Best Practices for Early Detection of Keratoconus

Our best chance of preserving our patients’ vision is to identify early changes in the cornea before a steep cone, corneal scarring, or significant vision loss develops. Doing this, however, requires vigilance on the part of the patient’s primary eye care provider to pick up on any subtle clues that point to a diagnosis of keratoconus (see Subtle Clues That Point to Keratoconus) and to have effective screening protocols in place for patients who are presenting for routine eye exams. It requires timely referrals to providers who can confirm a diagnosis of progressive keratoconus and set the patient on a path to treatment to halt progression. And finally, it requires optimization of vision, often with scleral lenses or other specialty contact lenses, so that the patient can appreciate a tangible benefit from their treatment.

UNDERSTANDING AND DETECTING KERATOCONUS

Although keratoconus is considered a rare disease because it is rarely diagnosed, its prevalence is likely far higher than reported and may be even higher in certain sub-populations. The most important aspect of effective screening is to simply keep keratoconus and its warning signs and symptoms top of mind any time there is an unexpected change in refraction or a patient’s VA is worse than 20/20. In an otherwise healthy young person with poorer-than-expected vision, the cornea tends to be the culprit over the lens or retina, in our experience.

Educate staff members about keratoconus and encourage them to notice irregularities on autorefraction, distorted mires, or discrepancies between the astigmatism in glasses and autorefraction. The more educated a practice’s staff is, the more they can help to elevate important clues to keratoconus on a busy clinic day. If practitioner and staff suspect keratoconus, the five best practices below can be followed to confirm its diagnosis and manage the condition.

NO. 1: DON’T HESITATE TO REFER

Particularly with young patients, clinicians should have a low threshold for obtaining topography maps or referring the patient to an optometrist or a cornea specialist who can manage keratoconus when even one of the clues discussed in Subtle Clues That Point to Keratoconus is present. You don’t need to be positive that the patient has keratoconus or have records proving progression to make a referral. The other doctor would greatly prefer to see a suspicious case that turns out not to be keratoconus than to miss true ectatic disease. When you send a referral, include all available records that may help the other doctor document changes over time if it is determined that the patient has keratoconus.

NO. 2: ALLOCATE TIME FOR PATIENT EDUCATION

Keratoconus is a serious, lifelong disease—and one that patients may not have any baseline knowledge about at all. Any provider who is diagnosing the condition should be prepared to educate patients about it at the time of diagnosis. Brochures or other written materials and a list of educational websites can be helpful takeaways to offer the patient. In our experience, patients with keratoconus often blame themselves or feel defensive and may have concerns about whether parents, children, or siblings could also be affected. If longer appointments and time for education can’t be built into your clinic flow, then be sure to refer out newly diagnosed patients to a provider, OD or MD, who has expertise in keratoconus and can take the time to help the patient understand next steps.

NO. 3: HELP PATIENTS ACCESS TREATMENT

With an FDA-approved treatment available to halt the progression of keratoconus (iLink corneal crosslinking, Glaukos Corporation) clinicians should feel a sense of urgency to treat the condition as soon as possible. Delays in providing crosslinking for progressive keratoconus can result in worsening keratometric indices and permanent loss of visual acuity,¹ with young patients likely to experience the most rapid progression.²

No teenager or young adult should have to deal with vision loss when we have a way to stabilize the cornea to prevent it. Taking care to make referrals to colleagues with expertise in keratoconus and cross-linking and providing them with good notes on the patient’s history can help to shorten the time to treatment. Staff should be enlisted to ensure that referral appointments are kept and that both referring and receiving doctors have all the notes and records that were supposed to be shared.

Other options available for improving vision in patients with keratoconus include treating the cornea with intracorneal stromal ring segments, corneal allogenic intrastromal ring segments, corneal tissue addition keratoplasty, and rigid gas permeable and scleral lenses. For patients with advanced stages of keratoconus, a corneal transplant surgery such as penetrating keratoplasty or deep anterior lamellar keratoplasty may be needed.

NO. 4: MONITOR CLOSELY

For a patient who doesn’t quite meet the criteria for keratoconus (eg, perhaps they have some irregular astigmatism or very high astigmatism but no changes in corneal steepness on topography), consider monitoring them more closely than you would a routine patient. Depending on their age, the extent of your records, and your level of concern, you may elect to see the patient in 3 to 6 months. If the patient is wearing rigid lenses that could affect the accuracy of topography or tomography, have them discontinue wear for a few days to ensure the lenses aren’t masking progression. Once you have determined their cornea is stable, you can schedule the next appointment a bit further out.

A patient who has stabilized later in life or after crosslinking may be able to be seen annually, but a 15-year-old with risk factors should not be on an annual schedule until keratoconus has been ruled out. Note: It’s important to realize that keratoconus management is never “done.” Even if a patient undergoes crosslinking and their cornea stabilizes, they will require monitoring for life, and their vision needs may always be more complex than those of a typical patient.

NO. 5: INVEST IN ADVANCED DIAGNOSTIC TECHNOLOGY

Advanced diagnostic tools are not an absolute necessity for detecting keratoconus. A significant change in astigmatism can be enough to refer a patient for further testing (see Subtle Clues That Point to Keratoconus). However, having in-house access to topography and/or tomography does make it much easier to quickly screen for keratoconus and compare scans over several visits. Most of these devices incorporate algorithmic and AI-based tools that can facilitate risk evaluation and are becoming increasingly accessible to optometric offices. Several combination devices now incorporate topography with keratometry and/or autorefraction.

Moreover, topography and tomography have uses beyond keratoconus, with applications for customizing and evaluating the fit of orthokeratology and scleral lenses. These valuable multi-use devices, much like posterior segment OCT or fundus cameras, allow optometrists to elevate the level of patient care they can provide.

THINGS ARE CHANGING FOR THE BETTER

There is evidence that progress is already being made on the early management of keratoconus. Thanks to better screening, clinicians are catching keratoconus sooner than we have in previous years.^3,4 At Massachusetts Eye & Ear and Boston Children’s Hospital, keratoplasty procedures for keratoconus have become less common. This mirrors international reports of up to an 80% decrease in transplant rates once crosslinking becomes well-established.^3,5,6 By following the best practices outlined here, many more patients can be positively affected and their vision preserved for years to come.