Biofinity--Spheric or Aspheric? Does asphericity provide a slight presbyopia correction? etc.

Are biofinity lenses spheric or aspheric?


I don't really understand exactly what the terms mean, but I will explain
why I ask.

I recall reading on this NG, probably a few years ago, that aspheric lenses
provide a little correction for presbyopia in and of themselves, due to the
asphericity, regardless of multifocal, monovision, etc. That just due to
being aspheric, they will help presbyopia a little.

I am both myopic and presbyopic, and wear monovision contacts--the right eye
for distance, the left for near.

Before I had Focus Night and Day -4.5 (8.4 BC) in the left eye. (A major
undercorrection for what I would need for good distance vision in that eye.)
That used to function fine for near work, but lately my presbyopia has been
a little worse. The OD changed the left eye to -4.0 for that reason. Since
that exact lens seems to have been discontinued, he gave me its replacement,
AirOptix Night and Day (8.6 BC). As I reported in another post, I had
serious comfort problems with that lens. (It could have been a bum lens
though.)

Anyhow, now I have a Biofinity in the left eye, -4.0 power. As to be
expected, with a half diopter less power in that eye, my distance vision is
worse, and also the depth perception, ability of the eyes to work together,
etc. (Therefore, I suggested to him -4.25, which have been ordered.)

However, one would expect, with the power having been lowered by a half
diopter on the reading eye, that the close vision, reading, etc., would have
improved. But surprisingly, it seems to me that my close vision is worse
now, with the Biofinity -4.0 in my left eye, than it was with the -4.5 N&D
in that eye!

I would imagine then, when I try the biofinity -4.25, that the distance and
binocular vision will be slightly better than with the -4.0, but that the
reading will be still worse!

If the Biofinity design is spheric, could the situation described above, of
worse close vision with Biofinity than N&D, be caused by the difference of
spheric vs. aspheric?

If so, what are all the silicon hydrogel lens brands that are aspheric?

Thank you.

P.S. Just in case it is relevant, I will give another piece of info. The eye
doc also made a change in my right eye prescription, the distance eye, for
which I wear a toric lens. The former prescription was -5.0, cyl -0.75, axis
180. The new rx for my right eye is -4.75, cyl -1.25, axis 180. He said the
astigmatism in that eye got worse. That is a pretty major change in the
cylinder no, from -0.75 to -1.25? Is there any possibility that that change
in the right eye could have made my near version get worse, even though my
left eye is the one for near vision?

Thanks again.

 

MS schreef:

They are of the aspheric type.

It makes a tiny difference, don't expect to much.
It also differs from one contactlenswearer to another in producing effect.

major snip.....

MS, it is difficult if not impossible to give you answers on the
internet not seeing you and not being capable to examining you.
You realy should asked your specialist and bring up the issues you have
complains about.
Monovision brings you solutions and on the other hand compromises.
Did you ever tried multifocal lenses or a modified monovisionsystem
(one monofocal, the other multifocal) ?

Ask your specialist.

Jan (normally Dutch spoken)

 

Thanks for your input, Jan.

Of course I will ask the OD, next time I see him. Always good to gather
information on one's own too though, which can give one good questions to
ask the doctor. Always good to hear different opinions as well.

I guess if Biofinity is also aspheric, then that could not be the reason,
for the difference i described.

Any other input into the situation I described?

 

PureVision lenses are aspheric. Felt pretty much the same as N&D to me (i.e.
not good), but much better optically.

 

PS

The reason that I added, in the PS to my original post, the info about the
change in astigmatism correction of my right (distance) eye, is that I
wondered if that could affect the near vision, making it worse?

Is that unusual, at age 57, to have a change in astigmatism correction from
0.75 cyl to 1.25 cyl? Well, it is a different OD than last time, and each
might have a different opinion, on what will work best for a given patient.
Notice that while increasing the cyl, he lowered the power of that (right,
distant) eye from -5.0 to -4.75.

Opinions?

 

Thanks for the info, Mike.

Is there any possibility, that that change in cylinder correction in the
toric lens in the distance eye, could negatively affect near vision, in a
person prescribed monovision contacts?

 

yes, the right (distance) contact is toric, and that changed from -0.75
to -1.25 cyl. The left (near) contact is not toric.