Help at Work II

[Sajeev]

You dancing around the question with out answering it... So where are the studies that say contacts are good, you was speaking off Gareth??? I take it you can not find then now or what is it??

[Barney]

Gareth, I think you have misunderstood.

As far as I’m aware no one is suggesting that all cases of KC are caused by the wearing of contact lenses. That would be nonsense.

But you seem to be assuming that the symptoms of KC can only have a single cause. Why? In most cases, KC is first found in teenagers and usually in both eyes - which I assume accords with your own experience. In the case of both my brother and myself the appearance of our symptoms has been significantly different from yours and yet you seem to assume that the corneal distortion must have exactly the same cause as your own.

Both of us were well into middle-age before there were any signs of KC. Both of us had worn rigid contact lenses in excess of 16 hours a day for over 20 years. My brother developed KC in just one eye which again is slightly unusual (but accords with the studies of Hartstein into the link between long-term contact lenses wear and keratoconus). Although both you and I have the common symptom of a misshapen cornea, the different way that symptom developed could be because the cause, or at least some contributing factor, is also quite different.

If KC results solely from genetics and environmental factors play no part then the obvious question would be why my brother developed KC in one eye but not the other? If on the other hand the wearing of contact lenses was a factor then an explanation is easier. Both of my lenses came from the Wigmore Street optician and both eyes developed KC. In the case of my brother, the lens worn in the eye that developed KC came from the same source as mine in Wigmore Street. The lens worn in his unaffected eye was supplied by another optician (because the original lens was lost) and therefore quite likely to have been different and possibly a better fit.

If KC is exclusively genetic with no environmental factors, it hasn't appeared for some reason in our parents, our grandparents, our siblings, or our adult children - while my brother and myself have been the only members of our family to ever have worn contacts. Three eyes affected in our extended family, all of which wore contacts from the same optician.

Here, http://www.clspectrum.com/article.aspx?article=12365, Professor Steven Wilson of University of Washington School of Medicine suggests that most patients have some combination of genetic and environmental factors, for example poorly fitting contact lenses, contributing to their disease. Here - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=2322155&dopt=Abstract- Macsai MS, Varley GA, and Krachmer JH (Department of Ophthalmology, University of Iowa Hospital) conclude in their paper: "We believe that these patients suggest that long-term contact lens wear is a factor that can lead to keratoconus."

As has been said on this forum in the past, rather than look at what causes KC perhaps we should be looking at what doesn't cause KC?

Well, I believe there’s no evidence that wearing a bowler hat causes KC if that helps your research but would suggest that finding the cause of KC is more important than you believe. It would be far preferable to prevent KC occurring than having to merely manage it mechanically with plastic lenses and corneal transplants.

If the wearing of contact lenses could possibly, with or without other factors, lead to KC it would be very important to know how and why. The manufacture and supply of contact lenses is now a huge industry. Today very many more people wear them than when I first wore them over 40 years ago. We need to know how wearing lenses could affect young users in 30 or 40 years time.

The problem is that IU does not say that contact lens wear is a cause of KC.

Correct as far as it goes Andrew. More precisely Macsai MS, Varley GA, Krachmer JH., Department of Ophthalmology, University of Iowa Hospital, wrote: “We believe that these patients suggest that long-term contact lens wear is a factor that can lead to keratoconus.â€Â

[GarethB]

Barney,

Much of what I have posted relates to where this subject has occured before.

What is apparent is that there is a group of people that have a predisposition to KC so yes it may be that in some contact lens wear agreavates the condition making it worse as could eye rubbing and has been reported KC being diagnosed after eye trauma.

Therefore perhaps we both ahve been talking at cross purposes.

I do think KC is a single soure correct but not for the reasons you suggest. My view is that KC is genetic and the result of the coming together of a certain set of genes, NOT a single one. Mt Tuft presented such research at this years AGM a few weeks after I posted this very suggestion. This would explain why KC can suddenly occur and then disappear as quick as it came into a familly. It can also explain why when it is in several generations rarely beyond 2 or 3.

In my mind the coming together of a set of genes gives a predisposition to KC. The envoronmental factors that cause the KC to progress are then environmental, trauma, hormone changes, eye rubbing, lens wear etc. So with your references I would whole heartedly agree.

Wearnig a bowler hat is just daft, but I see where you are coming from, however many a surgical and medical breakthrough has come from lookinmg at things differently that is all I was suggesting.

Sajeev,

You will notice my response was posted this morning while at work. Unfortunatly I do not carry a CD with links to vareaou opthalmic research documents. Some of what I have are paper copies which would necesitate me breaking copyright law by scanning and then posting such information. Not being a proficiant web designer this would actually take me weeks.

Therefore if being at work is

dancing around the question with out answering it...

Then yes.

I also have a life outside work and the KC forum, so once time allows links will be posted.

[Sajeev]

Most of the "paper" can be found on the net in a short or long version or a referance to it just by doing a seach on the topic header. Can you at least supply the headings?

This is just about helping to improve things in what ever we find... with out any bias or side taking (or camps as you say... thats just supporting something for the sake of supporting)

I have never seen more studies (if any at all with regards to KC) which show the opposite to what Barney has already high-lighted.

[Barney]

Therefore perhaps we both ahve been talking at cross purposes.

Hi Garath, could be. I know Stephen Tuft has been looking at the genetics of KC. I don’t think it will be an earth-shattering revelation to anyone that a pre-disposition to KC is likely to be genetic. If the occurance of a genetic pre-dispostion is not predictable or preventable it might also be of limited value. A large proportion of health problems have a genetic factor of some kind, cancers are the most obvious, even if not the whole story. Sometimes it can be unexpected. One of my dogs frequently gets fox-mange while the others living in the same way don’t. That suggests some pre-disposition. Yet we also know for certain that fox-mange only follows a physical infestation by the sarcoptic mange mite - Sarcoptes scabe.

If KC can be triggered by extended lens wear that would be extremely significant when so many young people are being sold lenses that it’s claimed can be worn continuously for up to 30 days. Despite any assurances by the industry, no one can know for certain what the consequences could be 30 years down the road. The tobacco industry was similarly complacent many years ago. I think the small clues we have should be looked at just as carefully as the more obvious ones.

If Steven Wilson is right, or even partly right, to believe that KC often requires a combination of both genetic and environmental factors to develop then that could be very important in prevention. Environmental factors are often easier to control than genetics.

[John Smith]

A very interesting discussion.

For me, the link to genetics is obvious; yet it is also obvious that it is not the only factor.

One of this forum's stalwarts is an identical twin; yet six years after developing KC, her twin had good vision. If genetics alone were the cause of KC then both twins would have KC together. The fact that there was a seven year offset in diagnoses demonstrates to me that there must be another factor there somewhere.

As for the contact lens theory; yes, I agree that lenses, especially RGPs could certainly damage the cornea; but I don't accept that they are the cause. Many of us only wear lenses in the first place because of KC.

When I was 18, I opted to wear lenses instead of glasses. For a reason not explained to me, I was advised to wear RGPs rather than soft lenses. I continued with RGPs until I was 22, when they were becoming more trouble than they were worth. At about 28, I was diagnosed with KC.

Who is to say that the lenses caused the KC, and not that I had sub-clinical KC initially, which is why I could not wear soft lenses?

I admit however that it is certainly possible that the use of RGP lenses accellerated the onset of KC, even though I can't see it as a cause.

[Sajeev]

Like with most arguments it over the definition... I think the word "cause" was used to describe "a contrubuting factor" on a weak cornea... and there just has to be other contributing factors or in combination...

I know someone who had hydrops, even before getting any RGPS... but the truma to the eye as a contributing factor does ring true to me... For example Kera-Elastisa which some people get is due to one of two reasons... undetected KC having laser treatment and the other is due to too much thinning of the cornea with a laser... you can not get more trumatic than that for a weak cornea.

I did a poll once just asking simply, what is your eye colour and hair colour ...I got a PM from someone telling me what their hair colour and eye colour was... and that they was married!!!!!!!!!!! Anyway, the intended result of the poll showed that yes there was a high percentage of people who had more brown and dark coloured eyes and hair who had KC...

I meet up with some Keratoconus Dr's at a lecture and I asked about this... and the answer (after thinking about it for a while... which is always a good sign of a good Dr) was "yes"... and he added "I think that is true" from his experiance... so very generally it can be seen that their are certain markers with the genes which are visable already.

There was lots of others stuff equally getting unraveled but I'll post about if and when it comes up sometime, otherwise this will be a very long post!!!! ...but its a shame...

[Andrew MacLean]

Sajeev

I think that the link you found in your poll is also well described in the literature. The odd thing is that, on the Indian sub-continent, KC is far more prevalent than in Europe, yet contact lens wear is more common in Europe than in the sub continent.

http://bjo.bmjjournals.com/cgi/content/full/89/11/1403

Andrew

[Matthew_]

Similarly, my brother has KC but his is posterior KC, affecting the rear face of the cornea, not treatable with lenses. His symptoms are completely different to mine. He also developed it at 17 and I developed it at 35. Perhaps we were both genetically pre-disposed but some environmental factor triggered his earlier and in a different way?

[Barney]

All I would say with my very limited knowledge and experience is that the belief of some eminent experts in the field that long-term use of contact lenses may be a factor in some incidences of KC is a plausible hypothesis that shouldn't be summarily dismissed without substantial contradictory evidence.

Because the wearing of contact lenses is now so much more widespread than it was 40 years ago, including 30 day continuous use (albeit using very different materials), every effort should be made to ensure that problems won't be caused many years hence.

Considering the increased number of lens users the amount of research either by the industry or by independent researchers into long term contact lens wear seems to be very limited.

If it can't be predicted whether some individuals may be genetically predisposed to problems that makes the research still more important.