BLOG: 5 considerations when screening for keratoconus in children
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Screening for keratoconus should be part of all pediatric eye exams. While this disease typically manifests around puberty, there can be signs of progressive keratoconus much earlier in some cases.
Keratoconus in young patients can progress more rapidly than in adults. The sooner progressive keratoconus is diagnosed, the greater the chance that patients can be treated with iLink (Glaukos), the only FDA-approved cross-linking system, and hopefully avoid some of the consequences of advanced keratoconus, such as permanent vision loss and corneal transplantation.
Although the safety and efficacy of iLink were established in clinical studies in patients aged 14 and older (Hersh PS, et al), many doctors perform cross-linking on patients younger than 14 years when it is needed, according to their clinical judgment, to avoid further progression.
However, the imperative to screen for keratoconus doesn’t mean that optometrists need to have fancy diagnostic equipment in house. Here are five ways to make sure your exams aren’t missing keratoconus in young patients:
- Perform a cycloplegic refraction. Young people — and especially children younger than 14 years — have a huge range of accommodation and can easily overfocus during refraction. For the most accurate refraction, it is necessary to temporarily immobilize the ciliary muscle to prevent accommodation.
- Make sure the puzzle pieces fit. Each component of the exam provides a piece of the overall puzzle. In an ideal world, subjective and objective data match up with the child’s experience. However, if the autorefraction and phoropter refractions don’t match, or everything looks great clinically but the patient is only refracting to 20/60 in one eye, something is wrong. In these cases, it is always wise to go back and check whether an error was made or whether there might be an underlying problem that requires more sleuthing.
- Think cornea first. Keratoconus is a rare disease, but outside of refractive error and conjunctivitis, it is still one of the top ophthalmic diagnoses in children. In my experience, when the puzzle pieces don’t match or vision can’t be corrected to 20/20, corneal issues are more likely to be the culprit, rather than retinal issues or juvenile glaucoma.
- Be alert for risk factors. Vigorous eye-rubbing and a family history of keratoconus are both associated with keratoconus. I find that parents will often proactively bring up eye-rubbing when it is a pronounced habit like we often see in children with keratoconus. Some doctors add questions about allergies, itching and eye-rubbing to their intake questionnaire. Asking about family history is helpful, but also know that people may not know details beyond that an aunt had “something” wrong with her eyes and had surgery for it. I often ask the family to find out more and enter the information in our patient portal.
- Trust the objective findings. The younger the child, the more unreliable subjective refraction can be, so I recommend trusting the objective, cycloplegic retinoscopy findings. Retinoscopy is actually quite a sensitive and reliable test for detecting keratoconus (Al-Mahrouqi H, et al). If you see an irregular reflex that can’t be neutralized, refer the patient to a specialist for further testing.
Once you suspect keratoconus, it is time to get tomography or topography to confirm or rule out the diagnosis. But always keep in mind that while technology is wonderful, we all have the ability to screen for keratoconus in children with simple, accessible tools like retinoscopy, cycloplegic refractions and a good patient history.
References:
- Al-Mahrouqi H, et al. Cornea. 2019;doi:10.1097/ICO.0000000000001843.
- Buzzonetti L, et al. Cornea. 2020;doi:10.1097/ICO.0000000000002420.
- Chatzis N, et al. J Refract Surg. 2012;doi:10.3928/1081597X-20121011-01.
- Hersh PS, et al. Ophthalmology 2017;doi:10.1016/j.ophtha.2017.03.052.
- Romano V, et al. J Refract Surg. 2018;doi:10.3928/1081597X-20180104-01.
For more information:
Christina Twardowski, OD, FAAO, is a pediatric optometrist and director of the pediatric optometry residency program at Children’s Mercy Hospital in Kansas City, Missouri. She can be reached at ctwardowski@cmh.edu.
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