A cataract is a clouding of the lens in the eye leading to a decrease in vision. They may affect one or both eyes. Often they develop slowly.

Keratoconjunctivitis sicca (KCS), also called dry eye syndrome or keratitis sicca, is an eye disease caused by eye dryness.

Conjunctivitis, also known as pink eye or Madras eye is inflammation of the conjunctiva. It is commonly due to an infection or an allergic reaction.

Bacterial conjunctivitis causes the rapid onset of conjunctival redness, swelling of the eyelid, and mucopurulent discharge. Typically, symptoms develop first in one eye, but may spread to the other eye within 2–5 days.

Allergic conjunctivitis is inflammation of the conjunctiva (the membrane covering the white part of the eye) due to allergy. Allergens differ among patients. Symptoms consist of redness (mainly due to vasodilation of the peripheral small blood vessels), oedema (swelling) of the conjunctiva, itching, and increased lacrimation (production of tears).