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Deteriorating eyesight and cxl in second eye

Posted: Mon 29 Apr 2019 9:16 pm
by Mly
Hi,
I’m looking for some advice. I was diagnosed with kerataconus when I was 15. Since then my prescription has changed around every 6-10 months. My vision progressively got worse (although never terrible I can cope without glasses I just get headaches).
I had cross linking done in my left eye which is my worse eye in 2017. The whole experience was a shambles (poor explanation of the procedure and poor after care I had blurred vision for along time post) and so have been left very anxious from it.
Fast forward to now, my kerataconus has reportedly stabilised (as the KMax has change less then 1.0d in the last 9-12 months) however my prescription keeps changing especially in this eye.
So my first question
should this occur after cross linking even with a stabilisation of the kerataconus?
Every ophthalmologist has dodged the question.
Secondly. Now they want to do the procedure in my right eye the KMax has changed my 1.9 in 18 months I think (is this a lot?)
However my right eye is my ‘good’ eye, my prescription does not change hugely though it does change again every 6-10months.
I am an intensive care nurse so my vision has to be good to make up infusion etc. I am nervous to have it done in case my vision blurs and I won’t be safe to do my job
However I want to get it done before my vision gets to bad if the cross linking will indeed stabilise it.

In summary.
Should glasses prescription still change even after stabilisation?
Is my KMax changing quickly?

Sorry for the long post.
Thanks.

Re: Deteriorating eyesight and cxl in second eye

Posted: Wed 08 May 2019 9:56 am
by Anne Klepacz
Hi and welcome,
You're asking some difficult questions there as every case of KC is different and there really aren't any hard and fast rules. On progression, CXL isn't offered on the NHS unless there has been a change of at least 1.5 in the KMax reading. But I also asked one of the Moorfields consultants about your posts. His answer on your bad eye was that the prescription shouldn't be changing if the KC was now stable, BUT that testing for glasses was subjective, and 3 different opticians could come up with 3 different prescriptions for the same eye!
On the question of progression he said -
'With regards to progression, Kmax isn’t the only thing to consider. I’d want to know how reliable the scan was. We usually repeat the scan 3 times at each visit to get an idea of how reliable the measurements are. One scan might show a Kmax change of 1.9. The other scan may show less or more. 1.9 may be significant if the cornea isn’t that steep (i.e. mild KC), but 1.9 could easily be measurement ‘noise’ with more advanced KC.'
I'm not sure how much that helps with making a decision - one option would be to ask for a second opinion. Do also have a look at our latest newsletter on the home page of this site. The article on page 3 'Collagen Crosslinking' gives information on results of the procedure with data on the proportion of cases where corneal haze is a temporary problem.

Re: Deteriorating eyesight and cxl in second eye

Posted: Mon 13 May 2019 9:51 pm
by Asif
Changes in glasses prescription are not exclusive to changes of the cornea. There's other parts of the eye, as well as the increasing length of the eye ball itself, that can cause changes in your glasses prescription.

As Anne said, a subjective refraction, especially on a keratoconic, may not be consistent even if everything else is stable.