الفهرس | Only 14 pages are availabe for public view |
Abstract Keratoconus (KC) is a fairly common bilateral, noninflammatory, degenerative axial ectatic condition of the cornea in which the cornea assumes an irregular conical shape. This results in progressive myopia and irregular astigmatism with associated progressive loss of vision and thus reduced quality of life. Keratoconus was initially broadly defined based on the shape and location of the cone. These include round or nipple cones with a central conical protrusion, and oval cones, often with inferior sagging. It is the most common primary corneal ectasia with an annual estimated incidence of 2 in 100,000 and a prevalence of 54.5 in 100,000 in the general population. It typically commences at puberty and progresses to the third or fourth decade of life at which time progression slows and often stops. It may occur in one eye initially but commonly affects both eyes, with one eye being more severely affected than the other. Both sexes are equally affected. The goals of management of keratoconus are to prevent progression of ectasia, improve refractive error and aberrations, correct ectasia, and restore the normal prolate shape of the cornea. Keratoconus management varies depending on the disease severity. Soft lenses or soft toric contact lenses may be adequate early in the disease to correct both myopia and regular astigmatism. As the disease progresses, rigid gas-permeable (RGP) lenses or various specialized lenses, may be required. Intrastromal Corneal Rings Segments (ICRS) implantation surgery is one of the alternate options for regularization of the cornea. It aims to induce a geometric change in the central corneal curvature, thus, reducing the refractive error and flattening of the cornea, and tends to preserve corneal asphericity without removing tissue or contact with the cornea center. When the advanced stage is reached, the only treatment option is corneal transplantation. |