EyeCare

The eyes are a precious, extremely delicate organ. Seeing and knowing how to see are activities at the core of our existence. From early infancy, good eyesight is the key to perceiving the world, discovering shapes and colors and putting us in contact with our surroundings. Here you will find everything you need to know to care for your eyesight and that of children.

This is for the opticals section.If you don't find the answer that you were looking for write to us, we will be glad to answer.

Q :What are Contact Lenses?
A:Contact lenses are thin transparent plastic discs that sit on the cornea. Just like eyeglasses, they

correct refractive errors such as myopia (nearsightedness) and hyperopia (farsightedness). With these conditions, the eye doesn't focus light directly on the retina as it should, leading to blurry vision. Contact lenses are shaped based on the vision problem to help the eye focus light directly on the retina.

Contact lenses are closer to natural sight than eyeglasses. They move with your eye and correct the refractive error closer to the eye to allow for a more natural field of vision. They don't get in the way of your line of sight, like glasses can. Contact lenses can be worn all day, or even several weeks at a time, so you don't have to worry about putting them on and taking them off.

Contact lenses stay in place by sticking to the layer of tear fluid that floats on the surface of the eye. Eyelid pressure also holds them in place. As the eye blinks, it provides lubrication to the cornea and helps flush away any impurities that may have become stuck to the lens.

Q :What types of contact lense are available?
A:Types of Contact LensesOriginally, all contact lenses were made of a hard plastic called polymethyl methacrylate (PMMA). This is the same plastic used to make Plexiglas. But hard lenses don't absorb water, which is needed to help oxygen pass through the lens and into the cornea. Because the eye needs oxygen to stay healthy, hard lenses can cause the wearer a lot of irritation and discomfort. The upside to these lenses is that they are relatively easy to clean because bacteria don't stick very well to them.

Soft contact lenses are more pliable and easier to wear than hard lenses because they're made of a soft, gel-like plastic. Soft lenses are hydrophilic, or "water loving," and absorb water. This allows oxygen to flow to the eye and makes the lens flexible and more comfortable to wear. Many companies bill their soft contact lenses as "breathable" because they transmit a high amount of oxygen to the eye. Letting more oxygen reach the eye means that you can wear soft

contact lenses for longer periods with less chance of irritation

Several different types of soft contact lenses are available:

Daily-wear lenses - You remove these each night before going to bed.
Extended-wear lenses - You can wear these for several days or weeks without removing them.
Disposable lenses - You can wear these lenses for a day, a week, or even several weeks before throwing them away.
Color-tinted or cosmetic lenses - These lenses change the color of your eyes or tint them for clearer vision outdoors. Other cosmetic lenses drastically change the eye's appearance. Many people use them for the theater or for Halloween.
Ultraviolet (UV) protection lenses - These lenses protect against harmful ultraviolet rays from the sun.
Corneal reshaping lenses - You wear these lenses overnight and they gradually reshape the cornea to correct your vision. When you take them out, you can temporarily see clearly without contact lenses.

Q :Can contact lenses cause a problem to the eye?
A:To get a prescription for contact lenses, you need to visit an optometrist or ophthalmologist. Both can examine your eyes, give you a vision test and prescribe the right kind of corrective lens for your eyes. Today you can buy contacts from mail-order catalogs, over the phone and on the Internet. You still need a current prescription, though. The Food and Drug Administration (FDA) advises that you order from a reputable supplier and get a regular check-up from your eye doctor to ensure that your lenses fit properly. Ill-fitting lenses can move around in the eye and scratch the cornea. Although contact lenses are generally safe, they can cause problems. Usually, the problems are minor, such as eye discomfort, redness, or excess tearing. In rare cases, contact lenses, especially extended-wear lenses, can cause a serious infection called a corneal ulcer. This infection can cause redness, pain, tearing and light sensitivity. If left untreated, it can lead to permanent vision damage. Infections are most common in extended-wear contacts, because the eyes produce fewer oxygen-carrying tears when they are closed during sleep. But even lenses worn just during the day can cause vision loss if they don't allow enough oxygen flow to the cornea. Failing to keep the lenses clean can lead to an infection, for example with the parasitic Acanthamoeba keratitis. This infection causes symptoms similar to those of corneal ulcers.

You should also be careful if you buy cosmetic lenses at places (such as a flea market or costume store) that don't specialize in contact lenses. Lenses that aren't properly sterilized, or that don't fit your cornea correctly, can cause infections and damage your vision.

Cleaning Tips

Clean, rinse, and disinfect your daily-wear and extended-wear lenses, and clean the case regularly.
Wash your hands before putting in your lenses.
Never touch a contact lens to your mouth. Saliva has bacteria that could cause an eye infection.
Only use commercial sterile saline solutions to clean your lenses. Homemade versions made with salt tablets can lead to dangerous infections.
Never swim while wearing your contact lenses.
Never share your lenses with anyone.

Q :What key signals might reveal a vision disorder in infants or children?
A:Behavior

Squints, especially for distance vision.
Holds objects unusually close or far away.
Complains of double vision or a stiff neck
Intolerance to light
Pressing of the hands over closed eyes
At one month, does not fix gaze on people or objects 6 feet (2 mt.) away
Continuous or jerky movement of the eyes
Doesn't perceive obstacles

Physical indications

Misalignment of the eyes, cross-eyes
Extremely small eyes or voluminous eyes that don't open properly
Persistent or abundant tearing
Milky, cloudy cornea

Q :What is a cataract and how would i know i have a catract?
A:A cataract is a clouding of the lens of the eye. The normal lens is clear and brings light into focus so we can see. A cataract can be compared to a window that is frosted or “fogged” with steam. It is a common cause of poor vision, especially for older people, but it can be treated. A cataract is not a film over the eye, or a cancer; It is not caused by using your eyes too much; it is not spread from one eye to the other. A complete exam by your eye doctor, can find out if your eye has a cataract and whether your eyes have any other problems.

If you have a cataract, you may have:

Blurry vision, with no pain;
Glare, or sensitivity to light;
Many eyeglass prescription changes;
Double vision in one eye;
A need to read with brighter light;
Poor vision at night;
Dull or yellowed color.

Q :What are the existing eye conditions?
A:Normal Vision: Much like a camera,the eye works by focussing light rays. Light rays enter the eye through the cornea. The cornea takes widely diverging rays of light and bends them through the pupil. The lens of the eye then makes the delicate adjustments in the path of the light rays in order to bring the light into focus upon the retina. The photoreceptor nerve cells of the retina change the light rays into electric impulses which are carried by the optic nerve to the brain where an image is perceived.

Myopia: Myopia or "nearsightedness" is that dioptric condition of the eye in which parallel rays of light from infinity come to a focus in front of the retina. When you are myopic, you are able to see clearly up close, but everything in the distance is blurred. Myopia is the result of an eyeball that is too long, or a cornea that is too steeply curved.

Symptoms of Myopia
The inability to see distant objects clearly or the need to hold a book too close to the eye while reading are the usual complaints of myopic patients. Eyestrain and headache may also occur due to myopia. Sometimes the patient sees black spots floating before the eyes and occasionally flashes of light are also noticed.

Treatment
The treatment of myopia comprises prescribing appropriate concave lenses and paying attention to ocular hygiene. The myopic patient is fitted with eyeglasses or contact lenses that compensate for the elongated shape of the eyeball, thus allowing the light to focus properly on the retina.

Hyperopic Eye:Hyperopia or "farsightedness" is an error of refraction wherein parallel rays of light come to a focus behind the retina. When you are hyperopic, you will have no problem seeing objects in the distance, but there will be difficulty in focusing clearly on near objects. Hyperopia occurs when the eyeball is too small or the cornea is too flat.
Symptoms of Hyperopia
Common symptoms of farsightedness include difficulty in concentrating and maintaining a clear focus on near objects, blurred vision, eyestrain, fatigue and/or headaches after close work, aching or burning eyes, poor reading ability, general tension and irritability or nervousness after sustained concentration.

Treatment

Hyperopia is corrected by prescribing appropriate convex lenses. Eyeglasses, contact lenses, or refractive surgery such as Lasik is recommended for the correction of hyperopia.

Astigmatism:Astigmatism is that condition wherein the refraction varies in different meridians of the eye. It occurs when light entering the eye is "split" into two separate parts instead of focusing on one precise point on the retina. Astigmatism is commonly caused by abnormalities in the curvature of the cornea. If you are astigmatic, you will experience a distortion or blurring of images at all distances, nearby as well as distant.
Symptoms of Astigmatism
Astigmatism may cause blurred vision, eyestrain or even headaches. It can also cause images to appear doubled, particularly at night.

Treatment

Astigmatism can be corrected with appropriate eyeglasses or 'Toric' lenses. Refractive surgery such as Lasik is also recommended for the correction of astigmatism.

Presbyopia:Presbyopia is progressive farsightedness that develops as we grow older. It is a condition that occurs as the eye's lens grows older and begins to lose some of the elasticity needed to switch focus between viewing near and far objects. The age at which presbyopia is first noticed varies, but it usually begins to interfere with near vision in the early forty's.

Symptoms of Presbyopia :

Need to hold reading material further and further away to be able to focus.
Vision is blurred at the normal reading distance; especially in poor light.
Headaches and/or eye fatigue after or during concentrated close work.

Treatment
Presbyopia is treated by wearing the prescribed eyeglasses or contact lenses that allow the eye to refract light rays effectively.

Q :How Do i prevent Vision problems related to computer work?
A:

Reduce glare. Avoid placing your computer in front of a window, as the difference in brightness from outside and your screen can strain your eyes. Also, make sure all windows have adjustable shades, so you can control the amount of light coming into the room. Anti-glare screens help too.

Check your contacts. People blink about three times less frequently than normal when they are sitting in front of the computer. While infrequent blinking can cause dry eyes for everyone, it especially affects contact lens wearers. Try to use rewetting drops often, and speak to your optometrist if you find the problem continues.

Adjust your monitor. To minimize back and neck strain, the center of your monitor should be about five to nine inches below your line of sight. In other words, if you look straight ahead at your desk, you should be able to peer over the top of your monitor.

Take a break. Keep your eyes moving while looking at various objects at various distances.

See an eye doctor for routine eye exams. Uncorrected or under-corrected vision problems can be a major contributing factor to computer-related eye stress.

Q :What are floaters? What causes this?
A:Floaters are spots or wispy objects that people see in front of their eye, typically when they're looking at a background that doesn't provide much contrast, like a blue sky or a blank wall. People are able to see particles of different sizes or shapes, wispy lines or little dots. When people move their eyes in one direction, they will see these "floaters" move in different directions and then settle down.

Almost everybody at one point in their life will see floaters. Floaters were documented thousands of years ago by the Latins as muscae volitantes, or flying gnats, so it is not a new phenomenon.

The front part of the eye is comprised of the cornea, which refracts the light coming into the eye. The lens focuses an image on the retina, which is like camera film in the back of the eye. The large space between the lens and the retina is filled with a gel known as the vitreous humor. It's a gel of the same consistency of the white of a raw egg. That gel has debris left over from the formation of the eye. So, if some debris in the vitreous humor floats between the front part of the eye and the retina, it casts a shadow on the retina, and we see this as floaters. At different times the debris moves more in line with a patient's line of sight, which is why floaters come and go.

Q :What checks should be done before i start out on the road?
A:Essential Checks
To help you see the road ahead more clearly, ensure that your windscreen is clean and scratch-free, both inside and out, at all times. Your car lights are important so make sure that the headlamp glass is clean, the bulbs are working at full strength and your lights are properly adjusted to provide good road illumination while not causing glare for other road users.

Look slightly to the left of oncoming traffic at night to avoid suffering from glare which can take some time to recover from.

Q :What type of Eye-wear is requiered for driving?
A:Drivers' Eyewear

Some spectacles are better than others for driving, with rimless designs or those with thin rims being particularly suitable as they allow greater all-round vision than those with heavy frames. Spectacles with plastic lenses are lighter and safer. Anti-reflection coatings can be applied to any lenses at a reasonable cost, helping you to see more clearly and cut down on glare, especially when driving at night.

Make sure you keep your spectacles and contact lenses clean at all times - it's best to keep a cleaning cloth in the car. It's also sensible to keep a spare pair of glasses in the car so that you never forget them. This is also important if you normally wear contact lenses because on long journeys when your eyes get tired it is often more comfortable to switch to a pair of glasses. It's also a useful safeguard if you suffer from hay fever.
Sunglasses
If you need to wear prescription glasses to drive, never replace them with non-prescription

sunglasses when it is sunny. It is dangerous and you will be breaking the law. Instead, get a pair of prescription sunglasses (which need look no different to normal sunglasses) or clip-on lenses over your prescription lenses. When using clip-on sunglasses make sure you check their suitability for plastic lenses.

You should never use tinted glasses at night. Nor should you use them in conditions of poor visibility such as heavy rain and fog . This rule also applies to sunglasses and tinted motorcycle helmets.

Q :What is a sty?
A:A sty (sometimes spelled stye) is a tender, painful red bump located at the base of an eyelash or on, inside, or under the eyelid. The medical term for a sty is hordeolum.

A sty results from an acute infection of the oil glands of the eyelid (meibomian glands) that occurs after these glands have become clogged. A sty also may arise from an infected hair follicle at the base of an eyelash. The bacterium Staphylococcus aureus is responsible for 90-95% of cases of styes. A sty can develop as a complication of Belpharitis (inflammation of the eyelid).

The term external hordeolum has been used to refer to a sty that develops at the base of an eyelash involving a hair follicle of the eyelid, whereas the term internal hordeolum refers to a sty arising due to blocked meibomian glands in the eyelid.

A sty is sometimes confused with a chalazion (see below), which is a cyst or a specific type of scarring (chronic inflammation) arising in the meibomian glands of the eyelid. In contrast to a sty, a chalazion is usually painless.

Q :What is "pink eye"? What infections cause pink eye and how are they treated?
A:Pink eye or conjunctivitis refers to a redness or irritation of the membranes on the inner part of the eyelids and the membranes (conjuctiva) covering the whites of the eyes. These membranes react to a wide range of bacteria, viruses, allergy- provoking agents, irritants, and toxic agents, as well as to underlying diseases within the body. Viral and bacterial forms of conjunctivitis are common in childhood but can occur in people of any age. Overall however, there are many causes of pink eye. These can be classified as either infectious or noninfectious.

Viral Pink Eye

The leading cause of a red eye is virus infection. Viral pink eye symptoms and signs are usually associated with more of a watery discharge, not green or yellow in color, and is frequently associated with viral "cold-like" symptoms. The eyelids may be swollen. Sometimes looking at bright lights is painful. While viral pink eye may not require an antibiotic, those affected should see a doctor, as occasionally this form of pink eye can be associated with infection of the cornea, (the clear portion of the front of the eyeball). This infection must be correctly detected and treated. Viral pink eye is highly contagious. Viral pink eye usually resolves in seven to ten days after symptoms appear.

Bacterial Pink Eye

The bacteria that most commonly cause infectious pink eye are staphylococci, pneumococci, and streptococci. Bacterial pink eye symptoms include:

eye pain,
swelling,
redness, and
a moderate to large amount of discharge, usually yellow or greenish in color.

The discharge commonly accumulates after sleeping. Affected children may awaken most unhappy that their "eyes are stuck shut," requiring a warm wash cloth applied to the eyes to remove the discharge and lots of reassurance that their "eyes still work!" This bacterial pink eye responds to repeated warm wash cloths applied to the eyes (try applying these to your child's eye one eye at a time during a favorite video!) and antibiotic eye drops or ointment prescribed by your doctor.

Be careful not to use medication prescribed for someone else, or from an old infection, as these may be inappropriate for your current infection or may have been contaminated from other infections by accidentally touching the medicine bottle to infected areas. A safe, effective, and "less-scary-for-your- child" method of putting drops into the eyes involves asking your child to lie down flat, suggesting she merely "close your eyes" and placing the recommended number of drops in the inner corner of the eye, next to the bridge of the nose, and letting them make a little "lake" there. When your child relaxes and opens the eyes, the medicine will flow gently into the infected mucous membranes without the need to "force open" the eyes.

When you feel that you or your child might have bacterial pink eye, it is very important to see your doctor immediately for several reasons. First, if the cause is a bacterial infection, an antibiotic will be needed to help the infection-fighting immune system to kill this infection. Secondly, if you are experiencing other symptoms such as a runny nose, cough, earache, etc., there is a good chance that these symptoms are caused by the same bacteria and an oral antibiotic may very well be needed to reach these germs along with the antibiotic drops or ointment for the eyes. Finally, your doctor will want to exclude the possibility that the infection has spread to areas where the symptoms may not yet be recognizable.

Chlamydia Pink Eye

Pink eye due to infection with Chlamydia is an uncommon form of bacterial pink eye in the U.S., but is very common in Africa and the Middle Eastern countries. It can cause pink eye in adults and neonates. It is a cause of pink eye in adolescents and adults that can be sexually transmitted. Chlamydia pink eye is typically treated with tetracycline (except in children less than eight years old, because of possible teeth discoloration) or erythromycin.

Q :What is a visual field test? What is a visual field test used for? How is visual field testing done?
A:A visual field test is a method of measuring an individuals entire scope of vision. Visual field testing actually maps the visual fields of each eye. Visual field testing is used to detect any early (or late) signs of glaucoma damage to the optic nerve and/or damage to the retina. There are a variety of methods of measuring the visual fields. A crude visual field test can be done by having the patient look straight ahead and count the fingers shown by the examiner from the side. More typically, however, visual fields are measured by a computerized assessment in a optometrist's or ophthalmologist's office. For this procedure, one eye is covered and the patient places his or her chin in a type of bowl. Then, when the patient sees lights of various intensities and at different locations, he or she pushes a button. This process produces a computerized map of the visual field.

Q :What type of Opthalmic lens materials are available?
A:

Glass Lenses

Glass lenses provide good optical performance and they produce the least amount of chromatic aberration. Glass lenses are considerably scratch resistant and they generally do not require protective coatings. However, glass lenses are easily broken and they are heavier and thicker as compared to plastic, high index or polycarbonate lenses

Plastic Lenses
Plastic lenses are thinner, lighter and more attractive as compared to the conventional glass lenses and are hence very popular. Plastic lenses provide good optical performance and can be easily tinted for cosmetic appeal and sunwear. The most common plastic lens material is called CR-39

High Index Lenses
High index lenses are made from special blends of exotic materials to enable the lens to bend light "faster". Hence they are lighter and thinner than standard lenses. They can be made in both glass and plastic. They are recommended for medium and strong prescriptions.

Polycarbonate Lenses
Polycarbonate is a special polymer blend of plastic. Polycarbonate lenses are more impact-resistant than regular glass or plastic lenses. They are also thinner and lighter than the conventional lenses.

Q :How can my glasses change from transparent, when I'm inside, to dark when I go outdoors?
A:Sunglasses or prescription eyeglasses that darken when exposed to the sun were first developed by Corning in the late 1960s and popularized by Transitions in the 1990s. In fact, because of the extreme popularity of the Transitions brand, these lenses are usually referred to as transition lenses. The correct term for these glasses is photochromic or photochromatic, which refers to a specific chemical reaction the lenses have to ultraviolet (UV) radiation.

Photochromic lenseshave millions of molecules of substances such as silver chloride or silver halide embedded in them. The molecules are transparent to visible light in the absence of UV light, which is normal for artificial lighting. But when exposed to UV rays, as in direct sunlight, the molecules undergo a chemical process that causes them to change shape. The new molecular structure absorbs portions of the visible light, causing the lenses to darken. The number of molecules that change shape varies with the intensity of the UV rays.

When you go indoors and out of the UV light, a different chemical reaction takes place. The absence of the UV radiation causes the molecules to "snap back" to their original shape, resulting in the loss of their light absorbing properties. In both directions, the entire process happens very rapidly.

In the original PhotoBrown and PhotoGrey products made by Corning, the lenses are made of glass, and the molecules are distributed evenly throughout the entire lens. The problem with this method was apparent in prescription glasses where different parts of the lens were of varying thickness. The thicker parts would appear darker than the thinner areas. But with the increasing popularity of plastic lenses, a new method has been developed. By immersing the lenses in a chemical bath, the photochromatic molecules are actually absorbed to a depth of about 150 microns into the plastic. This is much better than a simple coating, which would only be about 5 microns thick and would not provide enough molecules to make the lenses sufficiently dark. This plastic lens absorption process has been popularized by Transitions, the leading manufacturer of photochromic lenses.

An important note about photochromic lenses: because they react to UV light and not to visible light, there are circumstances under which the darkening will not occur. A perfect example of this is in your car. Because the windshield blocks out most UV light, photochromic lenses will not darken. For this reason, most sunglasses with photochromic lenses also have a certain amount of tint already applied to them.

Q :Does vision capacity change at night?
A:Nocturnal myopia: At night we are all myopic. Nocturnal myopia is largely caused by increased dilation of the pupil, which results in an excessive elongation of the eyeball, thus rendering the eye myopic (from 0.7 to 1.5 diopters). Therefore, for night driving it is a good idea to uses lenses with a different prescription than for daytime use.

Peripheral vision: At night the central and nearby surrounding area of the eyes become blind, while lateral vision is not altered. An object observed with peripheral vision attracts the eye, but when the gaze is fixed upon it, the object disappears. Furthermore, at night only objects with high contrast are clearly visible.

Q :When do age-related vision problems begin to appear and how can they be diagnosed?
A:After 40 almost everyone needs to wear glasses. The eyes' ability to focus is no longer as flexible as it was in youth. It is a good idea to have a general eye exam at least once a year to determine visual acuity. Even slight vision defects should be detected as early as possible, even though they may not be readily apparent. Over time, if left uncorrected, they can lead to impairment of normal activity. It is especially important, after 40, to schedule an ophthalmologic exam to check for possible pathologies and an optometric exam to evaluate visual acuity

Q :What kind of lenses provide the best protection from the sun's rays?
A:There are three kinds of sunlenses: standard or normal, polarized and photochromic. Polarized lenses not only protect the eyes from radiation but also help screen out glare and can improve visibility, especially on sunny roads, on highly reflective water surfaces, etc. Photocromic lenses automatically adjust the filtering power of the lenses under different conditions, based on the amount of UV rays contained in solar radiation. This kind of eyewear is convenient because it can be worn all the time, indoors and out.
Mirroring involves a coating process applied to lenses and can be useful in high-intensity light situations, as occur at high altitudes and on snowfields or glaciers. Colored lenses can also ensure the same protective effects. Lenses also differ in terms of screening power. For example, in town or at sea level, light conditions are quite different from those found in the mountains or in snow, where greater screening power is required, both for the eyes and for the skin. This means it is also important to check the filtering power of lenses, which is based on a scale defined in another European standard: En 1836/97.
Lens Categories and Descriptions of Use:
Cat. 0 - 1 for interior environments, fashion accessories, or for use on dark days without strong light (wind protection). Transparent or provide weak or light filtration
Cat. 2 for average light conditions, cloudy skies, in town, etc. average filtration
Cat. 3 general use in full sun, dark filter
Cat. 4 for use in very bright light, mountaineering, highly reflective surfaces, etc. very dark filters (not safe for driving!)

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