonamblyopic eye in patients with strabismus and amblyopia with unpredictable, initial, surgical results. We present a series of 13 patients with amblyopia and strabismus plus anomalous head positions who underwent surgery on their nonamblyopic eye. The good, initial, surgical results in 77% of these patients suggest that operating on the good eye is important to dictate the final surgical results in correcting the deviation and normalizing the head position.

Adolescent↗

PubMed1977

[Results of objective accommodation determination in eyes with alternating functional central scotoma (alternating strabismus) (author's transl)].

Objective determination of monocular accommodation in young eyes revealed a different behaviour in strabismus alternans from that in normal binocular vision. This manifested itself by strongly differing individual responses, less correct values in physiological and unphysiological accommodation tests, and different reactions on hindering clear vision that cannot be compensated by refraction changes. The possibility of central scotoma, persisting during fixation and varying in density, occurring in alternating strabismus, is discussed.

Accommodation, Ocular↗

PubMed1992

Ineffectiveness of acupuncture and droperidol in preventing vomiting following strabismus repair in children.

The antiemetic effects and side-effects of P6 acupuncture and droperidol pre-treatment were evaluated in a randomized, patient- and observer-blinded study. Ninety unpremedicated children of ASA physical status I or II undergoing outpatient strabismus repair, and aged over one year, were studied. All patients received intravenous thiopentone 5 mg.kg-1, atropine 0.02 mg.kg-1 and succinylcholine 1.5 mg.kg-1, and the trachea was intubated. Patients then received either intravenous droperidol 0.075 mg.kg-1, droperidol plus five minutes' P6 acupuncture, or acupuncture alone. Anaesthesia was maintained with nitrous oxide 66% and halothane 1.5-2.0% in oxygen with spontaneous ventilation. There was no difference in the incidence of vomiting in the droperidol group (17% before discharge from hospital and 41% up to 48 hours after discharge), combined treatment group (17% and 34% respectively) and acupuncture group (27% and 45% respectively). Corresponding figures for the incidence of vomiting before discharge were 17%, 17% and 27% respectively; these values were also not different. The incidence of restlessness was significantly greater in children receiving droperidol (63%) or both treatments (67%) than in those receiving acupuncture alone (30%; P = 0.007). P6 acupuncture and droperidol are equally ineffective in preventing vomiting within 48 hours of paediatric strabismus repair. Droperidol is associated with increased incidence of postoperative restlessness.

Acupuncture Therapy↗

PubMed1995

Oral clonidine premedication reduces vomiting in children after strabismus surgery.

This is a prospective randomized double-blind trial conducted to determine whether preoperative orally administered clonidine causes or potentiates postoperative vomiting in 140 children (3-12 yr) undergoing strabismus surgery. They were all inpatients and classified randomly into four groups (n = 35 each); placebo (control), diazepam 0.4 mg.kg-1, clonidine 2 micrograms.kg-1, and clonidine 4 micrograms.kg-1. These agents were administered 93-112 min (mean; 100 min) before the anticipated time of induction of anaesthesia. All children received inhalational anaesthesia with halothane and nitrous oxide in oxygen. Muscle relaxation in all patients was obtained with vecuronium and residual neuromuscular blockade was antagonized with neostigmine and atropine before tracheal extubation. Diclofenac suppository was prescribed to prevent postoperative pain. No opioids or postoperative antiemetics were administered. All children remained in hospital for two days postoperatively. The incidence and frequency of vomiting were compared in the groups with Kruskall-Wallis Rank test. Clonidine 4 micrograms.kg-1 caused a lower incidence and frequency of vomiting than did placebo and diazepam (incidence and frequency: 11% and 1.37% and 3, and 34% and 2 in clonidine 4 micrograms.kg-1, placebo, and diazepam, respectively; P < 0.05 for clonidine 4 micrograms.kg-1 vs placebo and diazepam). However, low-dose clonidine was ineffective. These data suggest that preanaesthetic medication with clonidine 4 micrograms.kg-1 may be useful for preventing emesis following strabismus surgery. This property of clonidine indicates that it may be superior to other sedative premedicants such as diazepam and midazolam.

Administration, Oral↗

PubMed1997

Vomiting after strabismus surgery in children: ondansetron vs propofol.

PURPOSE: To compare the antiemetic efficacy and costs associated with two anaesthetic regimens in children undergoing strabismus surgery. One regimen contained halothane, nitrous oxide and ondansetron, while the other contained propofol and nitrous oxide. METHODS: Three hundred children aged 2-14 yr undergoing strabismus surgery were enrolled into this single-blind, randomized, stratified, blocked study with a balanced design. Anaesthesia was induced by inhalation with halothane/N2O/O2 (Group O) or with 2.5-3.5 mg.kg-1 propofol + 0.5 mg.kg-1 lidocaine i.v. (Group P). Group O patients were administered 0.15 mg.kg-1 ondansetron (maximum dose 8 mg) i.v. and all patients received atropine 20 micrograms.kg-1 i.v. immediately after induction of anaesthesia. Anaesthesia was maintained with N2O and halothane (Group O) or N2O and propofol (Group P). Patients were followed for 24 hr after their operation primarily to assess the incidence of postoperative vomiting. For each case, the costs of the anaesthetic drugs administered and their associated intravenous administration tubing were determined. Drug costs were those prevailing at the study site at the time of the investigation. Fixed costs, such as the cost of the anaesthetic equipment were not assessed. RESULTS: Groups were similar with respect to demographic data. The incidence of vomiting in both groups was 11% while in-hospital and 23% after discharge. Each episode of in-hospital vomiting prolonged discharge by 17 +/- 4 min, P < 0.001. Mean cost per case for anaesthetic drugs was less in Group O, 18 +/- 8 vs 21 +/- 10, CDN$, mean +/- SD, P < 0.01. CONCLUSION: The two methods of antiemetic prophylaxis were equally effective. Propofol-based anaesthesia was more expensive.

Adolescent↗

PubMed1997

Dose-response of flurbiprofen on postoperative pain and emesis after paediatric strabismus surgery.

PURPOSE: Intravenous flurbiprofen, a non-steroidal antiinflammatory drug (NSAID), has been used recently for postoperative pain relief in adults. The drug is also likely to have antiemetic property. The present study was undertaken to investigate the effect of flurbiprofen on postoperative pain and emesis in children undergoing strabismus surgery, which is well known to produce postoperative nausea and vomiting. METHODS: In a prospective, randomised, controlled clinical trial, 90 children aged 2-11 yr received saline (control), flurbiprofen 0.5 mg.kg-1, or flurbiprofen 1 mg.kg-1. Saline and flurbiprofen were administered i.v. immediately after induction of anaesthesia. Anaesthesia was induced and maintained with sevoflurane and nitrous oxide in oxygen. Postoperative pain was assessed by a blinded observer using an objective pain scale (OPS). No opioids or antiemetics were administered throughout the study. The incidence and frequency of vomiting were compared among groups. RESULTS: Flurbiprofen 1 mg.kg-1 provided lower OPS (highest) scores during the eight hours after surgery and a reduced requirement for postoperative supplementary analgesic (diclofenac suppository) compared with the other two regimens. The two doses of flurbiprofen failed to decrease the incidence and frequency of vomiting. CONCLUSION: These data suggest that preoperative flurbiprofen 1 mg.kg-1 iv is a simple and effective approach to postoperative pain relief but not to the prevention of emesis following paediatric strabismus surgery.

Analgesics↗

PubMed1996

Granisetron reduces vomiting after strabismus surgery and tonsillectomy in children.

PURPOSE: To evaluate the antiemetic efficacy of granisetron, a selective 5-hydroxytryptamine type 3 receptor antagonist, on postoperative vomiting in children undergoing general anaesthesia for strabismus repair and tonsillectomy with or without adenoidectomy. METHODS: In a randomized, placebo-controlled, double-blind study, fifty patients, 4-10 yr of age, were given a single dose of either placebo (saline, n = 25) or granisetron (40 micrograms.kg-1, n = 25) iv over 2-5 min after the induction of anaesthesia and prior to the surgical procedure. Postoperatively, during the first 24 hr after anaesthesia, the frequencies of retching and vomiting were recorded. RESULTS: There were no differences between the two groups with regard to patient characteristics, surgical procedures and anaesthetic or postoperative management. The incidence of retching was 36% and 12% after administration of placebo or granisetron, respectively (P < 0.05); the corresponding frequencies of vomiting were 32% and 8% (P < 0.05). Four children who had received placebo required another rescue antiemetic drug, whereas none who had received granisetron needed this agent. CONCLUSION: Granisetron is effective in the prevention of retching and vomiting after strabismus repair and tonsillectomy in paediatric patients.

Antiemetics↗

PubMed1995

[Strabismus surgery in children. The effect of paracetamol and bupivacaine].

Postoperative vomiting is induced by different mechanisms such as age, anaesthetic technique and medications, postoperative analgesia, and surgical traction on the extra-ocular muscles. The influence of anticholinergic premedication and the use of benzodiazepines as factors affecting the incidence of vomiting is controversial. In a prospective, randomised, single-blind study we examined two different treatments with regard to postoperative pain, vigilance, and vomiting in young children undergoing strabismus repair. METHODS. After institutional ethical committee approval, informed written consent was obtained from all parents. The children were randomly assigned to three groups: (1) paracetamol (P)--17 patients who received 250-500 mg paracetamol rectally (dependent on body weight) immediately after intubation of the trachea; (2) bupivacaine (B)--17 patients who received two drops 0.5% bupivacaine hydrochloride on the conjunctiva of the eye(s) being corrected following intubation of the trachea and again 10 min after intubation. After the surgeon had exposed the extra-ocular muscle and before readaptation of the conjunctiva, two drops of the same solution were applied again each time directly on the muscle; and (3) controls (C)--16 patients who received rectal paracetamol after completion of the operation but before extubation. The children were premedicated with 0.05 mg/kg flunitrazepam sublingually. After 0.25 mg atropine i.v., anaesthesia was induced with 0.1 mg/kg vecuronium, 5 mg/kg thiopentone, 1.5 vol% enflurane, and N2O/O2 50:50. When the trachea was intubated anaesthesia was maintained with enflurane as required and 70% N2O in oxygen. Extubation was performed only if the patient could touch or did not tolerate the tube. Oral diet was allowed 6 h after extubation at the earliest. EXAMINATION OF VIGILANCE AND ANALGESIA. The degrees of vigilance and pain were evaluated preoperatively and after extubation over 24 h using two different scales. Evaluation of the scales was performed during the first 3 postoperative h at 12 different time points (Figs. 1, 2) and 6, 12, and 24 h after extubation. The evaluation was conducted by nursing staff who were blinded to the treatment (single-blind study). Postoperative analgesia consisted of 250-500 mg rectal paracetamol (all patients). Parametric data were expressed as mean +/- SD, and comparisons were made with the one-way analysis of variance. Fisher's exact test was applied to ordinal data. P < 0.05 indicates a statistically significant difference. RESULTS. Two patients (P) were excluded from the study postoperatively because of refusing rectal paracetamol in spite of pain and postoperative infection of the upper airways, which had manifested on the afternoon of the operative day. No significant differences were found between the three groups in patient characteristics (Table 1). The quantity of enflurane administered, rate, postoperative consumption of rectal paracetamol, and postoperative emesis were highest in the control group (Tables 2, 3), but the incidence of postoperative vomiting ranged only between 13% and 24% (Table 3). Children with preoperative paracetamol needed more time to fulfill the criteria to "stick out the tongue" and "recognising the mother". VIGILANCE. The time to postoperative crying or screaming and restlessness was shorter in the control group. The values reached significant difference at 10 min (P) and 25 min (P and B) after extubation compared with the other groups (Fig. 1). ANALGESIE. At 5, 10, and 150 min after extubation pain was significantly higher in patients in the control group (Fig. 2). CONCLUSIONS. Intraoperative administration of rectal paracetamol or topical 0.5% bupivacaine was most effective in the treatment of postoperative pain for strabismus surgery in younger children. Sublingual flunitrazepam and i.v. atropine given as premedication probably decrease postoperative vomiting.

Acetaminophen↗

PubMed1995

[The effect of propofol on vomiting after strabismus surgery in children].

Strabismus surgery in children is associated with a high incidence of postoperative nausea and vomiting (PONV). METHODS. Ninety ASA class I and II children aged 6 to 16 years and scheduled for strabismus surgery were randomly assigned to one of the following groups: Group 1 (n=30):thiopentone 4-6 mg/kg i.v., halothane 0.8-1.5%, N2O--O2 2:1, no opioids, droperidol 75 micrograms/kg i.v.; Group 2 (n=30):propofol 2-3 mg/kg i.v., propofol 6-9 mg/kg.h, alfentanil 30 micrgrams/kg.h, N2O-O2 2:1, no antiemetics; Group 3 (n=30):similar to group 2, but ventilation with air and O2 2:1. All patients were mechanically ventilated during anaesthesia and gastric contents were aspirated. Recovery scores were calculated for 2 h, emetic scores for 24 h postoperatively.

Adolescent↗

PubMed2006

Changes in the structure of neuronal connections in the visual cortex of cats with experimentally induced bilateral strabismus.

The spatial distribution of neuronal connections in cortical field 17 was studied in cats with experimentally induced bilateral convergent strabismus on postnatal days 10-14. Horseradish peroxidase was applied microiontophoretically to individual columns of neurons in fields 17 and 18 and retrograde-labeled cells were identified in both hemispheres. Increases and decreases in the extent of intra-hemisphere connections were seen in the mediolateral direction (projections of the horizontal meridian of the visual field). Most columns showed increases in inter-hemisphere connections in this same direction, which may support the more reliable unification of the two visual hemifields. In addition, some columns showed increases in intra-and inter-hemisphere connections in the rostrocaudal direction (projections of the vertical meridian). Thus, bilateral strabismus induced during the critical period of development leads to changes in the structure of both intra-hemisphere and inter-hemisphere connections of individual cortical columns in fields 17 and 18.

Animals↗

PubMed2006

Interhemisphere connections of the visual cortex in cats with bilateral strabismus.

The distribution of retrograde labeled callosal cells after microiontophoretic application of horseradish peroxidase into individual cortical columns in fields 17 and 18 was studied in cats reared with bilateral strabismus (with an angle of eye deviation of 10-35 degrees ). The area containing labeled cells was located asymmetrically in relation to the position of the injected column in the opposite hemisphere. Some of the cells were located in those parts of the transitional zone between fields 17 and 18 whose retinotopic coordinates corresponded to the column coordinates (as in intact cats). Other labeled cells were located in fields 17 and 18 and were grouped into clusters located at distances of about 1000 microm from the marginal clusters of the transitional zone. The locations of labeled cells in the lateral geniculate body showed that most columns receive inputs from the ipsilateral eye. Evidence for eye specificity of these monosynaptic interhemisphere connections is presented. The functional significance of changes in these connections in bilateral strabismus is discussed.

Animals↗

PubMed1975

Genetic analysis of vergence measures in populations with varying incidences of strabismus.

Genetic parameters were contrasted for vergence amplitudes within three populations--esotropic, exotropic, and randomly selected populations-who differed in their incidence of subtypes of strabismus. In general, heritabilities for convergence exceeded those for divergence, and heritabilities for recovery points exceeded those for break points. Heritability estimates for diveregence amplitudes were significantly different for the random and esotropia populations, while convergence heritability estimates for these groups were similar. Thus, gene differences influencing divergence ability contributed to genetic variance for strabismus.

Accommodation, Ocular↗

PubMed1979

Current techniques of adjustable strabismus surgery.

Adjustable strabismus surgical procedures provide the opportunity to reposition a surgically altered muscle position, which is often necessary for nonaverage cases of strabismus correction. The usual surgical procedure is extended into the postoperative period (same hospitalization) so that the surgeon may satisfactorily monitor the total end result (by cover test and rotations) at the time of adjustment. Adjustable techniques should be considered whenever a desired goal is unlikely to be reached in one surgical session. Recent technical improvements allow satisfactory globe position control during the adjustment stage for ease of recession or resection adjustment. Globe stabilization is attained during surgery and the postoperative adjustment by means of a scleral loop handle, placed near the corneoscleral limbus. Millimeters of adjustment are easily estimated by means of a sliding suture knot technique.

Humans↗

PubMed1979

Myelinated retinal nerve fibers associated with ipsilateral myopia, amblyopia, and strabismus.

Four patients had extensive unilateral myelinated nerve fibers associated with ipsilateral myopia, amblyopia, and strabismus. Their profound visual impairment, exotropia, and the early age onset of symptoms indicated that the amblyopia may have been organically caused. Prognosis is poor for even partial correction but good results have been obtained with intense therapy that includes full correction of the refractive error in each eye and extraocular muscle surgery if cosmetically necessary. In patients with axial myopia, images of a similar size will be produced by placing a lens of the correct power at the spectacle plane. In younger patients, a contact lens should not be used to correct the refractive error because it creates an undesirable anisometropia. Younger patients who have parafoveal fixation and no strabismus respond best to amblyopia therapy.

Adolescent↗

PubMed1984

Graphic analysis of paralytic strabismus with the Lancaster red-green test.

We used the Lancaster red-green test to monitor changes in ocular alignment in patients with paralytic strabismus. By inferring the position of the right eye and that of the left eye at many different positions of gaze and then plotting the data on a graph, one can derive a static eye position curve. The location of the curve relative to the line depicting normal ocular alignment ( orthophoria ) indicates whether there is an esodeviation or an exodeviation . The slope of a line drawn tangent to the curve indicates, for that particular point, whether the deviation is concomitant or not and which eye is relatively weak or restricted and by how much. This graphic technique provides a simple, sensitive, and quantitative measure of ocular alignment that may be especially useful for detecting subtle changes in the relative positions of the two eyes. This method may be a useful adjunct in the planning and evaluation of therapy for patients with paralytic strabismus.

Humans↗

PubMedDate not supplied

Preschool vision screening for amblyopia and strabismus. Programs, methods, guidelines, 1983.

Amblyopia and strabismus, which afflict at least 5% of children, require treatment early in life for best visual results. At present, many such children are treated late or not at all. Mass screening at preschool age, and perhaps ultimately of infants, appears the only viable solution to this problem. To ascertain the present status of preschool screening in the United States, on-site visits, mail questionnaires and telephone interviews were used to study existing preschool vision screening programs at the federal, state and private organization levels. We estimate that, at most, 21% of preschool children receive any form of vision screening. Only two states, Michigan and Minnesota, have legislated requirements for such screening. Several organizations have attempted to establish screening guidelines, with suggestions of specific test and referral criteria. These guidelines are reviewed. The guidelines are of particular interest because screening programs following them typically indicate far lower prevalence rates than most studies indicate actually exist, suggesting that the guidelines result in underreferrals. In order to assess this matter, vision screening methods appropriate for preschoolers or infants, based on current evidence, are reviewed. Stereoscopic testing, utilizing a random dot stereogram format, appears the best instrument available for amblyopia and strabismus screening, but large scale comparative studies of the different test methods are needed to arrive at a final determination. Suggestions are made for the physician interested in initiating preschool vision screening programs.

Amblyopia↗

PubMed1982

Interocular transfer of the motion aftereffect in strabismus.

The interocular transfer of the motion aftereffect (MAE) was measured in three groups of strabismic subjects (six with monofixation, nine with alternation, four with anomalous retinal correspondence) and compared with a group of four normal subjects. The duration of the MAE was measured using sinusoidal gratings of 0.5 c/deg subtending a visual angle of 8. Contrary to previous findings, a substantial amount of MAE transfer was found in some stereoblind individuals with strabismus. The mean amount of transfer for each group was found to correlate with binocularity; the order of decreasing transfer being: normal, monofixation, alternation, and anomalous retinal correspondence (ARC). This reduction in transfer which accompanied the loss of binocularity was asymmetric, that is, right-left transfer did not equal left-right transfer. The amount of asymmetry was found to correlate inversely with the amount of transfer. The direction in which the greatest transfer occurred did not correlate with visual acuity. These data substantiate the overall poor binocularity in subjects with ARC, and the relatively good binocularity of subjects with monofixation. Furthermore, the substantial amount of transfer found in subjects with alternating strabismus may be a measure of potentially achievable binocularity.

Adolescent↗

PubMed1994

Spatial phase discrimination in monkeys with experimental strabismus.

Human strabismus amblyopes show deficits in spatial vision that are revealed in a variety of visual tasks. In particular, they show severe deficits in their ability to encode the relative spatial phase of the sinusoidal components in a compound grating. To investigate the neural basis of strabismic amblyopia we tested the ability of monkeys with experimentally induced strabismus to encode spatial phase relationships. First, we trained them to discriminate between compound gratings (made of a fundamental sinusoid and its third harmonic) that differed only in the relative phase of their components. These monkeys exhibited a pattern of severe deficits that resemble those described in the human population of strabismic amblyopes. We conclude that these animals represent a valid model of strabismic amblyopia. Second, we show that a model that had been used to account for the performance of normal human subjects and of humans with anisometropic amblyopia fails to predict the performance of monkeys with strabismic amblyopia.

Amblyopia↗