Practical tips and tricks: Kerataconus treatment advice for peers

Keratoconus presents clinicians with a persistent challenge: a progressive, vision-threatening corneal condition that is most treatable when caught early, yet frequently goes undetected until significant damage has occurred. With corneal collagen cross-linking now offering a reliable means of halting progression, the stakes of a delayed or missed diagnosis have never been higher. In this Q&A, 2 clinicians with extensive experience managing keratoconus — Clark Chang, OD, MSA, MSc, FAAO, FSLS, of the Cornea Service at Wills Eye Hospital in Philadelphia, Pennsylvania, and Susan Gromacki, OD, MS, FAAO, FSLS, DipAAO, of First Sight Vision Care in Maryland and with more than 3 decades in the field — discuss the diagnostic blind spots, clinical red flags, and management pitfalls that define this disease in practice. From subtle refractive changes that warrant a second look, to the importance of treating the whole patient rather than just the Snellen line, their perspectives offer a practical framework for identifying and managing keratoconus at every stage.

Do you believe some patients are referred too late for intervention, and why?

Clark Chang, OD, MSA, MSc, FAAO, FSLS: Early diagnosis is key to timely intervention, especially because we have access to cornea cross-linking (CXL) which is highly successful in stabilizing this progressive disease. However, as demonstrated by Kreps et al (2020)¹ in a retrospective study involving referrals of 399 newly diagnosed keratoconus (KC) patients, over 70% of these patients have already reached stage 2 or worse on the TKC grading scale (Average Kmax was 58.4D in the worse eye). While this clinical trend may be exaggerated in a specialty referral center, this is similar experience to what I have clinically observed in Cornea Service at Wills Eye Hospital.

A large part of the reason for this trend has to do with how challenging it is to detect KC during emerging and early stages of this disease. As KC often exhibits asymmetry between eyes, many patients are visually asymptomatic due to minimally affected binocular vision - and either delay seeking care or do not report visual complaints during their routine eye exams. The fact that neural compensation has been reported in KC patients² which diminishes the detrimental effects of higher order aberrations may also further complicate the diagnostic timing in some of the patients.

Susan Gromacki, OD, MS, FAAO, FSLS, DipAAO: KC is a progressive disease, so ideally I want to treat a patient with corneal collagen cross-linking as soon as possible. If treatment is delayed for any reason, the condition will progress and the patient will lose best corrected vision. The good news is, the cornea naturally cross-links with age, so KC will eventually stop progressing on its own.

What subtle red flags have you learned not to ignore in potential keratoconus cases?

Chang: Since patient’s subjective symptoms may obscure the timing of diagnosis during early stages of this condition, we need to rely on objective clinical findings. Currently, corneal tomography that analyzes data on corneal elevations and global pachymetric metrics are some of the recognized gold standards in diagnosing early KC, but this imaging technology is not always accessible during a routine eye exam.

Without advanced corneal imaging tools, we should consider reducing our clinical thresholds in suspecting the presence of KC, so that patients may get the earliest opportunity for confirmed diagnosis and be considered for interventions such as CXL. Subtle red flags that may be highly suspicious for KC can include:

• Any unexplained loss of monocular visual acuity (ie, if patient has been documented as 20/15 in the past, then 20/20 still counts as loss of vision)
• Consistent report of unexplained loss of monocular quality of vision (ie, halo, glare, starburst, monocular diplopia)
• Moderately high Steep K or Maximum K at baseline (especially with consistently increasing trend even only with small steps) (ie, >47D and increasing)
• Moderately high refractive astigmatism at baseline (especially with consistently increasing trend even only with small steps) (ie, >2D cyl and increasing)
• Irregular corneal reflexes, such as Scissor or oil droplet reflex upon retinoscopy – a helpful protocol is to perform diagnostic retinoscopy after dilation to facilitate the clinical detection of paracentral or peripheral optical irregularities

If patients with above symptoms reports possible family history and/or chronic and heavy eye rubbing, then undiagnosed KC should highly suspected until proven otherwise.

Gromacki: A young healthy patient should correct to 20/20. Any time a young patient in their teens or 20s, cannot be corrected to 20/20, this is a red flag. Too many of our colleagues see nothing on the retina, then send the patient to a retinal specialist, only to have them find nothing. It is more likely to be KC than a retinal problem at that age. Secondly, watch the astigmatism. If it is >2 D, increasing more than 1D over the years, or if there is a change in axis, consider keratoconus.

How do you manage patients who are frustrated by lens discomfort or adaptation challenges?

Gromacki: A precise refraction is critical. Many of my patients come in with glasses that are useless. For most of my patients, a good pair of glasses helps their eyes take a break from long hours of contact lens wear. And for others who may struggle with contact lens insertion, glasses are important to help them see something on the days that they are unable to apply their contact lenses. Now, for those who wear contact lenses, it is imperative to ask them at every visit how they care for them. Noncompliance with contact lens wear and care, if the lens fit looks ideal, could be the source of their lens discomfort.

How do you address chronic eye rubbing and allergy management in keratoconus patients?

Gromacki: KC patients rub their eyes because they itch, and atopy and KC go hand in hand. Patients with KC feel better after rubbing their eyes. However, eye rubbing is not beneficial for the overall health of the eyes, so we need to recommend measures to reduce the urge to do it. Examples are topical allergy eye drops, oral allergy medications, and improving the contact lens fit. Unfortunately, over my 33 year career in treating keratoconus, I have encountered too many patients who are anxious at best/hysterical at worst because another eye doctor yelled at them for rubbing their eyes. This is counterproductive, as many of these patients already suffer from mental health challenges. Many of them will rub their eyes anyway; if we as practitioners can help diminish the eye rubbing even a little bit, that will pay dividends for the patient-- and their cornea.

What’s a common mistake clinicians make when managing keratoconus?

Chang: Since KC denotes high level of optical aberrations associated with loss of vision, it is easy to think that the only clinical outcomes that KC patients care about is their visual acuity. Subsequently, eyecare professionals have become obsessed with rehabilitating their KC patients to constantly chase the best high contrast visual acuity line on the Snellen chart. However, quality of vision may be equally important as patients can’t perform well in daily activities with significant glare, halo or ghosting despite being 20/20 or better.

And while we are focusing on resolving patients’ visual symptoms, we also need to take a step back and remind us to examine KC patients wholistically and aggressively manage their comorbidities such as ocular allergy or dry eyes that may lead to eye rubbing and potential KC progression. As well, any suspicion of KC progression calls for immediate corneal referral to determine if CXL is required before returning to designing visual rehabilitation tools for our KC patients.

It is also important to understand that while the risks of KC progression decrease with aging, likely due to age-related corneal cross-linking that is naturally occurring, the risk is never zero. So, it would be clinically prudent to avoid advising patient that their KC condition will automatically stabilize after age of 40 or similar age thresholds.

Gromacki: The most common mistakes are missing the diagnosis or referring to the wrong provider. Either way, KC can progress and the patient may permanently lose vision. If you are considering a KC diagnosis—and you want the patient to see their best—refer to an optometric colleague who has topography/tomography and fits specialty contact lenses. Also refer directly to a corneal specialist who performs corneal collagen cross-linking in their office. If you refer to anyone else, the patient will not only be struggling to see their best, but also their disease will progress as they wait to be seen by each subsequent provider.

How do you incorporate keratoconus screening into routine exams for at-risk patients?

Gromacki: The easy answer is that I perform corneal topography/tomography and corneal thickness. But it's much more complex than that. Clues to diagnosing keratoconus exist in many of our routine tests—such as auto-refraction, retinoscopy, and slit lamp examination—so it's important to be on heightened awareness for the subtle signs of KC in at-risk patients.

References:

1. Kreps EO, Claerhout I, Koppen C. Diagnostic patterns in keratoconus. Cont Lens Anterior Eye. 2021;44(3):101333. doi:10.1016/j.clae.2020.05.002

2. Sabesan R, Yoon G. Neural compensation for long-term asymmetric optical blur to improve visual performance in keratoconic eyes. Invest Ophthalmol Vis Sci. 2010;51(7):3835-9. doi:10.1167/iovs.09-4558