Eye Health: Introduction, Symptoms, Conditions & Treatment.

Introduction

They say the eyes are the windows to the soul. We don't know if that's true, but what we do know that having perfectly healthy eyes—excellent vision and clear eyes, free of pain or other symptoms—are crucial to your health and well-being. The good news is that it's easy to learn more about eye problems, symptoms, and the treatments that will keep you in tip-top shape.

About 21 million Americans have some type of vision problem, according to a survey conducted by the Centers for Disease Control and Prevention (CDC). While many of these problems are relatively benign, such as mild nearsightedness, other eye conditions like glaucoma and age-related macular degeneration can trigger vision loss and even blindness.

Symptoms of eye disease

In some cases, the symptoms of certain eye diseases can overlap with others. For example, watery eyes could be a sign of pink eye (conjunctivitis), allergies, or a sty; likewise, light sensitivity could indicate a cataract, migraine, or chalazion (a bump on the eyelid). Resting your eyes might help ease symptoms, but in general, if you’re experiencing severe or lasting pain, you should call a doctor right away.

Below, some of the most common symptoms of eye diseases:

• Blurriness
• Discharge
• Flashes of light
• Irritation
• Light sensitivity
• Pain
• Tearing
• Vision loss

What should patients expect during an eye examination?

Routine eye exams today often use state-of-the-art technology to examine all portions of the eye in order to both determine the eye's refractive state (whether or not glasses are necessary) and allow the diagnosis of certain eye diseases, such as macular degeneration and other retinal diseases, cataracts, glaucoma, and diabetic changes in the eye. Vision problems may be due to either a need for glasses or a disease of the eyes. Your eye care provider will determine the cause of any vision loss and evaluate your eye health. A prescription for glasses will be provided if needed. Contact lenses or refractive surgery, such as LASIK, may be discussed. If eyeglasses are prescribed, an optician will fit you for eyeglass frames and order the appropriate lenses, which may be for distance or near or may be for both, as in a bifocal or multifocal glass.

What common eye conditions usually require treatment by an ophthalmologist?

Trauma: Blunt trauma to the eye requires immediate evaluation by an ophthalmologist. Trauma to the eye can cause bleeding into the eye from ruptured blood vessels or result in structural ocular alterations that may cause detachment of the retina. Any of these situations can seriously impair vision.

Abrasion: An abrasion usually occurs when a fingernail or other foreign object rubs across the cornea or conjunctiva and removes some surface tissue. There is a risk of bacterial or fungal contamination and infection following an eye abrasion.

Chemical exposure: Exposure of the eye to household cleaning solutions, fumes, or an actual chemical splash requires immediate evaluation by a physician, though initially it may be self-treated with water or another irrigant.

Keratitis: Keratitis is an inflammation of the cornea that may occur alone or simultaneously with conjunctivitis. This inflammation may be infectious (resulting from a virus, bacteria, fungus, or parasite) or noninfectious in origin. The symptoms of keratitis include blurred vision, pain, and intolerance to light (photophobia). It also may be due to contact lens overwear.

Corneal swelling: Corneal swelling, or edema, is a condition in which excess fluid accumulates within the cornea. The edema causes visual disturbances such as halos or starbursts around lights. Reduced vision may or may not occur. Corneal swelling can arise as a complication of contact lenses, trauma, surgical damage to the cornea, elevated intraocular pressure or an inherited defect of the cornea. Hyperosmotic drops or ointment can be used to treat corneal swelling, but additional treatment by a physician is usually necessary.

Uveitis: Uveitis is an inflammation of the eye structures in the uveal tract (the iris and other structures within the eye to which the iris attaches). Uveitis may occur without an obvious cause or may be due to trauma or an inflammatory disease present throughout the body. Symptoms and signs of uveitis include eye pain, tearing, light sensitivity, and visual blurring. Treatment is directed at both the cause of the uveitis and these symptoms.

Acute angle-closure glaucoma: Angle-closure glaucoma is due to an obstruction of the system that drains aqueous fluid from the inside of the eye. As a result, fluid accumulates within the eye and the pressure within the eye increases. Some people have a tendency to develop angle-closure glaucoma because of crowding of the anatomy of the front of their eyes. It is more common in people who are hyperopic (farsighted). This disorder may be triggered after an eye exam in which the pupils have been dilated or by taking certain oral medications in the susceptible individual. Common symptoms include a severe headache or eye pain accompanied by nausea and vomiting. Vision is also usually blurry. Angle-closure glaucoma should be suspected if these symptoms develop after an agent is used to dilate the pupils for an eye exam. Most patients with acute angle-closure glaucoma in one eye are at risk for developing it in the other eye. The treatment of acute angle-closure glaucoma is surgical.

What is the structure of the eye?

The eyes are extremely complex sensory organs. About 85% of the total sensory input to our brains originates from our sense of sight, while merely 15% comes from the other four senses of hearing, smell, touch, and taste. The eyes are designed to optimize unobstructed vision under conditions of varying light. Their location, on the outside of the face, makes them susceptible to trauma, environmental chemicals and particles, and infectious agents. The eyelids and the position of the eye within the bones of the orbital cavity are the major protective mechanisms for the eye.

The eye itself has the shape of a sphere measuring about 1 inch in diameter. It consists of a clear, transparent dome at the front (the cornea) that is surrounded by the white of the eyeball (the sclera). The iris of the eye is the circular, colored portion within the eye. Behind the cornea is located the pupil, which is the central opening within the iris. Behind the iris and pupil is the eye's lens. The space between the back of the cornea and the front of the lens is called the anterior chamber and is filled with a fluid, called the aqueous humor. Behind the lens is a large space that is filled by the transparent vitreous liquid gel. The inside of the back of the eye is lined by the retina, the thin, light-sensitive tissue that changes light images to electrical signals via a chemical reaction. These electrical signals generated by the retina are sent to the brain through the optic nerve. Our brain interprets what our eyes see.

The inner sides of the eyelids, which touch the front surface of surface of the eye, are covered by a thin membrane (the palpebral conjunctiva) that produces mucus to lubricate the eye. This thin membrane folds back on itself and covers the visible sclera of the eyeball. (This continuation of the palpebral conjunctiva is called the bulbar conjunctiva.) Natural oil for the tears is produced by tiny glands located at the edges of the eyelids, providing additional lubrication for the eye. The main component of tears is formed by the lacrimal gland located under the upper lid at the outer corner of each eye. The tears are composed of a combination of the substances produced by the lacrimal gland, the oil glands, and the mucus glands. Tears flow toward the nasal side of the eye and drain into the lacrimal sac, located in the area between the eye and the side of the nose, and then ultimately into the nose.