Keratoconus is a condition in which the normal clear and dome-shaped cornea becomes thin and bulges outward to form a cone shape. The cornea plays an important role in refracting and focusing rays of light for clear vision; hence, an altered shape disrupts the function and distorts normal vision. Keratoconus usually affects both eyes and can either develop suddenly or progress slowly over several years. It can manifest anytime; from childhood, up to the age of about 30 years.

Keratoconus is caused due to the weakening of collagen fibres, which is the tissue that holds the cornea in place. It can be passed on from one generation to the next. Vigorous rubbing of eyes, conditions such as keratoconjunctivitis (inflammation of outer layers of the eye), retinopathy of prematurity (abnormal blood vessels in the retina), and retinitis pigmentosa (degeneration of retina) and wearing contact lenses for several years may also cause keratoconus.

The signs and symptoms of keratoconus vary with the progression of the disease. Early symptoms include blurring of vision. Halos (rings seen around lights), night vision problems and glare may develop over time. You may also experience sudden clouding of vision. When you present with any of these symptoms, your doctor will review your medical history, conduct an eye examination, and order a few diagnostic tests to measure the corneal curve to evaluate the projection and shape of your eyes. Your doctor may suggest appropriate treatment options based on the severity and progression of the keratoconus.