Seeing starburst around light sources

When a light source deforms into a star, it is called a starburst. When you look at a light source with keratoconus without contact lens correction, light will radiate upwards. The length of the rays is caused by the degree of keratoconus. When you look at a light source with keratoconus with scleral lenses, light will radiate downwards. Depending on the residual error, these light streaks will be large or small. The greater the uncorrected residual error, the longer the rays.

See the cause of streaks in light sources

As light makes its way through the eye, it can change direction. For example, a ray of light can be split into several fine rays of light by turbidity. This splitting of the light is called light scattering. Some scans of the keratoconus cornea show a decrease in corneal clarity. It seems that this slight loss of brightness leads to stray light nuisance. Scattered light nuisance (glare) manifests itself in blurred vision, loss of contrast and loss of color. Stray light nuisance increases the optical problem of less sharp vision, despite the correction of contact lenses.

See stripes in the dark

Seeing stripes around light sources, such as car lamps or lampposts, is especially visible in the dark. The stripes can make driving difficult, which in some cases can even lead to dangerous situations. How the stripes appear is quite different. Sometimes you see fine rays and other times you see thicker rays. What they have in common is that they can significantly reduce vision.

Seeing streaks in light sources during the day

You may also see streaks of light during the day. For example, in cloudy, gray weather and when cars are driving with the lights on. Some people with keratoconus say that they also have problems with driving during the day due to, for example, double contours, blurred vision and loss of contrast sensitivity.