Abstract: An apparatus is provided for performing corneal refractive surgery by ablating a portion of a corneal surface of an eye. The apparatus includes a pulsed laser for producing a pulsed output beam of light. A scanning mechanism scans the output beam, and the output beam is operatively associated with the scanning mechanism such that the output beam may be scanned over a predetermined surface defined by a mathematically derived ablation layer boundary curve for each ablation layer. A controller is operatively associated with the scanning mechanism so as to deliver output beams to the predetermined surface such that center points of output beams may be disposed within the ablation layer boundary curve, on the ablation layer boundary curve, and outside but within a predetermined distance from a nearest point on the ablation layer boundary curve so as to integrate the edges of the ablation layer boundary curve to more closely correspond to the desired ablated shape.
Abstract: A device for controlling the position of a patient's eyes during ophthalmic laser surgery is disclosed which comprises a first fixation object positioned within view of the patient's eye that is undergoing treatment, a second fixation object positioned within view of the patient's eye that is not undergoing treatment, and structure for controlling the position of the second fixation object. The present device allows the patient to maintain fixation on a visual target and maintain the eye undergoing treatment in a steady position even when vision in the eye undergoing treatment becomes blurred during laser ablation.
Abstract: A multizone, multipass photorefractive keratectomy (MP-PRK) technique to treat 315 eyes with the 193-nm VISX 20/20 excimer laser. The procedure includes making multipass ablations that increase in ablative depth to create as step-wise ablation of the corneal to the predetermined dioptric correction. It also includes making multizone ablations that create of variable widths that result in a predetermined ablative depth with smooth transition edges. A combination of multizone, multipass ablations are used to treat astigmatism. New algorithms effectively treat the full range of myopia, including low myopic eyes (-1 to -6 D), moderately myopic eyes (-6 to -10 D); and highly myopic eyes (-10 to -27 D).