Astigmatism

Useful Terms

Cornea = a clear, round dome within the eye that covers the iris and pupil

Refractive error = improper focusing of light onto the eye

Astigmatism = a condition marked by an impaired curvature in either the cornea or the shape of the lens

within the eye; blurs and distorts the vision in regards to objects near and far

Corneal astigmatism = when the condition creates an irregular shape in the cornea

Lenticular astigmatism = when the condition creates an irregular shape in the eye’s lens

Common Symptoms

  • Blurry vision
  • Distorted vision
  • Resorting to squinting to see better and more clearly
  • Eyestrain
  • Discomfort in the eyes
  • Headaches
  • Children who experience these symptoms are less likely to notice and complain about them

Risk Factors

  • Hereditary = medical history of astigmatism in the family

Causes

  • Mainly caused by the irregular curvature of the cornea or lens
    • The irregularity prevents the proper focusing of light onto the eye, leading arefractive error
    • This refractive error is the reason why those who suffer from astigmatism getblurred and/or distorted vision at both near and far distances
  • Most of the people who have astigmatism are born with it
  • Astigmatism can also develop after an injury or disease has already occurred in the eye and mayalso come about after a surgery to fix those pre-existing conditions and maladies
  • Reading in low light or watching TV while sitting very closely to it exacerbates astigmatism =MYTH

Diagnosis

  • The eyes will be thoroughly examined throughout the course of a comprehensive eye exam in a varietyof different ways:
    • The patient will be asked to read letters off of a distance chart in order tomeasure visual acuity and clarity at certain distances.
    • There will be a series of lenses placed in front of the eyes and the patient willbe asked to determine which lenses offer clearer vision
      • This tests the focusing power of the eyes
  • The ophthalmologist will use a keratometer to measure the curvature of the cornea in order todetermine the extent and axis of astigmatism present
    • This is supplemented by a corneal topography test to examine the shape of thesurface of the cornea
  • All of these tests will let the doctor know how powerful the eyeglasses or contact lenses that areprescribed to the patient need to be to enable clear vision

Treatment

  • If astigmatism goes unrecognized as early as possible and/or untreated, then a child who suffersfrom the condition will have his/her scholastic and athletic abilities in school and sports, respectively, verymuch hampered and impaired
  • Those who experience only a mild to moderate form of astigmatism can have it corrected with theproperly prescribed eyeglasses or contact lenses
  • There are now soft contact lenses called toric contact lenses that can correct astigmatism
    • Those who have a severe form of astigmatism could benefit more from the customaryrigid contact lenses or eyeglasses, depending on the suggestions of the ophthalmologist
  • LASIK surgery may also be useful in correcting vision
    • There are also options for surgery to correct refractive errors