The Frontier of Keratoconus Diagnosis
The introduction of accessible genetic testing for keratoconus helps detect the condition and introduce treatment early
Elizabeth Yeu | | Opinion
There are a number of eye-based genetic diseases that impact overall health, including a particularly complex disease to diagnose: keratoconus. One Middle Eastern study shows that it can affect as many as 1 in 20 (1). In my practice, we diagnose keratoconus in approximately one in 40–50 patients, which translates to two keratoconus cases every day. For some patients, keratoconus begins in youth; however, other patients may not show obvious physical signs until well into adulthood – when the shape of the cornea has changed. What physical changes practitioners do detect in many cases is rapidly increasing astigmatism and/or myopia. Due to the difficulty in identifying keratoconus, these issues in turn may be misdiagnosed and addressed with ineffective treatments, such as a new lens prescription or hard contact lenses.
As a medical professional, I have certainly seen the rapid rise of genetic testing in other specialties, including oncology and cardiovascular disease. For example, the development of genetic tests that identify the BRCA genes, which are associated with breast and ovarian cancer, became an important turning point in the management and treatment of these life-threatening diseases.
Turning to eye care, in the WHO Vision Report they state at least 2.2 billion people have some type of vision impairment, and nearly half of these cases could have been prevented, so it makes sense for the medical and scientific community to look to our rapidly growing knowledge about genetics to help treat eye disease. Thankfully, this research is happening and these discoveries are being brought to market.
Indeed, a new genetic test – AvaGen (Avellino) – is now available in the US, changing the landscape for the treatment and management of keratoconus patients. The test identifies the common genes involved in keratoconus and provides a risk score. A simple buccal (cheek) swab collects the patient’s DNA sample, the sample is sent to the Avellino lab, and the practitioner receives an intuitive report through a HIPAA-compliant portal – along with information to connect with a genetic counselor at no additional cost.
Genetic counselors are highly trained professionals who can break down the complexity of genetics and inheritance and help guide conversations regarding the test results. From my own experience with the AvaGen test, I have found the genetic counseling reassuring for both the patient and myself, as it helps ensure I correctly interpret the findings and communicate the test results and intricacies of genetics in understandable terms.
There are three common groups of patients where I use the AvaGen test:
i) I commonly test family members of patients diagnosed with keratoconus. One aspect I cannot stress enough is that early detection of this disease makes all the difference. I can now identify risk scores in patients in their teens or younger, even when there are no clinical signs present. With this early knowledge, I can start treatment (if needed) decades earlier and guide them to start important lifestyle habits now, such as not rubbing their eyes, using allergy eye drops to better manage allergies, or using dry eye drops to manage dryness.
ii) In refractive evaluations where there are suspicious or suspect findings on ocular images that make me pause in making a clear surgical decision, I run the genetic test for keratoconus. I can then select the best refractive surgery procedure for the patient (or rule them out). We know vision loss can occur when a patient with undetected keratoconus gets LASIK or other corneal refractive surgery procedures, so it has been a game-changer to rule patients in or out for these types of procedures with new confidence. When the AvaGen test risk score is high for an individual, such patients may better benefit from ICL (implantable collar lens) surgery, or even corneal cross-linking for irregular astigmatism.
iii) When a patient has more progressive astigmatism, irregularly aligned astigmatism, or when I’m suspicious about undetected keratoconus, I also use AvaGen to help diagnose or rule out this condition to inform my management decisions regarding interventions and follow-up and therapeutic vision options (such as spectacles and contact lens options).
As mentioned previously, early detection of keratoconus is a modern eye care breakthrough. The advent of genetic testing opens the door to early detection not only for keratoconus patients, but also for children or siblings in their teens and twenties with diagnosed parents. With early detection there are more treatment avenues available, including corneal cross-linking, refractive surgery decisions that can preserve the cornea, and stronger management around eye rubbing and allergies – all of which help protect vision and improve quality of life.
In my practice, AvaGen is a powerful diagnostic tool that allows me to manage and treat my patients with a whole new level of personalized medicine. Genetic tests are the new frontier in eye care, and I am enthusiastic about future tests and treatments that will bring more precision medicine to our industry.
- H Hashemi et al., “The prevalence and risk factors for keratoconus: a systematic review and meta-analysis,” Cornea, 39, 263 (2020). PMID: 31498247.
Elizabeth Yeu is Assistant Professor at Eastern Virginia Medical School and Cornea, Cataract and Refractive Surgeon with Virginia Eye Consultants, VA, USA
