Running out of ideas.

[Luca]

Pat you just made my day. Why the mystery on those lenses? Sounds promising I shall PM you about it.

[Luca]

I am on bausch & lomb softlens toric now. Not the miracle I need, but it actually reduces haloes and double images a fair bit. I like them. Yet my vision seems to fluctuate with them from 70% - 100%

[Luca]

I have now done the wavefront exam.

Here is the scanned document:



You will notice that the truck in the picture has a halo in an upward direction, and indeed I do yet it is far worse than shown, and more of a double image, yet it got it sort of right, I now understand why I can eliminate the double image and halo by placing my finger above the upper part of my eyes, I basically cover the nasty yellow and red area.

I was told that the problem is not only the astigmatism of the cornea but large pupils, the lens, which then somehow plays out wrong on the retina.

He said that it is unlikely the contact lenses reduce the symptoms, which is not entirely true because I do experience a slight improvement.

He was 100% sure however that it is not keratoconus.

The problem I have is a financial one, to correct my vision I need the iZon glasses which cost 280eur per eye.

But atleast now I know the cause of my problems.

[Lynn White]

Luca

It seems that you do have a significant amount of coma from that print out which would give you the symptoms you talk about. This is what Pat suffers from too. Coma is what we call a "higher order aberration" and the glasses that they are selling are designed to reduce those aberrations for you.

However, you do say you get better vision with your Bausch and Lomb torics. Pat was asked to trial some contact lenses lenses for us that corrected such aberrations in the same way as the special glasses but in actual fact we found that using toric soft lenses with a general aberration control actually made a great improvement for her. This may be why the contact lenses you tried helped.

At any rate, you are NOT going crazy - you do have a specific problem and knowing that does help!!

[Luca]

Thanks for your input you obviously know what you are talking about,

I was told that I should not try and adapt the wavefront prescription to a normal one, it would not work.

When he did the normal "is this better or that" thing, I got these values:

R sphr +0.75 Cyl -1.50 Ax 180º
L sphr +0.50 Cyl -2.00 Ax 10º
(values of this very day)

This raises a question, how is it that the wavefront exam showed a cylinder of 2,75 for the right eye, but good vision is achieved with 1,50.

For the left eye it's not that dramatic the difference between the wavefront device and the actual sight test is 0,37D

Interestingly for the contact lenses I was given: (at another opthamologist)

R sphr -1.25 Cyl -1.75 Ax 180
L sphr -0.50 Cyl -2.25 Ax 10

The opthamologist that did the wavefront told me that maybe the symptoms are reduced with the soft lens because of the -1.25 which forces the pupil to become smaller or something like that I didn't quite get it.

[Lynn White]

Actually Luca, we got better results with Pat when we used the wavefront prescription!

OKay.. what is happening with your two prescriptions is that with the -1.25 lens, you are over focussing. This will cause the pupil to become smaller. When the pupil becomes smaller, you stop more peripheral rays from entering the eye and get a sharper image. For this reason it is very easy to "overcorrect" people when testing them.

I would say that for now you go with whatever lenses give you the most comfortable vision until you can afford to do something more. I am a little unhappy with spectacle lens solutions to this problem, as your eye can move behind the spectacle lens and as it does this, the effect of the aberrations changes. With a contact lens, you are always looking through the centre of the lens.

However, I do know there have been successes with the spectacle lens option.

[Luca]

What I meant was that I was told not to use the wavefront prescription values to order "normal" glasses, maybe he was just wanting to say that if I get normal ones that would not take into account the "aberrations".

Of course ordering the proper wavefront glasses from that izon company should improve vision.

I see what you mean with the eye moving but the glasses stay in a fixed position, would that imply that the higher order aberration is only reduced if I look straight ahead?

I will PM you about contact lenses.

[Lynn White]

Yes Luca....

The aberrations are measured for straight ahead vision. Doesn't take account of looking through the lens at an angle. In a similar way, if you wear a contact lens that is completely corrected for your own aberrations, it is possible that if the lens moves a mm or so when you blink, you will not be looking through the right part of the lens and thus get blurred vision. It is actually possible to calculate this and demonstrate theoretically how much blur you would get.

However..... what complicates all this is that the human brain has adapted to various aberrations present in the visual system and actually makes use of them. If the brain did not adapt to them, no-one would ever be able to wear spectacles, especially not high powered ones. So one could say that your problem is not just unusual aberrations but also the fact you are not adapting to them.

I have seen patients who have not worn glasses for years, put on a pair with a high power and walk away totally unconcerned. I have seen others where you change the prescription by the smallest possible margin and they feel physically ill. Its the wonder of working with people!!!

[Andrew MacLean]

Luca

I remember when I got my first pair of glasses. For years I had been pretending that I could see much better than I really could. Eventually I bowed to the inevitable and got my first pair of glasses fitted. They were sort of horn-rimmed and extremely ugly.

I was told that I needed to wear them all the time, so I set out from the shop with them on and failed to judge the step from the shop door down to the pavement. I fell and broke my glasses.

When I got my second pair (metal framed and rather stylish) I was ready for the visual distortion. It still felt like the pavement was coming up to hit me in the face, but wearing my glasses all the time I quickly found that I adapted, so that within a week or so I looked out onto a world that was in sharper focus than before and in which things seemed to have reset themselves into a more ordinary shape.

The next big visual distortion I noticed was when I got my first pair of glasses after my first graft. I was unused to looking through glasses that corrected for a steep astigmatism. Door frames seemed to curve around me and the world was bereft of straight lines! Within a day or so lines became straight again and door frames stood upright!

Actually your brain starts out making adaptations, even before you begin to look through any sort of lens. The image on your retina is always upside down, but once it has been processed by your brain, you "see" the world the right way up, with the sky at the top and the ground beneath!

Every good wish.

Andrew