Cornea is the clear, transparent, outer layer of the eye with smooth shining surface having 5 layers and is avascular. Diseases of the cornea include inflammations, degenerations, ectasis and pigmentations. Purulent keratitis is due to exogenous infection by bacteria. It can result in corneal opacity, ectatic cicatrix, desmetocele or perforation which is of extreme danger to sight. Corneal ulcer is treated mainly with antibiotics and atropine along with supportive treatment. Non-healing ulcers may be due to local or systemic causes and may require cauterization, paracentesis, tarsorrhaphy or keratoplasty. Perforated ulcers require intensive management in the form of bed rest, tissue adhesives, soft contact lenses or therapeutic keratoplasty. In hypopyon ulcer, pus is usually sterile. Fungal corneal ulcer is usually due to injury by vegetable matter. The symptoms are less marked than in bacterial ulcer. Non purulent keratitis may be due to herpes simplex or herpes zoster. Acanthamoeba keratitis usually occurs in contact lens wearers. Phlyctenular keratitis is an allergic reaction to endogenous allergen. Cornea may be involved in degenerations which may be central or peripheral. Dystrophies of the cornea may be anterior, stromal or posterior. Keratoconus is an ectatic condition of the cornea. Keratoplasty or corneal transplantation may be optical, therapeutic, structural or cosmetic. Stem cell transplantation is done in conditions of corneal damage like chemical burns, and Stevens-Johnson syndrome. Eye bank collects and stores good quality donor cornea and makes it available for transplantation.