Keratoconus is a non - inflammatory, progressive condition where the central or paracentral cornea undergoes progressive thinning and steepening causing irregular astigmatism and a ‘cone shaped’ cornea.
𝐄𝐱𝐭𝐞𝐫𝐧𝐚𝐥 𝐬𝐢𝐠𝐧𝐬 𝐨𝐟 𝐊𝐞𝐫𝐚𝐭𝐨𝐜𝐨𝐧𝐮𝐬
V shaped conformation of lower lid produced by the ectatic cornea in downgaze
Sharply focused beam of light near the nasal limbus produced by lateral illumination of the cornea
Other external signs :
Charleux sign: Dark reflex in centre of cornea with distant direct ophthalmoscope in dilated pupils
Scissoring reflex on retinoscopy
Image from Rajan Eye Care Hospital