Amblyopia (Lazy Eye)

Causes

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).

Symptoms

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

Diagnosis and Treatment

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

Astigmatism

Causes

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

Symptoms

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

Diagnosis and Treatment

Most astigmatism is treatable by eyeglasses, contact lenses, or refractive surgery.

Color Vision Deficiency

Causes

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.

Symptoms

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 typically correctable in most cases, although special tinted lenses may help. Occupational counseling may be helpful for those individuals who are color deficient.

Hyperopia

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 eye strain 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

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 typically correctable in most cases, although special tinted lenses may help. Occupational counseling may be helpful for those individuals who are color deficient.

Myopia

Causes

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 arms' 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

Symptoms of myopia may include:

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

Causes

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

Symptoms of the onset of presbyopia include:

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

Causes

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.

Symptoms

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)

Causes

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.

Symptoms

The symptoms of strabismus may include:

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:

Cataracts

Causes

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.

Symptoms

Indications that cataracts may be forming include:

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

Causes

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.

Symptoms

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

Causes

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.

Symptoms

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

Causes

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.

Symptoms

Early symptoms of Keratoconus may include:

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

Causes

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.

Symptoms

The symptoms of macular degeneration include:

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.

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: 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: To view a listing of the components of a comprehensive eye exam, click here.

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.

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.