Alternate Patching
Alternate patching is a technique that can be used for reducing a very subtle “eye wobble” that occurs between the two eyes1-3 also referred to as “binocular fixation instability”. This should not be confused with “squint” which occurs when one eye can be observed to turn in or out. If we close one eye the eye wobble goes away (unless there is also “monocular fixation instability”!). Alternate patching or covering one eye when reading or doing eye tracking therapy over a period of weeks to months (no more than 3 months) has been shown to be helpful for students under 12 years of age by reducing their eye wobble and improving reading outcomes.4-6
Measuring this instability is very difficult in practice and cannot be done simply on observation. The best way to measure it is with an eye tracking device as this can directly observe any slight discrepancies in how the two eyes are positioned with respect to each other. If we are unsure about whether or not a student has this problem, there is no harm including alternate patching therapy to eye tracking therapy since it is so easy to do.
Note, that an eye wobble problem can be present even when the other components of eye movements (eg. saccades) are normal! If a student fails the central component of the Eye Track task on the iCept Testing, but passes when looking to the left or right, this may suggest a problem with binocular stability. If all components of the iCept Test are normal however, this does NOT guarantee that there is no problem with binocular stability!
Instructions for Alternate Patching
Cover one eye with a patch or some form of cover on the first day of training. The next day cover the other eye. Keep following this procedure until the eye tracking training has been completed. It can also be used for reading a book as well if the child or student is happy to do it. The patch should NOT be worn outside of these times and no longer than 3 months.
For alternate patching to work then a child should have reasonably good vision in each eye. If the vision is poor in one eye – even with glasses – then alternate patching may not be advisable. If a child normally wears glasses for reading then these SHOULD be used for alternate patching. In this case, the patch can be positioned over the glasses or a soft cloth can be tucked behind one lens to avoid having to wear a patch!
