The visible eye represents only about one tenth of the surface of the entire eyeball. The eyelids act as protective covers for the eye. Ocular muscles open and close the lids. The lid margins and eyelashes are lubricated by small glands called the meibomian glands located on the surface of the lid margin. The exposed surface of the eye is lined with a transparent mucous membrane called the conjunctiva. It has a watery fluid, tears, produced by the lacrimal glands. Tears lubricate the eye and wash away foreign bodies.
Ptosis (pronounced toe-sis) is a pathologic drooping of the upper eyelid so it partially or completely covers the eye. This is related to a weakness of the muscle(s) that raise the lid. It is often present at birth and has a familial tendency. At any age, if the nerve that controls the lid muscle is damaged, (diabetes, brain tumor, muscular dystrophy, myasthenia gravis) ptosis may result. Ptosis is correctable with surgery.
Sty. Like all hair, eyelashes grow from follicles (depressions in the skin). Commonly a follicle may become infected and create a boil on the lid margin. This is a “sty.” Eventually, the sty bursts and drains itself of the pus.
Chalazions, papillomas, xanthelasma, angioma, and basal cell carcinoma. These conditions all result in “lumps” on the eyelid. A chalazion (kuh-laze-ee-on) is a painless swelling on the lid margin caused by blockage of one of the meibomian glands. These generally just disappear within a month or two. Larger ones (up to the size of a small pea) do not disappear spontaneously and are often treated surgically. An incision is made in the eyelid and the chalazion contents are removed. A papilloma is a harmless outgrowth of skin, colored pink to black anywhere on the eyelid or lid margin. It may also be removed surgically. In xanthelasma (zan-thuhl-az-muh), yellow patches of fatty material accumulate beneath the outer skin of the lid, mostly near the nose.
Entropion. This is a condition where the lid margin (most often the lower lid) turns inward so the lashes rub the surface of the eyeball causing irritation and conjunctivitis and even corneal ulcers, eventually affecting vision. As people age, the fibrous tissue on the lower lids becomes more lax allowing the muscle in the lid margin to contract excessively.
Ectropion. In this condition, the lower lid of the eye hangs away from the eyeball. Notice it is the opposite of entropion. This creates dryness and soreness of the lid. It also prevents the tears from doing their job. This condition is also treated with surgery.
Blepharitis, is an inflammation of the lid margin causing persistent redness and scaliness of the skin margins. The disorder is usually a form of sebhorrheic (seb-or-ee-ick) eczema.
Dry eye is due to a deficiency of tear production by the lacrimal glands. It is seen often in patients with rheumatoid arthritis. Artificial tears are used to treat, and hot packs increase the meibomian oil production, which tends to keep the moisture in the eye in place.
Corneal ulcers and infections. The cornea is the transparent section of the eye’s outer covering at the very front of the eye. It is most susceptible to injury and infection. An ulcer may form and is usually the result of a foreign body or striking or scratching the cornea. The ulcer becomes infected by bacteria, viruses or fungi. Most often it is a virus, usually Herpes simplex.
Conjunctivitis is an inflammation of the conjunctiva (the transparent membrane lining the eyelids and outer eye up to the edge of the cornea). It is caused by an infection, allergy, or incompletely opened tear ducts. Infants in transit in the birth canal can get infected, the condition known as ophthalmia neonatorum. In serious cases of conjunctivitis, antibiotic drops or ointment may be prescribed. This condition is also commonly referred to as Pink Eye.
Episcleritis is a condition in the transparent tissue (episclera surrounding the eyeball). Occasionally, the tiny blood vessels in the episclera become inflamed for no apparent reason. It usually disappears by itself, but sometimes steroids are prescribed to hasten the process.
Scleritis, an inflammation of the sclera (outermost layer of tissue covering the eyeball, known as the “white of the eye”), can affect one or both eyes. It is a rare disorder but can be quite serious. Anti-inflammatory drugs (steroids, etc.) are used either in tablet form or in eyedrops, along with immunosuppressive drugs.
Iritis is inflammation of the iris (the part of the eye that shows the color), and sometimes of the ciliary body (behind the iris). Microscopic white cells from the inflamed area and excess protein leak from the small blood vessels inside the eye in the “aqueous humor,” the fluid behind the iris and cornea. The condition may set up a serious blockage and can cause glaucoma and if longstanding, cataracts. Eyedrops are used to treat.
Cataract is an opaque (cloudy) area that occurs in the normally clear lens of the eye. Over a period of years, the cataract blocks or distorts light entering the eye and reduces vision. When severe enough, surgery is often done. The operation entails removal of the lens. Removal makes the eye very farsighted, thus eyeglasses or a plastic lens implant is done.
Glaucoma is a serious disorder where the ciliary body in the eye constantly produces a fluid (aqueous humor) which circulates from behind the iris, through the pupil, and into the chamber between the iris and cornea. In a healthy eye, the fluid drains away. If it does not drain, it increases the pressure in the eye. Part of the extra pressure is created into the vitreous humor, the jelly-like fluid filling the eyeball. This pressure causes collapse of tiny blood vessels feeding the fibers of the optic nerve, extremely important in vision. When the nerves are denied the essential nutrients, the cells and nerve fibers begin to die and vision fades. This damage is usually permanent. Treatment with eyedrops is provided to encourage the iris to withdraw from the drainage angle. Dehydrating or drying agents are also used. After eye pressure is decreased, an operation called an “iridectomy” may be performed (often done with a laser beam). A tiny artificial channel is made to create drainage.
Macular degeneration. The macula, the area of the retina near the optic nerve at the back of the eye, is the anatomic feature that distinguishes fine detail at the center of the field of vision. As the eye ages, small blood vessels become constricted or narrowed and hardened, so the macula doesn’t get enough blood supply. This deficiency causes degeneration with blurring of vision. Usually both eyes are affected. Most cases are not treatable with traditional medicine.
Diabetic retinopathy occurs when the small blood vessels serving the retina (at the back of the eyeball) become constricted and die. Remaining vessels often leak blood into the retina and cause permanent reduction of vision. Treatment is usually effective using a laser beam on the leaking blood vessels. Sometimes drainage of the vitreous humor is done too.
Retinal detachment occurs when the retina (delicate layer of light-sensitive cells lining the eyeball) lifts away from the choroid (core-oyd). A hole occurs in most cases, causing the detachment. The hole (preceding detachment) may be treated surgically, sealing it, which is done by freezing or laser. If detachment has begun, the vitreous humor is drained away allowing the retina to sink back against the choroid and regain its blood supply, then the hole is sealed.
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Choroiditis – inflammation of the choroids (kore-oyd)
Optic neuritis – optic nerve inflammation
Exopthalmos (ex-op-thal-mose) is a bulging of one or both eyeballs.