Keratoconus is an eye disease that affects the structure of the front clear portion of the eye, known as the cornea. The shape of the cornea changes gradually over time from the ordinary round shape to a more cone shaped appearance. As the eye becomes more cone shaped and distorted, this leads to blurred vision, glare, halos, and visual distortions..
Causes, incidence, and risk factors
Although the cause for keratoconus is not known, there are many risk factors that can put some patients at a higher predisposition in developing keratoconus.. Keratoconus is thought to involve a defect in the corneal collagen, the tissue that delivers strength to the cornea and gives it its round shape. Research has shown that excessive eye rubbing is associated with keratoconus due to the constant mechanical movement of the corneal tissue. Additional risk factors are atopic disease such as eczema, family history, and demographics.
The initial symptoms may include subtle blurring of one’s vision that cannot be corrected with glasses or contact lenses. Over time, patients may also develop halos, glare, or other night vision problems, including difficulty driving. In severe cases there can be painful breaks in the cornea, which can lead to scarring.
Most people who develop keratoconus have a history of astigmatism and myopia (nearsighted vision). The astigmatism tends to worsen over time, leading to visual disturbances.
Signs and Tests
Historically, keratoconus was diagnosed during the second decade of one’s life. We are now able to detect the early signs of keratoconus well before the second decade and before the subjective symptoms develop. Corneal Topography and Aberrometry measurements have become the standard of care in diagnosing keratoconus. A computerized system images the shape of the cornea together with the entire optical system by taking tens of thousands of data points. The results are instantly analyzed and wave front topography maps are generated. These printouts will show Dr. Azman an eye-map-print (just like a finger print) of the location and severity of any corneal distortion and high order aberrations (HOA).
Specular Microscopy is noninvasive photographic technique that facilitates accurate and precise diagnosis of corneal disease in the back part of the cornea (endothelium). This instrument can pick up early signs of corneal edema, which cannot be picked up on routine examination. If there is any indication of corneal disease, such as keratoconus or edema we might recommend a different treatment modality.
Management and Treatment Objectives: Stabilize progression and Improve vision
CXL is a minimally invasive procedure that involves applying formulated riboflavin (vitamin B2) eye drops to the surface of the cornea, followed by treatment with a controlled application of ultraviolet A (UVA) light to strengthen the cornea. The procedure is designed to stop further progression of corneal ectasia (thinning) and bulging of the cornea, which is typically found in individuals with keratoconus.
Sometimes we choose to combine several techniques together with CXL to achieve the best optical and medical outcome. Our treatment decision is based on several parameters , such as degree of myopia or hyperopia, astigmatism, higher order aberrations (HOA) corneal thickness, tear layer, Pentacam /topography measurements, shape/location of cone, best corrected visual acuity (BCVA) and individuals goals.
Once progression of the disease has stabilized, there are multiple options to correct patient’s visual distortions. For mild keratoconus, glasses and soft contact lenses can be used. However, in moderate to severe cases, glasses and soft contact lenses will not provide improved vision. These patients need a more advanced solution such as rigid gas-permeable lenses (RGP), hybrid lenses (combination of soft and hard), Scleral lenses, PVR PROSE, and EyePrint PRO designs. These advanced designs are designed to provide excellent visual results for patients with keratoconus.
The last treatment for keratoconus to be considered may be a corneal transplant, also called a penetrating keratoplasty (PK or PKP). Even after a transplant, you most likely will need glasses or contact lenses for clear vision. For many years, the only options were surgical treatment with corneal transplantation, but with medical advances, we are seeing a major decline in the need for corneal transplants in keratoconus patients.
Dr. Irwin Azman of Keratoconus Specialists of MD is an expert in the field of contact lenses for keratoconus and other irregular corneas. He stays involved in up to date research and development in management and treatments of keratoconus, and has lectured at vision conferences, and has published numerous articles in professional contact lens journals. You can be assured that Dr. Irwin Azman will provide you with the highest quality of care.