Myopia
It is also known as Nearsightedness or Shortsightedness. It is a condition in which the affected person can see nearby objects but is unable to see far away objects. It occurs when the eyeball is too long, relative to the focusing power of the cornea and lens of the eye. This causes light rays to focus at a point in front of the retina, rather than directly on its surface. It is corrected by using concave lenses
Hypermetropia
Also known as Longsightedness, it is condition in which the affected person can see distant objects but is unable to see nearby objects. It is corrected using convex lens. Both Myopia and Hypermetropia are types of refractive errors of the eye.
Amblyopia
Also known as Lazy Eye, it is the loss of ability to see properly with one eye. Though the affected eye itself looks normal, it is not being used normally because the brain is favouring the other eye. One of the causes of amblyopia may be Strabismus.
Presbyopia
Presbyopia is an age-related eye disorder in which the eye is not able to focus light directly on to the retina due to the hardening of the natural lens. The ineffective lens causes light to focus behind the retina, causing poor vision for objects that are up close.
Glaucoma
Glaucoma refers to a group of related eye disorders that all cause damage to the optic nerve that carries information from the eye to the brain. Glaucoma usually has few or no initial symptoms. There is no cure for glaucoma and the vision lost cannot be recovered.
Achromatopsia
Also known as Colour Blindness or Colour Vision Deficiency (CVD), it is the decreased ability to see colour or differences in colour. The condition is genetic and the genes responsible for it are on the X chromosome. Hence more men are likely to be colour blind than women. The condition is diagnosed using the Isihara Colour Test. Other types of colour blindness - Protanopia or red-blind, Deuteranopia or green-blind, Tritanopia or blue-blind
Cataract
A cataract is a clouding of the eye's natural lens, which lies behind the iris and the pupil. The lens gets clouded due to protein present in it gets clumped together. Surgery replacing the natural lens with an artificial one can treat cataract.
Strabismus
Commonly known as crossed-eyes. It is a disorder in which both eyes do not line up in the same direction, so they do not look at the same object at the same time. The condition is caused when the muscles controlling the eye do not function together.