Climatic droplet keratopathy.

Climatic droplet keratopathy (CDK) is a degenerative condition characterized by the accumulation of translucent material in the superficial corneal stroma within the interpalpebral strip, beginning peripherally and spreading centrally. Progressive accumulation in later life can lead to significant visual disability, and people leading an outdoor life are particularly at risk. The translucent corneal deposits are composed of protein, but although they share some of the staining characteristics of degenerated protein, such as that found in pingueculae, their exact histochemical nature remains uncertain. The corneal deposits are thought to be derived from plasma proteins, which diffuse into the normal cornea, and may be photochemically degraded by excessive exposure to ultra-violet light (UV). The degraded protein material may then be deposited in the superficial stroma. UV light is now widely accepted to be the main etiological factor in the pathogenesis of CDK. Sector iridectomy, corneal epithelial debridement, lamellar keratoplasty, and penetrating keratoplasty have all been employed in the treatment of visually incapacitating CDK.