Eye Diseases

Belpharitis - Cataract - Chalazion - Conjunctivitis - Diabetic Retinopathy - Dry Eye - Glaucoma - Keratoconus - Macular Degeneration - Ocular Hypertension - Retinitis Pigmentosa - Retinoblastoma - Spots and Floaters - Strabismus (Crossed Eyes)

 

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Blepharitis

Blepharitis is an inflammation of the eyelids causing red, irritated, itchy eyelids and the formation of dandruff-like scales on eyelashes. It is a common eye disorder caused by either bacterial or a skin condition such as dandruff of the scalp or acne rosacea. It affects people of all ages. Although uncomfortable, blepharitis is not contagious and generally does not cause any permanent damage to eyesight.

Blepharitis is classified into two types:

1. Anterior blepharitis occurs at the outside front edge of the eyelid where the eyelashes are attached.

2. Posterior blepharitis affects the inner edge of the eyelid that comes in contact with the eyeball.

Individuals with blepharitis may experience a gritty or burning sensation in their eyes, excessive tearing, itching, red and swollen eyelids, dry eyes, or crusting of the eyelids. For some people, blepharitis causes only minor irritation and itching. However, it can lead to more severe signs and symptoms such as blurring of vision, missing or misdirected eyelashes, and inflammation of other eye tissue, particularly the cornea.

In many cases, good eyelid hygiene and a regular cleaning routine can control blepharitis. This includes frequent scalp and face washing, using warm compresses to soak the eyelids, and doing eyelid scrubs. In cases where a bacterial infection is the cause, various antibiotics and other medications may be prescribed along with eyelid hygiene.

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Cataract

A cataract is a cloudy or opaque area in the normally clear lens of the eye. Depending upon its size and location, it can interfere with normal vision. Most cataracts develop in people over age 55, but they occasionally occur in infants and young children. Usually cataracts develop in both eyes, but one may be worse than the other.

The lens is located inside the eye behind the iris, the colored part of the eye. The lens focuses light on the back of the eye, the retina. The lens is made of mostly proteins and water. Clouding of the lens occurs due to changes in the proteins and lens fibers.

The lens is composed of layers like an onion. The outermost is the capsule. The layer inside the capsule is the cortex, and the innermost layer is the nucleus. A cataract may develop in any of these areas and is described based on its location in the lens:

• A nuclear cataract is located in the center of the lens. The nucleus tends to darken changing from clear to yellow and sometimes brown.
   

• A cortical cataract affects the layer of the lens surrounding the nucleus. It is identified by its unique wedge or spoke appearance.
   

• A posterior capsular cataract is found in the back outer layer of the lens. This type often develops more rapidly.

The treatment of cataracts is based on the level of visual impairment they cause.

If a cataract affects vision only minimally, or not at all, no treatment may be needed. Patients may be advised to monitor for increased visual symptoms and follow a regular check-up schedule.

In some cases, a change in eyeglass prescription may provide temporary improvement in visual acuity. Increasing the amount of light used when reading may be beneficial. The use of anti-glare coatings on clear lenses can help reduce glare for night driving.

When a cataract progresses to the point that it affects a person's ability to do normal everyday tasks, surgery may be needed. Cataract surgery involves removing the lens of the eye and replacing it with an artificial lens. The artificial lens requires no care and can significantly improve vision. New artificial lens options include those that simulate the natural focusing ability of a young healthy lens.

Two approaches to cataract surgery are generally used:

1. Small incision cataract surgery involves making an incision in the side of the cornea, the clear outer covering of the eye, and inserting a tiny probe into the eye. The probe emits ultrasound waves that soften and break-up the lens so it can be removed by suction. This process is called phacoemulsification.
    

2. Extracapsular surgery requires a somewhat larger incision in the cornea and the lens core is removed in one piece.

Once the natural lens has been removed, it is replaced by a clear plastic lens called an intraocular lens (IOL). For situations where implanting an IOL is not possible because of other eye problems, contact lenses and in some cases eyeglasses may be an option to provide needed vision correction.

As with any surgery, cataract surgery has risks from infection and bleeding. Cataract surgery also slightly increases the risk of retinal detachment. It is important to discuss the benefits and risks of cataract surgery with your eye care providers. Other ocular conditions may increase the need for cataract surgery or prevent a person from being a cataract surgery candidate.

Cataract surgery is one of the safest and most effective types of surgery performed in the United States today. Approximately 90 percent of cataract surgery patients report better vision following the surgery.

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Chalazion

A chalazion is a slowly developing lump that forms due to blockage and swelling of an oil gland in the eyelid. It is more common in adults than children and occurs most frequently in persons 30 to 50 years of age.

Initially, a chalazion may appear as a red, tender, swollen area of the eyelid. However, in a few days it changes to a painless, slow growing lump in the eyelid. A chalazion often starts out very small and is barely able to be seen, but it may grow to the size of a pea. Often times they may be confused with sties, which are also areas of swelling in the eyelid.

A sty is an infection of an oil gland in the eyelid. It produces a red, swollen, painful lump on the edge or inside surface of the eyelid. Sties usually occur closer to the surface of the eyelid than do chalazia.

A chalazion is generally not due to an infection, but results from a blockage of the oil gland itself. However, a chalazion may occur as an after-effect of a sty.

Common signs or symptoms of a chalazion include:

• Appearance of a painless bump or lump in the upper eyelid, or, less commonly, in the lower eyelid

• Tearing

• Blurred vision, if the chalazion is large enough to press against the eyeball

Most chalazia disappear without treatment in several weeks to a month. However, they often recur. Rarely, they may be an indication of an infection or skin cancer.

Many chalazia require minimal medical treatment, resolving on their own in a few weeks to a month. To facilitate healing, warm compresses can be applied to the eyelid for 10 to15 minutes 4 to 6 times a day for several days. The warm compresses may help soften the hardened oil that is blocking the ducts thereby promoting drainage and healing. Lightly messaging the external area of the eyelid for several minutes each day may also help to promote drainage.

A clean soft cloth dipped in warm water and wrung out can serve as an effective compress. Remoisten the cloth frequently to keep it wet and warm. Once the chalazion drains on its own, keep the area clean and keep your hands away from your eyes.

If the chalazion does not drain and heal within a month, contact your eye doctor. Don’t attempt to squeeze or drain the chalazion yourself.

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Conjunctivitis

Conjunctivitis is an inflammation or infection of the conjunctiva, the thin transparent layer of tissue that lines the inner surface of the eyelid and covers the white part of the eye. Conjunctivitis, often called “pink eye,” is a common eye disease, especially in children. It may affect one or both eyes. Some forms of conjunctivitis can be highly contagious and easily spread in schools and at home. While conjunctivitis is usually a minor eye infection, sometimes it can develop into a more serious problem.

Conjunctivitis may be caused by a viral or bacterial infection. It can also occur due to an allergic reaction to irritants in the air like pollen and smoke, chlorine in swimming pools, and ingredients in cosmetics or other products that come in contact with the eyes. Sexually transmitted diseases like Chlamydia and gonorrhea are less common causes of conjunctivitis.

People with conjunctivitis may experience the following symptoms:

•  A gritty feeling in one or both eyes
   

•  Itching or burning sensation in one or both eyes
   

•  Excessive tearing
   

•  Discharge coming from one or both eyes
   

•  Swollen eyelids
   

•  Pink discoloration to the whites of one or both eyes
   

•  Increased sensitivity to light

The cause of conjunctivitis varies depending on the offending agent. There are three main categories of conjunctivitis: allergic, infectious and chemical:

Allergic Conjunctivitis

• Allergic Conjunctivitis occurs more commonly among people who already have seasonal allergies. At some point they come into contact with a substance that triggers an allergic reaction in their eyes.
   

• Giant Papillary Conjunctivitis is a type of allergic conjunctivitis caused by the chronic presence of a foreign body in the eye. This condition occurs predominantly with people who wear hard or rigid contact lenses, wear soft contact lenses that are not replaced frequently, have an exposed suture on the surface or the eye, or have a glass eye.

Infectious Conjunctivitis

• Bacterial Conjunctivitis is an infection most often caused by staphylococcal or streptococcal bacteria from your own skin or respiratory system. Infection can also occur by transmittal from insects, physical contact with other people, poor hygiene (touching the eye with unclean hands), or by use of contaminated eye makeup and facial lotions.
   

• Viral Conjunctivitis is most commonly caused by contagious viruses associated with the common cold. The primary means of contracting this is through exposure to coughing or sneezing by persons with upper respiratory tract infections. It can also occur as the virus spreads along the body’s own mucous membranes connecting lungs, throat, nose, tear ducts, and conjunctiva.
   

• Ophthalmia Neonatorum is a severe form of bacterial conjunctivitis that occurs in newborn babies. This is a serious condition that could lead to permanent eye damage unless it is treated immediately. Ophthalmia neonatorum occurs when an infant is exposed to Chlamydia or gonorrhea while passing through the birth canal.

Chemical Conjunctivitis

Chemical Conjunctivitis can be caused by irritants like air pollution, chlorine in swimming pools, and exposure to noxious chemicals.

Treatment of conjunctivitis is directed at three main goals:

1.    To increase patient comfort.

2.    To reduce or lessen the course of the infection or inflammation.

3.    To prevent the spread of the infection in contagious forms of conjunctivitis.

The appropriate treatment for conjunctivitis depends on its cause:

• Allergic conjunctivitis – The first step should be to remove or avoid the irritant, if possible. Cool compresses and artificial tears sometimes relieve discomfort in mild cases. In more severe cases, non-steroidal anti-inflammatory medications and antihistamines may be prescribed. Cases of persistent allergic conjunctivitis may also require topical steroid eye drops.
   

•  Bacterial conjunctivitis – This type of conjunctivitis is usually treated with antibiotic eye drops or ointments. Improvement can occur after three or four days of treatment, but the entire course of antibiotics needs to be used to prevent recurrence.
   

• Viral Conjunctivitis – There are no available drops or ointments to eradicate the virus for this type of conjunctivitis. Antibiotics will not cure a viral infection. Like a common cold, the virus just has to run its course, which may take up to two or three weeks in some cases. The symptoms can often be relieved with cool compresses and artificial tear solutions. For the worst cases, topical steroid drops may be prescribed to reduce the discomfort from inflammation, but do not shorten the course of the infection. Some doctors may perform an ophthalmic iodine eye wash in the office in hopes of shortening the course of the infection. This newer treatment has not been well studied yet, therefore no conclusive evidence of the success exists.
   

• Chemical Conjunctivitis – Treatment for chemical conjunctivitis requires careful flushing of the eyes with saline and may require topical steroids. The more acute chemical injuries are medical emergencies, particularly alkali burns, which can lead to severe scarring, intraocular damage or even loss of the eye.

Contact Lens Wearers

Contact lens wearers may need to discontinue wearing their lenses while the conjunctivitis is active.

Contact lens wearers may need to discontinue wearing their lenses while the condition is active. Your doctor can advise you on the need for temporary restrictions on contact lens wear.

If the conjunctivitis developed due to wearing contact lenses, your eye doctor may recommend that you switch to a different type of contact lens or disinfection solution. Your optometrist might need to alter your contact lens prescription to a type of lens that you replace more frequently to prevent the conjunctivitis from recurring.

Self-care

Practicing good hygiene is the best way to control the spread of conjunctivitis. Once an infection has been diagnosed, follow these steps:

• Don't touch your eyes with your hands.
   

• Wash your hands thoroughly and frequently.
   

• Change your towel and washcloth daily, and don't share them with others.
   

• Discard eye cosmetics, particularly mascara.
   

• Don't use anyone else's eye cosmetics or personal eye-care items.
   

• Follow your eye doctor's instructions on proper contact lens care.

You can soothe the discomfort of viral or bacterial conjunctivitis by applying warm compresses to your affected eye or eyes. To make a compress, soak a clean cloth in warm water and wring it out before applying it gently to your closed eyelids.

For allergic conjunctivitis, avoid rubbing your eyes. Instead of warm compresses, use cool compresses to soothe your eyes. Over the counter eye drops are available. Antihistamine eye drops should help to alleviate the symptoms, and lubricating eye drops help to rinse the allergen off of the surface of the eye.

See your doctor of optometry when you experience conjunctivitis to help diagnose the cause and the proper course of action.

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Diabetic Retinopathy

Diabetic retinopathy is a condition occurring in persons with diabetes, which causes progressive damage to the retina, the light sensitive lining at the back of the eye. It is a serious sight-threatening complication of diabetes.

Diabetes is a disease that interferes with the body's ability to use and store sugar, which can cause many health problems. Too much sugar in the blood can cause damage throughout the body, including the eyes. Over time, diabetes affects the circulatory system of the retina.

Diabetic retinopathy is the result of damage to the tiny blood vessels that nourish the retina. They leak blood and other fluids that cause swelling of retinal tissue and clouding of vision. The condition usually affects both eyes. The longer a person has diabetes, the more likely they will develop diabetic retinopathy. If left untreated, diabetic retinopathy can cause blindness.

Symptoms of diabetic retinopathy include:

• Seeing spots or floaters in your field of vision
   

•  Blurred vision
   

•  Having a dark or empty spot in the center of your vision
   

• Difficulty seeing well at night

In patients with diabetes, prolonged periods of high blood sugar can lead to the accumulation of fluid in the lens inside the eye that controls eye focusing. This changes the curvature of the lens and results in the development of symptoms of blurred vision. The blurring of distance vision as a result of lens swelling will subside once the blood sugar levels are brought under control. Better control of blood sugar levels in patients with diabetes also slows the onset and progression of diabetic retinopathy.

Often there are no visual symptoms in the early stages of diabetic retinopathy. That is why the American Optometric Association recommends that everyone with diabetes have a comprehensive dilated eye examination once a year. Early detection and treatment can limit the potential for significant vision loss from diabetic retinopathy.

Treatment of diabetic retinopathy varies depending on the extent of the disease. It may require laser surgery to seal leaking blood vessels or to discourage new leaky blood vessels from forming. Injections of medications into the eye may be needed to decrease inflammation or stop the formation of new blood vessels. In more advanced cases, a surgical procedure to remove and replace the gel-like fluid in the back of the eye, called the vitreous, may be needed. A retinal detachment, defined as a separation of the light-receiving lining in the back of the eye, resulting from diabetic retinopathy, may also require surgical repair.

If you are a diabetic, you can help prevent or slow the development of diabetic retinopathy by taking your prescribed medication, sticking to your diet, exercising regularly, controlling high blood pressure and avoiding alcohol and smoking.

Diabetic retinopathy is the result of damage caused by diabetes to the small blood vessels located in the retina. Blood vessels damaged from diabetic retinopathy can cause vision loss:

• Fluid can leak into the macula, the area of the retina which is responsible for clear central vision. Although small, the macula is the part of the retina that allows us to see colors and fine detail. The fluid causes the macula to swell, resulting in blurred vision.
   

• In an attempt to improve blood circulation in the retina, new blood vessels may form on its surface. These fragile, abnormal blood vessels can leak blood into the back of the eye and block vision.

Diabetic retinopathy is classified into two types:

1. Non-proliferative diabetic retinopathy (NPDR) is the early state of the disease in which symptoms will be mild or non-existent. In NPDR, the blood vessels in the retina are weakened causing tiny bulges called microanuerysms to protrude from their walls. The microanuerysms may leak fluid into the retina, which may lead to swelling of the macula.
    
2. Proliferative diabetic retinopathy (PDR) is the more advanced form of the disease. At this stage, circulation problems cause the retina to become oxygen deprived. As a result new fragile blood vessels can begin to grow in the retina and into the vitreous, the gel-like fluid that fills the back of the eye. The new blood vessel may leak blood into the vitreous, clouding vision. Other complications of PDR include detachment of the retina due to scar tissue formation and the development of glaucoma. Glaucoma is an eye disease defined as progressive damage to the optic nerve. In cases of proliferative diabetic retinopathy, the cause of this nerve damage is due to extremely high pressure in the eye. If left untreated, proliferative diabetic retinopathy can cause severe vision loss and even blindness.

Risk factors for diabetic retinopathy include:

• Diabetes — people with Type 1 or Type 2 diabetes are at risk for the development of diabetic retinopathy. The longer a person has diabetes, the more likely they are to develop diabetic retinopathy, particularly if the diabetes is poorly controlled.
   
• Race — Hispanic and African Americans are at greater risk for developing diabetic retinopathy.
   
• Medical conditions — persons with other medical conditions such as high blood pressure and high cholesterol are at greater risk.
   
• Pregnancy — pregnant women face a higher risk for developing diabetes and diabetic retinopathy. If gestational diabetes develops, the patient is at much higher risk of developing diabetes as they age.

Treatment for diabetic retinopathy depends on the stage of the disease and is directed at trying to slow or stop the progression of the disease.

In the early stages of Non-proliferative Diabetic Retinopathy, treatment other than regular monitoring may not be required. Following your doctor's advice for diet and exercise and keeping blood sugar levels well-controlled can help control the progression of the disease.

If the disease advances, leakage of fluid from blood vessels can lead to macular edema. Laser treatment (photocoagulation) is used to stop the leakage of blood and fluid into the retina. A laser beam of light can be used to create small burns in areas of the retina with abnormal blood vessels to try to seal the leaks.

When blood vessel growth is more widespread throughout the retina, as in proliferative diabetic retinopathy, a pattern of scattered laser burns is created across the retina. This causes abnormal blood vessels to shrink and disappear. With this procedure, some side vision may be lost in order to safeguard central vision.

Some bleeding into the vitreous gel may clear up on its own. However, if significant amounts of blood leak into the vitreous fluid in the eye, it will cloud vision and can prevent laser photocoagulation from being used. A surgical procedure called a vitrectomy may be used to remove the blood-filled vitreous and replace it with a clearfluid to maintain the normal shape and health of the eye.

Persons with diabetic retinopathy can suffer significant vision loss. Special low vision devices such as telescopic and microscopic lenses, hand and stand magnifiers, and video magnification systems can be prescribed to make the most of remaining vision.

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Dry Eye

Dry eye is a condition in which there are insufficient tears to lubricate and nourish the eye. Tears are necessary for maintaining the health of the front surface of the eye and for providing clear vision. People with dry eyes either do not produce enough tears or have a poor quality of tears. Dry eye is a common and often chronic problem, particularly in older adults.

With each blink of the eyelids, tears are spread across the front surface of the eye, known as the cornea. Tears provide lubrication, reduce the risk of eye infection, wash away foreign matter in the eye, and keep the surface of the eyes smooth and clear. Excess tears in the eyes flow into small drainage ducts, in the inner corners of the eyelids, which drain in the back of the nose.

Dry eyes can result from an improper balance of tear production and drainage.

• Inadequate amount of tears – Tears are produced by several glands in and around the eyelids. Tear production tends to diminish with age, with various medical conditions, or as a side effect of certain medicines. Environmental conditions such as wind and dry climates can also affect tear volume by increasing tear evaporation. When the normal amount of tear production decreases or tears evaporate too quickly from the eyes, symptoms of dry eye can develop.
   

• Poor quality of tears – Tears are made up of three layers: oil, water, and mucus. Each component serves a function in protecting and nourishing the front surface of the eye. A smooth oil layer helps to prevent evaporation of the water layer, while the mucin layer functions in spreading the tears evenly over the surface of the eye. If the tears evaporate too quickly or do not spread evenly over the cornea due to deficiencies with any of the three tear layers, dry eye symptoms can develop.

The most common form of dry eyes is due to an inadequate amount of the water layer of tears. This condition, called keratoconjunctivitis sicca (KCS), is also referred to as dry eye syndrome.

People with dry eyes may experience symptoms of irritated, gritty, scratchy, or burning eyes, a feeling of something in their eyes, excess watering, and blurred vision. Advanced dry eyes may damage the front surface of the eye and impair vision.

Treatments for dry eyes aim to restore or maintain the normal amount of tears in the eye to minimize dryness and related discomfort and to maintain eye health.

The development of dry eyes can have many causes. They include:

•  Age – dry eye is a part of the natural aging process. The majority of people over age 65 experience some symptoms of dry eyes.
   

•  Gender – women are more likely to develop dry eyes due to hormonal changes caused by pregnancy, the use of oral contraceptives, and menopause.
   

• Medications – certain medicines, including antihistamines, decongestants, blood pressure medications and antidepressants, can reduce the amount of tears produced in the eyes.
   

•  Medical conditions – persons with rheumatoid arthritis, diabetes and thyroid problems are more likely to have symptoms of dry eyes. Also, problems with inflammation of the eyelids (blepharitis), inflammation of the surfaces of the eye, or the inward or outward turning of eyelids can cause dry eyes to develop.
   

• Environmental conditions – exposure to smoke, wind and dry climates can increase tear evaporation resulting in dry eye symptoms. Failure to blink regularly, such as when staring at a computer screen for long periods of time, can also contribute to drying of the eyes.
   

• Other factors – long term use of contact lenses can be a factor in the development of dry eyes. Refractive eye surgeries, such as LASIK, can cause decreased tear production and dry eyes.

Dry eyes can be a chronic condition, but your optometrist can prescribe treatment to keep your eyes healthy, more comfortable, and prevent your vision from being affected. The primary approaches used to manage and treat dry eyes include adding tears, conserving tears, increasing tear production, and treating the inflammation of the eyelids or eye surface that contributes to the dry eyes.

• Adding tears – Mild cases of dry eyes can often be managed using over-the-counter artificial tear solutions. These can be used as often as needed to supplement natural tear production. Preservative-free artificial tear solutions are recommended because they contain fewer additives that could further irritate the eyes. However, some people may have persistent dry eyes that don’t respond to artificial tears alone. Additional steps need to be taken to treat their dry eyes.
   

• Conserving tears – An additional approach to reducing the symptoms of dry eyes is to keep natural tears in the eyes longer. This can be done by blocking the tear ducts through which the tears normally drain. The tear ducts can be blocked with tiny silicone or gel-like plugs that can be removed, if needed. A surgical procedure to permanently close tear ducts can also be used. In either case, the goal is to keep the available tears in the eye longer to reduce problems related to dry eyes.
   

• Increasing tear production – Prescription eye drops that help to increase production of tears can be recommended by your optometrist, as well as omega-3 fatty acid nutritional supplements.
   

• Treatment of the contributing eyelid or ocular surface inflammation – Prescription eye drops or ointments, warm compresses and lid massage, or eyelid cleaners may be recommended to help decrease inflammation around the surface of the eyes.

Self Care

Steps you can take to reduce symptoms of dry eyes include:

• Remembering to blink regularly when reading or staring at a computer screen for long periods of time.
   

• Increasing the level of humidity in the air at work and at home.
   

• Wearing sunglasses outdoors, particularly those with wrap around frame design, to reduce exposure to drying winds and sun.
   

• Using nutritional supplements containing essential fatty acids may help decrease dry eye symptoms in some people. Ask your optometrist if the use of dietary supplements could be of help for your dry eye problems.
   

• Avoiding becoming dehydrated by drinking plenty of water (8 to 10 glasses) each day.

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Glaucoma

Glaucoma is a group of eye disorders leading to progressive damage to the optic nerve, and is characterized by loss of nerve tissue resulting in loss of vision. The optic nerve is a bundle of about one million individual nerve fibers and transmits the visual signals from the eye to the brain. The most common form of glaucoma, primary open-angle glaucoma, is associated with an increase in the fluid pressure inside the eye. This increase in pressure may cause progressive damage to the optic nerve and loss of nerve fibers. Vision loss may result. Advanced glaucoma may even cause blindness. Not everyone with high eye pressure will develop glaucoma, and many people with normal eye pressure will develop glaucoma. When the pressure inside an eye is too high for that particular optic nerve, whatever that pressure measurement may be, glaucoma will develop.

Glaucoma is the second leading cause of blindness in the U.S. It most often occurs in people over age 40, although a congenital or infantile form of glaucoma exists. People with a family history of glaucoma, African Americans over the age of 40, and Hispanics over the age of 60 are at an increased risk of developing glaucoma. Other risk factors include thinner corneas, chronic eye inflammation, and using medications that increase the pressure in the eyes.

The most common form of glaucoma, primary open-angle glaucoma, develops slowly and usually without any symptoms. Many people do not become aware they have the condition until significant vision loss has occurred. It initially affects peripheral or side vision, but can advance to central vision loss. If left untreated, glaucoma can lead to significant loss of vision in both eyes, and may even lead to blindness.

A less common type of glaucoma, acute angle closure glaucoma, usually occurs abruptly due to a rapid increase of pressure in the eye. Its symptoms may include severe eye pain, nausea, redness in the eye, seeing colored rings around lights, and blurred vision. This condition is an ocular emergency, and medical attention should be sought immediately, as severe vision loss can occur quickly.

Glaucoma cannot currently be prevented, but if diagnosed and treated early it can usually be controlled. Medication or surgery can slow or prevent further vision loss. However, vision already lost to glaucoma cannot be restored. That is why the American Optometric Association recommends an annual dilated eye examination for people at risk for glaucoma as a preventive eye care measure. Depending on your specific condition, your doctor may recommend more frequent examinations.

What Causes Glaucoma

There are many types of glaucoma and many theories about the causes of glaucoma. The exact cause is unknown. Although the disease is usually associated with an increase in the fluid pressure inside the eye, other theories include lack of adequate blood supply to the nerve.

Primary open-angle glaucoma – This is the most common form of glaucoma. One theory is that glaucoma is thought to develop when the eye’s drainage system becomes inefficient over time. This leads to an increased amount of fluid and a gradual buildup of pressure within the eye. Other theories of the cause of the optic nerve damage include poor perfusion, or blood flow, to the optic nerve. Damage to the optic nerve is slow and painless and a large portion of vision can be lost before vision problems are noticed. Other theories also exist.

Angle-closure glaucoma – This type of glaucoma, also called closed-angle glaucoma or narrow angle glaucoma, is a less common form of the disease. It is a medical emergency that can cause vision loss within a day of its onset.

It occurs when the drainage angle in the eye (formed by the cornea and the iris) closes or becomes blocked. Many people who develop this type of glaucoma have a very narrow drainage angle. With age, the lens in the eye becomes larger, pushing the iris forward and narrowing the space between the iris and the cornea. As this angle narrows, the aqueous fluid is blocked from exiting through the drainage system, resulting in a buildup of fluid and an increase in eye pressure.

Angle-closure glaucoma can be chronic (progressing gradually) or acute (appearing suddenly). The acute form occurs when the iris completely blocks the drainage of the aqueous fluid. In people with a narrow drainage angle, if their pupils become dilated, the angle may close and cause a sudden increase in eye pressure. Although an acute attack often affects only one eye, the other eye may be at risk of an attack as well.

Secondary glaucoma – This type of glaucoma occurs as a result of an injury or other eye disease. It may be caused by a variety of medical conditions, medications, physical injuries, and eye abnormalities. Infrequently, eye surgery can be associated with secondary glaucoma.

Normal-tension glaucoma – In this form of glaucoma, eye pressure remains within what is considered to be the “normal” range, but the optic nerve is damaged nevertheless. Why this happens is unknown.

It is possible that people with low-tension glaucoma may have an abnormally sensitive optic nerve or a reduced blood supply to the optic nerve caused by a condition such as atherosclerosis, a hardening of the arteries. Under these circumstances even normal pressure on the optic nerve may be enough to cause damage.

Risk factors

Certain factors can increase the risk for developing glaucoma. They include:

•  Age – People over age 60 are at increased risk for the disease. For African Americans, however, the increase in risk begins after age 40. The risk of developing glaucoma increases slightly with each year of age.
   

• Race – African Americans are significantly more likely to get glaucoma than are Caucasians, and they are much more likely to suffer permanent vision loss as a result. People of Asian descent are at higher risk of angle-closure glaucoma and those of Japanese descent are more prone to low-tension glaucoma.
   

• Family history of glaucoma – Having a family history of glaucoma increases the risk of developing glaucoma.
   

• Medical conditions – Some studies indicate that diabetes may increases the risk of developing glaucoma, as do high blood pressure and heart disease.
   

• Physical injuries to the eye – Severe trauma, such as being hit in the eye, can result in immediate increased eye pressure and future increases in pressure due to internal damage. Injury can also dislocate the lens, closing the drainage angle, and increasing pressure.
   

• Other eye-related risk factors – Eye anatomy, namely corneal thickness and optic nerve appearance indicate risk for development of glaucoma. Conditions such as retinal detachment, eye tumors, and eye inflammations may also induce glaucoma. Some studies suggest that high amounts of nearsightedness may also be a risk factor for the development of glaucoma.
   

• Corticosteroid use – Using corticosteroids for prolonged periods of time appears to put some people at risk of getting secondary glaucoma.

The treatment of glaucoma is aimed at reducing intraocular pressure. The most common first line treatment of glaucoma is usually prescription eye drops that must be taken regularly. In some cases, systemic medications, laser treatment, or other surgery may be required. While there is no cure as yet for glaucoma, early diagnosis and continuing treatment can preserve eyesight.

• Medications - A number of medications are currently available to treat glaucoma. Typically medications are intended to reduce elevated intraocular pressure. One may be prescribed a single medication or a combination of medications. The type of medication may change if it is not providing enough pressure reduction or if the patient is experiencing side-effects from the drops.
   

• Surgery involves either laser treatment, making a drainage flap in the eye, inserting a drainage valve, or destroying the tissue that creates the fluid in the eye. All procedures aim to reduce the pressure inside the eye. Surgery may help lower pressure when medication is not sufficient, however it cannot reverse vision loss.
   

• Laser surgery - Laser trabeculoplasty helps fluid drain out of the eye. A high-energy laser beam is used to stimulate the trabecular meshwork to work more efficiently at fluid drainage. The results may be somewhat temporary, and the procedure may need to be repeated in the future.
   

• Conventional surgery - If eye drops and laser surgery aren't effective in controlling eye pressure, you may need a filtering procedure called a trabeculectomy. Filtering microsurgery involves creating a drainage flap, allowing fluid to percolate into and later drain into the vascular system.
   

• Drainage implants - Another type of surgery, called drainage valve implant surgery, may be an option for people with uncontrolled glaucoma, secondary glaucoma or for children with glaucoma. A small silicone tube is inserted in the eye to help drain aqueous fluid.

Treatment for acute angle-closure glaucoma

Acute angle-closure glaucoma is a medical emergency. Several medications can be used to reduce eye pressure as quickly as possible. A laser procedure called laser peripheral iridotomy will also likely be performed. In this procedure, a laser beam creates a small hole in the iris to allow aqueous fluid to flow more freely into the front chamber of the eye where it then has access to the meshwork for drainage.

Lifelong treatment

There is no cure for glaucoma. Patients with glaucoma need to continue treatment for the rest of their lives. Because the disease can progress or change silently, compliance with eye medications and eye examinations are essential, as treatment may need to be adjusted periodically.

By keeping eye pressure under control, continued damage to the optic nerve and continued loss of your visual field may slow or stop. The optometrist may focus on lowering the intraocular pressure to a level that is least likely to cause further optic nerve damage. This level is often referred to as the target pressure and will probably be a range rather than a single number. Target pressure differs for each person, depending on the extent of the damage and other factors. Target pressure may change over the course of a lifetime. Newer medications are always being developed to help in the fight against glaucoma.

Early detection, prompt treatment and regular monitoring can help to control glaucoma and therefore reduce the chances of progression vision loss.

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 Keratoconus

Keratoconus is a vision disorder that occurs when the normally round cornea (the front part of the eye) becomes thin and irregular (cone) shaped. This abnormal shape prevents the light entering the eye from being focused correctly on the retina and causes distortion of vision.

In its earliest stages, keratoconus causes slight blurring and distortion of vision and increased sensitivity to glare and light. These symptoms usually appear in the late teens or late 20s. Keratoconus may progress for 10-20 years and then slow in its progression. Each eye may be affected differently. As keratoconus progresses, the cornea bulges more and vision may become more distorted. In a small number of cases, the cornea will swell and cause a sudden and significant decrease in vision. The swelling occurs when the strain of the cornea's protruding cone-like shape causes a tiny crack to develop. The swelling may last for weeks or months as the crack heals and is gradually replaced by scar tissue. If this sudden swelling does occur, your doctor can prescribe eyedrops for temporary relief, but there are no medicines that can prevent the disorder from progressing.

Eyeglasses or soft contact lenses may be used to correct the mild nearsightedness and astigmatism that is caused by the early stages for keratoconus. As the disorder progresses and cornea continues to thin and change shape, rigid gas permeable contact lenses can be prescribed to correct vision adequately. In most cases, this is adequate. The contact lenses must be carefully fitted, and frequent checkups and lens changes may be needed to achieve and maintain good vision.

In a few cases, a corneal transplant is necessary. However, even after a corneal transplant, eyeglasses or contact lenses are often still needed to correct vision.

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Macular Degeneration

Macular degeneration is the leading cause of blindness in America. It results from changes to the macula, a portion of the retina that is responsible for clear, sharp vision, and is located at the back of the eye.

Most people with macular degeneration have the dry form, for which there is no known treatment. The less common wet form may respond to laser procedures, if diagnosed and treated early.

Some common symptoms are a gradual loss of ability to see objects clearly, distorted vision, a gradual loss of color vision and a dark or empty area appearing in the center of vision.

If you experience any of these, contact your doctor of optometry immediately for a comprehensive examination.

Central vision that is lost to macular degeneration cannot be restored. However, low vision devices such as telescopic and microscopic lenses can be prescribed to make the most out of remaining vision.

Recent research indicates certain vitamins and minerals may help prevent or slow the progression of macular degeneration. Ask your doctor of optometry about these. After age 60, an annual, comprehensive eye examination is important to maintain eye health.

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Ocular Hypertension

Ocular hypertension has no noticeable signs or symptoms.

Ocular hypertension is an increase in the pressure in your eyes that is above the range considered normal with no detectable changes in vision or damage to the structure of your eyes. The term is used to distinguish people with elevated pressure from those with glaucoma, a serious eye disease that causes damage to the optic nerve and vision loss.

Ocular hypertension can occur in people of all ages, but it occurs more frequently in African Americans, those over age 40 and those with family histories of ocular hypertension and/or glaucoma. It is also more common in those who are very nearsighted or who have diabetes.

Ocular hypertension has no noticeable signs or symptoms. Your doctor of optometry can check the pressure in your eyes with an instrument called a tonometer and can examine the inner structures of your eyes to assess your overall eye health.

Not all people with ocular hypertension will develop glaucoma. However, there is an increased risk of glaucoma among those with ocular hypertension, so regular comprehensive optometric examinations are essential to your overall eye health.

There is no cure for ocular hypertension, however, careful monitoring and treatment, when indicated, can decrease the risk of damage to your eyes.

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Retinitis Pigmentosa

The first sign of retinitis pigmentosa is often night blindness followed by a slow loss of side vision.

Retinitis pigmentosa (RP) is a group of inherited diseases that damage the light-sensitive rods and cones located in the retina, the back part of our eyes. Rods, which provide side (peripheral) and night vision are affected more than the cones that provide color and clear central vision.

Signs of RP usually appear during childhood or adolescence. The first sign is often night blindness followed by a slow loss of side vision. Over the years, the disease will cause further loss of side vision. As the disease develops, people with RP may often bump into chairs and other objects as side vision worsens and they only see in one direction - straight ahead. They see as if they are in a tunnel (thus the term tunnel vision)

Fortunately, most cases of retinitis pigmentosa take a long time to develop and vision loss is gradual. It may take many years for loss of vision to be severe.

Currently, there is no cure for RP, but there is research that indicates that vitamin A and lutein may slow the rate at which the disease progresses. Your doctor of optometry can give you more specific information on nutritional supplements that may help you.

Also, there are many new low vision aids, including telescopic and magnifying lenses, night vision scopes as well as other adaptive devices, that are available that help people maximize the vision that they have remaining. An optometrist, experienced in low vision rehabilitation, can provide these devices as well as advice about other training and assistance to help people remain independent and productive.

Because it is an inherited disease, research into genetics may one day provide a prevention or cure for those who have RP.

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Retinoblastoma

Every parent dreads to hear the word "cancer," but cancer has a high prevalence in the United States. Early detection of cancer can greatly reduce the severity of the illness and increase life expectancy.

Optometrists diagnose, refer, and comanage cancers that involve the eye area. The most common cancer involving the eye in young children is retinoblastoma. In the United States, this fast-growing cancer occurs in 1 in every 20,000 children, making it the tenth most common pediatric cancer.

There are 2 forms of retinoblastoma—hereditary and sporadic. Although sporadic retinoblastoma occurs more frequently, families with a history of hereditary retinoblastoma should be assessed.

Spots and Floaters

 Most spots are not harmful and rarely limit vision. But, spots can be indications of more serious problems.

Spots (often called floaters) are small, semi-transparent or cloudy specks or particles within the vitreous, which is the clear, jelly-like fluid that fills the inside of your eyes. They appear as specks of various shapes and sizes, threadlike strands or cobwebs. Because they are within your eyes, they move as your eyes move and seem to dart away when you try to look at them directly.

Spots are often caused by small flecks of protein or other matter trapped during the formation of your eyes before birth. They can also result from deterioration of the vitreous fluid, due to aging; or from certain eye diseases or injuries.

Most spots are not harmful and rarely limit vision. But, spots can be indications of more serious problems, and you should see your optometrist for a comprehensive examination when you notice sudden changes or see increases in them.

By looking in your eyes with special instruments, your optometrist can examine the health of your eyes and determine if what you are seeing is harmless or the symptom of a more serious problem that requires treatment.

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Strabismus (Crossed Eyes)

Crossed eyes, or strabismus as it is medically termed, is a condition in which both eyes do not look at the same place at the same time. It occurs when an eye turns in, out, up or down and is usually caused by poor eye muscle control or a high amount of farsightedness.

There are six muscles attached to each eye that control how it moves. The muscles receive signals from the brain that direct their movements. Normally, the eyes work together so they both point at the same place. When problems develop with eye movement control, an eye may turn in, out, up or down. The eye turning may be evident all the time or may appear only at certain times such as when the person is tired, ill, or has done a lot of reading or close work. In some cases, the same eye may turn each time, while in other cases, the eyes may alternate turning.

Maintaining proper eye alignment is important to avoid seeing double, for good depth perception, and to prevent the development of poor vision in the turned eye. When the eyes are misaligned, the brain receives two different images. At first, this may create double vision and confusion, but over time the brain will learn to ignore the image from the turned eye. If the eye turning becomes constant and is not treated, it can lead to permanent reduction of vision in one eye, a condition called amblyopia or lazy eye.

Some babies’ eyes may appear to be misaligned, but are actually both aiming at the same object. This is a condition called pseudostrabismus or false strabismus. The appearance of crossed eyes may be due to extra skin that covers the inner corner of the eyes, or a wide bridge of the nose. Usually, this will change as the child’s face begins to grow.

Strabismus usually develops in infants and young children, most often by age 3, but older children and adults can also develop the condition. There is a common misconception that a child with strabismus will outgrow the condition. However, this is not true. In fact, strabismus may get worse without treatment. Any child older than four months whose eyes do not appear to be straight all the time should be examined.

Strabismus is classified by the direction the eye turns:

• Inward turning is called esotropia
   

•  Outward turning is called exotropia
   

• Upward turning is called hypertropia
   

• Downward turning is called hypotropia

Other classifications of strabismus include:

• The frequency with which it occurs – either constant or intermittent
   

• Whether it always involves the same eye – unilateral
   

• If the turning eye is sometimes the right eye and other times the left eye – alternating.

Treatment for strabismus may include eyeglasses, prisms, vision therapy, or eye muscle surgery. If detected and treated early, strabismus can often be corrected with excellent results.

What causes strabismus?

Strabismus can be caused by problems with the eye muscles, the nerves that transmit information to the muscles, or the control center in the brain that directs eye movements. It can also develop due to other general health conditions or eye injuries.

Risk factors for developing strabismus include:

• Family history – individuals with parents or siblings who have strabismus are more likely to develop it.
   

• Refractive error – people who have a significant amount of uncorrected farsightedness (hyperopia) may develop strabismus because of the additional amount of eye focusing required to keep objects clear.
   

• Medical conditions – people with conditions such as Down syndrome and cerebral palsy or who have suffered a stroke or head injury are at a higher risk for developing strabismus.

Although there are many types of strabismus that can develop in children or adults, the two most common forms are accommodative esotropia and intermittent exotropia.

Accommodative esotropia often occurs because of uncorrected farsightedness (hyperopia). Because the eye’s focusing system is linked to the system that controls where the eyes point, the extra focusing effort needed to keep images clear in farsightedness may cause the eyes to turn inward. Signs and symptoms of accommodative esotropia may include seeing double, closing or covering one eye when doing close work, and tilting or turning of the head.

Intermittent exotropia may develop due to an inability to coordinate both eyes together. The eyes may have a tendency to point beyond the object being viewed. People with intermittent exotropia may experience headaches, difficulty reading, and eye strain. They also may have a tendency to close one eye when viewing at distance or in bright sunlight.

How is strabismus treated?

People with strabismus have several treatment options available to improve eye alignment and coordination. They include:

• Eyeglasses or contact lenses

• Prism lenses

• Vision therapy

• Eye muscle surgery

Eyeglasses or contact lenses may be prescribed for patients with uncorrected farsightedness. This may be the only treatment needed for some patients with accommodative esotropia. Once the farsightedness is corrected, the eyes require less focusing effort and may remain straight.

Prism lenses are special lenses that have a prescription for prism power in them. The prisms alter the light entering the eye and assist in reducing the amount of turning the eye has to do to look at objects. Sometimes the prisms are able to fully compensate for and eliminate the eye turning.

Vision therapy is a structured program of visual activities prescribed to improve eye coordination and eye focusing abilities. Vision therapy trains the eyes and brain to work together more effectively. These eye exercises help remediate deficiencies in eye movement, eye focusing and eye teaming and reinforce the eye-brain connection. Treatment may include office-based as well as home training procedures.

Eye muscle surgery can change the length or position of the muscles around the eye in an attempt to better align the eyes. Eye muscle surgery may be able to physically align the eyes so they appear straight. Often a program of vision therapy may also be needed to develop a functional improvement in eye coordination and to keep the eyes from reverting back to their previous condition of misalignment.

 

Information provided courtesy the American Optometric Association