Iris-fixated intraocular lens Iris-fixated intraocular lens Iris-fixated phakic intraocular lens is an intraocular lens that is implanted surgically into the eye and fixated to the iris to correct myopia (nearsightedness). Early models were sutured to the iris with a stitch; the claw fixation method made iris stitching unnecessary. The iris-claw lens is fixated to the anterior iris surface by enclavation of a fold of iris tissue into the two diametrically opposed claws of the lens. The fixation sites are located in the midperiphery of the iris, which is immobile during pupillary movement. This lens was modified into a convex-concave design and manufactured as
Lens clock clock can be used if a dial thickness gauge is not available. To do this, the contact lens is placed concave side up on a table or other hard surface. The lens clock is then brought down on it such that the center prong contacts the lens as close to its center as possible, and the outer prongs rest on the table. The thickness of the lens is then the sagitta formula_4 in the formula above, and can be calculated from the optical power reading, if the distance between the outer prongs is known. Lens clock A lens clock is