BLOG: An argument for more holistic cross-linking treatment guidelines
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Key takeaways:
- Determining when keratoconus progression has ceased can be tricky.
- Ophthalmologists should look at patients holistically to figure out risk and treatment benefits.
Do you need to hit the brakes to stop a car that is already in park? Probably not. That’s the idea behind the indication for cross-linking to treat progressive keratoconus. A patient who has stopped progressing doesn’t need to be treated.
But determining when progression has ceased can be tricky — not to mention that progression can occur after a time period of corneal stability in some patients. Insurance companies have tried to boil progression down into a few simple criteria, and fortunately, insurance coverage for the procedure has improved dramatically in recent years. Although payer criteria vary, many require documentation of one or more of the following criteria similar to those used in the iLink (Glaukos) clinical trial:
- 1 D or more change in maximum keratometry (Kmax) within 12 months.
- Myopic shift of 0.5 D or more within 12 months.
- Increase in cylinder of 1 D or more within 12 months.
These criteria don’t always adequately capture progression, particularly in young patients. For example, if I see a 15-year-old for the first time who has very steep corneas, I believe that patient needs to be cross-linked as soon as possible because their risk for future progression is so high, whether I have data to prove a certain amount of progression in the past year or not. I have personally seen teens experience a 5 D change in astigmatism within a single year, so I am very reluctant to just “wait and see” with young patients.
Sometimes we see a qualitative component to progression that does not fit perfectly within the suggested parameters. For example, the Kmax change may fall short of a full diopter, but it is accompanied by other changes in the overall shape of the cornea or in the distribution of keratometry or pachymetry that strongly suggest continued progression.
Similarly, I have seen patients with a relatively modest change in astigmatism that is accompanied by a decline in best corrected visual acuity. Perhaps the amount of astigmatism has stayed about the same, but there has been a significant change in the axis of astigmatism or its regularity. Factors such as a change in BCVA or in the axis may not be red lines for progression by the payer’s definition, but they should be. These are signs of progression, even if they aren’t as black and white as the three categories listed earlier.
In other cases, a payer won’t approve cross-linking until a patient has BCVA worse than 20/20. To me, this is like looking at a patient with a pressure of 35 mm Hg and a normal visual field and saying, “Oh, we aren’t going to treat this until you have permanent visual field loss.” It doesn’t make sense to wait for reduced vision to offer a preventive treatment. When I get this kind of feedback, I don’t hesitate to have a peer-to-peer conversation with the insurer to make sure they understand the purpose of cross-linking and the goal of avoiding vision loss.
Finally, we also have wonderful algorithms now, such as the Belin ABCD classification system, that can quantify meaningful change through a composite of various factors. Even when an eye doesn’t meet traditional definitions of progression, we may be able to demonstrate algorithmic change that is highly predictive of continued progression.
Fortunately, most patients with keratoconus do fit within insurance companies’ established criteria for progression. When they don’t, here are some steps you can take:
- Advocate for your patient. Schedule a peer-to-peer conversation or send a letter documenting risk for progression and the basis for greater urgency of treatment.
- Schedule the patient for another follow-up in 3 to 4 months rather than 6 to 12 months.
- Revisit whether records are available from a previous doctor, including earlier in childhood, to demonstrate change over time.
As a cornea specialist, I look at the whole patient and determine whether the cone is getting worse from what I see happening to the cornea and epithelium, the refractive error, visual acuity, the Kmax and pachymetric distribution. Viewing keratoconus holistically is the best way to determine whether a patient is at risk and would benefit from treatment.
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