Astigmatism is an optical condition that creates different points of focus. As a consequence someone with uncorrected astigmatism will experience blurred vision.
This uncorrected visual blur results when the front optical surfaces of the eye are not spherical. A spherical optical surface bends images evenly resulting in equally focused images within the eye.
Spherical surfaces focus images equally
The non-spherical astigmatic eye is curved unevenly so images are bent unequally and are observed out of focus.
Non-spherical (astigmatic) surfaces focus images unequally
For the most part astigmatism can easily be corrected with glasses, contact lenses and laser vision correction. Patients with cataracts can have their astigmatism corrected with femtosecond laser technology concurrent to cataract surgery.
There is a variety of high astigmatism that is associated with corneal disorders such as with keratoconus. With keratoconus the eye develops a pathological stretching and take the shape of a teardrop.
Tear drop cornea of keratoconus
Astigmatism in these cases may need specialty corrections.