What is this condition?

Uveitis is an inflammation of one uveal tract of the eye. (The uveal tract consists of the iris, choroid, and related tissue structures.) The disorder occurs as anterior uveitis, which affects the iris (iritis) or both the iris and the ciliary body (iridocyclitis); as posterior uveitis, which affects the choroid (choroiditis) or both the choroid and the retina (chorioretinitis); or as panuveitis, which affects the entire uveal tract.

Untreated anterior uveitis progresses to posterior uveitis, causing scarring, cataracts, and glaucoma. With immediate treatment, anterior uveitis usually subsides after a few days to several weeks; however, recurrence is likely. Posterior uveitis generally causes some residual vision loss and markedly blurred vision.
What causes it?

In most cases, the cause of uveitis is unknown. But it can result from allergy, bacteria, viruses, fungi, chemicals, traumatic injury, surgery, or systemic diseases, such as rheumatoid arthritis, ankylosing spondylitis, and toxoplasmosis.
What are its symptoms?

Anterior uveitis produces moderate to severe pain in one eye; severe ciliary congestion; sensitivity to light; tearing; a small, nonreactive pupil; and blurred vision. Posterior uveitis begins insidiously, with complaints of slightly decreased or blurred vision or floating spots. Pain and sensitivity to light may also occur.
How is it diagnosed?

In anterior and posterior uveitis, a slit-lamp exam shows a “flare and cell” pattern, which looks like light passing through smoke. It also shows an increased number of cells over the inflamed area. With a special lens, the doctor can also use slit-lamp and ophthalmoscopic exams to identifY active inflammatory fundus lesions involving the retina or choroid.

In posterior uveitis, serologic tests can reveal if toxoplasmosis is the cause.
How is it Treated?

Uveitis requires vigorous and prompt management, which includes treatment of any known underlying cause and application of eye­drops or ointment, such as 1 % Atropisol or steroids. For severe uveitis, therapy includes oral steroids. However, long-term steroid therapy can cause increased intraocular pressure and increased risk of cataracts.

The bony orbit in which the eyeball lies is lined with soft tissue. In rare cases, bacteria enter the tissue, usually from infected sinuses in the nose , or from a boil near the eye, and cause an inflammation. This is called orbital cellulitis.The pressure of the swollen tissue pushes the eyeball forward, giving your eye a staring appearance . Other symptoms are severe pain and redness in the eye, swollen eyelids that you may not be able to close, and usually a fever.

In rare cases the eye exudes pus. The condition often resembles conjunctivitis. If there is pressure on the blood vessels that supply the eye, you may temporarily lose some vision. There is also a slight risk that the infection may spread to the brain and cause meningitis .

Treatment consists of high doses of antibiotics, given as tablets or by injection. If infected sinuses are the source of the problem, you may need an operation to have them drained to prevent cellulitis from recurring .

The way that light from objects is focused through the eye into an image on the retina is called refraction. In a normal eye, the point where the light focuses is exactly at the retina, and it is this precise focusing that assures that a clear image is seen. In some eyes, however, the eye focuses the light either behind or in front of the retina, so that the image is blurred.The four most common disorders of refraction are nearsightedness (myopia), farsightedness (hypermetropia), astigmatism and presbyopia. Any of these disorders can be present in one or both eyes.

Acute otitis media is an infection, usually caused by a virus, but sometimes caused by bacteria, which inflames the cells lining the middle ear cavity. The disorder often develops when viruses from an infection of the nose and throat, such as a cold or measles, travel along the eustachian, or auditory, tube to the middle ear. Infection may also enter through a ruptured eardrum . The disorder is often associated with nasal allergy .

Middle ear infections occur often in children. At least half of them have an infected middle ear at some time, and often, repeated attacks of the problem occur.

What are the Symptoms?

There is usually a feeling of fullness in the ear, followed by severe stabbing pain. This pain may prevent sleep and many other normal activities if it is severe and persistent enough. Other symptoms are fever, and hearing loss in the affected ear. If the infection is caused by bacteria and is not treated, the pressure of pus within the middle ear may eventually burst the eardrum. This produces a pus discharge that is accompanied by sudden relief from the pain. If the infection is caused by a virus, the symptoms are similar, but the problem will usually clear up by itself without bursting the eardrum.

What should be done?

You should see your physician for treatment as soon as possible.

What is the Treatment?

Self-help: To provide some relief from pain, take aspirin and place an electric heating pad on the low temperature setting against the ear. Do not sleep with the heating pad under you. Carefully clean any pus off the pad after use to avoid re-infection.

Professional help: Your physician may pre­scribe drugs to help unblock the eustachian tube and clear up the infection.

If your eardrum is bulging, the physician may make a small cut, or myringotomy, in it to relieve the pressure and the pain. If the patient is a child, this may be done in a hospital, with a general anesthetic. The eardrum heals naturally in one to two weeks. Be sure to consult your physician before you stop any treatment. It may take as long as six weeks for the infection to clear up completely.

If a child has repeated middle ear infections, the adenoids may be acting as a reservoir of infection. In such cases, the doctor may suggest that the adenoids be removed. Persistent sinusitis also often leads to middle ear infection.

Your doctor will be able to determine if the middle ear infection has spread to the mastoid process, perhaps requiring a mastoidectomy operation.

Eye Disorders – Introduction

Sight is the most important of the five main senses. Your eyes tell you much more than your other senses do, and the part of the brain that deals with sight is far larger than the parts that deal with the other senses.

The eye is a complex, intricate, and fairly delicate structure . Each eyeball is a sphere about 25 mm (1 in) in diameter. Three concentric layers of tissue cover the eyeball. The tough outermost layer is the sclera, which is visible as the white of the eye. Its exposed surface at the front of the eye has a transparent covering, the conjunctiva, which also lines the inner surface of the eyelids. At the front of the eye, the sclera and conjunctiva join the cornea, a dome-shaped structure sometimes called the “window” of the eye.

Beneath the sclera is the choroid, a layer rich in blood vessels that supply the eye tissues with oxygen and nutrients. Toward the front of the eye, this layer thickens to form the ciliary body. From the front of the ciliary body extends a circular area of fibers, the iris, which varies in color from person to person and determines eye-color. In the center of the iris is an opening, the pupil, which looks like a black disc. Through this opening, light enters the eye. The amount of light is controlled by the contraction or dilation (widening) of the pupil. This adjustment is regulated by the muscles of the iris.

Immediately behind the iris and pupil is a transparent elastic body, the crystalline lens, which is attached to the ciliary body. Muscles thicken or narrow the lens, enabling the eye to focus on objects at varying distances. The space between the cornea and the lens is filled with a watery substance called aqueous humor. Behind the lens is a jelly-like substance called the vitreous humor, which makes up the bulk of the eyeball.

The innermost layer, the retina, lines the rear three­quarters of the eyeball. The retina includes a layer of light-sensitive nerve cells that are called the rods and cones because of their shapes. Light passes through the pupil and lens to the retina in such a way as to form an upside-down image of whatever you are looking at. The rods are very sensitive to light intensity and enable you to see in dim light. The cones detect color and fine detail.

There are 125 million rods and 7 million cones in each eye. Between them, the rods and cones transform the sensations of color, form and light intensity that they receive into nerve impulses. These impulses are then transmitted along retinal nerve fibers to the optic nerve, a stalk-like collection of nerves that connect the rear of the retina to the brain. The brain interprets the impulses received from each eye, reverses the images, and integrates them into one three-dimensional image.

The eye disorders covered in this section are dealt with in four groups. The first consists of errors of refraction such as problems of nearsightedness and farsightedness. The second group is concerned with disorders of those parts of the eye that you can see, mainly the eyelids, eyelashes, sclera, iris and lens. The third group deals with two forms of glaucoma, a disease that arises from a problem with drainage of aqueous humor. The final group is concerned with disorders that affect the structures in the inner layer of the eye, including the retina and its blood supply. The muscles and other tissues that surround the eyeball in its bony socket, which is known as the orbit, are also covered in this section.