With a perfectly shaped round eyeball, the light enters, bends evenly and focuses on the retina, which gives you a clear and sharp view.
Astigmatism, on the other hand, is a condition whereby the eyeball shape is no longer perfectly round, when the cornea or lens is curved more steeply in one direction than in another.
When the curvature of the eyeball is stretched or curved, the light is refracted or bent in different directions, rather onto the retina directly, which results in blurred distance and near vision.
When the cornea has mismatched curves, then one has corneal astigmatism. Meanwhile, lenticular astigmatism is when the lens has mismatched curves.
Either type of astigmatism can cause blurred vision. Blurred vision may occur more in one direction, either horizontally, vertically or diagonally.
Causes and diagnosis
For most, astigmatism is present from birth. It may also develop after an eye injury, disease or surgery.
Astigmatism, however, isn’t caused or made worse by reading in poor light, sitting too close to the television or squinting.
It is advised to visit an eye care specialist or optometrist when there are noticeable changes in one’s vision such as blurred or distorted vision, eye strain or tightness, headaches, difficulty with night vision and squinting.
With a comprehensive eye examination, eye specialists or optometrists can determine whether you have astigmatism and to what degree. They can then advise options to correct your vision.
Treatment
Almost all cases of astigmatism can be corrected with glasses or contact lenses.
Eyeglass lenses and contact lenses make the light bend into your eye properly.
Contact lenses are available in a variety of types and styles, including disposable soft; extended wear; rigid, gas permeable; and bifocal.
For normal level astigmatism, doctors or optometrists will probably prescribe special soft contact lenses, while for those with much severe astigmatism, they will be prescribed with a harder or rigid contact lenses.
Orthokeratology is a procedure whereby one wears Ortho-K contact lenses while they sleep, and it reshapes the cornea.
There is also option for refractive surgery, whereby eye surgeon uses a laser beam to reshape the curves of the cornea, which corrects the refractive error. Refractive surgery improves vision and reduces the need for eyeglasses or contact lenses. — The Health
