Why you probably need new sunglasses

Collection MM Productions / Digital Vision / Getty Images

Updated December 16, 2014.

Written or reviewed by a board-certified physician. See About.com Examination Council.

Even if you need to wear sunglasses all year round, while outdoor, sunny summer days usually have most of us running an ophthalmologist or an outlet mall to buy new glasses. However, with all the options of sunglasses available today, the choice of a partner can be a difficult decision.

It is very difficult to choose among the many options frame style, but also lenses picking face.

Objectives in many shades and colors and can be colored, if preferred. They know the advantages and disadvantages of polarized lenses?

These are polarized lenses?

The sunlight absorbed or reflected in many different directions. Sunlight bounces horizontal surfaces such as water, soil or the hood of a car is generally in the horizontal direction, as reflected. This reflection produces a dazzling source of agitation not only create visual discomfort, it can also lead to a potentially blinding eye. Glare has the potential to create a very dangerous situation, especially while driving. Polarized glasses contain a laminated filter which allows light to pass only vertically directed. This locks the horizontal light-oriented virtually eliminated.

The most common colors are gray and brown polarized lenses. However, according to the manufacturer, many other colors can be available.

What are the advantages of polarized lens?

Sunglasses quality usually includes polarized lenses. A polarized lens provides the following advantages over non-polarized lenses:

• Improved visual comfort
• Improves contrast and visual clarity
• Reduces eye strain
• Let true color perception
• It reduces glare and eliminates glare

You need polarized glasses?

Originally polarized lenses were mainly used by boaters and fishermen. Since a polarized lens reduces glare, it's much easier to fish and other obstacles, the display to see in the water. Today, however, polarized lenses are popular among the public and is available in many popular brands sunglasses. Polarized glasses are good for people who do a lot of driving and are also an excellent choice for sports enthusiasts.

What are the disadvantages of polarized lenses?

Polarized glasses can be confusing for people to see clearly (LCD) require LCD screen. In fact, the use of polarized lenses make difficult to read LCD display and can even disappear completely believe in certain angles. Therefore excavator driver or driver should not use polarized lenses. While polarized lenses are usually recommended for snow, skiers complain some, that they differ enough contrast between layers of ice, snow and mountains that do not offer a risk to the skier.

What are the alternative to have polarized lenses?

Most lenses sunglasses are simply colored with a single color. Sunglasses quality Some manufacturers offer different polarized lenses, often made of polycarbonate or glass of high quality and are very attractive to some companies even more polarized lenses. The disadvantage of friction colored lenses is that, although the reduction in brightness that does not eliminate glare like a polarized lens. In addition to color, some colors, the way we perceive and distinguish colors affect. Some researchers questioned whether a tinted lens allows it to expand the students who can provide visual comfort, but it can actually allow more ultraviolet radiation from the eye when the lens is not integrated UV protection.

Polarized lenses and UV protection

Most lenses Polarized Sunglasses offer quality UV protection. However, it is wrong to assume that just because a lens polarized to protect against UV rays. Always check the label or protect the product providers lenses against UV rays. Many products polarized lenses are as known from an impact-resistant polycarbonate, which contains a UV-protective material.

Sunglasses and lens options

When buying a pair of sunglasses, the following options can also appeal to you:

• Gradient shades: a gradient has a completely dark dye tip of a lens and gradually disappears almost transparent at the bottom of the lens. Double gradient colors are dark at the top, will be clarified and to be dark again. Double gradient will act to block light from above and below.
• Mirror coatings: A layer of mirror reflects light from the user. As the name implies, it is similar to a silver mirror. A mirror layer can be combined with a dye, which makes it an excellent alternative to a polarized lens. The user may not see the mirror, because it is only visible to others. Mirror coatings are also a popular addition as a fashion statement. The mirror layer as one-way mirrors, to prevent others from catching your eye works.
• Lenses: lenses darken and change color when the user leaves on sunlight. The color tone is activated by UV-light. When the user moves indoors, the lenses are Clear slowly. Although lenses are very diverse, they do not get as dark as sunglasses while driving. Car windows do not allow enough UV light to go completely to obscure the lens.

_Source:

_{White, Debra. Sponsored Manual Sunwear Sun Alliance Vision "Sun Meta Options 101", pages 4-6.}

Is it normal that & quot; the star & quot;?

Hitoshi NishimuraCollection / Taxi Japan / Getty Images

Updated June 7, 2014.

Question: Why do I see the stars?

Occasionally I see the stars. What do I see? Is it bad for the eyes?

Answer: "the stars" is a common visual claim, but is normal and usually harmless. If you close your eyes and rub, you will probably see spots and flashing lights. These pictures you can see, are called "phosphenes", a phenomenon that without seeing from entoptic experience the light, the light brings the eye.

Phosphenes generated by the pressure in the eye. These pressures lead to different patterns through the optic nerve.

Can see these stars or points of light after sneezing occur cough deep blow to the head or low blood pressure (such as that position too quickly.)

Some people see flashes or light lines, up to 10-20 minutes hot. These flashes of light are caused usually by a spasm of blood vessels in the brain, or migraine. If a headache follows the flashes, it is called a "migraine". If these lines of light flashes or no headache occurs, it is called an "eye migraine" or migraine without headache.

Although usually harmless, flashing light may be a warning sign of something more serious often. A comprehensive eye examination is needed to determine the cause.

_Source:

Patient Education Institute. Flashes and floaters. National Institutes of Health of 2004.

What the student is his health Size

Collection Tim Flach / Stone / Getty Images

Updated December 16, 2014.

Written or reviewed by a board-certified physician. See About.com Examination Council.

Question: student Size

Why pupil size is important?

Answer: The size of the pupil, a physician can tell a lot about your health. The size of the student press is an important tool for unlocking potential medical problems in your body.

What is the student?

The pupil is the black circle in the center circle of the iris, the colored part of the eye. The pupil is actually a hole, sensitive to light passing through the light onto the retina at the back of the eye layer.

The student is similar to an opening in the machine to be controlled as much light you want in the camera.

The student can develop greater (dilate) or small contract (narrowing). His iris contains muscles which respond to external stimuli to control the amount of light on the retina. In bright light, the pupil constricts to reduce the amount of light in the eye. In the dark or low light conditions, the pupil dilates to more light into the eye allows to improve visibility. Normal pupil size tends to between 2.0 and 5.0 mm, depending on illumination. Pupil size is usually larger in younger people.

What is the size of the pupil can reveal?

When the doctor examined her students, he or she should seek anisocoria first. Anisocoria is a condition in which the size of the pupils are uneven. Twenty percent of the population is anisocoria normally and shows nothing unusual. In some cases, however, the extent of unequal pupils may be a sign for the disease.

Your doctor examines the size and shape of the pupil both light and darkness. Aware of the speed and quality of pupillary response to stimuli has also been noted.

Your doctor may also test your pupillary response to stimuli, such as small print next. All differences between the students is also observed.

The pupil is controlled by a very long nerve pathway in the body. The nerves that begins to control the students in the brain, and then moves down into the spinal cord above the upper lung, below the subclavian artery, neck and brain enhancements and finally moves close to the optic nerve and then to the students , Any disruption along this route could potentially cause effects on the nervous and changes in the response of the student.

What conditions can affect the size of the pupil?

abnormal pupil size can sometimes be a sign of illness. The following conditions may affect the size of the pupil:

• Glaucoma: A student in the medium may be a sign of glaucoma long.
• Aneurysm: An aneurysm is growing in certain blood vessels in the brain and dilated pupils cause other symptoms.
• Lung cancer: Lung cancer, which affects the upper lungs may affect students nerve fibers.
• Brain tumor: When a tumor or mass near the origin of nerve fibers student, it can cause problems in the pupil.
• Recreational use of drugs: Certain drugs can dilate the pupils or contract abnormally.
• Drugs: glaucoma and antihistamines can sometimes cause dilated pupils.
• Head injury: head injury or concussion may cause unequal pupils.
• Horton headache: Cluster headaches can cause constricted pupil.
• AVC: Sometimes a stroke can cause changes in pupil size.
• Syphilis: Syphilis can Argyll-Robertson pupil lead. Argyll-Robertson pupils are not responding small, misshapen unequal pupils contract with a certain emphasis, but usually on light.

How does pupil size measured?

Pupillometer Ophthalmologists use infrared to measure the size of the pupil. The device consists of a chamber in line for infrared detection and two infrared lamps to illuminate the student side.

How does pupil size affect LASIK?

People with large pupils are usually good candidates for LASIK and other refractive procedures. Naturally expands have pupils or pupils who could expand much in low light to increase the occurrence of glare and halos after Lasik. Measurement of pupil size is in deciding whether LASIK is right for you step important.

_Source:

_{Slmovits, Thomas L and Ronald Burde. Neuro-ophthalmology. Yearbook Europe Ltd., in 1994th}

4 The causes of eye irritation

Choice RF / Getty Images B2M Productions / Photographer

Updated May 30, 2014.

Written or reviewed by a board-certified physician. See About.com Examination Council.

Many people visit the ophthalmologist with a common complaint: "I feel like sand in the eyes when I wake up in the morning," You complain that his tired eyes, itching, burning or gritty feeling like. a small piece of sand or particles stuck in the eye. They also complain of a hard time to open your eyes in the morning and speak very sensitive to light.

When they go to the ophthalmologist who have already purchased several types of over-the-counter eye drops, trying to find some relief.

Although sometimes falls a certain short-term relief, usually only sting or burn a little drop and do not contribute almost nothing (and if they need help, the cycle seems that begin the next morning).

If you think your eyes are gritty and irritated, you may be suffering from a particular disease. The following four conditions can cause a foreign body sensation in the eyes.

• Dry eye
  Dry eye syndrome often a gloomy feeling of sand in the morning that the situation in general, all the empire days. Can cause dry eye of varying severity unpleasant, irritating symptoms. If your eyes are dry eyes can do more than they burn itch. His view seems to be fluctuate too much and may take some time to have a good clear view of the morning. Additionally, the eyes must generate no tears during the night, because his eyes closed, and unstable tear film and includes a lack of quality and quantity.

  While artificial tears are a good start to treat dry eye, more importantly, is the type and brand of artificial tears that determined by your ophthalmologist. It's important to see your eye doctor because sometimes eye drops are not enough. You may have a gel or ointment in the eyes before he infuse sleep at night for protection. Your doctor may recommend medications or special procedures of the eye, as punctal occlusion to treat their dry eye.

• Nocturnal Lagopthalmos
  If you complain of sand in your eyes, your doctor may ask you if anyone, like your spouse, have you ever say that sleeping with your eyes open. You may think that your doctor is going too far with this, but lagophthalmos is a common disease, especially in children.

  In some people, the eyelids do not close, so that the cornea exposed to the end in the atmosphere overnight eye. Since not active flashes, his eyes dry and clearly called keratitis inflammation developed. This can cause light sensitivity and a very high sand, feeling of sand in the eyes in the morning.

  Lagophthalmos can be caused by a number of different conditions. In children, it is usually an anatomical problem which has become too fast. Lagophthalmos can also from a cosmetic eyelid surgery it was a little too aggressive occur. The skin may be high or too tight, without a full complement fixed or close during sleep.

  Other conditions, such as thyroid eye caused by proptosis cause lagophthalmos. People with nocturnal lagophthalmos should change not be afraid to use eye drops, ointments for thicker eyes to speed healing and reduce the symptoms.

• Floppy eyelid syndrome
  Floppy eyelid syndrome (FES) is a relatively rare condition that. By loose upper eyelids that are easily transferred to the interior FES usually in men who are overweight, middle-aged can be seen. Some people with FES also suffer from obstructive sleep apnea.

  Sometimes, people with the FES, turning in his sleep or accidentally a certain way on a cushion inadvertently moved to the inner eyelid. FES treatment often includes artificial tears and antibiotics to reduce irritation if signs of infection occur, are available. Eyeshield band or on the lid closed during sleep can help to keep your eyes dry.

• Blepharitis
  Blepharitis is a group of diseases affecting the eyelashes, eyelids and glands of the eyelid. Blepharitis is often a bacterium that caused in the skin, but some people, because of age, skin changes or lack of proper hygiene, tend to accumulate more of these bacteria eyelids. Sometimes the glands of the eyelid are clogged or infected may cause dysfunction of the meibomian gland styes or eyes.

  Blepharitis tends to cause redness and inflammation. People with blepharitis can wake up in the morning with crusty eyelids. Sometimes the dry mucus are falling into the eye, causing irritation or gritty sand.

What To Do

When you wake up more than once with a sandy beach, a foreign body sensation in the eyes, you should see your eye doctor as soon as possible. The doctor may ask the following questions:

1. If you have to sleep with partially open eyes?
2. Your symptoms worse on waking?
3. Have your symptoms improve as the day goes on?
4. You sleep in a withdrawal of air or on the roof?

Your doctor will check your eyes with a slit lamp to for signs of dryness and other signs of inflammation such as keratitis look. He or she will teach a special layer where the eye dryness or inflammation seen. The location of the patch to your doctor clues to the causes of these symptoms.

_Source:

_{Review of Optometry 'as the morning paper. " April 15th 2012, S. 75-77.}

10 reasons why you have red eyes

2. Blepharitis

Blepharitis causes inflammation of the eyelids and eyelashes and can be caused by lack of hygiene of the eyelids. The sebaceous glands of the eyelid, allergic reactions, bacterial infections, or lice on eyelashes are also frequent causes of blepharitis. If you have blepharitis, you can a gloomy or burning eyes, excessive tearing, itching, red and swollen eyelids, dry eyes, or crusting of the eyelids notice. The condition is not contagious and does not usually result in permanent damage to your eyesight. / P> More information »

Learn all about this annoying eye stye

Stye eye. Photo © ADAM

Update June 6, 2014.

Written or reviewed by a board-certified physician. See About.com Examination Council.

They start a little pain in the eyelid blinks feel every time. You look in the mirror to find a small red spot at the base of the bottom lashes. If you've ever had a stye, you probably know these symptoms as the beginning of a stye eye unhappy.

Although the occurrence of a stye may unsightly, sometimes, usually harmless. A stye is a small lump, somtimes outside or inside the eyelid appears.

A stye is also known as a stye. A stye develops from a follicle or sebaceous gland of the eyelid twitch is clogged with excess oil, dirt and bacteria. Styes can be a complication of blepharitis, but seem to be caused by stress.

Symptoms stye:

If you have a stye, you may be suffering from watery eyes, pain, tenderness, itching, or redness. Your eyes feel bruised and sensitive to light. You'll also notice a red bump on the eyelid. If the stye is severe, you can develop an internal stye. Pus built in the middle of the pigsty, which. To a yellowish stain that looks like a button If the stye is painful, you'll feel better when it breaks and drains pus.

Stye causes:

Blocked glands of the eyelid appears to be one of the causes of stye. If you often suffer from chronic blepharitis they can accumulate bacteria and infect the glands, making it more likely to develop stables. Eye makeup sometimes causes stalls, especially if you make up to share with others. Also, use extra eye makeup can sometimes lead to the development of a stye.

Some people notice the development of a stye in times of stress.

How to prevent a stye

Sty Treatment:

Styes are longer than most people usually want to stop. Use the following steps to the healing time for you to speed up:

• Hot compress:
  Press a warm washcloth against the eyelid 10 minutes easily. This assay up to 4 times per day.
• Massage:
  Massage the affected area.

• Apply a few drops ophthalmic eye drops or antibiotic ointments can help to cure the infection. Your ophthalmologist can tell you that it is best for your situation.

Stye complications:

As a stye draw more of a hailstone to be. A hailstone is clogged an oil gland that has become infected. A hailstone usually causes pain and inflammation, as well as a hard lump or bump on the eyelid. Your ophthalmologist can run propose chalazion puncture and possibly an injection of steroids to reduce the swelling.

Tips for Dealing with pigsties:

1. While you might be tempted to push or pop are a stye, is probably best to leave the pigsty drain itself. Press the stye can cause serious eye infection.
2. Ask yourself if you, if you are applying hot compresses to have your doctor a pigsty in particular.
3. To avoid the possibility of infection, avoid using makeup or eye contact lenses until the sty heals completely.

_{Source: University of Virginia Health System. Hordeolum (stye) on February 12 of 2004.}

What & # 039; Blind & # 039; Really it mean?

Clarissa LeahyCollection / The Image Bank / Getty Images

Updated December 16, 2014.

Written or reviewed by a board-certified physician. See About.com Examination Council.

Question: What does it mean blind!

Answer: A person is considered blind if he or she has a best corrected vision 20/200 in the better eye sight.

Many people think that they are, because if a pair of glasses or contact lenses that they can not see a foot in front of his face are blind away. However, if put in your vision correction, you have enough 20/20. Provided that it can be corrected to 20/20 with some visual aid, is not as blind.

Did you know that the "legal blindness" is at the best level of vision you can achieve the best view, or on the basis can be cured? Most governments and health care institutions agree that the legal blindness is defined as one of the following:

1. Legal blindness as visual acuity of 20/200 or worse in the better eye sight defined.
2. A field that is only 20 degrees.

What "blind" really mean?

Is your blind eyes see better can not be corrected better than 20/200 with glasses or contact lenses. The best way to understand this is to a normal person to think with 20/20 vision. This person has the ability to remain 200 meters away from an object and see every detail, while legally blind person would have to move all the way up to 20 meters, to see the same level of detail. A legally blind person has difficulty seeing far away or very near objects.

If a person is a field of 20 ° only, tunnel vision considered, he or she will be blind.

A normal person has a visual field of 180 degrees. People with a limited field of view can be seen central detail, but can not see anyone standing beside his own shoulder. These people have difficulty with mobility, such as safe driving is almost impossible. Hiking in a dark movie theater can be a big problem.

The definition of legal blindness was developed to help people on welfare. Also, as you can imagine, the Department of Motor Vehicles (DMV) has to have a safer means for measuring the vision of maintaining our roads and highways.

_Source:

_{Lavine, Jay B. Eye Care book, p.24-25. New Books 2,001th}