Contacts- have they done more harm than good?

[Fordy]

Guys,

Could I please have your opinion on something?

I was diagnosed with KC in my left eye about 15 years ago, and have got by with specs, and soft lenses for sport, but was told by my optician in Feb this year that they were going to refer me to the local hospital for specialist lens fitting, as the vision they could offer was not acceptable.

To cut a long story short I have gone through six lenses in each eye starting with RGP and have ended up with Flexi edge lenses in each eye ( hybrid type )

Through all this my good right eye has remained stable, as it has been for a number of years, but since I have had the flexi edge lens for the right eye I noticed a deteriation in vision and thought it was just a dodgy new lens, but was informed at my appointment today that the optom thinks there has been a sudden deteriation in the good eye and the KC is advancing, and has ordered me a stronger one.

This has caused me some concern ,and while I know that this can happen, surely it is too much of a coincidence that it has happened while I have been going through the fitting procedures of RGP and flexi edge lenses, and the optom also thinks this might be the case.

I suppose my question is does being fitted with RGP/Hybrid lenses carry a risk of worsening the condition, and if so why was I not warned?

Thanks,

Fordy

[rosemary johnson]

Hi - and sorry to hear about the deteroirating.
I haven't seen your eyes, obviously... either today or regularly ovr the last few months.
What strikes me as perfectly possible is that your eyes both started to change and get more KCish.
So, as you found you had to be referred to get speciailist lenses for the bad eye, the good eye was also starting to get worse.
Unfortunately, KC is a condition that can be stable for ages, then suddenly start developing again fast.
Hope it stabilises again soon and you get lenses that get you good vision.
Rosemary

[Andrew MacLean]

KC can advance all by itself. My own KC never changed gradually but in big steps.

I k ow that the instinct is to try to trace a change in your condition back to something you have done, but my own experience tells me that things are not always that simple.

All the best.

Andrew

[GarethB]

Without looking at your eyes, it might just be a case of the lens moulding the eye slightly so giving the impression things are worse.

I say this because of my experience transitioning from RGP lenses to Kerasoft lenses. The topographys showed less steeping in the right eye, so it was going flatter. The hypothesis we put forward was that the RGP lenses had moulded the cornea and the soft lenses lack rigidity to do this. I think we later found some papaers that suggested this hypothesis was correct.

Andrew is equally correct in that KC can progress lenses or not, in the Carabean and other countries where many people can't tolerate RGP lenses because fo the hot dry conditions and their KC progresses just like it does for those wearing lenses.

There was a time until relatively recently wher your choice was RGP lenses which people have said can make the condition worse, others have counterd this argument and you can have good vision.

The second choice was go without lenses and the condition still progress but you'll be registered partially sighted/legally blind.

Basically a choice of vison or no vision?

Most of us I think would opt for maintaining vision for as long as possible.

at least optoms have a wider choice of lenses to help manage or condition. My personal opinion having met many optoms and peope with KC is that many of the optoms who treat us have been using RGP's for so long they now lack the skill to fit soft lenses.

[rosemary johnson]

Gareth said: most optoms have been fitting RGP lenses for so long....


Surely not??!?!?
The RGP materials haven't been available for that long, surely?!
I got my first RGP scleral, what, 16 yearsa ago??
certainly no more than 18, absolute max.
I think you ean "hard lenses.....

Certainly for many decades it was a choice of: hard corneal lenses (made of Perspex, about 8mm in diameter); scleral lenses (made of Perspex); or nothing.
Before that for many decades it was glass lenses only.....
I thought when I first started with my first GP lens, that was "early" from a bit of a pioneer.
Maybe the corneal lenses went in to RGP materials earlier than sclerals.?? even so, cant;be any more than 20 years max.
Rosemary

[Andrew MacLean]

Actually, not only are RGP lenses made of material not previously available, but the material technology for this general class of lens is also constantly improving. The lens I wear now would not have been available ten years ago for any optom to fit.

The danger is that we think that because it looks the same, it must be the same.

Andrew

[GarethB]

OK so refering to lenses of a hard nature many of us automatically write RGP - Rigid Gas permeable.

I am sure otehrs would have realised that I was refering gto rigid lenses in general

[space_cadet]

Please try get an appointment with your local eye services asap, and explain to them what you have shared with us, I know how iritating it is to phone and try get a appointment, I was told lsat month, if you requre a appointment even if tis something you regard as able to deal with yourself, best to let the medics check it iver

[Lynn White]

Sorry Rosemary.,..

you are referring to RGP sclerals... RGP corneal lenses were first introduced in 1979 - 30 years ago! So Gareth scores on that point!! Also he is quite right about professional skills in RGP corneal lens fitting being thin on the ground nowadays..... the most fitted lenses in High Street practice nowadays are disposable soft lenses.

Having got that straight.... lets go back to the original point about rigid lenses causing a change in corneal shape or otherwise accelerating KC. This is still a contentious issue as it has not been proved but there are a few points to consider:

The practice of "Ortho-K" relies on the ability of RGP lenses to alter corneal shape. In this case, lenses are fitted flat in order to reshape the cornea so that less spectacle power is needed. Eventually, the idea is that the patient sees normally as long as he/she wears the RGP once or twice a week - usually when sleeping. So these lenses are used as an alternative to refractive surgery and this technique RELIES on the fact that RGP lenses can reshape the eye. So much so factual.

The theory as regards possible KC acceleration goes something like this: the best fitting RGP lens is considered to be one that is just steeper than the steepest curvature of the cornea. However, RGP lenses flex under pressure and will flex during a blink. If this happens, it is suggested that a vacuum effect is created under the lens when it flattens and then steepens during the blink cycle. This results in the softer KC cornea being pressured into steepening.

Anecdotally, many optoms have experienced KC patients corneas steepening rapidly once put into RGP lenses. I have, in fact, experienced this myself. I wore PMMA lenses from 13 years old and RGPs as soon as they were available. They were fitted steep back then and my cornea started to get steeper and steeper - so much so, when I was an optometry student, one of my instructors warned me I might be pre-keratoconic. However, once I converted to soft lenses a few years later, my corneas started to flatten again and now they are relatively steep but well within the normal range.

There are many arguments pro and con here but the fact does remain that rigid lenses DO mould the cornea simply because they are harder than the cornea. If there is any doubt, then non rigid alternatives should be looked at.

Lynn

[rosemary johnson]

Lynn, I take your work for the first types of FP material arriving in the corneal lens world in 1979.
But it ain't a competition!!!!!
And Gareth is of course quite right too in saying that there have been and are advances in types of RGP materials.
My point rests, however - the arrival of GP materials is well within the living memory - certainly of the wearers (inclding yourself) and of some of the fitters, surely (they don't all retire THAT early, do they????)
Similarly, I can believe that most buisiness now is disposable soft lenses in the High St - but only the youngest must have always worked like this.
When I started wearing lenses, most people wore hard lenses (corneal ones rather than sclerals, I agree!) - soft lenses were rather strange new tech.
ANd there must be fitters still working you remember that!
Is fitting hard lenses a kill that so rapidly goes out of kilter with lack of much regular practice? (servious question)
BTW, I think a lot of what you say about "RGP" lenses later inyour post actually applies to hard corneal lenses of whatever material they are made/
Maybe not all RGP lenses? - or maybe yes, to some extent????
I'm sure my RGP lensDOES change the shape of my cornea as it takes some time after I take it out for the vision to go back to "normal" - but a matter of hoa couple of hours rather than days or weeks.
Same witht he PMMA ones before - though maybe those even more, actually, as the contact zones were larger and even more pressing (RGP lenses I can't do that with so much, due to the nature of the surface at the microscopic level).
But I'd have thought it f they flattened them rather than steepening them.....?
Effect of blinking the air bubbles in and out of the air holes in the old PMMA days is another matter, of course!!
Sorry for typing, computer playing up yet again.
Rosemary