A common condition affecting the cornea is keratoconus, which involves a change in the shape of the cornea that is progressive, and results in errors of refraction which are unable to be corrected by using eyeglasses or contact lenses to improve these problems (Campbell 2010.). While there are multiple treatments for the condition, the worst possible scenarios are the cases in which none of the other, less drastic treatments are effective, and result in corneal transplants. This paper will discuss the causes and risk factors of keratoconus, symptoms, diagnosis and treatment.
When a patient is diagnosed with keratoconus, typically the surface of the cornea becomes thinner and rather than being round, takes on a cone-like shape (Campbell.) Various studies suggest that the condition results from one of several possible causes: a genetic corneal abnormality, since approximately 7% of patients with keratoconus report having a family history of the condition; an injury to the eye that can be caused by constant rubbing of the eye or using hard contact lenses for long periods of time; various diseases of the eye, including retinitis pigment to some or retinopathy of prematurity; and systemic illnesses such as Down syndrome and osteogenesis imperfect (Facts about the Cornea and Corneal Disease.)
Because the progression of keratoconus is typically very slow, it is frequently difficult to identify or diagnose; there are exceptions however since in some patients, theories of rapid progression of the disease. When the cornea takes on a more irregular shape the result is progressive nearsightedness as well as irregular astigmatism; this can create problems including distorted vision as well as blurred vision. Many patients develop glare and light sensitivity as well (Lusby.) This condition frequently results in patients needing changes in their eyeglass prescriptions whenever they have an eye examination.
Diagnosis of keratoconus can be made through variety of very specialized tests by an ophthalmologist. Using a slit-lamp evaluation, dilated retinascopy, pachymetry, and standard videokeratography, ophthalmologists are able to diagnose the majority of cases relatively early in order to prevent a condition called ectasia, or the dilation of, or the dilation or distention of the cornea (Rabinowitz.)
When a patient suffers only from a mild form of keratoconus, wearing eyeglasses or soft contact lenses may be the remedy but as the disease continues and causes the cornea to become thinner and more irregular, these remedies are typically no longer adequate to correct vision. Treatments for advanced keratoconus are: gas permeable contact lenses, which have a rigid lens material that covers the cornea and correct the year regularity with a smoother, uniform surface to enhance vision;”piggybacking” contact lenses, or utilizing two different types of lenses that will fit the cornea more comfortably and effectively; intacs, or corneal inserts, which are tiny plastic inserts that are put just beneath the eyes surface on the outside of the cornea, allowing the reshaping of the cornea to enhance vision (Lusby.) In cases where none of the aforementioned treatments are effective in slowing down or improving the patient’s vision, corneal transplant becomes an option.
Literature was very sparse regarding case studies about patients with keratoconus. In one such study however, a 26-year-old patient with a diagnosis of keratoconus displayed, on exam, vision problems including corneal thinning, irregular astigmatism that was unable to be corrected with contact lenses or glasses, and a typical sign: a “bowtie “pattern of irregular astigmatism. In order to design an effective lens, very specific measurements were taken of the cornea and sclera, resulting in a lens that fit more exactly and comfortably over the cornea. Ultimately, there was a significant tightening of the image of the retina, as well as a lessening of aberrations of the cornea. As a result, a corneal transplant was not necessary because the patient’s vision improved and the disease was treated by the use of a specially made sclera lens (Case Study: Keratoconus.)