THE USES OF CORNEAL TOPOGRAPHY IN THE ANALYSIS OF KERATOCONUS

Abstract

Keratoconus is a condition in which the cornea assumes a conical shape, as a result of non inflammatory thinning of the corneal stroma. The corneal thinning induces irregular astigmatism, myopia, and protrusion, leading to mild to marked impairment in the quality of vision. It has Incidence of approximately 1 in 2000 in the general population. Keratoconus, classically, has its onset at puberty and is progressive until the third to fourth decade of life, when it usually arrests. Keratoconus has a disproportionate impact on the quality of life, and causes significant loss of productivity as it is a disease of young. Despite extensive investigations, the etiology and underlying mechanism of stromal thinning in keratoconus is not understood. Etiology is most likely multifactorial. A positive family history has been reported in 6-8% of the cases and its prevalence in first-degree relatives is 15-67-times higher than the general population. It is most commonly an isolated condition, despite positive association between keratoconus and many conditions has been suggested, including atopy, eye rubbing, contact lens wear, handedness, cardiovascular disease (especially mitral valve prolapse), ocular trauma, collagen vascular disorders, pigmentary retinopathy, Marfan’s syndrome, and Down’s syndrome. The treatment of keratoconus depends on the severity of the disease. Rigid contact lenses are the principal optical means for managing visual impairment produced by keratoconus in early stage of disease. In advanced cases with severe corneal irregular astigmatism and stromal opacities penetrating keratoplasty (PKP) may be required to restore visual function. Several devices are available for detecting keratoconus by measuring anterior corneal topography. These range from simple inexpensive devices, to expensive sophisticated devices.