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
Focal cloud Focal cloud A focal cloud is the collection of focal points of an "imperfect" lens or parabolic reflector whether optical, electrostatic or electromagnetic. This includes parabolic antennas and lens-type reflective antennas of all kinds. The effect is analogous to the circle of confusion in photography. In a perfect lens or parabolic reflector, rays parallel to the device's axis striking the lens or reflector all pass through a single point, the focal point. In an imperfectly constructed lens or reflector, rays passing through different parts of the element do not converge to a single point but have different focal points. The