What Is Keratoconus? Symptoms, Causes, & Treatment
If your glasses prescription seems to change every time you visit the eye doctor, or your vision feels distorted in a way that new lenses never quite correct, the cause may not be a simple refractive error. It could be a structural change in the shape of your cornea itself. Keratoconus is a progressive eye condition that affects how light enters the eye, and catching it early makes a significant difference in how effectively it can be managed.
At St. George Eye Center, we diagnose and manage keratoconus regularly in patients across Southern Utah. This guide explains what keratoconus is, how it progresses, the symptoms that typically prompt a diagnosis, and what to expect from an evaluation.
What Is Keratoconus?
The cornea is the clear, dome-shaped surface at the front of your eye. In a healthy eye, it holds a smooth, rounded shape that helps focus light accurately onto the retina. Keratoconus occurs when the cornea gradually thins and loses its structural rigidity, causing it to bulge outward into an irregular, cone-like shape instead of maintaining its normal curve.
This change in shape disrupts how light travels through the eye. Instead of focusing on a single, sharp point, light scatters unevenly across the retina, producing blurred and distorted vision that glasses often struggle to fully correct.
Keratoconus usually affects both eyes, though it often progresses unevenly, with one eye becoming more affected than the other.
How Keratoconus Progresses
Keratoconus typically develops slowly, often beginning in the teenage years or early twenties. The condition tends to progress over a period of 10 to 20 years before it stabilizes, though the rate of progression varies significantly from person to person.
In its earliest stages, the changes to the cornea are subtle. Vision may seem only slightly blurry, and many people attribute the change to normal nearsightedness or astigmatism. As the condition advances, the cornea continues to thin and steepen, and vision distortion becomes more pronounced. Without monitoring or treatment, progression can continue until the irregular shape significantly limits corrected vision.
Because early keratoconus can closely resemble common refractive errors, it is often first identified during a comprehensive eye exam rather than by symptoms alone.
Key takeaway: Keratoconus develops gradually over years, which is why routine eye exams play such an important role in catching it before it advances significantly.
Common Symptoms of Keratoconus
Recognizing the signs of keratoconus early can lead to a faster diagnosis and more treatment options. Watch for the following:
Frequent prescription changes. Needing a new glasses or contact lens prescription every few months, rather than the typical one to two years, is one of the most common early signs.
Blurry or distorted vision. Straight lines may appear wavy or bent, and text can look doubled or ghosted even with an updated prescription.
Increased sensitivity to light and glare. Bright lights, headlights, and sunlight can feel more uncomfortable than they used to.
Difficulty with night vision. Halos and streaking around lights are common, particularly while driving after dark.
Eye strain and headaches. The eyes working harder to compensate for irregular focus can lead to fatigue and tension.
Frequent eye rubbing. Many patients with keratoconus report a history of habitual eye rubbing, which may also contribute to disease progression.
Vision that glasses cannot fully correct. Unlike typical nearsightedness or astigmatism, blur from keratoconus often persists even with an accurate prescription.
If glasses or contacts stop providing the clear correction they once did, and updates to your prescription do not resolve the issue, it is worth requesting a corneal evaluation specifically.
What Causes Keratoconus?
The exact cause of keratoconus is not fully understood, but several factors are known to contribute to its development.
Genetics: Keratoconus often runs in families, and having a close relative with the condition increases your own risk.
Chronic eye rubbing: Frequent, vigorous eye rubbing is one of the most consistently identified risk factors, as it may weaken corneal tissue over time.
Certain allergic and inflammatory conditions: Conditions like chronic eye allergies, asthma, and eczema are associated with higher rates of keratoconus, likely due to the eye rubbing they often cause.
Connective tissue disorders: Some genetic connective tissue conditions are linked to a higher incidence of keratoconus, since they can affect the structural integrity of the cornea.
Oxidative stress within the cornea: Research suggests that an imbalance between damaging molecules and the cornea's natural defenses may weaken corneal tissue and contribute to the thinning process.
Keratoconus is not caused by anything a person did incorrectly, and it is not preventable in the way some eye conditions are. Understanding personal risk factors, however, can support earlier and more attentive monitoring.
How Keratoconus Is Diagnosed
Diagnosing keratoconus requires more than a standard vision test. Our doctors use specialized corneal imaging, called corneal topography, to map the surface of the cornea in detail. This technology can detect the subtle irregularities and steepening associated with keratoconus long before they would be obvious through a standard exam.
Additional diagnostic tools may include measuring corneal thickness and evaluating how light bends as it passes through the eye. Together, these assessments allow our doctors to confirm a diagnosis, determine how advanced the condition is, and track any progression over time with objective, measurable data rather than guesswork.
Early diagnosis matters considerably. Catching keratoconus while it is still mild opens the door to treatments that can stop progression before vision is significantly affected, which is far more difficult to achieve once the cornea has advanced further.
What Happens After a Diagnosis
A keratoconus diagnosis is not the same for every patient, since the condition varies widely in severity and rate of progression. In its earliest stages, vision correction with glasses or specialty contact lenses may be enough to maintain clear, comfortable sight.
For patients with confirmed progression, halting further corneal changes becomes the priority. One of the most effective tools for this is corneal cross-linking, a treatment designed to strengthen corneal tissue and prevent further progression of keratoconus.
Talk to a Doctor If Something Feels Off
Keratoconus is manageable, especially when it is identified early. If you have noticed frequent prescription changes, persistent blur, or distorted vision that glasses do not seem to fix, a dedicated corneal evaluation can provide real answers.
Our cornea specialists, including our doctors, have the diagnostic tools and experience to identify keratoconus accurately and guide you through the right next steps. Visit St. George Eye Center to learn more about corneal care or schedule an evaluation with our team today.
