Silicon hydrogel lenses

[Stephen Borthwick]

Hi folks - I too have INTACS (in one eye, and I'm having the other one done in Jan 07). I can't wear RGP or even kerasoft lenses because they irritate me too much. I think it's more the physical fit and the shape rather than oxygen. I'm currently wearing the B&L PureVision mentioned earlier in the thread - a Toric on the INTACS eye and a plain one on the other. I can wear them for several hours - a great improvement on any other type of lens I've tried, and better for combatting keratonus effects than dailies. I find I am very sensitive to hydration - the more I drink, the less irritating the lenses are, so maybe in a dry workplace you could drink more water. They're not perfect, but in my case a good compromise.

[Ali Akay]

Gareth
To the best of my knowledge kerasoft lenses are NOT silicone hydrogel, hence have fairly low oxygen transmission due to the thickness. Incorporating silicone into soft lens materials had been the holy grail of contact lens industry for years.Currently 3 manufacturers make silicone hydrogels using slightly different methods but all lenses are moulded as it's not possible to machine ie lathe-cut the current materials. As kerasoft lenses are "made to measure " I would assume they are lathe-cut. There was talk of a macineable silicone hydrogel material but, as far as I know, it never materialised. It'd be a big breakthrough, and I would love to be corrected on this. One manufacturer advertises a "silicone hydrogel gas permeable " lens which is a bit of an oximoron really and it is essentially rigid gas perm.

Having said that, contact lens fitting is full of compromises.No point having a lens with excellent oxygen transmission if you cant tolerate it! Also, effects of oxygen deprivation of cornea cause problems over a period of time, so, as long as your corneas are monitored regularly, remedial action could be taken if signs start appearing. The main problem with rejection risk and blood vessels growing into the cornea is with deep vessels which tends to happen mainly if patients sleep in lenses against advice. A small amount of superficial vascularisation should not cause any problems. It's all about risk management really.

[samba_elite]

Are things like these B&L lenses availablr for KC then,my lenses are soft,although i've never once been told what type or make,the problem with fitting has always been caused mainly by my KC 'dragging down',therefore maiing it hard to fit a lens that will stay in shape for more than about 3-4 weeks,ive asked about alternatives but not really had any form of feedback,i dont know if this is because of commercial reasons or what,i cant wear the hard type lenses,tried that and they simply wont stay on due to the angle they drag down at,i was given 9mm ones,then 11.5mm ones but to no avail,they just couldnt get a pair to fit,then sclerals were suggested but the waiting time ot even get seen a MEH is a joke so in the mean time i'd love to have some alternative suggestions that maybe will never got offered to me or even discussed with me at my eye clinic

[Dave_W]

Thought I'd give a quick update on my progress with SHG lenses. I eventually went to a high street optician (who had a good knowledge of SHGs) as the hospital didn't really want to know (fair enough - would've required several visits, much more expensive, etc).

Am now fitted with SHGs in both eyes and have started wearing a left lens to work for the first time in about three years! My eyes seem to tolerate the lenses well and get enough oxygen through them to let me wear them for long periods of time (anything up to 12 hours, even longer very occasionally).

Vision with them is excellent, although a bit blurry in the left (the one with Intacs). Unfortunately, the haloes and ghosting are still there, but it has reduced a reasonable amount.

All in all, something worth looking at if you're struggling with oxygen permeability.

Now, if I could only sort out that dratted blepharitis...