What are the signs and symptoms of keratoconus and how can I tell if I have it?
What’s the difference between signs and symptoms? Symptoms are subjective, which means this is what you feel and notice yourself. Clinical signs are what your keratoconus expert will look for objectively.
Symptoms of keratoconus
Often the earliest symptom is frequent eye-rubbing to relief itchy eyes. The disease is associated with various forms of allergy (hayfever, ezcema etc) and itchy eyes can lead to eye-rubbing for comfort. While it is important to be aware of this symptom, it is also essential that the itch is managed so that eye rubbing is stopped. Unfortunately, prolonged eyeing can actually cause keratoconus to worsen.
Blurry vision; you may notice that things are not as clear as they should be – even with the best pair of glasses. The vision is usually more distorted than foggy and often there will be ‘ghosting’ where it looks like a second image is superimposed on top of the first. These are the symptoms
Signs of keratoconus
A steep central cornea, which shows up very clearly during a corneal topography. This is a map of the shape of the front of your eye, much like the geographical map of a country. On a map you can see steep, mountainous areas by their brown colour, compared to the green areas of flat land. A topographical map shows an area of steepness, usually below centre.
Corneal striae are subtle folds or striations in the surface of your cornea that may be seen on examination with a bio-microscope.
Corneal thinning, the earliest sign of keratoconus, can be picked up with an instrument called a global pachymeter, which measures the thickness of the whole cornea, not just the centre.
Increasing and irregular astigmatism, which is picked up when you are tested for glasses.
Deteriorating vision, even with your best possible glasses, (this can indicate many other eye diseases too).
Several prescription changes to your glasses in a short period of time.
Munson’s sign: This is the v-shape of the lower eyelid when you look down. The cone-shaped, bulging cornea is obvious by the shape it makes against your eyelid. This is seen in advanced keratoconus.
Your keratoconus expert may place a standard hard contact lens on your eye and examine the tear layer underneath. If you have keratoconus, there will be a classic pattern of touch in the centre (the dark area representing the steep cone) surrounded by a pool of tears (the green area).