초록 ▼

A surgical apparatus for partially modifying the curvature of the cornea of an eye while the eye is within the patient is disclosed. The device is able to ablate a zone of corneal material in the form of a lenticular lamina. The thickness of the lamina at any particular point on the cornea surface v

A surgical apparatus for partially modifying the curvature of the cornea of an eye while the eye is within the patient is disclosed. The device is able to ablate a zone of corneal material in the form of a lenticular lamina. The thickness of the lamina at any particular point on the cornea surface varies as a function of the radial distance between that point and the central optical axis of the eye. The surgical apparatus comprises: a source of light (31) capable of emitting a beam of light (4) having a wavelength which is about 200 nanometers; an optical system (32) for directing and focusing the beam of light onto the desired zone of the cornea in order to ablate a lamina of material of the desired dimensions; and, a series of diaphragms and screens for obscuring varying portions of the zone of the cornea undergoing ablation in order to effect differential irradiation of the corneal surface. The longer the light beam (4) is allowed to impinge a particular portion of the cornea, the more corneal material removed from that spot and the greater the thickness of the lamina ( 2 and 16), and vice versa.

대표청구항 ▼

Surgical apparatus for modifying at least partly the curvature of the cornea of an eye having a central optical axis by ablation of a zone thereof which has the form of a lenticular lamina, the thickness of said lamina at any particular point varies as a function of the radial distance to the centra

Surgical apparatus for modifying at least partly the curvature of the cornea of an eye having a central optical axis by ablation of a zone thereof which has the form of a lenticular lamina, the thickness of said lamina at any particular point varies as a function of the radial distance to the central optical axis of the eye with the result that the desired modification of curvature of the cornea is produced, comprising: (a) a source of light capable of emitting light having a wavelength which is close to 200 nanometers; (b) means for selecting out of the light emitted by said light source a portion of light which is essentially unidirectional in nature, whereby a beam of light having a width is formed, said beam having a substantially constant energy density transversely across the width of said beam, whereby said beam is able to produce photodecomposition of corneal matter; (c) an optical system for directing said beam onto the zone of the cornea to be eliminated and for forming thereon a light spot constantly centered on said optical axis; and, (d) means for progressively varying the surface area of said light spot on the cornea, so that the length of time said beam is allowed to impinge on a particular portion of said zone of the cornea and the thickness of the corneal material which is to be eliminated at a particular location are directly related, whereby the areas of the cornea which constitute the thicker portions of said lamina are exposed to said beam for longer periods of time and the areas of the cornea which constitute the thinner portions of said lamina are exposed to said beam for shorter periods of time.