Hello there, welcome to another Contacts with Conway. I was asked recently about which I
thought was the best method to determine eye dominance when fitting presbyopic or monovision
contact lenses, so I thought I'd go through a few of the options with you this afternoon.
The first and most commonly used method is to simply get the patient to look at the top letter
of the chart, forming a circle with the finger and thumb, just keeping both eyes open and looking at
the top letter through the finger and thumb and the practitioner can then determine which
eye the patient was chosen. This particular method is fraught with possible problems in as much that
by bringing the hand up from left to right, in this case it may cross the non-dominant eye and elect
to choose that. A better method of using this type of technique I find is to make a triangle with the
two hands, raise and keep both eyes open, both hands together and you can see I have actually chosen
the right eye again. I would always back up the either of these methods by using a plus blur test.
Using the patient's current prescription, whether it be contact lenses or spectacles, simply drop a
plus 1.50 lens over first the right and the left eye, warning the patient that it's going
to seem a little bit strange and ask them which felt more comfortable. The patient will generally
prefer to have the non-dominant eye blurred, they would not like to have their dominant eye blurred
and that i find is a better representative of the type of thing we're going to do with
monovision or multifocal contact lenses. We have a willing volunteer, Maurizio, who has agreed to help us
this afternoon and we'll go through these tests with him shortly. Okay Maurizio you've got your
contact lenses in today? Yes. Okay what I'd like you to do then is to look at one of the large letters up
on the chart there, form a circle with your hand, keep both eyes open and look up at the circle. Is
the large letter in the center of the circle? Yes. Is it still in the center? Yes, And what about now? Not in the centre.
Okay this time we do the same thing but this time I'd like you to make a triangle with your hands at
arm's length keep both eyes together get the large letter in the center of the triangle. Is it in the
center? Yes. Still in the center? Yes, still in the centre. And what about now? No. No, so again right eye dominant. one further test
that I prefer to do is using a plus 1.50. Now this will seem a little bit strange but I want you to
tell me which is the least at least uncomfortable. So look straight up at the large letters, keep both
eyes open. Does it feel better with the lens in position one or in position two? Two. One,
two? Two. This is showing that he prefers not to have the dominant eye
blurred so again it confirms that Maurizio is right eye dominant.
Thank you for watching, I hope you've enjoyed this video. If you have, remember
to like share and subscribe and leave any comments in the box below. If you
have any other tips you'd like to share with us and with everyone else or you
have any questions you'd like answered please get in touch. Thank you once more.