Botox Instead of Strabismus Surgery (BISS)

• Status: Recruiting
• Trial end date: 2023-08-01
• Target enrollment: 0
• Participant gender: All

Summary

The purpose of the study is to evaluate if strabismus can be successfully treated requiring less surgical interventions with a Botox-based treatment regimen compared to a purely surgery based treatment regimen.

Experimental arm: Botulinum toxin injection in the horizontal extraocular muscles.

Control (active comparator) arm: Strabismus surgery on the horizontal extraocular muscles. No investigational product is used.

In Switzerland the standard procedure for treating large angle esotropia is surgery, which is performed on the horizontal eye muscles that may be either recessed or shortened leading to reduced or increased muscle function respectively.

As an alternative to strabismus surgery, botulinum toxin (Botox) can be applied in extraocular muscles. Botox prevents the release of acetylcholine in the synaptic cleft and thereby blocks the neuromuscular transmission thus inducing a palsy.

Current evidence on the use of Botox in strabismus is incoherent, is poorly supported by basic research findings and leaves dedicated clinicians in the dark. The objective is to shed light into this field of clinical research, which may help to guide future pediatric ophthalmologists in their management of strabismic patients. In a best case scenario, the results from this trial will prevent strabismus operation for many children with acquired large angle esotropia.

• Phase: Phase 3
• Accepts Healthy Volunteers?: No

Details

• Lead Sponsor: University Hospital Inselspital, Berne
• Treatments: abobotulinumtoxinA; Botulinum Toxins; Botulinum Toxins, Type A; onabotulinumtoxinA

Criteria

Inclusion Criteria:

1. Informed consent of trial participant and/or legal representative documented per signature

2. Age > 1 year and <17 years

3. Esotropia > 10Prisms

4. Indication for an intervention (either Botox or surgery) has been made.

5. Any of the following:

• Presence of a secondary strabismus from binocular disruption the cause of the binocular disruption is no longer present

• Decompensated microstrabismus

• Decompensated phoria

• Acute acquired esotropia

6. Positive test of binocular function at any time point in the past, including any of the following

• Titmus test

• Bagolini striated glasses test

• Lang-stereo-test with correct naming of at least one panel

• Good ocular alignment after 6 months of age on at least 2 photographs

Exclusion Criteria:

1. Known hypersensitivity to botulinum toxin

2. Known neuromuscular disorder

3. Known present neurological disorder affecting the central nervous system Including paresis on cranial nerves number 3, 4 and 6

4. Any of the following:

• nystagmus

• dissociated vertical deviation

5. Vertical deviation in any gaze direction greater than 5°

6. Incomitance with more than 5° of difference between the left and right horizontal gaze direction

7. Previous strabismus surgery

8. Previous Botulinum toxin treatment on extraocular muscles

9. Presence of ophthalmic pathologies significantly preventing binocular functions.

A significant alteration of binocular function is assumed if vision is smaller than 0.1 or the visual field has a horizontal diameter of less than 20°.

10. Pregnancy. A negative pregnancy test before randomization is required for all women of child-bearing potential.

11. Preterm children born before 36 weeks of gestation.