A 23 year old girl presented with the complaint that her soft contact lenses, bought only 6 months back, were causing blurring of vision. VA was 6/18 in one eye with refraction of - 7.0/+3.5 X145.

Nuclear cataract and a dry eye is unlikely to occur in a 23 year old, as it is mostly seen in old people. Irregular astigmatism usually occurs in conditions leading to scarring of cornea and there is no such history given. The girl is suffering from keratoconus which can no longer be controlled by soft contact lenses. Keratoconus is more commonly seen in female patient and refers to abnormal protrusion of cornea. * Clinical features: Patient presents with a defective vision due to progressive myopia and irregular astigmatism, which does not improve fully despite full correction with glasses. * Signs. Following signs may be elicited: Window reflex is distoed. Placido disc examination shows irregularity of the circles . Keratometry depicts extreme malalignment of mires. Photokeratoscopy reveals distoion of circles. Slit lamp examination may show thinning and ectasia of central cornea, opacity at the apex and Fleischer's ring at the base of cone, folds in Descemet's and Bowman's membranes. Very fine, veical, deep stromal striae (Vogt lines) which disappear with external pressure on the globe are peculiar feature. On retinoscopy a yawning reflex (scissor reflex) and high oblique or irregular astigmatism is obtained. On distant direct ophthalmoscopy an annular dark shadow (due to total internal reflection of light) is seen which separates the central and peripheral areas of cornea (oil droplet reflex). Munson's sign, i.e. localised bulging of lower lid when patient looks down is positive in late stages.