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The "Becherer Twist" - How Will Your Patient Perform in a Soft Toric Contact Lens?
So, what do you know about the "Becherer Twist"? No... its not a new dance! This quick test
is an oldie but goodie, and can go a long way in saving you chair time.
Let me explain. We have all been in a situation where our
toric lens fits morph into multiple visits and multiple trial options. So much effort
is put into the process only to find out that this particular patient is a poor candidate
or is just going to have to deal with some lens limitations.
The "Becherer Twist" is a quick test that will help you determine the patients prognosis
for a good fit right from the start. Here is what you do.
1. Instruct the patient that you are going to make some adjustments and that this is
going to help determine if they are suited for soft toric contact lenses.
2. Display the full acuity chart 3. Keep the final prescription in the phoropter.
4. Tell the patient to indicate as soon as they notice blur.
5. Slowly twist the axis dial clockwise - Stop when they tell you.
6. Rotate the cylinder axis counterclockwise - Stop when they tell you.
So what information did we get from this exercise? The amount of rotation the patient can tolerate
tells you how sensitive they are going to be to axis alignment. In other words, how
easy or difficult this patient is going to be able to please in a soft toric contact
lens. If the patient allows you to get out 15-20
degrees then you are smooth sailing. If you are only getting out to about 5 degrees, that
patient is going to need a much more accurate axis alignment for a successful fit and education
on realistic expectations. Obviously, patient sensitivity has a lot to
do with lens power. The higher the cylinder, the more sensitive any patient will be to
small adjustments. In some instances we might have to explore additional lens options like
rigid lenses, mini-sclerals, hybrids etc.... but that's a whole different topic.
The point is that the "Becherer Twist" literally takes 15 seconds and can cut weeks of unnecessary
follow-ups out of your appointment book. Give it a try!
Happy prescribing
References: Becherer PD. Toric lenses then and now: some
timeless pearls. Eye Quest: 14-18. Oct 1991.