Why Does My Eye Twitch?
Mild twitching of the eyelid is a common phenomenon. Although these involuntary contractions of muscles are annoying, they are almost always temporary and completely harmless. The medical name for this kind of twitching is ocular myokymia. It is quite common and most often associated with fatigue. When your eye is twitching, it is not visible to anyone else. Ophthalmologists often are asked what causes the twitching and what can be done to stop it. Lack of sleep, too much caffeine or increased stress seem to be root causes. Often, gently massaging your eye will relieve the symptoms. Usually, the twitch will disappear after catching up on your sleep.
What is the difference between an ophthalmologist, an optometrist and an optician?
* An Ophthalmologist (MD) has a medical degree and is licensed to practice medicine and perform eye surgery.
* An ophthalmologist has had at least 12 years of education and training beyond high school and is qualified to diagnose and treat all eye diseases; perform surgery; prescribe and fit glasses and contact lenses.
* An Optometrist (OD) has a degree in optometry and is licensed to practice optometry. An optometrist has had at least six years of education and training beyond high school and is qualified to determine the need for glasses and contact lenses; prescribe optical correction; and screen for some eye conditions.
* An Optician usually has a combination of college (or two years of opticianry school) and on-the-job training. An optician is trained to fit and dispense eyeglasses or contact lenses based upon a prescription from a licensed ophthalmologist or optometrist.
How does normal vision develop?
Newborn infants are able to see, but as they use their eyes during the first months of life, vision improves. During early childhood years, the visual system changes quickly and vision continues to develop. If a child cannot use his or her eyes normally, vision does not develop properly and may even decrease. After the first nine years of life, the visual system is usually fully developed and usually cannot be changed.
The development of equal vision in both eyes is necessary for normal vision. Many occupations are not open to people who have good vision in one eye only. If the vision in one eye should be lost later in life from an accident or illness, it is essential that the other eye have normal vision. Without normal vision in at least one eye, a person is visually impaired.
How does the eye work?
When you take a picture, the lens in the front of the camera allows light through and focuses that light on the film that covers the back inside wall of the camera. When the light hits the film, a picture is taken. The eye works in much the same way. The front parts of the eye (the cornea, pupil and lens) are clear and allow light to pass through. The light also passes through the large space in the center of the eye called the vitreous cavity. The vitreous cavity is filled with a clear, jelly-like substance called the vitreous or vitreous gel. The light is focused by the cornea and the lens onto a thin layer of tissue called the retina, which covers the back inside wall of the eye. The retina is like the film in a camera. It is the seeing tissue of the eye. When the focused light hits the retina, a picture is taken. Messages about this picture are sent to the brain through the optic nerve. This is how we see.
When should my child's eyes be examined?
Most physicians test vision as part of a child's medical examination. They may refer a child to an ophthalmologist (a medical eye doctor) if there is any sign of an eye condition. The American Academy of Ophthalmology and the American Academy of Pediatrics recommend the first vision screening occur in the hospital as part of a newborn baby's discharge examination. Visual function (including ocular alignment, etc.) also should be checked by the pediatrician or family physician during routine well-child exams (typically at two, four and six months of age). Later amblyopia and alignment screenings should take place at three years of age and then yearly after school age.
If you suspect your child suffers from decreased vision - amblyopia (poor vision in an otherwise normal appearing eye), refractive error (nearsightedness or farsightedness) or strabismus (misalignment of the eye in any direction) - or if there are hereditary factors that might predispose your child to eye disease, please make an appointment with an ophthalmologist as soon as possible. New techniques make it possible to test vision in infants and young children. If there is a family history of misaligned eyes, childhood cataracts or a serious eye disease, an ophthalmologist can begin checking your child's vision at a very early age.
When should an adult's eyes be examined?
Adult examinations of the eyes should be performed on a regular basis.
o Young adults (ages 20 - 39) should have their eyes examined every three-five years.
o Adults ages (ages 40 - 64) should have their eyes examined every two-four years.
o Seniors (over 65 years of age) should have their eyes examined every one-two years.
High risk adults include:
o People with diabetes
o People with glaucoma or strong family history of glaucoma
o People with AIDS/HIV
Visual Acuity, Vision Impairments and Low Vision
What are the medical terms for nearsightedness and farsightedness?
* The medical term for nearsightedness is myopia, correctable with glasses, contact lenses or, in some cases, refractive surgery (LASIK or Corneal Ring Implants).
* The medical term for farsightedness is hyperopia, correctable with glasses, contact lenses or, in some cases, refractive surgery.
* Related conditions (also correctable with glasses or contact lenses) include astigmatism and presbyopia.
What is visual acuity?
Acuity is the measure of the eye's ability to distinguish the smallest identifiable letter or symbol, its details and shape, usually at a distance of 20 feet. This measurement is usually given in a fraction. The top number refers to the testing distance measured in feet and the bottom number is the distance from which a normal eye should see the letter or shape. So, perfect vision is 20/20. If your vision is 20/60, that means what you can see at a distance of 20 feet, someone with perfect vision can see at a distance of 60 feet.
What is legal blindness?
You are legally blind when the best corrected central acuity is less than 20/200 (perfect visual acuity is 20/20) in your better eye, or your side vision is narrowed to 20 degrees or less in your better eye. Even if you are legally blind, you may still have some useful vision. If you are legally blind, you may qualify for certain government benefits.
What is visual impairment?
If neither of your eyes can see better than 20/60 without improvement from glasses or contacts, you may be defined as visually impaired. In addition, poor night vision, limited side vision, double vision and loss of vision in one eye may also determine visual impairment.
What is low vision?
Low vision is a term describing a level of vision below normal (20/70 or worse) that cannot be corrected with conventional glasses. Low vision is not the same as blindness. People with low vision can use their sight. However, low vision may interfere with the performance of daily activities, such as reading or driving.
Can eyes be transplanted?
No. Currently, there is no way to transplant a whole eye. However, corneas have been successfully transplanted for many years.
What is human genetic research?
The basis for many, if not most, diseases can be found in our genes. Genes and their protein products determine how we look and develop, how efficiently we process foods, how effectively we detoxify poisons and how vigorously we respond to infections. It is thought that more than 4,000 diseases arise from changed or mutated genes that are inherited from one's mother and/or father. Common disorders such as age-related macular degeneration, diabetes, heart disease and most cancers arise from a complex communication between multiple genes and between genes and factors in our environment. Genetic research studies are aimed at identifying these genes and understanding how changes in these genes lead to disease.
The benefits of human genetic research include medical breakthroughs made possible because of the combined commitment of participants and researchers. Identifying a gene opens many new diagnostic and treatment possibilities including earlier diagnosis of inherited eye diseases. Researchers also work to determine exactly what causes a particular eye disease and why the same disease does not effect everyone in the same way. As a result, researchers hope to develop improved treatment for specific eye diseases such as glaucoma and inherited retinal diseases including AMD. These discoveries will lead to improved eye care for future patients.
What is genetic testing?
Genetic tests, also called DNA-based tests, are some of the newest and most sophisticated techniques that we can use to test for genetic diseases. Most tests involve looking directly at the DNA in a specific disease-associated gene. The actual information of each gene is carried within the DNA itself. The DNA can be taken from cells in a sample of blood or, occasionally, from other body fluids or tissues.
The UM Kellogg Eye Center offers state-of-the-art genetic testing services through its Ophthalmic Molecular Diagnostic Laboratory. Testing allows ophthalmologists to confirm diagnoses and help patients understand their risks for certain inherited eye diseases. Kellogg is unique in its ability to offer this genetic testing service, which also provides patients with an exceptional genetic counseling program.
Are genetic study participants all patients at Kellogg?
Not necessarily. Enrollment involves donating a blood sample one time only and providing medical and family history information. This can all be done long distance. There is no cost to the participant.
What is genetic counseling?
Genetic counseling is a communication process which deals with the human problems associated with the occurrence, or the risk of occurrence, of a genetic disorder or birth defect in a family. As part of this process, the patient obtains information regarding diagnosis, treatment, prognosis and inheritance of the genetic condition or birth defect of concern to the family. In some cases genetic testing is available for specific genetic diseases.
Can my child wear contact lenses during sports activities?
Yes, contact lenses provide excellent vision for most sports. However, they do not protect the eyes from injury. Therefore, contact lens wearers should use polycarbonate sports safety goggles or glasses when participating in sports. Also see information about preventing eye injuries.
Do contact lenses prevent nearsightedness (myopia) from getting worse?
No, there is no evidence that wearing contact lenses improves vision or prevents myopia from getting worse. Also see information about contact lenses.
Can I use my eyeglass prescription to buy over-the-counter contact lenses?
No, because it does not provide the specifications for lens diameter, thickness and base curve. A new prescription must be carefully fitted by an eye care specialist to avoid serious adverse reactions.
Is it safe for me to clean my contact lenses with a homemade solution?
Using commercial saline solutions is the safest method of cleaning lenses. Some studies have shown that homemade solutions may lead to corneal infections. Also see information about contact lenses.
Computers, TVs, Lighting and Glasses
Will working at a computer screen hurt my eyes?
No, there is no evidence that working at a computer damages the eyes. However, long hours of work can be fatiguing to the eyes, neck and back. Monitor glare from various light sources can also be a problem. It is often helpful to take periodic breaks, looking off in the distance and adjusting your work station (angle of the monitor, height of the chair, changing the lighting, etc.).
Is pink-eye contagious?
Yes, viral conjunctivitis (pink-eye) is very common and is extremely contagious. Avoid touching eyes with your hands, wash hands frequently, do not share towels, and avoid work, school or daycare activities for a least five days or as long as discharge is present.
Will sitting too close to the television set hurt my child's eyes?
No, there is no scientific evidence that TV sets emit rays that are harmful to the eyes.
Why have I gradually found it harder to read without glasses?
The ability to focus on near objects decreases steadily with age and is referred to as presbyopia. Presbyopia is a natural aging of the lens. It is usually near the age of 40, when glasses or bifocals are prescribed to correct this condition.
Are sunglasses good for my eyes?
There is a benefit to wearing UV protective lenses--wearing them may protect against cataract formation. Clear lenses with UV protection may offer greater protection than dark lenses because they allow the eyes to be exposed to more light. This causes greater constriction of the pupil which lets less light enter the eyes.
Is my child likely to inherit my need for glasses?
Possibly. If both the biological parents wear glasses, your children are likely to need them as well.
Will reading in dim light hurt my eyes?
No, but most people are more comfortable reading with proper lighting which is bright enough to provide good illumination but not so bright as to cause glare.
How often do I need to get my prescription changed?
There is no predetermined schedule for changing glasses or contacts. It is necessary to change your prescription only when it no longer provide adequate correction. However, it is still a good idea to have regular eye examinations.
What materials are available for glasses?
Some of the newest materials for frames include titanium (virtually indestructible) and polycarbonate materials (recommended for high impact sports). Lenses are also made from polycarbonate materials, other types of light weight plastics and glass. Coatings include UV protection (recommended for all types of lenses), scratch-resistant protection, polarization, anti-glare and others. See the Kellogg Optical Shop for more information about glasses.