Retinal vascular occlusions may involve both arteries and veins. Far more common are retinal vein occlusions. They occur when a retinal vein becomes obstructed by an adjacent blood vessel. This causes hemorrhage in the retina, which can result in swelling and lack of oxygen to the retina and sometimes

Uveitis is an inflammation of the eye's structures responsible for its blood supply. The structures, called the uveal tract, include the iris, ciliary body and choroid. There are three major types of uveitis, each classified by the structures it affects. 1. Anterior uveitis (also known as iridocyclitis)

One of the causes of a red eye is subconjunctival hemorrhage. This happens when a small blood vessel under the conjunctiva breaks and bleeds. A red patch of blood appears on the white of the eye, but causes no pain or change in vision. In some cases, the hemorrhage is caused by coughing, heaving lifting

Presbyopia is a difficulty in focusing that many people begin noticing after age 40. Most people first notice difficulty in reading very fine print. Print seems to have less contrast and a brighter, more direct light is needed for reading. In many cases, patients begin holding reading material further

Keratoconus is a degenerative disease of the cornea that causes it to gradually thin and bulge into a cone-like shape. This shape prevents light from focusing precisely on the macula. As the disease progresses, the shape becomes more pronounced, causing blurred or distorted vision. Patients with keratoconus

Nearsightedness occurs when light entering the eye focuses in front of the retina instead of directly on it. This is caused by a cornea that is steeper, or an eye that is longer, than a normal eye. Nearsightedness causes difficulty seeing at a distance. It is often discovered in school-age children who

Blepharitis is a common inflammatory condition that causes burning, itching and irritation of the eyelids. In severe cases, it may also cause styes and irritation or inflammation of the cornea (keratitis) or conjunctiva (conjunctivitis). Blepharitis is characterized by sandy, itchy eyes, red or swollen

Glaucoma is a disease caused by increased intraocular pressure (IOP) resulting either from an overproduction of fluid or from a malfunction of the eye's drainage structures. Left untreated, an elevated IOP causes irreversible damage to the optic nerve and retinal fibers, which leads to progressive and

If you see black spots or spider webs that seem to float in a cluster or singly in your vision, or if you see spots that move or remain suspended in one place, or flickering or flashing lights that are most prominent when you look at a bright background, then you have experienced floaters and flashes.

Patients with diabetes are more likely to develop eye problems such as cataracts and glaucoma, but the disease's effect on the retina is the main threat to vision. Over time, diabetes affects the circulatory system of the retina, and this effect is called diabetic retinopathy. In its earliest phase,

Farsightedness occurs when light entering the eye focuses behind the retina instead of directly on it. This is caused by a cornea that is flatter, or an eye that is shorter, than a normal eye. Farsightedness causes difficulty seeing up close. Symptoms of farsightedness include blurred distance vision,

Strabismus is caused by one or more eye muscles functioning improperly, resulting in a misalignment of the eyes. Each eye has six muscles that work in unison to control movements. The brain controls the eye muscles to keep the eyes properly aligned. These muscles must function together for the brain

A cataract is a clouding of the natural lens, the part of the eye responsible for focusing light and producing clear, sharp images. The lens is contained in a sealed bag or capsule. As old lens cells die, they become trapped within the capsule. Over time, the cells accumulate, causing the lens to cloud

Color vision deficiency is a term that is used to describe one of a number of hereditary or acquired color vision problems. The inherited form is the most common deficiency. It affects both eyes and does not worsen over time. This type of color vision deficiency occurs more in males than in females.

Astigmatism often refers to a cornea that is oval in shape, rather than round shaped. The oval shape of the cornea causes light to focus on more than one point in the eye, resulting in blurred vision. Astigmatism typically occurs along with nearsightedness and farsightedness. Astigmatism can easily be

Age-related macular degeneration (AMD) is the most common cause of blindness in individuals age 65 and older in the western world. It results from a hardening of the arteries that nourish the retina affecting the macula, part of the retina that is responsible for clear vision. Deprived of oxygen and