Rotation of lenses throughout the day - Preference Toric

I'm hoping some of the MDs on this board can recommend possible
solutions to this problem with my right CooperVision Preference toric
lens...

I recently ordered new lenses from my ophtalmologist. My right eye
starts out with perfect vision at the beginning of the day, centering
perfectly on its own, but the lens keeps rotating to a different
position (subtracting axis) after the first 15-30 mins, especially
during times when I'm reading or looking at the computer (I suspect
due to eye position during closer convergence). After the first few
hours, it almost consistently goes to this second position, and
turning the lens back slightly towards its original position produces
perfect vision, but usually only for a few minutes.

When I see perfectly, the reference mark (which should point straight
down at 0 rotation) is very slightly off-center, pointing to the right
corner of my mouth. When the reference mark points straight down, I
see ok but not great, and when it rotates slightly past center (ever
so slightly towards my right cheek), the vision is unacceptable. I can
see the reference mark using an LED flashlight.

Other than rotating it back into position, I find that a change in
conditions (going outdoors and looking far away, or taking a shower)
often resets the lens and I see well for a while.

The left eye is quite stable all day. Why would the right lens rotate
to a negative axis as the day wears on? Is there a way to get a lens
to be more stable in the right eye? How much total rotation does the
range described represent? Do I need a different curvature or a lens
with different characteristics?

My eyeglass prescription for the right eye:

OD -5.75 cyl -2.25 axis 166

My contact lens prescription for the same eye:

OD -5.25 cyl -1.75 axis 165

I would appreciate any ideas -- Alex.

 

Return to your fitter, book the appointment so you have been wearing the
lenses for a few hours and tell him about the problem, including that the
best vision is with the lens slightly rotated. Your fitter can then
precisely measure the number of degrees of rotation and reorder the lenses
with the correct axis. No charge exchange for axis adjustment should be
included in the fee you paid for fitting.

Dr Judy

 

If I order lenses that fit the second position (+5-10 deg), I will no
longer see well when the lens is in the first position... I will
simply invert the problem.

One solution is to get something between the two so I see marginally
at both positions but well in between... but the question is why
progressive motion to the second (minus) as the day advances, and how
to get lenses that stay in one position so I can settle on one axis?

-- Alex.

 

In your first post you stated that the lens changes after 15 to 20 minutes
of wear. This is common with toric lenses and surely it is better to be
clear for 12 hours and blurry for 15 minutes than vice versa.

If the lens is not fitting properly it may rotate less predictably. If this
is the case, you need to see your fitter to adjust fit which may mean
changing lens brand.

Dr Judy