None listed
Conditions
Brief summary
the aim of this study is : 1. To compare BLR recession and recess/resect for basic (N=D angle) intermittent exotropia 2. To compare BLR recession and recess/resect for and simulated divergence (N=D with +3’s) 3. To assess 20, 40, 60 mins patch tests to determine whether these are equivalent. 4. Does the patch test alter the distance measurements and therefore the surgical target
Interventions
Surgery for intermittent exotropia, Bilateral lateral recti recession or recession/ resection. the recession of the lateral recti muscle involves weakening the muscle by pulling it back few mm [ each mm will weaken the muscle by 3 diopters] so the amount will depend on the degree of divergent squint. e.g to correct 30 diopters of divergent squint will need to weaken each lateral recti muscle by 5 mm on each side so in total 10 mm = 30 Diopters.
for the medial rectus resection means strengthening
Surgery for intermittent exotropia, Bilateral lateral recti recession or recession/ resection. the recession of the lateral recti muscle involves weakening the muscle by pulling it back few mm [ each mm will weaken the muscle by 3 diopters] so the amount will depend on the degree of divergent squint. e.g to correct 30 diopters of divergent squint will need to weaken each lateral recti muscle by 5 mm on each side so in total 10 mm = 30 Diopters. for the medial rectus resection means strengthening the muscle by cutting it { each mm will strengthen the muscle by 4 mm] and that is again depend on the amount of squint. the duration of each procedure will be approximately 20 min / muscle.
Sponsors
Auckland District health board
Study design
Allocation
Randomised controlled trial
Intervention model
Parallel
Primary purpose
Treatment
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
3 Years to 18 Years
Healthy volunteers
No
Inclusion criteria
Age 3-18 years History of intermittent exotropia intermittent at either near or distance Full eye movements Visual acuity 6/9 or better each eye best corrected with crowded test by the time of surgery Any myopic refractive error, anisometropia or astigmatism of 1 dioptre or greater or hyperopia which is reducing the vision to less than 6/9 must be treated prior to inclusion. Basic exotropia with difference between near and distance measurements <10 dioptres, or simulated divergence excess with difference between near and distance measurement <10 dioptres after +3.00 test and/or patch test. Able to obtain full informed consent from the family for randomisation Able to obtain accurate prism cover test measurements (distance and near cover test within 5^ on at least 2 visits)
Exclusion criteria
Unable to obtain accurate prism cover test measurement Convergence insufficiency exotropia or true divergence excess Anyone with neurological/systemic abnormalities as the surgical result can be unpredictable Anyone requiring oblique muscle surgery Previous eye muscle surgery Adjustables “A” greater than 10 or “ V” greater than 15dioptres Anyone unwilling to be randomized
Outcome results
None listed