Eye infections and eye diseases

A cataract is a cloudiness in the eye's lens that impairs vision. The cause isn't usually known, although sometimes cataracts can result from exposure to X-rays or strong sunlight, inflammatory eye diseases, or certain medications. Symptoms progressive, painless loss of vision disturbance to bright lights (seeing halos around lights, glare, or scattering of light) Treatment Usually, you can decide when to have a cataract surgically removed.

A stye is an infection of one or more of the glands at the edge of the eyelid or under it. It is usually caused by one of the group of bacteria called Staphylococcus.

Orbital cellulitis is an infection of the tissues around the eyeball. The infection may spread from the sinuses, teeth, or bloodstream, or it may develop after an eye injury. Symptoms extreme pain bulging eyes reduced eye movement swollen eyelids Complications If not adequately treated, orbital cellulitis can lead to blindness, infection of the brain and spinal cord, or blood clots in the brain.

Conjunctivitis is an inflammation of the conjunctiva, which is a thin, transparent membrane that lines the eyelids and portions of the underlying eyeball. Conjunctivitis is usually caused by viruses, bacteria, or allergies.

Glaucoma is a term used to describe a number of diseases of the human eye, all of which have different causes and treatments. Unfortunately, the onset of glaucoma rarely has any warning signs. Yet it is estimated that 4 million Americans have glaucoma and 14 million people worldwide have glaucoma. At least half these people are unaware they have glaucoma. In fact, untreated glaucoma is a leading cause of irreversible blindness.

The front of the eye is a D-shaped chamber in which the lens and iris (the coloured part) make up the straight wall, while the cornea (the surface of the eye) forms the curved wall. A gland behind the upper eyelid fills this chamber with a clear liquid (aqueous humour) that supplies the front of the eye with oxygen and nutrients and keeps it inflated. A steady supply of liquid is produced, and it drains out through a mesh of tiny holes behind the lower eyelid, called the trabecular meshwork.

Because glaucoma is really a number of different disorders and affects everybody differently, there is no singular definitive treatment. The purpose of glaucoma treatments is ultimately the same in every case and that is to prevent the deterioration of the optic disc and preserve normal vision. This is achieved by lowering the intraocular pressure.

A basic eye examination There are many tools that eye doctors use for diagnosing glaucoma, including the most basic - the eye chart - which tests the sharpness of your central vision. Your pupils will also be tested to see if your pupils react normally and equally to light stimulation. This is done by shining a bright light in your eyes.

In the absence of a cure for glaucoma, eye drops and pills are used to control its progress. All glaucoma medications do either one of two things: decrease the flow or production of aqueous humour (the fluid in the eye), or increase the outflow or drainage of aqueous humour

Frequently asked questions about glaucoma

Glaucoma is usually categorized as open- or closed-angle glaucoma, and then subdivided into primary or secondary open- or closed-angle glaucoma. Most people with glaucoma have the type known as chronic open-angle glaucoma, which demonstrates virtually no detectable symptoms early on. In fact, most types of glaucoma don't have any symptoms, so you would not expect to be aware of any eye problems, however, some more unusual types of glaucoma, which begin with rapid high elevation of intraocular pressure, are associated with eye pain or headache, blurred vision with the appearance of colored halos around lights, or occasionally, redness of the whites of the eyes.