Corneal lenticular formation using a femtosecond laser for hyperopia and mixed astigmatism correction

Abstract

An ophthalmic laser system and related method for performing corneal lenticule incision and extraction for treating hyperopia and mixed astigmatism of the eye are described. Various techniques are used to optimize the procedure for concave lenticule incisions. One technique employs a fast-scan-slow-sweep scanning scheme to form the lenticule incisions, where the sweep angle increment is set to ensure at least double-pass cut for the entire lenticule. Another technique allows for desired distribution of refractive powers between the top and bottom lenticule incisions. Other techniques configure the lenticule such that its edge thickness is a constant; or such that the highest point of the top lenticule incision, located near the lenticule periphery, is at a predefined depth below the anterior corneal surface; or to maximize lenticule thickness for refractive treatment while ensuring that minimum anterior depth and minimum residual bed thickness in the peripheral region of the lenticule are maintained.