摘要 |
A noninvasive method is described for performing accurate and controlled reshaping of the anterior surface of the cornea in order to correct ocular refractive errors such as myopia (nearsightedness), hyperopia (farsightedness), and astigmatism. The invention uses a light source emitting a wavelength or wavelengths with correct optical penetration depth(s) to induce changes in corneal stromal collagen without damaging the corneal endothelium, together with a light delivery and control means for producing the required irradiance, exposure time, and geometric pattern, in order to achieve the desired change in corneal shape. Corneal shape is monitored before, during, and after the procedure by a corneal topography system. Anterior corneal surface cooling by a transparent heat sink is used to prevent damage to the epithelium and to Bowman's layer. |