Botulinum toxin as a postoperative diplopia test - it can also reduce the angle of deviation prior to surgery

Adult reference values of the computerized diplopia test

AIM

To estimate the adult reference values for measured deviations by a computerized diplopia test and testify the validity.

METHODS

Totally 391 participants were recruited and taken the computerized diplopia test. The plots and amplitude of deviations were recorded. The differences in different gender, age and visual acuity groups were analyzed respectively. Of 30 subjects were enrolled to testify the interobserver reliability. Another 46 subjects (including 26 normal subjects and 20 patients) were taken the test and theirs deviations were recorded to testify the validity of the reference value.

RESULTS

The max horizontal and vertical deviations were 2.55° and 0.76° with normal corrected visual acuity while 3.88° and 1.46° for subjects with poor corrected vision. The differences between age groups was insignificant (Z=3.615, 4.758; P=0.461, 0.313 for horizontal and vertical respectively). The max horizontal deviation of female was smaller than male (Z=-2.177; P=0.029), but the difference in max vertical deviation was insignificant (Z=-1.296; P=0.195). The mean difference between observers were both -0.1°, with 95% confidence limits (CI) of -1.4° and 1.6° in max horizontal deviations while -2.1° and 1.8° in max vertical deviation. The mean deviation of 26 normal subjects was 1.02°±0.84° for horizontal and 0.47°±0.30° for vertical which both within the range of reference values. The mean deviation of 20 patients was 13.51°±11.69° for horizontal and 8.34°±8.58° for vertical which both beyond the reference range.

CONCLUSION

The max amplitude of horizontal and vertical deviation is pointed as the numerical parameters of computerized diplopia test. The reference values are different between normal corrected visual acuity and poor corrected vision. These values may useful for evaluating patients with diplopia in veriety conditions during clinical practice.

Botulinum toxin uses in strabismus: A review of the injections performed during one year in a general hospital

OBJECTIVE

To analyse the indications, dosage and efficacy of botulinum toxin A injection performed in patients in a Strabismus Department.

METHODS

In this prospective study, botulinum toxin A was injected into 28 patients diagnosed with strabismus. Data was obtained from the records of patients that were evaluated during 2013 in the Strabismus Unit of Rey Juan Carlos Hospital (Móstoles, Madrid, Spain) in order to assess the indications and dosage of botulinum toxin A use in strabismus, as well as its clinical effect and differences in paediatric and adult patients. The outcomes in the last visit, at least 14 months after the injections, were analysed.

RESULTS

An analysis was performed on the data from 11 children, 6 females (54.5%), and 17 adults, 11 males (64%). The mean age was 4.42±3.48 years and 58.71±18.07 years in the children and adult groups, respectively. The majority of cases in both groups were esotropia (81.8% in children and 47.1% in adults). However the pathologies in the adult group were quite heterogeneous, including 4 patients with exotropia (26.5%), 4 with hypertropia (26.5%), and one with isolated nystagmus (5.9%). The mean number of the botulinum toxin injections in children was 1.45±0.93, although 72.7% received a single injection. In the adult group, the mean number of injections was 3.27±1.41. There was a statistically significant difference between pre- and post-injection in the tropia and phoria measurements in children and adults group (P<.05). In both groups there was a statistically significant improvement in post-injection torticollis when compared with the pre-injection measurement (P<.05). An improvement in the stereoacuity could be detected in 4 children. Two children (18.2%) and 5 adults (29.4%) required subsequent surgical intervention. Eight adult patients (49.1%) complained of diplopia in the primary position, which was resolved in 6 cases with toxin injection, whereas 2 needed surgery for diplopia correction.

CONCLUSIONS

Botulinum toxin is a very useful tool in the management of strabismus, obtaining better sensory and motor results in children, but it is also effective as a symptomatic treatment in some types of strabismus in adults.