Astigmatism

Astigmatism occurs in about one in three people when the cornea is misshapen. Normally, the cornea is spherical, but when astigmatism occurs, it is oval. Astigmatism causes difficulty in seeing fine detail and can also cause vertical lines to appear as if they are tilting. A person might have a slight astigmatism and not even notice it. It can be corrected with glasses, contact lenses or surgery.

Cataracts

A cataract occurs when the cells in the lens die and become trapped in the lens. As more cells die and become trapped, the lens becomes cloudy which causes vision to become blurry or fuzzy.

For the majority of individuals, cataracts are a normal part of aging. In fact, cataracts are the leading cause of vision loss for individuals over 55 and more than half of Americans over the age of 65 have cataracts.

Cataracts can also be caused by eye injury, certain medications, diabetes, and alcoholism. Cataract surgery can be performed to restore vision. The fluid in the lens capsule is drained and a plastic lens is put into the empty lens capsule. This surgery can be done under local anesthesia, and the patient is allowed to go home on the same day as surgery.

Color Blindness

Color blindness is the inability to see the difference between some commonly perceived colors. Most often this is the result of genetics, but can also be caused by eye, brain, or nerve damage as well as exposure to some chemicals.

Color blindness is usually partial and affects only some colors, the most common being distinguishing between red and green. Difficulty seeing the difference between blues and greens occurs less frequently. Complete color blindness is extremely rare and allows the individual to see only shades of grey.

Color blindness occurs much more frequently in males than in females. It is X-chromosome linked and is almost always passed down from a mother to her son.

Computer Vision Syndrome

Computer Vision Syndrome (CVS) is a relatively new condition. It is temporary and is the result of focusing the eyes on a computer screen for uninterrupted periods of time. The usual human blinks approximately 16 to 20 times per minute. However, when working on a computer that rate decreases to 6 to 8 per minute.

The symptoms of CVS include:

 

• headaches
• blurred vision
• neck pain
• fatigue
• eye strain
• dry, irritated eyes
• difficulty refocusing

 

There symptoms can be worsened when there is improper lighting or the computer is in an area where there is moving air.

Some ways to avoid CVS are to take a break every 20 minutes and look at something 20 feet away for 20 seconds. This gives the eyes a break and a chance to refocus. CVS has not been shown to cause any permanent damage to the eye.

Conjunctivitis (Pink Eye)

Conjunctivitis, more commonly known as Pink Eye, is the inflammation of the conjunctiva. It is commonly due to an allergic reaction or an infection which can be either bacterial or viral. The non allergic type of conjunctivitis is extremely contagious and can be spread from one eye to the other, or from person to person. The severity of the infection depends on the type of bacteria involved.

Diabetic Retinopathy

Diabetic Retinopathy is the ocular manifestation of the disease diabetes mellitus. It affects up to 80% of all people with diabetes who have had the disease for over 10 years. With proper nutrition and yearly eye exams, 90% of new cases could be reduced.

With Diabetic Retinopathy, new blood vessels develop in the retina. Those delicate blood vessels can then bleed, causing blurred vision and/or floaters. This may be slight at first, but if left untreated, can lead to a major hemorrhage. These large hemorrhages happen mainly while the individual is sleeping. In later stages, scar tissue on the retina can lead to retinal detachment or glaucoma.

Glaucoma

Glaucoma is a group of diseases caused by an increase in intraocular pressure which affects the optic nerve. There is no set threshold for the amount of pressure that will cause damage to the optic nerve as it varies from person to person.

With Glaucoma, vision loss often occurs over a long period of time and an individual may only realize that there is a vision loss after a significant amount of damage has been done. Once the damage to the optic nerve has occurred, it can not be reversed.

Glaucoma is the second leading cause of blindness and affects one in 200 people under the age of 50. Early detection of glaucoma can slow or even stop the progression of the disease.

Hyperopia (Farsightedness)

More commonly known as farsightedness, hupeopia is caused by an imperfection in in which the eye is too short and the lens is unable to compensate. Due to this, the focal point of the light entering the eye is behind the retina which causes images to become blurry.

People with hyperopia have difficulty seeing objects that are close to them, and in extreme cases may also have difficulty with distance vision. Glasses can accommodate this condition.

Legally Blind

The American Medical Association defines legal blindness as “Central visual acuity of 20/200 or less in the better eye with corrective glasses or central visual acuity of more than 20/200 if there is a visual field defect in which the peripheral field is contracted to such an extent that the widest diameter of the visual field subtends an angular distance no greater than 20 degrees in the better eye.”

Less than 15% of all individuals who have been determined to be legally blind have no usable vision, meaning that approximately 85% of legally blind individuals have some vision.

Light Perception/Projection

Individuals with light perception have the ability to tell light from dark and may be able to see shadows and/or outlines of objects. Individuals with light projection can only tell the general direction of a light source and are otherwise unable to visually distinguish objects.

Macular Degeneration

Macular Degeneration is a degenerative condition caused when the arteries that feed blood to the macula (the central area of the retina) harden, causing a loss of oxygen and nutrients to the retina. The result is a loss of central vision. The effects can vary from a slight distortion to a complete loss of central vision. However, it does not cause complete vision loss because the peripheral vision is not affected.

Age related Macular Degeneration is the leading cause of vision loss in the United States for individuals over the age of 50.

Myopia (Nearsightedness)

Myopia is caused by an imperfection in the eye in which the eye is too long and the lens is unable to compensate. Due to this, the focal point of the light entering the eye is in front of the retina which causes images to become blurry.

People with myopia have difficulty seeing objects that are at a distance, but objects that are close are clear. It is often discovered in school age children when they begin to read the chalk board. Proper glasses can accommodate for nearsightedness.

Optometrist

Also known as doctors of optometry, optometrists are able to examine, diagnose and medically treat eye diseases and disorders. Although they do not perform surgical procedures, in some locations optometrists may perform laser surgery. Some optometrists specialize in persons who are partially sighted and need visual devices.

Ophthalmologist

An ophthalmologist is a medical doctor who specializes diseases of the eye. Because they are able to prescribe medication and perform surgeries, they are often classified as surgeons. They are also qualified to prescribe glasses and contacts.

Ophthalmologists must attend four years of medical school and one year of an internship before obtaining a state medical license. Following that they must have three years of training in ophthalmology at an approved residency program.

Ocular Dexter
Ocular Dexter (OD) is the medical term for the right eye.

Ocular Sinister
Ocular Sinister (OS) is the medical term for the left eye.

Ocular Unitits (OU)
Ocular Unitits (OU) is the medical term for the right eye.

Presbyopia

Presbyopia is sometimes called the “short arm syndrome.” It occurs naturally as people age, generally starting between the ages of 40 and 50. People start to notice the inability to focus well on objects that are close and frequently complain that their arms are “too short” to read well. This is due to the lens thickening over time and losing its ability to focus on near objects. Presbyopia can be compensated for with reading glasses, contacts, or refractive surgery.

Retinal Detachment

When retinal detachment occurs, the retina begins to separate from its supportive tissue. This can occur when an individual ages and the vitreous becomes more fluid, causing it to pull on and tear the retina. At the beginning, this may be a small area, but if immediate steps are not taken, it can rapidly progress, leading to vision loss and/or blindness.

It can be caused by eye trauma, near-sightedness, problems from eye surgery, or other retinal and macular diseases. When it is caught early, there are several surgeries which can be performed in order to reattach the retina and keep vision loss to a minimum.

Retinitis Pigmentosa

Retinitis Pigmentosa (RP) is a rare, degenerative, hereditary disease that affects the rods in the retina. Night blindness generally occurs near the beginning of the disease which progresses to tunnel vision and then possibly total vision loss.

The progression of this disease is generally gradual and most people do not become legally blind until their 40s or 50s and may never become totally blind. In some cases, however, the progression is more rapid and complete blindness can occur in childhood.

Retinopathy or Prematurity

Retinopathy of Prematurity (ROP) has been also known as retrolental fibroplasia (RLF). It is a disease of the eye that affects premature babies. The main belief is that it is caused by premature retinal blood vessels which can result in scarring and detachment of the retina. Oxygen toxicity (too much oxygen) from incubators and hypoxia (oxygen deprivation) are also believed to contribute to ROP. ROP can be mild and may even resolve itself spontaneously, but can also lead to blindness in more severe cases.

Totally Blind

Total Blindness is the lack of visual perception due to either physiological or neurological factors. It is the inability to see. Only 10% of the individuals labeled as legally blind are totally blind. The remainder of the individuals labeled as legally blind have some measure of vision.

Vitreous Hemorrhage

A Vitreous Hemorrhage occurs when one or more blood vessels in the eye burst. It most frequently occurs due to diabetes, retinal detachment, retinal vein occlusion, sickle cell anemia, or trauma to the eye.

Symptoms include blurred vision, light flashes, floaters, or loss of vision. It is suggested that individuals with these symptoms consult with an eye care professional to decrease the possibility of further vision loss.