Keratoconus-Answers
Keratoconus
Definition: Noninflammatory condition characterized by the change in eye form from normal round shape to a cone shape. Cone shape results from the bilateral central ectasia of the cornea with anterior protrusion of the cornea. Keratoconus results when the cornea thins and protrudes. Abnormal eye shape distorts visual images.
Incidence/Prevalence: Disease manifests during the late teens or early twenties, then progresses slowly for the next decade or two as the cornea scars and becomes more elongated. Although affecting both eyes, one may be more severely affected than the other. Myopia and an irregular astigmatism may result from the alteration in the normal corneal contour. Keratoconus occurs mostly as an isolated finding, but can be associated with other ocular disorders or systemic conditions (i.e. Down syndrome).
Etiology: The cause of keratoconus is unknown. Patients with the disease should avoid rubbing their eyes since it can contribute to disease progression.
Clinical Presentation: Changes in focal disruptions of the epithelial basement membrane and Bowman’s layer are initial indicators of keratoconus. Thinning of the central stroma and the anterior stroma are usually present. The Prussian blue stain (Perls test) detects iron depositions in the basal epithelial layers.
Histopathology: This macrophotograph of a bisected cornea is taken at the dissecting microscope with the cornea placed on edge. Here a brown ring called Fleisher's ring (black arrows) is evident on the surface of the cornea. At the very edge of the specimen (black arrow 1) the brown (oxidized iron) can be seen deposited within the epithelium. The white arrows show Descemet's membrane, click to enlarge. The central cornea (left side of photo) is thinner than the peripheral portion of the cornea.
Treatment: Mild cases can be treated with glasses or contact lenses. In severe cases, a corneal transplant may be recommended.
Definition: Noninflammatory condition characterized by the change in eye form from normal round shape to a cone shape. Cone shape results from the bilateral central ectasia of the cornea with anterior protrusion of the cornea. Keratoconus results when the cornea thins and protrudes. Abnormal eye shape distorts visual images.
Incidence/Prevalence: Disease manifests during the late teens or early twenties, then progresses slowly for the next decade or two as the cornea scars and becomes more elongated. Although affecting both eyes, one may be more severely affected than the other. Myopia and an irregular astigmatism may result from the alteration in the normal corneal contour. Keratoconus occurs mostly as an isolated finding, but can be associated with other ocular disorders or systemic conditions (i.e. Down syndrome).
Etiology: The cause of keratoconus is unknown. Patients with the disease should avoid rubbing their eyes since it can contribute to disease progression.
Clinical Presentation: Changes in focal disruptions of the epithelial basement membrane and Bowman’s layer are initial indicators of keratoconus. Thinning of the central stroma and the anterior stroma are usually present. The Prussian blue stain (Perls test) detects iron depositions in the basal epithelial layers.
Histopathology: This macrophotograph of a bisected cornea is taken at the dissecting microscope with the cornea placed on edge. Here a brown ring called Fleisher's ring (black arrows) is evident on the surface of the cornea. At the very edge of the specimen (black arrow 1) the brown (oxidized iron) can be seen deposited within the epithelium. The white arrows show Descemet's membrane, click to enlarge. The central cornea (left side of photo) is thinner than the peripheral portion of the cornea.
Treatment: Mild cases can be treated with glasses or contact lenses. In severe cases, a corneal transplant may be recommended.
posted by Mission for Vision at 12:01 PM
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