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Vision Health

The importance of regular eye exams often is under-rated. Having annual eye exams should be as routine as having a dental checkup every six months.

Regular eye exams are crucial to maintaining healthy vision and can often detect major medical problems in the early stages of development, such as diabetes and high blood pressure. The information provided in this section details some of the eye conditions that may be detected during a thorough eye exam, as well as the procedures that your eye care professional follows when checking eye health.

This content is being provided for informational purposes only and is not intended for diagnostic or treatment purposes. As with any detected symptom, we always recommend that you seek the care of the appropriate health or eye care professional for further evaluation.


Eye Conditions

Amblyopia (Lazy Eye)
Amblyopia, or lazy eye, is a loss of vision or lack of development of central vision in one eye caused by inadequate use during early childhood. Amblyopia may develop from conditions such as: a squint or strabismus (eyes not positioned straight), congenital cataract, uncorrected high near-sightedness (myopia) or far-sightedness (hyperopia) in one eye or both eyes and severe ptosis (droopy eyelids).

While symptoms are not always obvious, they typically appear during early childhood and may include:

  • Noticeably favoring one eye
  • Eye turning in, out or up
  • Closing of one eye
  • Squint
  • Headaches or eyestrain

Diagnosis and Treatment:
Comprehensive eye exams during early childhood are highly recommended and can lead to the diagnosis of amblyopia at an early age, increasing the chance for a complete recovery. The most effective treatment is to encourage the use of the amblyopia eye, which may include using a combination of prescription lenses, prisms, vision therapy and eye patching.

Astigmatism occurs when the cornea is misshapen to some degree, causing light to focus improperly on the retina.

Astigmatism is a common condition and may affect many people to some degree or another. Symptoms may include:

  • Burred or distorted vision
  • Headaches
  • Eyestrain
  • Fatigue

Diagnosis and Treatment:
Most astigmatism is treatable by eyeglasses, contact lenses, or refractive surgery.

Color Vision Deficiency
The term "color blindness" is not entirely accurate. The more accurate statement may indicate that a person is "color deficient." Color deficiency is an inherited genetic trait that affects about 1 out of 12 males, and 1 out of 100 females.

Only in very rare cases is color vision deficiency so severe that the individual can detect no color at all. In most cases, the ability to distinguish certain colors is simply less than normal. Red-green color deficiency is the most common form of this condition, but some people may also have difficulty distinguishing blue and gray.

Diagnosis and Treatment:
Color vision deficiency is not typically indicative of disease and is not correctable in most cases, although special tinted lenses may help. Occupational counseling may be helpful for those individuals who are color deficient.

More commonly referred to as farsightedness, hyperopia is a condition by which distant objects appear clearly, but those close up may appear blurred or cause eyestrain when trying to focus. Like myopia, the condition is caused when the shape of the eyeball or cornea is such that light entering the eye cannot be properly focused on the retina.

Symptoms of hyperopia may include:

  • Difficulty seeing objects at close range
  • Squinting, headaches or eyestrain when working up close

Diagnosis and Treatment:
Hyperopia is a common vision problem, affecting about a fourth of the population and can be detected by a comprehensive eye exam. Farsightedness can be corrected with glasses or contact lenses to change the way light rays bend into the eyes. You may need to wear your glasses or contacts all the time, or only when reading, working on a computer, or doing other close-up work. Refractive surgery is another option for correcting hyperopia.

Myopia is the medical term for nearsightedness. It is a condition in which objects that are up close are usually in focus and clear, but those at a distance (outside of arm's length) appear blurred. Like hyperopia, the condition is caused when the shape of the eyeball or cornea is such that light entering the eye cannot be properly focused on the retina.

Symptoms of myopia may include:

  • Difficulty seeing distant objects
  • Lack of classroom participation due to difficulty seeing the chalkboard

Diagnosis and Treatment:
Myopia is a very common vision problem affecting about 30 percent of Americans and can be detected by a comprehensive eye exam. It generally develops before the age of twenty. Corrective lenses (glasses or contact lenses) or refractive surgery may be used in the treatment of myopia, depending on the severity of the condition and the preference of the patient.

Presbyopia usually occurs at or around age 40, when the natural lens inside the eye loses flexibility, making it difficult to focus on objects or print at close range. It is a natural process of aging, not a disease, and cannot be prevented.

Symptoms of the onset of presbyopia include:

  • The need to hold reading materials at a distance
  • Blurred vision and eye fatigue, including headaches, when doing close work ("arms are too short")

Diagnosis and Treatment:
A comprehensive eye exam can detect presbyopia. Your eye care specialist may prescribe single vision reading lenses or multifocal lenses, such as bifocals, trifocals, or progressive ("no line") lenses. Contact lenses are also available to correct presbyopia. Since the eye continues to change in the aging process, changes in your prescription may be required periodically.

Spots and Floaters
Small cloudy specks of various sizes may form within the eye. These spots are usually encapsulated in the vitreous fluid, a liquid substance that fills the posterior two-thirds inside of the eye. They are caused by protein deposits trapped in the eye before birth and are usually considered harmless. They may also occur later in life due to aging or certain eye diseases.

Spots or floaters move as your eyes move. They rarely limit vision, but may be bothersome and are noticed when looking into space or at a blank wall when sufficient light is present.

Diagnosis and Treatment:
Although floaters are generally considered harmless, they may be indicative of more serious problems that can be detected only by a comprehensive eye exam. Your eye care specialist can examine your eyes and determine if you may be at risk for, or have developed, a more serious problem that requires treatment.

Strabismus (misalignment of the eyes)
Difficulty with eye muscle balance can cause one or both eyes to turn in, out, up, or down. This condition typically appears in young children prior to age seven, and may continue undetected or uncorrected into later life.

The symptoms of strabismus may include:

  • One or both eyes out of alignment as the person looks at or tries to focus on an object
  • Double vision
  • Headaches and nausea when trying to focus

Diagnosis and Treatment:
One common misperception of strabismus is that a child will outgrow the condition. This is not true. In fact, without treatment, the condition may worsen and cause other eye conditions, including amblyopia.

The American Optometric Association recommends a pediatric eye exam before six months and again at age three. (If there is a family history of strabismus, your eye care professional may recommend a more frequent examination schedule.) If detected early, strabismus can often be corrected.

Treatment for misaligned eyes may include:

  • Eyeglasses
  • Prisms (a lens application that helps focus the light entering the eye on the retina)
  • Vision therapy
  • Surgery

Eye Conditions

Cataracts occur when the natural lens inside the eye becomes discolored or cloudy, causing blurred or distorted vision. This blurring is the result of a chemical change within the eye, most often occurring after the age of 55. The direct cause of cataracts is not known, although heredity, injury, and/or disease might be factors. Additional factors that may contribute to the development of cataracts include exposure to ultraviolet light, smoking, and certain prescription drugs.

Indications that cataracts may be forming include:

  • Blurred/hazy vision
  • Spots in front of the eyes
  • Increased sensitivity to light and resulting glare
  • Feeling of "film" over the eyes
  • A temporary improvement in near vision
  • Decreased vision in low illumination (night driving)

Diagnosis and Treatment:
Although there is currently no known method to keep cataracts from developing, your eye care specialist can diagnose and monitor cataracts and also prescribe glasses or lenses that may improve vision. Ultimately, most cataracts should be surgically removed.

Diabetic Retinopathy
People with diabetes must be particularly careful to have regular eye exams, because diabetes can contribute to an eye disease called "diabetic retinopathy." Undiagnosed and untreated, diabetic retinopathy may significantly reduce both central and peripheral vision and may lead to blindness.

In its early stages, diabetic retinopathy may cause blurred vision or may actually have no visual symptoms at all. Undetected or untreated, more serious symptoms may develop, including blind spots or floaters. Untreated, diabetic retinopathy may lead to blindness.

Diagnosis and Treatment:
Early diagnosis and treatment is very important. If detected early, the effects of diabetic retinopathy may be significantly reduced. Diabetics may also help prevent the onset or worsening of diabetic retinopathy by taking care to follow all medical instructions including medications, eating a healthy diet and exercising regularly.

Glaucoma is a leading cause of blindness in the United States. It typically affects people over the age of forty. The early signs may occur when the passages that filter and exchange fluid from within the eye become blocked, causing the internal eye pressure to increase. Undiagnosed and untreated, this increased pressure may cause permanent damage to the optic nerve. The chances of developing glaucoma are increased when there is a family history of the disease or when an individual is of African descent, very nearsighted, or has diabetes.

Glaucoma tends to develop gradually and without symptoms. If there are symptoms, they may include minor blurring of vision, loss of central or peripheral vision, the appearance of colored rings around lights and eye pain or dull headaches.

Diagnosis and Treatment:
Glaucoma cannot be prevented, but it can, in most cases, be controlled. A comprehensive eye exam can detect the onset of signs and symptoms of glaucoma. Your eye care specialist will do further testing and may prescribe medication to control the pressure inside the eye or recommend other forms of treatment, including laser or conventional surgery.

Keratoconus is a condition in which the normally symmetrical, round corneal surface becomes cone shaped. This change in shape distorts light entering the eye and causes blurred vision. Early symptoms usually appear between the late teens and late twenties and result in reduced or distorted distance vision.

Early symptoms of keratoconus may include:

  • Blurred or distorted vision
  • Increased light sensitivity
  • Mild to severe nearsightedness and astigmatism

Diagnosis and Treatment:
In the early stages of keratoconus, eyeglasses or contact lenses may be prescribed. Rigid, gas-permeable contact lenses may help correct vision as the disease progresses. In some cases where the cornea cannot be stabilized with contact lenses, a corneal transplant may be the treatment of choice.

Macular Degeneration
Macular degeneration is the leading cause of blindness in the United States. In macular degeneration, the macula (i.e., the part of the retina responsible for clear central vision) undergoes vascular changes that may cause loss of central vision. This condition is usually permanent and may progress if it goes undetected and untreated.

The symptoms of macular degeneration include:

  • Gradual loss of clear central, or "straight-ahead" vision
  • Distorted or wavy vision
  • Gradual loss of color vision
  • A dark or empty area (i.e., "blind spot") in the center of your field of vision

Diagnosis and Treatment:
The more common form of macular degeneration is the dry form. Unfortunately, there is no known treatment for this form. A less common form of macular degeneration is the wet form, in which fluid leaks from blood vessels surrounding the macula. If detected early, this form may be treatable with certain laser procedures. Although central vision loss cannot be restored, special optical devices can be prescribed to help maximize the effectiveness of remaining vision. In addition, certain vitamin and mineral supplements may help prevent or slow the progression of macular degeneration.


Eye Exams

The Elements of a Comprehensive Eye Health Exam and Vision Analysis
The American Optometric Association (AOA) recommends the following information be gathered and tests be performed during a comprehensive eye examination:

  • Chief Complaint: assessment of the patient's reason for getting an eye exam
  • General Physical Health History: complete health history to screen for physical conditions and medications that may affect eyesight
  • General Ocular Health History: complete eye health history including family history of eye conditions, disease, or medication
  • External and Internal Eye Health Evaluation: examination for the signs of eye disorders, including cataracts and other eye disorders
  • Current Prescription Analysis: evaluation of current lens prescription, if applicable
  • Visual Acuity: test for the eyes' ability to see sharply and clearly at all distances
  • Refraction: test for the eyes' ability to focus light rays properly on the retina at distances and close by
  • Tonometry: test to measure internal fluid pressure of the eye (increased pressure may be an early sign of glaucoma)
  • Visual Coordination: check for external eye muscle balance and coordination
  • Accommodative Ability: test of the eyes' ability to change focus from distance to near

An exam may also include tests for color vision and depth perception, visual fields, and other vision skills, as needed.

Children's Eye Exams

Children should receive their first eye exam at the age of six months, then again when the child turns three. Subsequent exams should be given before the child starts school, then every two years after that. Based on family history or other indicators, your eye care professional may recommend a more frequent exam schedule.

Many eye disorders, including hyperopia (farsightedness), myopia (nearsightedness), and amblyopia (lazy eye), can occur in early childhood, and may affect your child's ability to learn. A comprehensive eye exam can detect these and other disorders.

In between eye exams, you can take an active role in monitoring your child's vision. For instance, regularly ask your child to describe the way he or she sees objects up close or at a distance (across a room or street). The child may not realize if his or her vision is not clear and sharp.

Additionally, look for the following signs that your child may have vision problems:

  • Squinting
  • One or both eyes turning in, out, up, or down
  • Head turn or head tilt
  • Frequent headaches
  • Inability to copy notes from a blackboard
  • Reversals of words or letters
  • Frequent rubbing of eyes or tearing
  • Eye redness or crusting of eye lids/lashes
  • Eye pain
  • Disinterested in close work, such as coloring or reading
  • Sitting very close to the television (indicating that he/she can't see if made to move back)

Vision and Aging
People today live longer, more active lives than ever before. For this reason, senior eye health has become increasingly important. As we age, some vision changes are normal; others might be indicative of more serious problems, such as deterioration or damage to our eyes.

Among eye conditions of particular concern to older adults are farsightedness, floaters, cataracts and glaucoma as well as diabetic retinopathy and other diseases of the retina such as macular degeneration. Many serious conditions of the eye are easily treatable if detected during their early stages. For this reason, persons over 40 should make it a point to have a routine eye exam at least once a year.

By having regular eye exams, seniors can help prevent eye health problems and continue with the activities that promote independence, including driving, recreational activities, and reading.

Glossary of Related Terms

A condition resulting in the functional non-use of one eye due to a problem of focusing an image on the retina; also known as "lazy eye."

Aniseikonic Lenses
Lenses made to compensate for aniseikonia, a visual defect in which the shape and size of an ocular image differ in the two eyes.

Anti-Reflective Coating
Anti-reflective coatings consist of several layers of metal oxides applied to the front and back lens surfaces. AR coating reduces glare, reflections and halos around lights. Also, anti-reflective coating reduces both internal and external reflections on the lenses themselves. Internal reflections appear as rings that make lenses look thick. External reflections mask your eyes from a clear, complete view when someone is looking at you.

Aspheric Lenses
Aspherics are ideal for strong prescriptions because they are flatter and thinner. They also provide better vision than ordinary lenses and look better because they lessen farsighted eye magnification and nearsighted eye minification.

A condition that occurs when the cornea is misshapen to some degree, causing light to focus improperly on the retina.

A condition caused by a clouding of the internal lens of the eye, causing blurred or distorted vision.

Color Vision Deficiency
A genetically inherited trait in which the ability to distinguish some colors is less than normal.

The transparent, rounded tissue covering the front of the eye and serving as the first focusing mechanism of light entering the eye.

Diabetic Retinopathy
Associated with diabetes, an eye disease that can lead to blindness.

See Hyperopia.

Small, cloudy specks of various sizes that form in the vitreous fluid of the eye.

An eye disease in which the internal pressure of the eye increases; it may cause permanent damage to the optic nerve that can lead to blindness if not properly treated.

High-Index Lenses
The higher the prescription, the thicker the lenses, especially in near-sighted prescriptions. High-index lenses are made from variety of new plastic materials that can provide the same prescription by using thinner, lighter weight material as traditional lenses.

Farsightedness; a condition in which close-up objects appear blurred.

A disease in which the cornea becomes misshapen, causing blurry vision.

LASIK (Laser-Assisted In Situ Keratomileusis)
A type of laser eye procedure used to treat various refractive or focusing errors of the eye. LASIK creates a flap that is opened to expose inner corneal tissue for reshaping, thereby eliminating (or reducing) the corneal refractive error and significantly changing the requirement for corrective eyewear. The procedure is relatively painless with a rapid healing process.

A crystalline, biconvex tissue within the eye that focuses light rays upon the retina; this is the structure on which cataracts may form.

The area of the retina responsible for clear, detailed central vision.

Macular Degeneration
A disease in which the macula undergoes vascular or aging changes that may lead to the loss of central vision if untreated.

Multifocal Lenses
Multifocal refers to either bifocal or trifocal lenses. Multifocals let you focus through different prescriptions at different distances through the same lens. Bifocal lens or trifocal lenses are designed to treat presbyopia or overconvergence.

Nearsightedness; a condition in which distant objects appear blurred.

Optic Nerve
The nerve that carries visual impulses from the retina directly to the brain.

The teaching and training process for the improvement of visual perception and coordination of the two eyes for efficient and comfortable binocular vision.

When the eyes work too hard to see close-up.

A condition related to the normal aging process, in which it becomes difficult to focus on close-up objects.

Photochromic Lenses
Photochromic lenses change from light to dark depending on the amount of ultraviolet light they are exposed to.

Plano Lens
Lenses which have no refractive power.

Polycarbonate lenses are not only thinner and lighter in weight than traditional plastic eyeglass lenses, they also offer ultraviolet (UV) protection and scratch resistance. In addition, they are very impact resistant. This extra toughness makes them the lenses of choice for children's glasses, sports eyewear and safety glasses. Polycarbonate lenses are sometimes referred to as featherweight lenses.

PRK (Photo-Refractive Keratectomy)
A type of laser eye procedure used to treat various refractive or focusing errors of the eye. PRK reshapes tissue on the surface of the cornea, thereby eliminating (or reducing) the corneal refractive error and significantly changing the requirement for corrective eyewear. The procedure, although less surgically invasive, generally requires a longer healing process.

The nerve fiber layer or inner surface of the eyeball on which images are projected and delivered to the optic nerve as impulses for transmission directly to the brain.

Scratch-Resistant Coating
A clear, hard coating that is applied to a lens to make it more resistant to scratching.

See Floaters

A condition in which difficulty with eye muscle balance and coordination causes one or both eyes to turn in, out, up or down.

Tint is added to lenses for cosmetic purposes or to make the prescription lenses into prescription sunglasses. Tint remains constant at all times, as opposed to photochromatic, which changes depending on the amount of light present. A tint can be solid, when the entire lens is the same color, or gradient, which is a gradual fade from dark to light, usually fading from the top down.

A test that measures the internal fluid pressure within the eye. Increased fluid pressure is an indicator in the diagnosis of glaucoma.

Ultraviolet Treatment
UV treatment in eyeglass lenses blocks UV rays from damaging our eyes. Overexposure to ultraviolet light is thought to be a cause of cataracts, retinal damage and other eye problems.

Visual Acuity
A test of the eyes' ability to see sharply and clearly at all distances; part of a comprehensive eye exam that may be tested with or without a vision correction.

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