UK Keratoconus Self-Help and Support Association

Hello,

I have keratoconus and I have been using contact lenses since I was 15 years old - I am now 40. All the lenses I bought so far I bought them in Brazil as that is where I came from. However I have been living in the UK for the past 17 years and during this time when I needed new contact lenses because either I lost mine or they just getting too old I call my mum in Brazil, she call the specialist and he ships a new one to me, simple! But I thought it is time to go to the NHS and see if I can manage my keratoconus in the UK instead.

Pls tell me if any of you had a similar experience with NHS.

Long story short I have been having appointments every 6 months and the NHS have checked my eyes, they were really impressed with my contact lenses from Brazil, so much that they even asked me to get the measurements (curve diameter, power etc) from my specialist in Brazil to compare with their findings.
Then few months ago my right eye start to bother me and NHS specialist says it's time to change my lenses as they are too old so I went there and he said it might take a while to find the right fitting so he came with a catalogue full of contact lenses which are trial lenses and the first one he put it on my eye, he looked at it and said it was a good fitting but it might be blurred since the power of that lens was -10 and mine is -2.75. But when I tried I said oh it's not blurred at all, I can see well, I can see up the last line. He then tried a couple more different power (but same contact lens) but still that first one was better and he sent me home with that and told me he would check again in a month time.
I got home and started to feel my right eye very heavy and the vision started to get blurry, then few mins after I got a call from the nhs specialist and said that lens was a trial and he needed to ordered me a new one, he said he called the the manufacture and was told that the difference is that the trial ones will not be as comfortable to wear it so I was not to use it anymore and wait till the new arrives in 1 week time. Oh and btw he said, you must pay £56.00 for it when it arrives. All right I said.
Then I started to wonder how can I see well with a -10 power as well as a -2.75, could this be why my vision was getting blurred? When the new lens arrived I started using it and it felt just as heavy and blurred as the trial one.
Today I had another appointment with the same specialist and I told him how it was feeling and my concerns about the -10 power. He then told me that the -10 power is playing on my mind and that he is the specialist, if I can see up to the last line my vision is good and I should just trust him. But I was questioning how can it be that with -2.75 I can still see the same way? He was incredible defensive and then he gave me a -2.75 to put on top of my right eye and told me to see if I can see any better with that - I couldn't.
He said the power depends on the diameter and other elements of the fitting, because the fitting is different then the power is different. I didn't know that at all but he could just have explained to me without being so rude and defensive, after all it is my eyes and my right to question. He kept going on saying that he made it better and is not getting any thanks for it, he is the specialist what if someone will tell me how to do my job??
Er.. I was quite shocked as I wasn't questioning in a rude way nor did I suggest he didn't do his job properly. Ok I can see well but I could see just as well with my old contact lenses, the new one get's blurry much quicker and feels so heavy in the eye that I can't wear the same amount of time.

After looking into the fitting he said there's nothing he would change everything is perfect I just need to get used to it and all my concerns is all just in my head.

Hi Fabianaf,

It's not unusual to find contact lenses fitting a frustrating process especially when an old favourite lens has to be replaced.

New lenses can feel different from old ones; especially when we start thinking about it! With a new lens you may need to build up wearing time, even though you have worn lenses for years, because the lenses may sit on a slightly different part of the cornea.

Don't worry about the different power of the new lens, what is important is that your sight is optimisied and that the lens is a comfortable healthy fit. Do follow the optometrist's instructions about wear time etc. and see how things go. If the lens is still uncomfortable and the vision is still blurry do discuss the issues at your next appointment, and if necessary arrange an earlier one.

Lia

Hi Fabian
I'll try to explain, hopefully, without confusing you too much!
The only explanation for you to have good vision with both -2.75 and -10 lens is that your old -2.75 lens is definitely much flatter in curvature than the new one. There's a thin layer of tears between your lens and your cornea and this tear film has a "power" which contributes to the overall power of the lens. When the lens is flat, the tear film between your lens and cornea has a negative (minus) power. Conversely, with your new lens which would be much steeper curvature, the tear film would have a positive (plus) power, hence the contact lens power needs to be much stronger to compensate for the plus power of the tear film. I hope this makes sense so far!


Coming to the reason for the change, your old lens would most probably have been "too flat" for your eye. This would be probably due to you not having regular check ups. Your KC probably progressed over the years, but you kept to the same lenses. It's also worth mentioning that it used to be common practice to fit lenses very flat to try to "push the cone back", hence your lenses may always been flatter than they needed to be. We tend to avoid fitting very flat lenses nowadays as it can cause scarring of the cornea. The fit of the new lens is probably good- based on current practice-, but you're clearly having some issues. The reason is that -10 lens would be quite a bit thicker/chunkier than -2.75. We also know that, despite our concerns on fitting flat lenses, patients usually get better vision with flat lenses. This may explain why your vision is not as sharp and probably more variable with the new lens.


I suggest you try to explain your concerns to your practitioner and make him listen to you! He may need to alter the fit to reduce the strength needed. If you like, he may need to forget about "textbook fit" and have the approach "If it aint broke, don't fix it!".


I hope this helps you understand what's happening. If you adapt to the new lens and can wear it comfortably, don't worry about the power, but, if you're having issues, they need to be addressed.