BLOG: One simple test can identify keratoconus early
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What kind of patient comes to mind if you heard the following information about them?
His astigmatism measurement doubled from last year; he complains of ghosting in his vision with any prescription; he saw 20/20 last year in glasses, but no better than 20/30 “blurry” with his new prescription; and he had his glasses remade three times this year and still has streaks in his vision.
Now let me inform you that this patient is a healthy 18-year-old man with no history of eye problems. If these phrases sound familiar, it is a great time to train staff on how they can help as you come to the possible diagnosis of keratoconus in an otherwise healthy and young individual.
I rely heavily on my staff to look for these red flags and change the direction of the exam from my usual comprehensive work-up. Once I alerted them to these warning signs, my clinic flow became a lot smoother instead of being stopped dead in its tracks with no plan of what to do next or simply settling that the healthy young man could only see 20/30.
Of course, obtaining a topography of the corneas and measuring corneal thickness can be useful information in the detection and diagnosis of keratoconus, but not all of us have access to that type of equipment in our own offices. Oftentimes at this stage of early onset there are no slit lamp findings to go off of either. Signs like corneal striae and Fleischer’s rings do not develop until the condition has progressed further. Something that I feel to be underused in the day-to-day clinical operations is the information one can gather from a simple hard lens over-refraction.
If any of the above statements are heard in our clinic, staff are trained to grab a gas-permeable (GP) lens from our spherical fitting set starting with the base curve that matches the patient’s mean K. They numb the patient’s eyes (as many of these cases have never worn a GP before), place the lens on the eye, obtain an auto-refraction over the lens, and find a new best corrected acuity. By doing this, the GP negates any corneal irregularities that may be present and lets you know if another part of the eye is causing the issues.
My plan in this testing is not necessarily to prescribe this lens at the end of the day but to simply find out two things. First, can the patient’s best corrected visual acuity in the lens improve from the BCVA of the spectacle manifest refraction and, second, through this hard lens over-refraction, does the patient subjectively note that the quality of vision is improved?
If the answer is yes to even one of these questions, you and your staff should seriously consider further testing for keratoconus because there is likely some form of corneal irregularity at play. This finding might mean a referral to another doctor for more specialized testing, starting a specialty lens fitting and/or also a discussion on corneal collagen cross-linking.
This simple test in the office has helped me countless times realize that the cornea is the issue and not wrongly diagnose a condition such as amblyopia or search for a less likely nerve or retina problem with unnecessary testing in a young person. It has also saved me on numerous glasses remakes and an unhappy customer to go with it.
So, when outcomes are not as they were last year for your otherwise healthy patient, train your staff on those possible red flags for keratoconus and reach for that hard contact lens set!
For more information:
Katie Greiner, OD, MS, MBA, FAAO, is chief operating officer and a practicing optometrist at Northeast Ohio Eye Surgeons, located in Stow, Kent and Akron. She completed a surgical comanagement and contact lens residency at Davis Duehr Dean in Madison, Wis. She can be reached at: kgreiner@neohioeye.com.
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