On Nov 10, 12:45 am, "MS" <m...@nospam.com> wrote:
> Does anyone ever prescribe that combination? Does it make any sense?
> Or--does it only make sense to use multifocal lenses if in both eyes?
>
> I'll explain why I'm asking this, and hope that the helpful eye
> professionals here will give their opinion.
>
> I have always been very nearsighted. I wore RGP lenses for many years. In
> the last few years though, I've come to like the comfort and convenience of
> silicon hydrogel soft lenses, wearing them overnight. Even if the vision is
> not quite as clear, to me the comfort and convenience is a good trade-off. I
> have been wearing Focus Night&Day for about five years now, monovision.
> (Currently 55, becoming increasingly presbyopic.)
>
> My prescription has remained stable for those years-Right -5.25 (distance),
> Left -4.5 (near). (BC 8.4 both eyes) I can get by with that Rx, passed the
> driving test last time, drive in them, etc., but I have noticed that my
> distance vision leaves a lot to be desired, although I can get by. (And I
> realize that presbyopic solutions such as monovision and multifocals always
> involves compromise, lessening of distance vision in order to have near
> vision without reading glasses.) (My left eye is actually more nearsighted
> than my right--so that 4.5 rx left is undercorrected a lot for near vision.)
>
> At my recent eye exam the O.D. recommended a toric lens for my right eye.
> (I'm actually surprised that that hadn't been recommended to me earlier,
> since I had started with soft lenses, since I do have some astigmatism.) He
> said there wasn't enough astigmatism in my left eye to warrant a toric lens,
> but there was in my right eye. He gave me an Acuvue Advance Toric to try out
> in the right eye, also -5.25, with a cylinder of .75, bc 8.6. I kept the
> N&D -4.5 in my left eye.
>
> I immediately noticed a significant improvement in my distance version, and
> did wonder why the toric lens hadn't been suggested to me in other years.
>
0.75D of astigmatism is marginal. Personally, I do like to use it in
patients who are fit for monovision because every little bit of acuity
I can squeak out of their distance eye is worth it (to me) since that
eye is working all by itself in the distance. So docs would simply
ignor it, which would leave you "slightly" blurry by comparison. Some
patients would notice it and like it, some patients wouldn't.
> After reading here that the Advance is not rated for overnight wear, and has
> a lower dK than the Purevision Toric (see recent thread about silicon
> hydrogel torics), I asked my doc to try a Purevision Toric. As I was also
> curious about the new Biofinity lens, having read about it here, I requested
> a Biofinity lens to try for my left eye. I picked up these lenses yesterday,
> and first put them on today. The Purevision Toric is the same RX as the
> Acuvue, with the bc being 8.7, and the biofinity is the same RX as the N&D
> (-4.5), with a bc of 8.6.
>
> Comments on these--comfort--both lenses are comfortable, but so far I
> haven't noticed a difference from the lenses I was wearing before. (I
> haven't yet slept in them though.) Vision--I notice still clearer distance
> vision with the Purevision than with the Advance. Yet, I notice a decrease
> in near vision. Even the letters on the computer screen are not as clear as
> usual. I don't know if that difference could be attributed to the PV Toric
> in my right eye, or the Biofinity rather than N&D in my left.
I don't know either. Your doc could probably figure it out. Your PV
Toric lens might be slightly rotated while the AV Adv. Atig. wasn't so
that might explain it. It takes an office visit to know for sure.
>
> The myopia correction in the right eye is the same as before (-5.25). Does
> the addition of the toric astigmatism correction negatively affect near
> vision?
Quite possibly. Uncorrected astigmatism can help a little bit seeing
near things. Correcting it would improve distance but hurt near.
> Is there any reason why a Biofinity lens in the left (close vision)
> eye could create worse near vision than a N&D lens with the same
> prescription?
Unfortunately I have no experience fitting Biofinity yet. It has only
been released on a very limited basis in the US so far.
> So--although I like the improvement in distance vision, I don't like the
> decrease in near vision. I realize that presbyopic prescribing is a
> compromise, and it's impossible to get perfect vision far and near with the
> same lenses. But--of course I'd like to get it as good as possible. I'm
> wondering whether to suggest any other lens combinations to the OD, for me
> to try out?
You understand the most important point-- you can't get perfect, only
"good enough".
Yes, you should try a lower lens power in your near eye to improve
near VA, or as you suggest, try a multifocal lens in your near eye to
boost your near power.
>
> One possibility occurred to me--which I don't know if it is a good idea--but
> I'll ask about it here first. That is, to keep the Purevision toric in the
> right eye, and try a Purevision multifocal in the left eye. Does that make
> any sense--to have a toric single-vision lens in the dominant eye for
> distance, and a multifocal lens in the weaker eye?
Sure it does. Its quite logical. There is no "rule" that says both
eyes must have the same brand.
> Is there any advantage to
> having the same brand in both eyes, even if one is toric and the other
> multifocal? (I think it could be advantageous economically, as there are
> often rebates for buying multiple boxes of the same brand.)
The only advantage would be the economic one you indicate. Otherwise,
just wear what works the best.
>
> I should mention that I tried the Purevision Multifocal in both eyes last
> year, and decided not to stick with them, and I kept with the N&D
> monovision. Theoretically I like the idea of multifocals much better than
> the idea of monovision. The vision wasn't bad with them, but I didn't see
> much benefit over the monovision n&ds I was used to, thought they (pv)were
> slightly less comfortable, so stuck with N&D. The first trial pair of the
> multifocals that the doc gave me, although high add, gave improved distance
> vision, but much worse near vision. So, he kept trying a lower distance
> power in the left eye (modified monovision), to improve the near vision.
> When it went down to -4.75 left, almost as low a distance power in that eye
> as I have with straight monovision, and my near vision was still not as
> good, I decided to stick with N&Ds.
I too find the HIGH add powers in the B&L lenses (Purevision and
Soflens Multifocals) to be distorting and not very useful but some of
my patients like them. Everyone is different.
> This year though, in switching to the Purevision Toric in my right eye, I'm
> wondering whether it might be good idea to try the PV multifocal in my left,
> and see how the two work together. (Again, the left would still need to be
> undercorrected for distance, as the "add" created by the multifocal aspect
> is apparently not enough to give me usable near vision. But I'm wondering if
> it still might be worth trying a multifocal in that eye.)
It will just give you a little extra "boost" at near. Otherwise,
there is no reason to wear the same brand in each eye (except for the
rebate issue you mentioned earlier).