What is keratoconus - Ojaseyehospital

What is Keratoconus?
Keratoconus is a progressive disease of the outer transparent layer of the eye
ball (cornea) affecting young adults mostly in their twenties. It is characterized
by Progressive thinning of the normally round cornea causing it to bulge
forward and assume a cone like shape. This irregularity in the cornea results in
the formation of a distorted image of objects on the retina & gives rise to
Blurred vision. It generally affects both eyes but can also occur unilaterally.
What are the symptoms & signs of keratoconus?
Keratoconus is diagnosed usually on routine eye examination by the eye doctor. Keratoconus causes myopia
or nearsightedness & astigmatism. The patient experiences frequent change in glasses prescription with
fluctuation in vision. Some patients also have glare & sensitivity to light especially during night.
In advanced stage of Keratoconus, corrective prescription glasses do not help the patient to see clearly and they
have to switch to using hard or semi-soft contact lenses.
Your eye doctor practitioner can diagnose early stage of keratoconus after a detailed eye examination which
includes Retinoscopy, Slit lamp examination and sophisticated tests like Topography (Corneal Mapping) to
check the shape and curvature of cornea & Pachymetry to determine the thickness of the cornea.
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Suspect Keratoconus when:
• A late teen or young adult myope is no longer correctable to 20 / 20 at the phoropter
• There is a change in astigmatism. (cylindrical power)
• There is a change in axis of astigmatism.
• Frequent change in eye glass power.
What causes Keratoconus?
The exact cause of keratoconus is not known but latest research suggests that the cornea becomes weakened
due to an imbalance of enzymes within the corneal tissue. Young patients produce high level of free radicals
which cause oxidative damage to the cornea in absence of protective enzymes. This causes thinning and bulging
of the cornea.
Keratoconus also shows some genetic predisposition. It may transmit from parent to children and affect more
than one family member.
The Integrity and shape of the cornea are maintained by small protein fibers know as Collagen, which are
extremely robust proteins which are distributed throughout the body and help in maintaining its structure. When
these collagen fibers in the cornea become friable and damaged the cornea fails to maintain its shape and
therefore cones outward.

Corneal damage occurs due to the formation of free radicals which damage the collagen architecture. Free
radicals are by-products of the functioning cells and they cornea is abundant in Mitochondria, which are the
powerhouses of cells. During the production of energy for cells free radicals are formed which are neutralized
antioxidant substances in the body, yet if there is a deficiency in antioxidants which may be due to reduced
production within the body or reduced intake by means of antioxidant rich food, will lead to free radical damage
to the cornea amongst other body structures.
Keratoconus can be an acquired condition but an entity known as Familial Keratoconus has been described in
literature in which it states that certain individuals with a significant family history of keratoconus in direct
relatives have a greater risk of developing the same condition. Since keratoconus is a very slow progressing
condition which in some cases do not lead to significant compromising of sight most individuals are
undiagnosed in the population.
Irritation of the outer aspects of the eye is one of the causes of keratoconus. The conjunctivae which are the
outer linings of the eye lids are prone to become infected. A commonly known disease entity known as
Conjunctivitis where there is reddening, inflammation and irritation of these outer covering of the eyelids causes
itchy eyes in most individuals. Also any foreign objects such as hairs or dust particles or some cosmetic
products can also cause irritation of the eye. Irritant eyes become progressively itchy and due to this there is
friction damage to the sclera and cornea.
Ultraviolet light poses a great danger to the cornea and the lens of the eyes. The most potent source of natural
Ultraviolet light is sunlight and individuals who have prolonged exposure to sunlight such as police officers,
construction workers and members of the armed forces have a significantly high risk of catastrophic damage to
the cornea.
Another source of irritation of the cornea is the use of loose fitting incorrectly positions inferior quality contact
lenses, some of which are sold over the counter for cosmetic purposes. These cause irritation of the conjunctivae
and eye which in turn leads to the attraction of infections to the eye which will damage the cornea.