Wavefront glasses

My eye doc will soon be offering wavefront, or "high def" (or
something) glasses. They have a fancy machine (aberometer) and make
the lenses accordingly, instead of just doing sphere and cylinder. I'd
be interested to hear opinions and experiences related to this. I'm a
sucker for this type of thing, so I'll probably give it a shot, but
does it really work noticeably better than the old way?
--

 

I wear them.

I like them, but ... don't particularly LOVE them.

Much will depend on the amount of higher-order aberrations YOU have.
The MORE you have, the MORE you will, theoretically, benefit. The
wavefront aberrometry will determine this.

Mine simply weren't that high, so ... no overnight miracles, but ...
good, crisp vision.

Neil
Not a doctor

 

There are two kinds of wavefront lenses, those requirement special
measurements, and those which use a regular Rx. The ones that require a
special measurements with the machine you mentioned are mostly hype,
although for certain kinds of problems it may be useful.

Here is an article that explains it in more detail lists all the
manufacturers of wavefront lenses individually ground to your Rx.
http://www.allaboutvision.com/lenses/wavefront-lenses.htm

The Hoya ID is considered by many to be the best.

 

You might have better luck with wavefront soft contact lenses which
actually move along with the eye. The correction of higher order
aberrations requires very close registration of the optical
correction, and this is difficult to accomplish in spectacle lenses.
Some aberrations are more forgiving, however, such as spherical
aberration, one of the more common and prevalent ones. WaveTouch
Technologies is the manufacturer of the wavefront generated soft lens.

I'm a little puzzled, however. If you are the same Chuck who is being
fitted with some type of semi-scleral GP lens, wearing the contact
lenses will change your aberrations profile enough to make the
spectacles useless.

What's going on here?

 

I am not a vision professional. But I do have reasons why wavefront
(figured) corrected glasses are not a good idea.

Wavefront correction can be carried out for looking in a particular
direction. If done on the cornea of an eye, it will correct errors for
looking in a particular direction. That would be for looking in the
direction that images onto the fovea, As you look in different
directions by turning the eye,the correction turns with the eye. Light
that does not focus on-axis is likely to be aberrated more than if there
were no wavefront correction. That would not be expected to be a problem
because sharpest vision is desired for foveal vision. Off-axis
aberration is not that great a problem because the eye's retina is
losing acuity anyway.

For wavefront corrected glasses, however, your eys turn to see through
portions of the lens that are designed to correct best in another
direction.

Bill

 

Yeah, I'm the same guy, and I'm just taking many stabs in the dark
trying to find satisfaction. My eyeglass Rx has changed a bit since
wearing RGP, so I understand that I might be wasting money on wavefront
if I change my contact wearing habits.

On the "macrolens" front, my eye doctor is not proficient enough to
deal with the fact that my astigmatism is persisting. I went in for a
follow-up today and we decided to just give up on them. I wasn't going
to argue if he didn't feel confident going forward. I also was kind of
down on them due to the difficulty of getting them in without bubbles
and out without making my eyes bloodshot. I don't doubt these issues
could be dealt with with practice though.

I think wavefront soft lenses will be an option here, so I'll follow up
on that next visit. He had some new (to him?) custom soft contact that
he said he's had good luck with, so we're giving that a shot next. My
experience with soft lenses so far is that they don't stay oriented
right and are generally worse than nothing, but we'll see. He seems to
think that these hold some promise that "off the shelf" ones don't.

Back on the wavefront glasses, what I've read on-line is mostly a lot
of skepticism and negativity, but I asked him today and he said that
many of his patients (at his other office that already offers it) are
really impressed and happy with it. I guess I'll just wait and see.

--

 

What's your goal? What's your overall Rx?

Have you considered wearing contacts to take care of the near/
farsighted, and then glasses (over the contacts) to take care of the
astigmatism?

This might give you a much broader choice of contacts, stable vision,
and a good 'cosmetic' appearance.

I wear my wavefront glasses over Boston Foundation Scleral Lenses.

 

I have a pretty mild Rx, basically all astigmatism, 0.75 diopter when I
regularly wear RGP and 1.0-1.5 diopter when they settle out. I had
some issues adapting to the astigmatism correction in glasses as my
astigmatism creeped up past 1.0 (or possibly I have higher order stuff
for which cylinder was the best approximation). Anyway, I tried RGP
and life was great except that wind and AC irritate my eyes with them
in and my night vision is marginal. Comfort is also not great,
especially around 12 hours of wear.

So, I'm just trying to find my best solution. Nothing complex, just
comfort, vision, wear time, etc.
--

 

I'm sorry to hear about your experiences. I know precisely what you
are going through.

 

I'm not an expert in this field, but why would you expect everyone's
error to be fully corrected with only sphere and cyl corrections?
Surely some people have other errors that remain uncorrected with only
those.

--

 

It is possible to design lenses so that you get perfect imaging of a
point object to a point image. Such a design does not cover chromatic
aberrations or diffraction. The key is to design the surfaces of the
lens so that for every direction of light leaving the object will have
the same optical path length. This is Fermat's law. The trouble is that
as soon as you chage the object point, that path length to the image
point has changed. Moreover, it is unlikely that there will be pairs of
conjugate points (pair of an object point and an image point) that will
meet the criteria for the constant path length. As you swivel your eye
in different directions,other than that for which the lens is designed,
you can expect decreased performance.

Sphere and cylinder are used for most prescriptions because they are
relatively easy to grind and polish using classical techniques.

Bill

 

Snellen lines aren't the whole story though. I can see the 20/20 line,
but the contrast is much worse on my right eye, and it gets worse the
darker it is, with point sources smearing out. I keep thinking I want
more cylinder for this, but the doctor tells me that I reject it in the
batter/worse chair. With RGP's things look great until it gets dark,
then I get uniform starbursts. It _seems_ like there's something going
on that sphere/cyl isn't getting. Not that I'm bumping into stuff,
it's just annoying.

I just don't know enough about optics to have an informed opinion about
the scientific merits. I'm in engineering though, and I keep wanting
to make an analogy to fitting a curve with a polynomial. It's like
we've been using a 1st order polynomial for hundreds of years and now
we have the option of using a 6th order polynomial. Maybe 6 is overkill
because of the alignment issues and variation over the day, etc, but
perhaps 2nd or third order will make a noticeable difference to 10% of
glasses wearers? Fine tuning the diopters would be analogous to
dialing in the terms of the 1st order polynomial to ridiculous accuracy
but not adding any more. There are cases where that wouldn't hack it.

I'm not sure my analogy is right though...

 

Higher order aberrations are third order and above. Sphere and
cylinder are second order. Higher order aberrations are pupil
dependent. This has been well-documented, and tables are available.
In fact, I have documented it myself (I have an aberrometer). The
most common ones are spherical aberration (fourth order) and coma
(third order). Coma often results in a cylindrical correction that
never seems good enough. It also makes a difference as to where the
aberrations are located. If the origin is corneal, then a GP lens
with an optical zone that is sufficiently large should work. If the
origin is not corneal, then the GP lens will not work.

There is a company called WaveTouch Technologies that has the only
commercially available wavefront-correcting soft contact lens. Their
product can theoretically correct corneal and internal aberrations. I
might pursue this route first. The Marco OPD and Tracey aberrometers
are both approved to be used with the WaveTouch lenses.

 

My educated guess is that this is not the case. The OP clearly stated
that this effect was more pronounced in low light situations, and this
is an entirely different phenomenon than clouding of the media. Terms
like "smear," "low contrast," "worsening at night" are very familiar
to anybody who has worked with eyes having elevated spherical
aberration, coma, etc.

Otherwise, you are correct in that wavefront corrections are not going
to help eliminate scatter from cloudy media.

 

Since I see great in my GP's in all but dark situations, and based on
Dr. L's comments, my theory is that I have a little bit of higher order
abberation in the cornea. If I could get a big enough optical zone in
GP's, life would be pretty good, though my eyes do still get irritated
in the wind, etc, as I've posted before. Oh, and ideally I wouldn't be
getting residual astigmatism in my other eye...

I will pursue the wavefront glasses and soft contacts (if the latter is
an option), and see if I get lucky.

Dr. L, is it possible for the GP's to induce higher order abberations?
Specifically, I was as high as -1.5D cylinder prior to GP's, and now
I'm at -0.75D. Is it possible the 1.5 was pure cylinder and now I'm at
0.75 cylinder plus higher order junk?

--

 

Even if the problem arises out of enhanced aberrations from increased
pupil size, wavefront correction from external lenses are not likely to
solve the problem. That would only mean that the wavefront correction
will introduce optical distortion near the view angle for which the
correction is designed. That is, the correction is useful only when you
are looking through a lens in the design direction. For other
directions, the wavefront is merely another aberration.

On the other hand, if the correction swivels with the direction of
viewing, as might be the case when wavefront correction is built into
the contac lens system, the correction will track with the viewing
direction.

Bill

 

Sphere and cylinder corrections are also only perfect when looking
straight ahead, right? But they seem to hold up okay. The net benefit
is still there even when looking pretty far off axis. Do you have
reason to believe that this breaks down when we get to 3rd or 4th order
correction?

--

 

This point has been made several times in this thread.

 

Any change to the cornea can increase higher orders. Orthokeratology
and refractive surgery increase higher orders while simultaneously
reducing lower orders.

 

These "quadratic" corrections are only slightly sensitive to direction.
Looked at from the wavefront point of view, the added thickness varies
smoothly. That is, there are no sudden bumps in the surface. Wavefront
correction will add thickness rather suddenly as the fourth power of the
radius. It will be a ring around the design direction that would be of
no use unless the pupil is large and you are looking in the design
direction. For everything else, this will be a ring of spherical
aberration introduced unnecessarily.

Bill