Keratoconus Detection by Ultrasound

Keratoconus is the most common degenerative disease affecting the cornea. As keratoconus develops, the cornea thins and bulges. Eventually, a corneal transplant may be needed to maintain vision. In its earliest stages, the disease is particularly difficult to detect. This is of great importance to the corneal refractive surgeon because surgical treatment of a keratoconic cornea will weaken it and greatly accelerate the occurrence of symptoms. Early detection of keratoconus will benefit patients because of the recent development of methods for strengthening the corneal stroma and preventing disease progression.

The investigators have developed a technique based on the use of high resolution ultrasound for imaging the cornea and measuring the thickness of its component layers, including the epithelium and the stroma. In early keratoconus, as the anterior stromal surface begins to bulge forward, the epithelium will thin above the apex of the bulge and thicken around it, to maintain a smooth anterior surface. The investigators have also developed methods for characterizing the elastic properties of the cornea by inducing and measuring surface displacements in response to a pulse of acoustic radiation force.

The investigators' goal is to reduce the percentage of screened cases deemed keratoconus-suspect by at least a factor of two by allowing an unambiguous diagnosis of early keratoconus. This would provide two major benefits; (1) to be able to predict eyes with higher risk of developing ectasia after corneal refractive surgery, and (2) early diagnosis would allow earlier treatment of the condition with collagen crosslinking, preserving the cornea from disease progression.