0.25 Cylinder?

[fjpod]

dear amiga,
in my experience, i've learned that a .25 cyl has made a difference for the young healthy eyes when viewing the 20/20 line.
however, now that i am refracting much older patients with poorer quality of vision, the .25 cyl doesn't really make much of a difference if any.

gracias,

gil

Good point.

[Bill West]

This is the very reason that I am confident that I will always be able to make a very good living.

I agree with John every .25 cyl should be exact. I mean exact.

John next time you are checking out a progressive with a .25 cyl and any power try to get exact on the cyl and spend the better part of the day changing your mind on the axis.
Long ago before hand rocked cyl's every one got a sphere and saw pretty good.
Then came progress and .25 cyl's changed this business forever.
Talk about straining at a gnat.

[Johns]

Bill,

So long as we have the technology to refract a 35 cyl, and we have the technology to fabricate a 35 cyl, why not just do it ?
(gnats aside)

[SpecialT]

Bill,

So long as we have the technology to refract a 35 cyl, and we have the technology to fabricate a 35 cyl, why not just do it ?
(gnats aside)

I don't understand this, do you mean .37 diopters of cyl? Are you referring to eights of a diopter or very high cyl?

[drk]

What QDO1, Dr. Stacy, and the amigo said.

Why NOT Rx 0.25 DC? Yes, I've seen those quarter cyls emerge and vanish over time, but what they say is what I give.

If you think about it, if you say -0.25 DC doesn't matter, then you might as well refract cylinder in 1/2 D steps for everyone, right?

(BTW, refracting in 1/2D steps for the oldsters is a major boon to my life...I even have a +/-0.25 DC handheld flip-cross that I hold in front of the standard +/- 0.25 DC Jackson flip cross lens: Works great! You have to change the 2 for 1 rule, though, to keep the interval centered on the retina...)

I never have bought this "if the sphere power is over x amount, blah, blah." The truth is, -0.25 DC blur is ABSOLUTE, and NOT relative to sphere power.

[High_Abbe]

I had a sale today with an rx of:

OD:Pl -0.25 x170
OS:Pl -0.25 x175

She had Lasik three years ago and just wants something for night driving. I think it's kinda like money, "every little bit helps".

[SpecialT]

I never have bought this "if the sphere power is over x amount, blah, blah." The truth is, -0.25 DC blur is ABSOLUTE, and NOT relative to sphere power.

In terms of optics, you are correct. But what I have noticed is that in terms of patient perception, this statement is not correct. It is the same reason, that contact lens dropout is higher for people in which their astigmatism correction is stronger than their spherical correction (at least for soft contacts). It has nothing to do with lens rotation, otherwise we would see the same problems with all spherical powers as well because all lenses rotate by some amount. This is so hard for me to put into words, so I won't go any further than what I have said. However, I want to offer what I believe is a valid counterpoint to your use of the word ABSOLUTE.

[Stephanie Yee]

Wow -- thanks for all of your replies, everyone! :)

It's good to hear viewpoints from varying perspectives here.

But with regards to whether or not I prescribe .25 cyl in my Rx's, I'm not going to change a thing. I'm going to continue Rx'ing them so long as my patients subjectively choose it during the refraction.

[kisselt]

I know these posts are from a long time ago, but I'd like to add something. I personally have moderate hyperopia with a quarter cyl in both eyes and can tell the difference without the cyl. My vision is still practically 20/20 without it and it in no way affects my quality of life (I can still read road signs and everything clearly) but I can see a noticeable difference in clarity. Maybe it's because I'm a perfectionist and most people couldn't tell a difference, but if i subjectively choose a quarter cyl on refraction and an autorefractor prescribes me with a quarter cyl I know it's not just in my imagination. Ive worked with people who will pass things that lack a prescribed quarter, or that are nearly a quarter off, and it's true that the patient won't come back. But I think that's because many of them don't realize that things could be ever so slightly crisper. I understand there is some fluctuation throughout the day depending on various factors that can affect vision slightly, but if someone subjectively chooses a prescription I will make sure I make their lenses to as close as I can. It's how I make my own lenses so I wouldn't want to do any less, just for that 5 percent of people who will notice the discrepancy and get less than the best vision I can give them. Maybe I'm just one of those problem customers with OCD, but I feel like too many opticians excuse their lasiness by blaming the customer for expecting the best quality product.