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Post Info TOPIC: Spasm of accommodation


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Date: Sun Sep 24 11:41 PM, 2017
Spasm of accommodation
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Hi all,

diagnosed with keratoconus in 2014... vision 20/20 (but some ghost vision, bad contrast etc).
Eventually got a RGP lens (Rose K2), contrast insanely good (photos for example seem unnatural to me with lens in the eye) but could never really achieve nowhere near the vision with "eyes only" in terms of focus.
3 years later, corneal thickness is stable, but the cone may be increasing slowly.

The keratoconus was discovered by accident, my chief complaint was in still is (years later) the eyes getting tired in the afternoon - sometimes, in late evening my vision is sharp only at distance of about 5-10cm! After a long vacation, away from computers (2-3 weeks) I need about two weeks to be able to work 8 hours per day again, right after I return the eyes get tired after few hours of near distance work...
At night, I see elongaged (downwards) circles around street lights, traffic lights and other point sources of light - as I move closer to them, they get smaller.
When I tried with RGP lens, I could not completely focus the image, and if I wore the lens for say 6 hours, I needed several hours to get my "normal" vision back.

Now the theory is this is due to spasm of accommodation, meaning the focusing muscles in the eye are constantly in "near" state, I spend most of the day at the computer, tablet, smartphone etc. That also means the refraction readings the doctors get are different every time and it's impossible to prescribe the correct lens...

Anyone had similar problems?

Thanks,
Peter



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Veteran Member

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Date: Tue Sep 26 2:33 AM, 2017
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There are lots of factors with refraction and when the cornea contour and its configuration are sensitive and become involved. Even cornea thickness changes through out the day by 10%. The corneas thickness is more in the mornings and less towards the end of the day. To find the right lens fit is sometimes very frustrating and time consuming. Do not just seek and clinical solution but also look in to surgical, sometimes a little bit of both are required.



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Date: Wed Sep 27 12:03 AM, 2017
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Have you been evaluated for corneal cross-linking (CXL)? These days the first step is to see if CXL can be used to prevent further progression of the keratconus (KC). Improving your vision is simplified if your eyes are stable.

With KC, getting consistent refractions is always hard. So it is hard to say if your accommodation is causing additional inconsistencies. Have they done a Cycloplegic Refraction where they paralyze your eye with drops? www.verywell.com/cycloplegic-refraction-3421806 I think that is the definitive way to deal with case where the accommodation might be interfering with getting a proper refraction. Of course, with KC thrown in on top of that, doing a cycloplegic refraction will probably be extra hard.

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Newbie

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Date: Mon Oct 9 12:59 PM, 2017
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Hello Peter,

I have similar issue.

The first time I started to use glasses/contact lenses, I had minus power in both eyes.
Two years later, I use corrections with plus power...

You probably need to ask your eye doctor to have a correction that can help to read near distance screens (computer).

It can take weeks/months to get better as the eyes will slowly be more relax to read the computer.

Once the eyes are more relaxed, you should be able to focus better.



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GRS


Optometrist

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Date: Wed Oct 11 5:09 PM, 2017
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Most KC patients I see have terrible accommodative spasm.  This happens because the cornea is multifocal, even with contact lenses.  The eye is simply searching for a clear image by running through this focusing routine.

The solution is to be able to provide the proper optics to correct the multifocal condition.  It can be done but requires something called wavefront-guided optics.



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Dr. G.

www.laserfitlens.com



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Date: Sat Oct 14 1:21 AM, 2017
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Thanks for all the replies so far.

@JimKC
Yes, CXL was in plays years ago, but the doctors didn't exactly push for it (even ones who "sell" it), as I have only one usable eye (central vision in other lost due to treatment of other condition) so I would risk getting clouded vision for several months and be unable to work etc. I would still do it if KC was definitely progressing but the evidence is not very convincing. Not to mention I'm 39.

I have now turned my full attention to this problem so things are starting to happen. I got the new RGP lens - previous one which I could not wear as it was useless (could not focus) has 7.2 basal curve and -2.25 sph and this new one has 7.1 basal curve and -3.00 sph. With the new one, which also seems to be a better fit (more stable on the eye, less annoying to wear), I'm quite close to being able to focus well, but the glow around light sources + double image on screen, subtitles is still there, above the light sources/letters (without lens it's below).

The optometrist where I picked up the lens was quite interested in my case so he tried to correct my vision and we tried for 3 hours. And miracle, we managed to come up with parameters where I could read 20/15 on the eye chart and that was at 7pm. This is actually the first time anyone was able to come up with something better than my unaided eye, so I'm quite hopeful. I don't remember what the cylinder parameter was, but the sphere was -3.50. This optometrist also doubts I have spasm of accommodation since I can rapidly switch focus between near and far, but the image is not perfect in both cases. He thinks I have a wide range of accommodation as I can do 20/20 with -3.5 sph...

Next week we will have another session with my new RGP lens in and try to correct that if possible. Then my plan is to make two pairs of test glasses - one with parameters where I got 20/15 without RGP lens and the other with whatever corrections we come up with RGP lens in. Then, I will do a trial of every option for a week and write down how I see things (near vision / computer work, driving, driving at night, ...): 1) unaided eye, 2) glasses, 3) RGP + glasses.





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Date: Mon Oct 16 9:15 PM, 2017
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@peter5slo
I agree that by age 39 you probably won't need CXL.

Glad to hear you found an optometrist who is interested in your case. I think an intellectual interest in finding a visual correction for a KC patient is necessary to get good results. Anyone who does it for the money, or out of a sense of obligation to serve all patients, is most likely going to give up in frustration before they find a solution. KC can be very perplexing when it comes to building a optical system to neutralize the irregular cornea. You can't converge on a solution the way you can with a normal cornea. For the KC patient, you can be one step away from a good solution with no indication that you are even close. Dr. G. had enough intellectual interest and was sufficiently frustrated by the hit and miss trial lens approach to fittings that he developed a technique for fitting scleral lenses and designing the visual correction on the front surface analytically using advanced measurement techniques. I am not aware of anyone else who uses a similarly methodical, analytic approach to fitting contact lenses.

My view of KC optics, at least for those who see two distinct images with one eye, is that the cone creates a second optical system with an optical axis that is at a slight angle to the normal optical system. The cone is a more positive lens than the normal cornea, so it focuses on closer objects than the normal cornea. This type of KC cornea is like a pair of bifocals. The goal of a contact lens for such a cornea is to neutralize the patient's irregular cornea with a tear layer between the contact lens and the cornea, and create a better optical system based on the regular front surface of the contact lens. If the tear layer does not succeed in neutralizing the KC irregularities, then you still have a double optical system and a "ghost" image. The contact lens can reduce the power of the cone so the image produced by the cone becomes the normal image and the previously normal image is thrown out of focus and becomes the "ghost" image. So it isn't that the "ghost" image moves from below the good image to above, it is that the focus changes and the roles of the good and the "ghost" images is reversed. My thinking is that if there a double images, the first step should be to fit a lens that eliminates the double images. Only when the double images are eliminated should you move on to trying to refract the trial contact lens on the eye. So long as there are two images, the irregular cornea is still having a strong optical effect and any attempt to refract that is going to be confusing at best. If the double images aren't eliminated by the fit of the lens, they can't be eliminated by the refraction of the lens. By the way, this is my own theory based on what I've observed through my keratoconic eyes pieced together with some bits of the usual procedures for fitting a KC lens. I have never heard of a lens fitter thinking of the fitting process this way. If your optometrist is game, see if you can find a trial lens that fits such that the double image is eliminated and then see what you can do with the refraction. If your optometrist has the 8 lens Kerasoft IC fitting set, he might want to give that a try. My double vision is eliminated with a Kerasoft lens. Tip, the Kerasoft fit is probably flatter than you would expect.  



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Date: Fri Jan 26 7:08 PM, 2018
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Some updates on my quest for better KC vision, wow this condition is really one giant PITA!!! Good god!!!

The experiment with the glasses made according to specs of 20/15 vision (1.25 decimal) I got with trial lens set at the friendly optometrist failed - those glasses produce the most distorted vision I ever got, so the optometrist must have written down incorrect values or something, it's just weird!

The new Rose K2 RGP (-2.25 Sph, 7.2 BC) gave noticeably better vision than old one (-3.00 Sph, 7.1 BC), much more "natural" image. But the sharpness (not contrast) is still better with unaided eye, so I'm not wearing that lens either.

As the public health system here only uses RGP lens I went to a private ophthalmologist with decent KC experience, with me specifically requesting a soft KC lens. They have SwissLens and I will get Hydrocone SL3 lens with -1.5 Sph in few weeks.
A question for optometrists here - is for example -2.25 Sph correction on Rose K2 RGP the same as -2.25 Sph on soft KC lenses? The thing is, with this Hydrocone SL3 soft lens + -1.5 Sph correction I managed to get all 5 letters in 20/15 and even 2/5 letters in 20/12 row, which is something I couldn't achieve even before KC. Now I'm wondering what would happen if I got Rose K2 with -1.5 Sph... when fitting Rose K2 they were always baffled by my refraction measurements... I have only one refraction measurement from 2001 and it was -1.25 Sph +0.25x102 Cyl for this eye, so could this be my real refractive error which is now impossible to measure due to KC?

This "new" ophthalmologist also pointed out that it looks like what bothers me the most are HOAs (higher order abberations), specifically coma. True, this is what I see below light sources and is most annoying and even dangerous when driving at night.

I did some research and came across this article: http://www.jaypeejournals.com/eJournals/ShowText.aspx?ID=10530&Type=FREE&TYP=TOP&IN=~/eJournals/images/JPLOGO.gif&IID=807&isPDF=YES - which says: "The larger the pupil, the more the HOAs.". So I drove home before sunset today and noticed I see glow around and maybe above headlights and traffic lights. Ok, I waited for 2 hours, never looked at a computer or phone screen not to pollute this experiment - and so when it was dark outside, I looked at a streetlight and voila, coma below! Then I took my smartphone, and used its LED light to constrict my pupil - coma below streetlight more or less disappeared and when I turned off the LED light, I actually saw coma come down like a curtain - obviously due to pupil dilating!!!! I can replicate this experiment anytime after dark on any light source, even small led lights on TV etc...

Then I also remembered how the Milky Way is less bright since I lost the central vision of my other eye and as the image in that eye is getting darker every year (due to radiation retinopathy). I went looking for a research on average pupil size in binocular vs monocular conditions and here it is: https://www.omicsonline.org/open-access/natural-pupil-size-and-ocular-aberration-under-binocular-and-monocular-conditions-jcsb.1000015.php?aid=23047&view=mobile
"Pupil diameter, total, total higher-order, coma-like, and spherical-like aberrations under monocular conditions were significantly greater than the binocular condition."

So, here is a very viable theory : what's bothering me are higher order aberrations and these are very noticeable due to my visual system being more monocular every year, which causes on average larger pupil, which causes more higher order aberrations.

But, what to do now? Somehow try constricting the pupil? With a colored contact lens?
I will need to explore this pupil size connection with RGP lens inserted and with new soft lens as well - that might tell me how much do those lenses actually correct for HOAs...

Of course, this does not address my other problem "eyes getting tired in the afternoon - sometimes, in late evening my vision is sharp only at distance of about 5-10cm" - this might be caused by something entirely different, not KC at all...



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