1. What is the difference between an ophthalmologist, an optometrist, and an optician?
An Ophthalmologist (M.D.) is a physician and surgeon who specializes in the prevention and treatment of eye disease and injury and the complete medical and surgical care of the eyes. After four years of undergraduate college, an ophthalmologist completes four years of medical school training to gain broad experience in all aspects of healthcare. A year of general internship is then completed, followed by three or four more years of training in ophthalmology specialty studies are completed to gain in-depth knowledge of the treatment and management of all eye and visual system diseases. Further subspecialty training can be obtained by choosing to spend an additional year or more in fellowship training in a particular area of interest (such as glaucoma). For example Dr. Hasty attended St. Louis University Medical School, then did his internship at the Oakland Naval Hospital, Oakland, California. His ophthalmology residency training was in Oakland, California, the University of California San Francisco, Stanford University, and the University of Florida Gainesville. His Glaucoma subspecialty fellowship was completed at the Doheny Eye Institute of the University of Southern California Los Angeles.
An Optometrist (O.D.) is an eye doctor who examines, diagnoses and treats disease of the eye and associated structures. Optometrists also prescribe glasses, contact lenses and low vision aids. An optometrist completes four years of undergraduate studies and then four years of optometry school. Further subspecialty training can be obtained if selected to do an optional residency program.
An Optician makes, verifies, and delivers glasses (lenses and frames) and contact lenses using a prescription from an ophthalmologist or optometrist. Opticians analyze and interpret prescriptions and help determine which products best meet the customer's needs, and then deliver these finished products to the patient.
2. Do computer video display terminals damage your eyes?
There is no convincing scientific evidence that computer display terminals (VDT) are harmful to the eyes. However, complaints of eyestrain and fatigue are common with VDT. Because of this, safety concerns are receiving much attention and research. So far, extensive testing by government laboratories has established that VDTs emit little or no harmful ionizing radiation (such as x-rays), nor non-ionizing radiation (such as ultraviolet) under normal conditions. In fact, the amount of ultraviolet produced by a VDT is a fraction of that produced by fluorescent light bulbs.
Can VDTs cause eyestrain?
VDTs definitely are associated with eyestrain. One can notice a variety of symptoms from redness, watering, and irritation to fatigue and heaviness of the lids along with difficulty in focusing. Much of this is related to focusing at a single distance for a prolonged period of time while sitting at a VDT. Headaches, backaches, and muscle spasms can also occur and are related to the ergonomic positioning of the person at the VDT. Rearranging your work station and providing proper periodic breaks relieve many of these symptoms.
How can I prevent eyestrain at the VDT?
Most people prefer their workstation to place the VDT slightly farther away than usual reading distance. The top of the screen is most comfortably placed at eye level. Lighting should be arranged so that reflections and glare are minimized.
Remember that periodic rest breaks are important. Prolonged use of a VDT results in long periods of unchanged body, head, and eye position, which can lead to fatigue. Blinking is decreased during concentration at the VDT so that dryness results. Lubricating eye drops (artificial tears) can help with this situation.
What are the special vision needs of VDT users?
Because the VDT screen is usually higher and at a slightly greater distance than usual reading, normal bifocals or reading glasses may not be sufficient. If one uses a VDT for many hours a day, a special pair of "computer" glasses can be tremendously helpful. Even people who normally do not need glasses may need a small correction to help them with eyestrain at prolonged VDT usage. An ophthalmologist can evaluate you for these needs and prescribe them when necessary. A comprehensive medical eye exam will also help rule out other problems that could be perceived as eyestrain.
3. What are floaters?
You can occasionally see small specks or cobwebs moving in your field of vision. These are known as floaters. They are most easily seen against a plain background such as the sky or a blank wall. Floaters are actually tiny clumps of cells or gel within the eye that cast shadows on the retina. While they may appear to be an object floating in front of your eye, they are actually floating inside your eye. The central part of your eye is filled with a gel known as vitreous. Commonly, in middle age, this vitreous gel begins to thin and shrink, and can form lumps, clumps, and strands inside the eye.
Are floaters ever serious?
As the vitreous gel shrinks and pulls away from the back of the eye, the retina can sometimes be torn. This can result in a small amount of bleeding, which appears as innumerable fine specks of floaters in your vision. A torn retina is always a serious problem as it can lead to retinal detachment and serious visual damage. You should see an ophthalmologist as soon as practical for a sudden onset of new floaters or floaters associated with flashes of light. If you have symptoms of lost vision or loss of peripheral vision, this is an emergency and you should immediately seek an ophthalmologist's care.
4. What causes flashing lights?
Any injury to the retina results in flashing lights since the retina is not capable of any sensation of pain. Usually flashes represent some tugging of the vitreous on the retina, creating the sensation of light. For any new sudden onset of flashes, you need a complete ophthalmologist's examination to rule out the possibility of a torn or detached retina.
Can migraines cause flashing lights?
Some people experience flashing lights that appear as zigzag or jagged lines of "heat wave" appearance in both eyes preceding the onset of a migraine headache. Typically, this visual symptom lasts 10 to 20 minutes, and then gradually fades away on its own. Commonly, a migraine headache, nausea, weakness, or dizziness can follow this. On some occasions, no other symptom of headache or other migraine symptom follows the eye symptom. If this is a new occurrence for you, a complete eye exam is indicated; however, if you have had these before with your migraines you need to watch to be sure the symptoms clear over a normal time frame.
5. What about sunglasses and UV hazards?
Americans enjoy outdoor living, sports, hunting, fishing, boating, and skiing. It is important to recognize that sunlight is a major source of UV radiation that can be harmful to the delicate tissues of the eye.
Ultraviolet radiation is divided into two major bands, UV-A and UV-B. UV-B is the more energetic shorter wavelength and causes blistering of sunburn as well as being associated with skin cancer formation. UV-A is close to the blue of visible light and is responsible for skin tanning and browning. It has been implicated as an accelerator of aging changes of the skin. Midday sun and reflected sunlight off of snow, water, and white sand cause the highest UV exposure.
UV rating of sunglasses
There are no consistent labeling standards for sunglasses; however, several features should be looked at carefully. Sunglasses labeled as "UV absorbing" will usually absorb all of the UV-B but may or may not completely remove the UV-A or protect you on the blue spectrum. Sunglasses marked as "blocks 99% of ultraviolet" will give good blockage of both UV-A and UV-B. Some manufacturers use the description "UV absorption up to 400 NM. This should absorb 100% of UV-A and UV-B. Outdoor enthusiasts claim that an amber tint makes distance objects more distinct in snow and haze, and these are popular among skiers, hunters, and pilots. Be certain that this type of sunglass also indicates complete UV absorption.
"Polarized" lenses cut down reflected glare and are especially useful for boating, fishing, and driving. Polarization has no effect on UV absorption so check UV absorption rating also.
"Wrap-around" glasses are shaped to keep light from entering around the edges of your frame into your eyes. Studies show that enough UV enters around ordinary flat eyeglass frames to reduce the benefit of this protection. Large framed wrap-around glasses will provide significantly better protection as long as they have good UV absorption qualities.
"Gradient" lenses are shaded from top to bottom and help significantly in cutting the glare from the sky. They are useful for driving but not very useful for use on the snow or at the beach where reflection from below is a concern.
"Photochromic" lenses automatically darken when outside and lighten when brought inside. The darkening takes place in 30 to 40 seconds, however, the lightening of these lenses takes about three to five minutes. Check the label on these lenses for specific UV absorption characteristics.
Living near the equator, having reflection off of snow, water, or sand, and being out in the midday sun all increase your UV exposure significantly. For those at special risks (family history of cataract, family history of macular degeneration, or a personal history of pterygium), special care should be given to always wearing good UV blocking wrap-around sunglasses and a brimmed hat during significant sunlight exposure. Just wearing a brimmed hat reduces UV exposure roughly in half.
Be careful with your eyes! They need to last your entire life!