Keratoconus in the last 40 years has been principally managed with rigid gas permeable contact lenses, also called RGPs. The category of rigid contact lenses is vague, as within this, there are half a dozen possibilities that can work very well.
So, which is the best visual option when correcting blurry vision caused by keratoconus?
First, find the right contact lens expert...
Possibly what the average patient with Keratoconus does not realise is that in a country the size of Australia, there are probably around 10 contact lens experts that have adequate experience in fitting all keratoconus contact lens designs.
What is normal to find, is the average optometrist will not have any contact lens templates designed specifically for keratoconus. This is because at most they might run into one keratoconus patient per year, therefore investing in contact lens designs and high tech equipment for keratoconus is a waste of time and money.
To try and fit a patient with keratoconus, the average optometrist will either refer the patient to a specialist (usually the best option) or borrow a trial set from one of the contact lens laboratories and take on the challenge.
At The Eye Practice one of our areas of expertise is fitting contact lenses to eyes that cannot wear glasses due to irregular corneal topography. The conditions include:
- Failed Laser Eye Surgery
- Corneal Grafts
- Failed Radial Keratotomy (this was the old Russian technique)
- Pellucid Marginal Degeneration
- Traumatised Eyes
- Other conditions that cause irregular corneal topography.
Every person that has any of these eye conditions tends to be unique, therefore having all options available in template format is critical to success.
At The Eye Practice, Dr Jim Kokkinakis has over the years travelled around the world to not only extend his knowledge in Keratoconus and all other irregular corneal conditions, but to also source as many different contact lens templates to try and maximise successful outcomes for patients. These people would otherwise not be able to visually function.
What are the BEST contact lenses for these irregular corneal conditions?
The honest answer is - it depends! The trick seems to be to try and follow a process that will begin with the simplest contact lens options first followed by more complex ones if the simpler ones fail.
The following is a series of lens fittings that occurred for a complicated keratoconus patient:
- Left Eye: 9.0mm diameter rigid gas permeable keratoconus design - even after adjustment lens was unsuccessful due to being unstable and uncomfortable.
- Changed to a larger diameter 10.2mm rigid gas permeable keratoconus design - one change was required to loosen the lens and success was achieved for the left eye with 6/7.5 vision. Patient could wear the lens all day with minimal discomfort.
- After 6 months patient returned and wanted a lens that she could play high level soccer in. We fitted her with a Synergeyes ClearKone. This lens is much more stable, but tended to dry out in air conditioned environments for this particular patient. She therefore wears the ClearKone for sport and the rigid gas permeable for work and other activity. She was delighted with this outcome.
- Right Eye: Required a corneal transplant as previous lens fitted by inexperienced practitioner had caused scarring and therefore reasonable vision was impossible.
- The right eye was followed over the rehabilitation process, which took over 12 months for the sutures to be removed. During this period glasses could not be prescribed as the surface of the cornea was too irregular for reasonable vision. Luckily she was doing very well with the left eye.
- Sutures were finally removed and a contact lens had to be fitted over the corneal transplant to achieve reasonable vision.
- Corneal topography and observation revealed that the junction between the host cornea and the graft cornea had a deep ridge. Fitting with a smaller rigid lens was impossible.
- The eye was therefore fitted with a 15mm miniscleral design, which could achieve great vision of 6/6 or 20/20 but was still rubbing on the ridge.
- The miniscleral was changed to a 18.5mm scleral imported from the US and after one adjustment to tighten the lens we finally had a great result.
This is not a common case but without having the ability to use over 30 different lens designs, fitting this patient successfully would have been impossible. The following points are worth mentioning:
- A successful outcome can be very inconvenient and expensive on both the patient and the practitioner.
- Occasionally many options need to be worked through to achieve what is perceived as a successful result. This really only can be achieved by an expert contact lens practitioner, who has available a plethora of different lens designs.
What price can you put on getting your vision and life back? Come and see the experts. Call The Eye Practice on (02) 9290 1899 or make an appointment online today.
(Note: This post has been updated for relevance and accuracy. It first appeared on The Eye Practice blog in Nov 2011).