MODEL RELEASED. Eye examination. Patient having a corneal topography measurement made of her eye. The device at centre projects bright rings onto the eye, which are reflected in its surface. By studying the reflection, an accurate model can be built up of the shape of her cornea. The cornea is the front part of the eye that covers the iris and pupil. It is responsible for the majority of light focusing, with only fine focusing being done by the lens. Defects in the shape of the cornea can lead to a wide range of focusing disorders. These can be treated by surgery or by the wearing of tailored contact lenses or spectacles.