UK Keratoconus Self-Help and Support Association

Hi,
How long does a Kerasoft lens last?
Should it be replaced after a few months? If so how many?

Thanks

Think I was told they last between 3-6 months. Although I never went beyond a trial with these... hopefully a long term user will be able to help a little more.

3 months sounds about right. I always kept a spare pair in reserve as it took a couple of weeks for replacements to arrive. The usual need for a change was noticing that a sliver or chunk of the lens edge was missing.

It depends on which Kerasofts you have as they do a 3 month and 12 month version. The 12 month is the 77% lens while the 74% is the 3month lens, you can find these numbers on the side of the bottle and more on the Kerasoft Web Site

When I had the three month lenses, I used to wear them for beyond the three months so that I built up spares should I damage or loose a lens but I did find that my eyes would get a bit gritty towards the end of the day the longer I went beyond this due to protein build up. Yet to experience this on the 12 month lens option which I have been using for about three years or so changing them at their recommended date.

With respect to bits coming off the lens, I have found this can be caused by rough finger nails gauging the lens or accidently catching the lens edge when it is placed in the cleaning vessel. As yet I have found it has no impact on the lens wear time, longevity of the lens or comfort of the lenses. They are extremely robust and I have found to be more robust than any RGP lens I used to have.

Followers of this forum will know that Gareth is an enthusiastic advocate of Kerasoft / KIC lenses based on his personal experience. However it needs to be noted that it's not advisable to continue to wear a damaged lens as the rough edge could cause a corneal abrasion or irritate the lining of the top eyelid resulting in "giant papillary conjunctivitis". I am also surprised by his comment that he found 77% water content hydrogel lens (this literally means 77% of the lens is water and only 23% is the polymer) more robust than any RGP lens he has worn in the past! All I can say is that the RGP lenses he has worn must have been very poorly made as it's not uncommon for patients to wear RGP lenses for several years.

Ali

Blink out or drop an RGP lens and it will more than likely chip as it hits a hard surface. A soft lens there is no such issue.

So far I have never had a bist of grit or dust go under a soft lens, in an RGP lens it always did and abraded bothe the lens and my eye. With a soft lens any dust or grit in my eye just gets blinked out before it can do any damage to the lens.

All my RGP lenses were made by as far as I am aware one of the top Rose K lens providers (David Thomas) and I think the main robustness issue had nothing to do with lens manufacture quality but more down to the lens design and the shape of my eye it was trying to fit made it very fragile compared to a soft lens. Anyone reading my past posts will notice that I had good success with these lenses and it was the fact that I became intolerant of the RGP lens material and the shape of RGP lenses available to my hospital could no longer accomodate the shape of my eye. Sodft lenses were the only ones that could manage this.

To be completely correct there is no such thing as an ideal lens that works for everyone and anything you read on this forum is based on personal experience.

Thank you all for your comments.
Like Gareth I am a Kerasoft fan. I have a hybrid lens for when I need 'good vision' ie long car journeys, jumping competitions with my horse etc. But if I wear it everyday it rubs, so for every day use I wear Kerasoft. Whilst the vision is not as good as the Hybrid the durability and comfort is great.

Gareth
Thanks for clarifying that you were referring more to issues with fit and stability of corneal RGP lenses rather than "robustness" of soft lens materials compared to rigid materials. The reason I felt I had to reply to your post was:
1.I didn't want other members thinking it's OK to continue wearing lenses with chipped edges
2.I didn't want other soft lens wearers giving their practitioners a hard time over split or deposited lenses under the impression that soft lenses are intrinsically more robust than rigid lenses.

As you say, its all about what works best for a patient. As you know there's a lot of interest in larger RGPs lenses nowadays ranging in diameter from 13-16.5mm or even larger and they can overcome a lot of the stability issues with smaller corneal lenses. Kerasoft/KIC are great lenses when they work BUT they just don't work for everyone, and its not simply due to practitioners not knowing how to fit them!

This has been interesting. As someone who has never been able to wear soft lenses and who is, therefore destined to wear RGP lenses, I have always been impressed by the insight of another optometrist who posts here that KC is a bespoke condition. Each of us is different and none of us should ever assume that what works for somebody else will be ideal for us.

In terms of the interface with the eye, what is the difference between Kerasoft ICs and regular soft lenses? As I understand things RGP lenses allow a tear film to form at the interface of the eye and the lens which filling in the troughs of the distortion on the surface of the cornea. Soft lenses just mould to the distortion providing acuity but not correcting distortion (ghosting) even with a good fit.