When tissue thins or deteriorates in the center of the retina, in an area known as the macula, the condition is called dry macular degeneration. Wet macular degeneration occurs when abnormal blood vessels leak under the macula causing it to become distorted. Both types degrade central vision.

In people with diabetes, abnormal blood vessels may develop and rupture in the viscous material that fills the back of the eye. The leaking of blood and fluid obscures vision.

Dry eye is a condition that occurs when the eye does not produce the normal volume of lubricating tears. Symptoms include over-production of non-lubricating tears.


Flashes and floaters are shadows cast by tissue strands and clumps in the vitreous, the gel-like substance that fills the back of the eye. In youth, these objects are stationary. With age, the vitreous becomes more fluid and the strands and clumps begin to move around causing shadows on the retina.

Keratoconus is a weakening and thinning of the central cornea.
Fuchs' endothelial dystrophy is an inherited abnormality of the endothelium, the inner cell layer of the cornea. A normal endothelium pumps fluids out of the cornea, keeping it clear. An abnormal endothelium causes swelling, leading to a cloudy cornea and decreased vision.
Bullous keratopathy is a condition in which the endothelium has been damaged and no longer pumps fluids out of the corneal tissue. The result is a permanently swollen cornea.

Corneal abrasions are scratches in the epithelium, the thin, outer layer of the cornea.

Corneal abrasions are sometimes deep enough to allow microorganisms to reach the layer beneath the epithelium, called the stroma and cause a corneal ulcer.

Pink eye is also known as conjunctivitis and is the inflammation of the conjunctiva, the transparent membrane that lines the inside of the eyelid and the outside of the eye. Pink eye caused by bacteria is highly contagious.