Equipment for the correction of presbyopia by remodelling the corneal surface by means of photo-ablation

Equipment for the correction of presbyopia by shaping of a corneal surface at a pupil of an eye using an output of laser energy, said pupil having a periphery having a curvature, said laser output being capable of removing a thin layer of tissue from said corneal surface when pulsed, said equipment comprising:

• a mask interposed between said laser output and said corneal surface, said mask having an aperture for allowing said laser output to pass therethrough, said aperture having a curved edge, said curved edge having a curvature substantially similar to said curvature of said pupil;
• a frame for supporting said mask above said corneal surface;
• said mask having two mask elements slidably mounted within said mask, each of said mask elements having a curved edge, said two mask elements positioned within said mask such that said aperture is blocked by said mask elements except at an aperture portion defined by said two curved edges when in a facing arrangement, a first of said curved edges being convex, a second of said curved edges being concave, said mask elements being slidable to vary the dimensions of said aperture portion.