Keratoconus
Keratoconus is a disorder of the cornea, which is the clear, dome like surface of the eye. In keratoconus, the cornea thins, and then bulges out, forming a cone shape. This results in distorted vision, because the change in the shape of the cornea affects how light travels through the eye. Keratoconus does not cause blindness, but it can reduce the ability to focus without the aid of glasses or contact lenses. Early diagnosis of keratoconus is rare, because changes in the cornea usually occur very slowly. Keratoconus is bilateral, it almost always affects both eyes, usually one more than the other, and degenerative. It is most commonly detected in individuals in their early twenties, and affects roughly 1 in 2,000 people. The cause of keratoconus is unknown, but ultraviolet light, allergic conditions, and poorly fitted contact lenses have all been associated with the disorder.
Symptoms
Symptoms of keratoconus include:
-Blurred or distorted vision
-Photophobia- Abnormal sensitivity to light
-Disturbed night vision
-Headaches caused by eyestrain
-Nearsightedness
-Astigmatism
Treatment
There are several treatment options available for individuals with keratoconus. Half of keratoconus patients can be treated with corrective lenses. The other half experience a continuation of corneal changes, and require more extensive treatment, including corneal transplant. Treatments for keratoconus include:
-Soft contacts and glasses- Most helpful in the early stages.
-Rigid Gas Permeable(RGP) lenses-These provide a smooth surface for light refraction and work well in the moderate stages of keratoconus.
-Hybrid contact lenses-Provide the refractive surface of an RGP lens, but are comfortable to wear like a soft contact lens.
-Corneal inserts- Can be placed into the cornea to flatten and stabilize its shape.
-Ck-3 – A treatment in which ultraviolet light is used to activate enzymes in the cornea which may strengthen corneal fibers, helping the cornea to maintain a proper shape.
-Surgery- A corneal transplant may be indicated when corrected visual acuity falls below a level which allows an individual to maintain functional activities.
Implications
-Individuals with keratoconus should be provided a work environment with good lighting and no glare.
-Activities that can cause corneal damage, such as swimming, should be avoided. Other activities may require safety glasses to protect the eye.
-In severe cases, services from a Teacher of the Visually Impaired and/or an Orientation and Mobility Specialist should be provided. This will include a functional evaluation and an assessment of needs such as low vision devices.
-In cases where acuity is severely impaired, there may be a need for enlargement of classroom materials, such as tests and worksheets, and extra time allowed for completion of assignments. Preferential seating should be provided. Also, a “buddy” to help with travel and to verbalize distance activities may be needed.
References
Keratoconus-What is Keratoconus. (n.d.). Retrieved on July 1, 2010 from
Keratoconus (n.d.). Retrieved on July 1. 2010 from
Bailey,Gretchyn & Lee, Judith (n.d.).Keratoconus. Retrieved on July 1,
2010 from
Region 4 EducationServiceCenter (Eds.). (2004). Program in Low Vision
Therapy. Houston: Region 4 EducationServiceCenter
Goldberg, M.D.,S. & Trattler, M.D., W. (2009). Ophthalmology Made
Ridiculously Simple (4th ed.) Miami: MedMaster, Inc.