WHAT IS ASTIGMATISM? An optical defect. Vision is blurred. Inability to focus. Cause An irregular curve in the lens.
Types of Astigmatism? Regular Three types With-the-Rule Against-the-Rule Oblique Caused by an irregularity in the cornea or crystalline lens. Irregular Caused by a corneal scar or scattering in the crystalline lens.
TYPES OF REGULAR ASTIGMATISM With-the- Rule This is when the vertical meridian is steepest. Oblique This is when the steepest curve lies in between 120 and 150 degrees and 30 and 60 degrees. Against- the-Rule This is when the horizontal meridian is steepest.
SIMILAR/CONCURRENT DISORDERS Astigmatism can occur with other ocular disorders. Disorders such as Nearsightedness and Farsightedness.
Nearsightedness (Myopia). When the cornea is curved too much or the eye is longer than it should be. This causes the light to be focused in front of the retina, blurring images at a distance.
Farsightedness (Hyperopia). When the cornea is curved too little or the eye is shorter than it should be. This causes light to be focused behind the retina, blurring images up close.
TREATMENTS Corrective Lenses Contact Lenses Types Hard, Soft, Extended wear, Disposable, Rigid gas permeable, and Bifocal. Eyeglasses Can correct most optical defects.
TREATMENTS (continued) Surgery LASIK-Laser-assisted in-situ keratomileusis Makes a hinged cut then reshapes the cornea. LASEK-Laser-assisted subepithelial keratomileusis A much thinner layer of the cornea is folded. PRK-Photorefractive keratectomy Removes the outer protective layer of the cornea, then reshapes it.
Information Compiled from http://en.wikipedia.org/wiki/Astigmat ism_(eye) http://www.mayoclinic.com/health/as tigmatism/DS00230/DSECTION=treat ments-and-drugs