Keratoconus Vision Simulator

Keratoconus is a progressive eye disorder where the normally round, dome-shaped cornea, the clear front surface of the eye, thins and gradually bulges outward into an irregular cone shape. This structural change, which typically begins in the late teens or early adulthood, alters the way light enters the eye and prevents it from focusing correctly on the retina. While the exact cause remains unknown, it is thought to involve a combination of genetic and environmental factors, such as a family history of the condition, excessive eye rubbing, and certain allergic or systemic disorders.

The primary symptoms of keratoconus are directly related to this progressive deformation of the cornea. Individuals often first notice blurry or distorted vision, where straight lines may appear wavy or bent, and experience a need for frequent changes in eyeglass prescriptions, particularly an increase in astigmatism and nearsightedness. As the disease advances, other common symptoms include heightened sensitivity to bright light and glare (photophobia), which can make night driving particularly difficult, and the appearance of halos or streaks around lights.

The impact of keratoconus on vision stems from the irregular surface of the cornea, which acts like a distorted lens. In a healthy eye, the cornea focuses light evenly. However, the cone shape of a keratoconic cornea creates irregular astigmatism, meaning the light is scattered and focused at multiple points instead of a single, sharp point on the retina. This results in the characteristic blurring and distortion, and can lead to double vision or ghosting (seeing multiple, partial images) when looking with just the affected eye.

In more advanced stages, the corneal tissue can become excessively thin and, in rare instances, swell suddenly due to a break in an inner layer, causing a sharp decrease in vision. Over time, scarring can develop at the apex of the cone. This corneal scarring further reduces the clarity and transparency of the cornea, drastically worsening vision and making it difficult or impossible to correct with standard eyeglasses or soft contact lenses, often necessitating specialized treatments like rigid gas permeable or scleral contact lenses, or surgical interventions to restore functional eyesight.