I wish I understood lens design

[Lia Williams]

After wearing the same pair of lenses for more than five years I’m currently under going a lens refit which is taking forever.

I currently have three lenses for my right eye

A) – A Rose K2 which has reasonable vision (I can read a number plate easily at 25 yards) but there is still some annoying ghosting - and the optometrist doesn’t like the fit.

B) – A slightly larger RGP which has fantastic distance vision (I can read a number plate at 40 yards) and there is very little ghosting and glare. I love the vision with this lens. It’s the best this eye has seen for over twenty years. It’s possibly slightly too strong as close up vision is from 6ft rather than arm’s length with the left eye. BUT after a couple of weeks’ wear it becomes intolerable.

C) – A new Rose K2 lens which I was hoping would have a good fit, vision and comfort. The comfort is fine, but the vision is poor. The vision is worse than I thought; I can only read a number plate at 10 yards but although it seems to be very underpowered I can’t read with it and it’s actually a stronger lens than the other Rose K.

I wish I could make sense of this. So it’s back to lens A until my next appointment in July.

Lia

[longhoc]

Hello there Lia

I learnt an awful lot just by reading an informative website covering this topic -- the link is:

http://www.opt.indiana.edu/lowther/html ... manage.htm

… it’s a good balance of technical info, terminology, fitting issues and solutions. It shows the fine balance the optometrist has to get just-right in order to juggle the various parameters of RGP lens design to fit a keratoconic cornea. Hope its a bit of help (you might well know all this basic stuff anyway !)

Have you considered alternative lens types to "traditional" small RGPs ?

Also, I'd be very interested in knowing where you go. Just moved to Hampshire so I've landed with Moorfields as the NHS clinic for my "RGP eye". Going for my first appointment there in a little under a month. Am wondering what standards of care to expect...

Kind regards

Chris

[Lia Williams]

Chris,

Thank you for the link.

I've actually collected quite a file of information about different KC lenses all appearing to be the perfect solution to my contact lens problems. But why when I get a new lens, and it doesn't behave as the trial lens plus the additional refraction, I just don't understand it. It's so disappointing!

Yes, I have had the opportunity to try corneo-scleral (SoClear) lenses. They didn't work for me. I didn't even get to take them home! I was warned that they don't work in all cases, but when they do they can be very successful. The next plan is to try piggy-backing and this aim was based on the assumption that the new lens would work.

Lia