Keratoconus Signs and Symptoms: Identifying the Red Flags

In its earliest stages, keratoconus can be a "silent" condition. Because it often starts with mild blurring, many people assume they simply need a stronger pair of glasses. However, as the cornea thins and the irregular "cone" shape develops, the symptoms become more specific and more disruptive to daily life.

Recognizing these signs early is crucial because modern treatments like Cross-linking are most effective when the condition is caught before significant thinning occurs. Here is a detailed look at the physical signs and visual symptoms of keratoconus.

The Primary Visual Symptoms

Unlike nearsightedness, which just makes things look "fuzzy," keratoconus causes distorted vision. This is due to irregular astigmatism, where the light entering the eye is scattered in multiple directions.

• "Ghosting" or Monocular Polyopia: This is one of the most common symptoms. Patients often see multiple "ghost" images of a single object. For example, when looking at a white letter on a black background, you might see several faint versions of that letter overlapping or "bleeding" off to the side.
• Progressive Nearsightedness and Astigmatism: If you find yourself at the eye doctor every six months because your vision has changed again, this is a major red flag. Rapidly changing prescriptions are a hallmark of a cornea that is actively shifting shape.
• Starbursts and Halos: At night, light sources like streetlights or oncoming headlights may appear to have long "spikes" of light (starbursts) or glowing rings around them (halos). This can make night driving extremely difficult.
• Clouded or "Smeary" Vision: Even with a new pair of glasses, the world may still look slightly smeared, as if you are looking through a window with a smudge on it that you can't wipe away.

Physical Signs and Sensory Clues

Beyond what you see, there are physical behaviors and sensations often associated with the progression of the disease:

• Sensitivity to Light (Photophobia): The irregular cornea scatters light inside the eye, which can cause significant discomfort in bright sunlight or under harsh fluorescent office lights.
• Frequent Eye Rubbing: There is a strong "chicken or the egg" relationship here. Many patients feel a persistent itch or "foreign body sensation" in their eyes, leading to rubbing, which in turn can worsen the keratoconus.
• Eye Strain and Headaches: Because the brain is constantly trying to "stitch together" distorted images from the two eyes, many patients suffer from chronic headaches and physical exhaustion after tasks like reading or computer work.
• The "Squinting" Habit: You may find yourself squinting or tilting your head at specific angles to try and find a "sweet spot" in the cornea that provides a clearer image.

Advanced Signs: Hydrops and Scarring

In more advanced stages, the physical changes to the eye become more apparent to a clinician, though they can sometimes be felt by the patient as well:

• Corneal Scarring: As the cone becomes more prominent, the tissue can develop tiny scars at the "peak." This further blocks and distorts vision and may eventually require surgical intervention.
• Acute Hydrops: This is a rare but serious complication where a tiny crack develops in the back of the cornea, allowing fluid to enter. This causes sudden, painful swelling and a significant loss of vision that looks like a "cloud" over the eye. If this happens, it is a medical emergency.
• Munson’s Sign: In very advanced cases, when a patient looks downward, the lower eyelid takes on a V-shape because it is being pushed out by the cone-shaped cornea.

When to See a Specialist

If you have any of the symptoms mentioned above, particularly the ghosting of images or frequent prescription changes, a standard vision screening is not enough. You should request a corneal topography map. This test is the only definitive way to "see" the signs of keratoconus before they cause permanent damage to your vision.

Note: Many patients find that their symptoms are vastly different in each eye. It is common for one eye to be "functional" while the other is significantly more advanced. Monitoring both eyes is essential for a successful management plan.