[redbird]

I had my eye sight successfully corrected by lasik surgery around 7 years ago, however while my myopia remains pretty good (+/- 0.25) my astigmatism has returned. I've been using glasses for screen-work and reading for a couple of years, but I'm getting close to needing correction for driving and flying.

I'm in two minds about repeating the lasik, and it appears my prescription isn't particularly suited (not enough myopia). I've read of a discipline called orthokeratology, where you wear a rigid contact lense overnight which forces the cornea into the correct shape after which you can go one or more days without needing correction.

It sounds like an interesting solution, but also like something the CAA medical group may be suspicious of? Does anyone have any experience of flying with this solution?

[Dodo]

the CAA don't like it.. see https://www.caa.co.uk/Aeromedical-Examiners/Medical-standards/Pilots-(EASA)/Conditions/Visual/Guidance-on-the-use-of-contact-lenses---pilots/

"Orthokeratology (or Ortho K) lenses – these are ‘reverse geometry’ lenses designed to remould the front corneal surface. They are often worn at night and removed during the day. Any change to the corneal shape (and hence improvement to unaided vision) tends to be lost during the day and wearers of these lenses are unable to have optimum vision throughout the day. For this reason, this type of lens is not acceptable."

[redbird]

Thanks Dodo, I had a feeling that would be the case. Guess its contacts then ...

[Dodo]

Or corrective flying spectacles? https://www.caa.co.uk/Aeromedical-Examiners/Medical-standards/Pilots-(EASA)/Conditions/Visual/Guidance-on-pilot-spectacle-frame-and-lens-choice/

[redbird]

I'm not a big fan of specs, but was a 20yr user of contacts before my lasik op. Will have a chat with my optician next week, but thinking of toric daily lenses.

Thanks again.

[Bathman]

How much cylinder do you have and what's the axis?

How mypoic were you pre op?

[redbird]

R: sphere -0.25, Cyl -1.00, Axis 30
L: sph +0.25, Cyl - 0.50, Axis 162

Before the op I was -2.75/-3.75


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[Morten]

This is quite interesting. There is a bit of a gap between the text on Wikipedia (which reads like it was put there by a party which also manufactures the stuff and may be biased...) referring to a 72 hours 'fall back into bad shape' period and the CAA advice which uses the phrase 'during the day'.
Whereas it seems clear that, once these are taken out, the eyes will slowly fall back into their wrong shape again and so the vision will get slowly worse, if the time constant could be managed so that it was 'guaranteed' that for e.g. 12 hours the vision would be good enough to pass an examination, this seems 'safer' than glasses which could break (even with a spare pair). I also guess that if you are not very myopic to begin with, your vision will stay relatively better for longer.
A quick google shows annual costs which are higher than what I would spend on my glasses, but the additional flexibility, being able to use normal diving goggles, normal shades and safety goggles would be nice.
I also like the hinted at side effect that it could delay/slow the degradation with age (although unproven). With no apparent negative sides other than normal lenses, it does sound interesting and, from what I gather, it's also something which you can try and, if it's not right for you, you can just stop again.
Unlike laser surgery which I don't like for that reason - I've had a bad prescription once lead to glasses which I had to return after a couple of days. They redid the examination and manufactured some new lenses - for free - but if that had been laser surgery I'm not quite sure what would have happened...

I might have a chat with my optician ...

Morten

[Bathman]

R: sphere -0.25, Cyl -1.00, Axis 30
L: sph +0.25, Cyl - 0.50, Axis 162

Before the op I was -2.75/-3.75


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Assuming you meant pre op R:-2.75 and L:-3.75

I don't think I would bother with ortho K. Your uncorrected refractive error is small and I would argue the risk of microbial keratitis outweighs the visual benefit.

Just watch the astigmatisum post lasik ectasia is not uncommon and can be treated to prevent progression.