UK Keratoconus Self-Help and Support Association

Hi can anybody explain to me how good or bad this prescription for a lens is please ?
Rad ; 5.50
Dis ; 8.70
Power ; -22.50

Rose K2 Boston ES lens

Many thanks

Hi Mikkey

The specifications you posted suggest fairly advanced KC. 5.50 is the radius of curvature of the lens which is quite steep. The radius typically ranges from 7.40 for very mild KC to around 5.00 for very steep, so, I am afraid 5.50 is nearer the steep end. I hope this helps.

Hi Ali . thank you very much i knew i was fairly advanced but never did understand my prescreptions , got new lens coming and think nearer to 5 now so dont know what options are open after that , i know im not suitable for crosslinking as im 40 and advanced on the boston k2 at present , dont know if any other lens will give me decent vision ?

Hi Mikkey

If you start needing lenses steeper than 5mm in radius of curvature it can start getting a bit tricky. In theory you can have steeper RGP lenses made, but sometimes stability can be a problem and lenses start popping out easily. I sometimes find large diameter RGP lenses can work well, typically 11-13 mm in diameter. SO Clear lenses dont usually work well in very steep cones, so I usually design them as a one-off. Another option would be sclerals. One other problem is that vision can start going off a bit due to thinning and possibly scarring. Soft lenses sometimes work in very steep cones but vision is likely to be worse than with rigid lenses. Has corneal graft been mentioned at all?

Hi Ali , you are totally correct on everything you say , tried large sklres no good . pain and poor cloudy vision , tried nearly all lenses , the only ones that give good vision for me are the small rosek lenses and the problem is they pop out not stable , yes i was told grafting was an option but im not keen as spent too much time in hospital for bowel disease / colostomy , so i just take every day at a time , learned to live with KC and its problems im new to this forum really so im learning as wasnt told too much about it through the NHS over the last 20 years .

Hi Mikkey

Rose K is quite a small lens hence not surprising it pops out easily in very steep curvatures. As I said before I sometimes get good results with larger lenses extrapolated from corneal lenses which are usually very stable and more comfortable than corneal lenses. I am sorry to hear about your health problems, I have a few KC patients with inflammatory bowel disease and I wondered if there was any link, but I was told by an eminent corneal surgeon that there was no proven link.

Hi Ali . thanks for your nice words and no there is no link between bowel disease and KC as far as im aware ... mine was due to fistula , bowel /bladder... it made KC feel like a sneeze , 2 very different diseases , life is a test ! Im picking up new lenses tomorrow these are 1mm larger than the rose K lens , my optician says the extra 1mm is a big difference ? i will have to wait and see ? i can still see these popping out personally and agree with what you say i appreciate your expertise , thanks Ali .