Ans. a. Calcium (Ref: Parson's 20/e p202; Yanoff's 2/e p449; Kanski 6/e p304-305)Band shaped keratopathy is essentially a degenerative change associated with deposition of calcium salts in Bowman's membrane, most superficial part of stroma and in deeper layers of epithelium.Band Shaped Keratopathy/Calcific band KeratopathyBand shaped keratopathy is essentially a degenerative change associated with deposition of calcium saltsQ in Bowman's membrane, most superficial part of stroma and in deeper layers of epithelium.Causes of Band Shaped KeratopathyIdiopathicChronic Eye Disease (MC)Systemic Conditions associated with hypercalcemiaLocal corneal damage* Idiopathic and age related in otherwise healthy eyes* Chronic uveitis: JRA, Sarcoidosis* Chronic glaucoma* Chronic keratitis* Sarcoidosis* Hyper-parathyroidism* Vitamin D toxicity* Extensive metastatic neoplasm to bone* Chronic renal failure (secondary hyperparathyroidism)* Intraocular silicon oil* Phosphate forms of corticosteroids Comeal PigmentationConditionDeposited MaterialSite of DepositionArgyrosisSilver nitrate (AgNO3)Brown discoloration of Descemet's membraneChalcosis (Kayser Fleisher ring)Copper (Cu)Grayish-green or golden brown discoloration of stroma of peripheral corneaHudson-Stahli lineElderlyBrown horizontal line in inferior third of corneaKrukenberg's spindleMyopic menVertical spindle shaped brown uveal pigment depositionFleisher ringIron (Fe)Epithelial iron deposits at the base of KeratoconusSiderosisFe (hemosiderin)* Green or brown discoloration of deeper layers of cornea* Fleisher's ring representing deposition of hemosiderin is found in KeratoconusStocker's linePterygium Topical epinephrineUsed for glaucomaResult in black corneaWilson's disease (Kayser Fleisher ring)Copper (Cu)Greyish green or brown ring is seen just inside the limbus due to Cu deposition between Descemet's membrane and endothelium