How do we treat keratoconus?
Thankfully, the management of keratoconus has revolutionised over the last 20 years. Twenty years ago the management was optical just providing people with spectacles, contact lenses, rigid gas permeable contact lenses to restore the vision but nothing to alter the natural history. The keratoconus would likely progress, and some of those patients would end up requiring a corneal transplant in order to restore normal corneal shape and restore normal vision.
And we could do that. All the research and all the work at that time was geared towards achieving better outcomes from corneal transplants. Thankfully, all this changed ten years ago with the advent of corneal cross-linking and this is a treatment to strengthen and stabilise the cornea. This is exciting that we now have an intervention that we can use early on in the condition providing it’s picked up to strengthen that cornea and stop it going on that journey to possibly need a corneal transplant. We’re now able to hold patients at a level where spectacles can provide them with good vision.
Over the last five to ten years, with the advent of femtosecond laser technology to create very precise incisions within the cornea, we’ve been able to combine that technology with the placement of little rings of plastic within the cornea. They’re made of PMMA or Perspex.
We have different shapes and sizes that we can tailor and adjust to individual corneas, and we can use them to reshape the cornea in patients with mild to moderate keratoconus. These are patients who may find that their vision can be corrected with a spectacle prescription, but it’s really quite a high prescription. They may, for example, require four diopters of corneal astigmatism, which is quite a lot. They may be like this general practitioner who came to see me and became a friend of mine who had normal vision in one eye and an eye with only two diopters of corneal astigmatism but a relatively poor quality of vision. So his optometrist could get him to see almost all the way down the chart with that spectacle correction in one eye, but the quality of vision wasn’t good. There was a slight ghosting to it even when the spectacle correction was in place. After we had placed a corneal ring in his cornea, we made the cornea more regular such that not only we got rid of the prescription, but the quality of vision was there, and the vision was balanced and matched in each eye.
What we’re able to do now at St. James Hospital in Leeds and Custom Vision Clinic is look at our keratoconus patients and tailor treatment to them. First of all, when we treat keratoconus, we’re interested in whether there are signs of them progressing and if they’re progressing, the priority is to stop that, and we use corneal cross-linking to achieve that. But for those patients with mild to moderate and even some advanced cases, we want to see if we can reshape the cornea and improve the shape of the cornea and the quality of vision. It’s such a simple, elegant procedure to use the laser to make a tunnel and place one of these rings to achieve that for patients.
There is still a role for corneal transplantation and one of my ambitions over this next decade is to ensure that we’ve established some kind of screening program such that we can identify patients early enough that we can stop all of them from going on to needing a corneal transplant. Ideally, I’d love to make corneal transplantation to treat keratoconus an operation that becomes extinct as a historical artefact that young surgeons just read about in the textbooks.
