KERATOCONUSKERATOCONUSLusy AlwiLusy Alwi(from Greek:(from Greek: kerato- kerato- horn, cornea; andhorn, cornea; and konos, konos, cone), is acone), is a degenerative disorder of the eye in which structural changes withindegenerative disorder of the eye in which structural changes within the cornea cause it to thin and change to a more conical shape thanthe cornea cause it to thin and change to a more conical shape than its normal gradual curve its normal gradual curve Keratoconus can cause substantial Keratoconus can cause substantial distortion of distortion of visionvision and augmented and augmented sensitivity to lightsensitivity to light..It is typically diagnosed in It is typically diagnosed in adolescentadolescent years.years.The exact The exact causecause of keratoconus is of keratoconus is uncertainuncertain, but has , but has been associated with been associated with detrimental enzyme activitydetrimental enzyme activity within the cornea.within the cornea. genetic linkgenetic link seems likely, as the incidence rate is seems likely, as the incidence rate is greater if a family member has been diagnosed.greater if a family member has been diagnosed.The progression of keratoconus is rapid in patients The progression of keratoconus is rapid in patients having having !own syndrome!own syndromeIncidence" Incidence" # in $%%# in $%%& & mean incidence rate of '.% mean incidence rate of '.% new new casescases per #%%,%%% population per yearper #%%,%%% population per year(rocollagen)ollagen fibrils)ollagen*ung, +" , -iomed .ater /es 01"1'23145,'%%46corneal thinning and ectasia is the result of an interlamellar and an interfibrillar slippage of collagen within the stroma, due to a loss of cohesion between collagen fibrils and the noncollagenous matrix..eek K., Tuft *,, +uang 7 et al. Changes in collagen orientation and distribution inkeratoconus corneas. Invest 8phthalmol 9is *ci '%%$&10"#:153$0)ollagen altered metabolism ed organization )ollagen altered metabolism ed organization ;.aatta et al, )ornea '%%0 )8ye /es '%%# )8xp 8phthalmol. #::%6!ecreased metabolic activity of keratocytes"!ecreased metabolic activity of keratocytes"proteins syntesis or degradation proteins syntesis or degradation ;7ue -.7.;7ue -.7. RNARNA metabolism in cultures of corneal stromal cells from patients with keratoconus metabolism in cultures of corneal stromal cells from patients with keratoconus, (roc *oc >xp, (roc *oc >xp -iol .ed #:5$6 -iol .ed #:5$6ugmented collagenolytic activity of ugmented collagenolytic activity of proteases ;..(', )athepsin - e B6proteases ;..(', )athepsin - e B6 ;)ollier *..;)ollier *.. Expression of membrane-type 1 matrix metalloproteinase!"1-!!#$ and !!#% inExpression of membrane-type 1 matrix metalloproteinase!"1-!!#$ and !!#% in normal and keratoconus corneas normal and keratoconus corneas, )urr >ye /es. '%%%6 ;Chou ye /es. '%%%6 ;Chou