Statistics regarding keratoplasty rates for keratoconus typically are quoted to be somewhere between 10% and 25%, however, it seems that rates significantly vary between countries and ranges from 16% in Canada to 47% in Italy (Fasolo et al. 2006). One of the primary indications for performing keratoplasty for keratoconus is “contact lens intolerance”. It is a term that is commonly used in the eye care field and suggests to patients with the disease that they have come to the end of the road with contact lenses.

As you would think, that would be quite a frightening thing to hear as a patient. However, it is a very subjective term and often left to the opinion of the individual providing care for the patient. So we need to explore what actually does contact lens intolerance mean?

Penetrating keratoplasty for keratoconus

Corneal GP lens on a keratoconic cornea

Contact lens intolerance should refer to the state of disease where either acceptable contact lens corrected vision is unable to be achieved or comfortable and sustainable contact lens wear is unable to be achieved or finally where physiological compromise induced by any form of contact lens wear is unable to be addressed. If these criteria come into play then for sure alternative treatments including keratoplasty need to be considered.

Unfortunately for so many patients with keratoconus, they are at the mercy of their ECP and the level of sophistication of their contact lens management skills. Additionally, they may be influenced by the ECP’s bias towards or against any particular treatment approach. For example, in one practice environment, there may be a bias towards early surgical intervention while at another a bias against surgical intervention and perhaps an approach to ongoing contact lens treatment that may further compromises the corneal health response. This is not to infer that there is intentional malice with any of these approaches.

Unfortunately, in regards to keratoconus management, there has not been any agreed upon consensus pertaining to clinical care. The first step towards such a consensus was attempted with the publication in the journal Cornea of the Global Consensus on Keratoconus and Ectatic diseases in 2015 (Gomes et al. 2015). This project aimed to reach consensus of ophthalmology experts from around the world regarding keratoconus and ectatic diseases, focusing on their definition, concepts, clinical management, and surgical treatments. Unfortunately, there were no optometrists involved in this project and as such the section on contact lenses was quite weak. However, many critical points regarding early diagnosis, progression determination along with medical and surgical management were covered in this landmark paper. Anyone who manages keratoconus should be obligated to read this publication.

Today our options for the contact lens treatment of keratoconus have virtually exploded. It was not long ago that when someone said the word keratoconus the next word would be “hard contact lenses” – of course referring to corneal rigid contact lenses. Thankfully our armamentarium of contact lens options now includes; corneal GP’s, soft standard and custom keratoconic designs, vaulting hybrid lenses, tandem or piggyback systems and the ever-expanding options in gas permeable scleral contact lenses. With so many “tools in our toolbox”, the problem can be that everything starts to look like a nail! It is so important that those of us who manage keratoconus regularly understand the global approach that is required to do right by our patients. The following is an outline of what I think we must consider as part of a comprehensive keratoconus management strategy:

  1. Understanding the underlying disease itself ( prevalence, pathophysiology, hereditary components, influences of environment, etc.).
  2. The critical importance of early diagnosis in light of our ability to halt progression today.
  3. Having access to advanced technologies that allow for early diagnosis (either within your practice or by appropriate referral)
  4. Implementation of treatments that can halt progression (today this would be corneal cross-linking – CXL) along with a clear understanding of when such treatments are effective and appropriate and when they are not as well as the risks/benefits and alternatives to them.
  5. Understanding the array of contact lens options available and which are most applicable along the spectrum of the disease. Having access and clinical expertise in the application of these CL options (either by direct care or by referral to highly skilled and experienced practitioners).
  6. Understanding of the surgical options available for keratoconus treatment and when those options should be considered along the spectrum of the disease. Consideration of the risks/benefits and alternatives to these procedures. Having a network in place for appropriate surgical referral and/or co-management with highly skilled and experienced corneal surgeons.

Corneal Cross-Linking (CXL)

So we began this discussion with the question of “what is contact lens intolerance in keratoconus?” and we came to realize that it opens a wider discussion on overall keratoconus management and the importance of further development of an evidence-based treatment consensus. We have much work to do in the eye care field in this regard. I hope reading this document encourages you to reflect on your current approaches and perhaps inspires you in some way.