Cataract
 

Eyes works as a camera. Light rays are focused on the retina with the help of the crystalline lens of the eye. Over a period of time the lens becomes hazy and starts loosing its transparency. This opacified or hazy crystalline lens is called Cataract.

 
   
  Glaucoma
  Glaucoma is disease wherein the pressure inside the eye gradually increases to a level which is sensitive to the tissue of the eye. The optic nerve, the main nerve of the eye which carries visual signals to the brain (similar to a cable wire) gets damaged. Such damage is irreparable so visual loss due glaucoma is irreversible.
 
   
  Dacryocystitis
 

Tears from the eyes are drained by a system called lacrimal apertures. Tears from the eyes flow in to nasolacrimal duct which opens in to nose.