Contact Lenses

Successful contact lens wear requires a "partnership" between the fitter, that is, an ophthalmologist, an optometrist, or possibly an optician, and you.

Contact lenses are miraculous pieces of plastic that allow you to see without glasses. In most cases, contact lenses are used as a substitute for glasses, allowing you to dispense with them. Contact lenses may also be used to treat certain eye diseases or may be used for cosmetic purposes to change the apparent color of your eyes.

Successful contact lens wear requires a "partnership" between the fitter, that is, an ophthalmologist, an optometrist, or possibly an optician, and you, the wearer.

• The fitter must first decide if your eyes are healthy enough to wear contact lenses. If so, the fitter then fits the correct lenses for your eyes and your needs and teaches you how to use and care for them.
• The fitter should be available if problems develop; if not available, the fitter must then have a system in place to address those situations.
• You must follow the instructions, care for, and wear the lenses correctly and return as required for routine and emergency care.

A fitter can be an ophthalmologist, an optometrist, or possibly an optician.

• Ophthalmologists are physicians who have graduated from college and a school of medicine (MD) or osteopathy (DO), after which four to six years of additional training (residency and optional fellowship) are required and spent studying about eye examinations (including the fitting of contact lenses and glasses), diagnosis and treatment of eye diseases, and performing eye surgery. Ophthalmologists perform both intraocular rather than conventional surgery and laser surgery.
• Optometrists have graduated from college and a school of optometry (OD), where they are trained in eye examinations, fitting of contact lenses and glasses, and depending on state licensure, treatment of certain eye diseases. Optometrists do not perform conventional eye surgery or laser surgery. Select states permit optometrists to perform certain laser procedures only.
• Opticians fit glasses based on the prescription of an ophthalmologist or an optometrist. In some states, opticians may fit contact lenses. Opticians do not perform eye examinations, do not diagnose or treat eye diseases, and do not perform surgery.

Soft lenses and rigid gas permeable (RGP) lenses are the main types of contact lenses available. Each has specific indications as well as a specific wear and care regimen. The older hard (PMMA) lenses are rarely used today and have risks similar to RGP lenses. There are larger scleral lenses available for special eye conditions.

How to read the numbers on a contact lens case. 8.6 refers to the base curve (BC); BC is determined by measuring the curvature of the cornea. -1.50 refers to the prescription. Photo courtesy Michelle Rhee, MD.

Contact lenses are mainly used to avoid wearing glasses in conditions such as nearsightedness, farsightedness, and astigmatism or to avoid the use of bifocal glasses once presbyopic (having trouble with near vision activities such as reading). Contact lens options for presbyopia include bifocal contact lenses, monofocal contact lenses, and the use of reading glasses, or monovision. Monovision, also known as blended vision, uses a technique of correcting one eye for distance vision and the other eye for near vision. Some people adjust to and enjoy this method of obtaining freedom from glasses.

Contact lenses may also be used to treat conditions other than those described above. Keratoconus is a condition in which the surface of the eye has a very irregular shape (astigmatism). When glasses no longer provide adequate vision, contact lenses are used.

Contact lenses may also be used after refractive or cataract surgery if under- or over-corrections occur. After eye surgery, and in some cases of eye diseases of the cornea, bandage soft contact lenses may be used to allow the cornea to heal or may be used to alleviate pain. They may be used in young infants or children after cataract surgery, with children who have very strong prescriptions, or when there is a big difference in the prescription between the two eyes.

• Some lenses are meant for daily wear. With daily wear soft lenses, the lenses are worn for a day, then discarded. This allows one to dispense with solutions, cleaning, and disinfection of the lenses. It allows intermittent wear such as weekend or occasional wear as desired. Most soft lenses and some RGP lenses are worn for a day and then removed, cleaned, and disinfected each night. Soft lenses are usually replaced regularly, which varies from one day to one week to one month to three months to one year. RGP lenses may last for years with regular care.
• Extended wear lenses, usually soft, are worn overnight for one week and then replaced every one to two weeks. Trying to extend the wear of lenses beyond the recommended replacement schedule is a false economy and an invitation to potential disaster.
• Overnight wear decreases the amount of oxygen available to the eye and increases the (rare) chance of infection by fourfold. Because of this, some practitioners do not recommend extended wear of contact lenses. Newer lenses may be safer.

Cosmetic Contact Lenses

• Contact lenses may be used to change the color of the eyes. This may be for professional reasons such as for actors and models wanting to have a different eye color. This is of great concern when lenses are sold in stores such as gas stations and party stores during the Halloween season without a professional examination to determine the health of the eyes and the safety of wearing lenses. Every year, several cases of blindness are seen by ophthalmologists around the United States due to infections or damage to the eyes.

Contact lenses may be used for the treatment of diseased eyes. Soft contact lenses may be used as bandage lenses to protect the cornea in some disease situations. Large scleral lenses that cover the entire eye may be used to correct some unusually shaped eyes or to treat some unusual eye conditions.

Problems resulting from contact lens wear range from the inability to remove the lenses (usually after first being fit) to blindness from infections. Proper fitting, instruction, and care, and maintenance can prevent most problems.

• When being fit with contact lenses, the fitter should provide the patient with information as to what to do in case of a problem (call the office, go to the emergency room, etc.).
• After being fit, the inability to remove lenses occasionally occurs. Do not panic. Call your fitter for instructions as to how to proceed.

The most common reasons for contact lens wearers to seek care are irritation of the eyes, redness, or blurred vision. These may be caused by the lenses wearing out or warping, a change in the eyes requiring new lenses, poor fitting of the lenses, poor care of the lenses, sensitivity to solutions, or something (a foreign body) getting under the lens on the surface of the eye. These relatively minor inconveniences must be evaluated because they may signal the onset of corneal ulcers and deeper infection.

• With the glut of contact-lens solutions available, it is important to use only the solution recommended by the fitter. Some solutions may be incompatible with certain lenses or may contain components, such as Thimerosal (20% of people are allergic to this substance) that are not compatible with the eyes of certain people.
• One major concern, from the wearer's viewpoint, is the danger when a contact lens slips off the eye. The lens sits on the surface of the eye but cannot travel "back to the brain" because the clear covering of the eye goes under the eyelid and keeps the lens from going further back. If the lens cannot be repositioned on the cornea, it is under the eyelid and can be easily slid or moved to its correct position on the cornea (sometimes requiring the help of the fitter). It will not harm if it is under the eyelid for several hours.
• Redness of the eyes associated with pain, blurred vision, and light sensitivity is more serious and may signal a potentially blinding condition, such as a corneal ulcer due to an infection.
• Abrasions (scratches) on the surface of the cornea (corneal abrasions) usually result from insufficient oxygen reaching the surface of the eye, although they may also result from dirt or other foreign bodies getting under the lens. It may be due to either over-wear of the contact lenses or lenses that are not tolerated by the eye. These disturbances of the cornea not only may be very painful but also may predispose the eye to a serious, blinding infection.
• Occasionally, someone inadvertently soaks his or her lenses in a cleaning solution or soap solution, resulting in redness of the eye with a great deal of pain. This is extremely uncomfortable but usually causes no permanent damage. Drops and irrigation of the eye may be necessary to relieve the pain.
• Makeup may get under a lens and cause irritation or a greasy film on the lens, making it difficult to see clearly. Sometimes polishing in the office will be necessary to remove this film. If not, it may be necessary to replace the lens.

It is important to keep in mind that any of these eye complaints may occur and have nothing to do with the contact lenses and may be signs of other unrelated eye conditions such as infections, cataracts, or glaucoma. It may be necessary to see your eye-care professional for the correct diagnosis and treatment.

Any change in the condition of the eyes of contact lens wearers must be evaluated for the cause and possible treatment. Whether or not these eye complaints are due to the contact lenses, they still must be diagnosed and treated. When in doubt, call your fitter for information as to how to proceed; remember that opticians do not treat eye diseases.

Irritation may occur as a result of worn-out lenses, over-wear of lenses, poor care of lenses, intolerance to solutions, or infections. Irritation may also occur from poor hygiene on the part of the lens wearer.

• If worn longer than recommended or in people whose eyes are particularly sensitive, deposits may develop on the surface of the lenses and cause irritation.
• A major cause of blinding eye infections is spitting on a contact lens or putting the lens in one's mouth when no solution is available. This happens when a contact lens wearer must remove a lens or if a lens falls out of the eye and no solution is available. The best prevention is to have a small bottle of rewetting solution with you at all times. Never, never put your contact lenses in your mouth to lubricate them.
• Some people use homemade or non-contact-lens saline solutions in an effort to save money. These solutions may cause severe irritation or blinding infections (some saline solutions are not sterile) and should never be used. Always use the correct contact lens solution recommended by the fitter. If you want to change solutions, you should first check with your fitter because some solutions may be incompatible with certain lenses.

It is not unusual to have some general irritation, even some redness, upon beginning contact lens wear. However, persistent redness, light sensitivity, pain, and blurred vision are the main signs and symptoms of potential eye problems. Depending on the cause, symptoms vary in intensity. In more serious infections, the pupil in the infected (red) eye may be smaller than the other pupil.

• With a torn or broken lens or if there is something in the eye, there is usually a slight feeling of general irritation as if something is in the eye. There may be some associated redness.
• With a poor-fitting lens or a lens that is old, there may be a slight irritation and redness associated with some blurring of vision.
• Makeup on the surface of the eye or a reaction to solutions can vary from slight to marked redness of the eye with slight to marked pain.
• Corneal abrasions (scratches) are usually quite painful, with or without the lens in the eye, and are associated with light sensitivity and redness. Vision may or may not be blurry.
• Infections are a major concern because they may cause severe eye damage or blindness.
  • Simple pinkeye (a mild infection) is usually associated with redness, clear or mucous discharge, and matting of the eyelids. Vision is usually clear. When this happens, remove the contact lens in hopes of avoiding spread of the infection to the eye. Contact your fitter as to how to proceed.
  • Subconjunctival hemorrhages (bleeding on the surface of the white part of the eye) may look bad, but they do not cause any damage and disappear over one to two weeks without any treatment.
  • Infections of the cornea are of more concern. These infections cause marked redness, light sensitivity, blurred vision, and a variable degree of pain. Occasionally, it is possible for the lens wearer to see the infection, which may appear as a white spot on the surface of the eye. These infections require immediate evaluation and care. Infections may be secondary to contaminated solutions, poor hygiene, contaminated tap water, or dirty contact-lens cases.
  • When a lens slips off the surface of the eye, vision immediately becomes blurry, which may or may not be associated with a sensation of something under the upper eyelid. If you can't move the lens to the correct position on the eye, you might have to seek the advice of your fitter. Do not panic since this rarely causes any damage.
  • Severe, blinding infections may occur when contact lenses are worn while swimming.

If you have a question about your contact lenses, you should contact your fitter.

If you experience redness, blurred vision, pain, or light sensitivity, you should contact your ophthalmologist or optometrist. (If he or she is not allowed by state law to treat eye problems, he or she will refer you to a practitioner who can handle these problems.) Normally, you will need to be seen that day. If you need to seek help, it is best to try to contact your eye doctor during the day, rather than waiting until evening or late at night.

• Most ophthalmologists are available 24 hours a day via their answering service. If your ophthalmologist is not available, you should be seen by the ophthalmologist on call, a hospital's emergency room, or an urgent-care center.
• Optometrists and opticians may or may not provide 24-hour availability. If not available, you should ask about the routine if a problem develops, especially after regular office or store hours. Many have an ophthalmologist to whom they refer medical problems; others may tell you to go to an urgent-care center or a hospital's emergency department. Recognize that emergency departments or urgent-care centers usually do not have an ophthalmologist on site.
• Because of the specialized nature of eye examination equipment, contact lens problems are best handled in the ophthalmologist's office.

Common questions and answers about contact lenses are:

• Should I have a backup pair of glasses?
  • Yes.
• How often should I remove my contact lenses?
  • Every night...
• How long can I wear my contact lenses at one time?
  • It depends on the individual, but 10-12 hours is usually tolerable.
• How do I care for my contact lenses?
  • See below.
• How often should I exchange my contact lenses for a new pair?
  • See below.
• How often should I have my eyes examined?
  • At least once a year...
• How often should I change my contact lens case?
  • At least every three months...
• What should do I do in case of questions or problems?
  • See below.

Diagnosis and treatment of contact lens problems entail a complete history and an eye examination.

During the history, you are asked questions about your symptoms and how long you have been bothered by these symptoms (for example, light sensitivity, redness, blurred vision). You should also be prepared to tell your eye doctor the following:

• The type of contact lenses being worn (soft, gas permeable, or the older hard lenses)
• What type of care regimen you use (cleaning, disinfecting, and rinsing solutions): This should include the specific name (manufacturer) of solutions.
• The type of wear regimen used: daily disposable, weekly overnight wear, or daily wear
• How often the lenses are replaced (daily, weekly, monthly, quarterly, or yearly)
• When you last wore your lenses
• Whether your vision is affected

The examination of the eye involves checking your vision (with your glasses because you have removed your contact lenses).

• If your vision cannot be corrected, your eye doctor may suspect the presence of a serious problem.
• Your eye doctor looks into your eye with various types of lights, starting with a flashlight type of instrument and followed by a slit lamp (a microscope to examine the eye with high magnification and different color lights).
• Your eye doctor may obtain corneal topography, a noninvasive study that shows the curvature, power, and thickness of your corneas. (See figure.)
• Your eye doctor may place a dye called fluorescein on the eye. This makes abrasions (scratches) and ulcers show up clearly.
• Your eye doctor may use an anesthetic eyedrop to facilitate examination. Once the anesthetic wears off, the pain you had when you walked into the office will recur; that is normal. Do not use anesthetic on your own as it can worsen the damage to the cornea and interfere with healing.
• With apparently severe infections, cultures of the eye may be taken and sent to the laboratory for evaluation. (See figure.) Bring your contact lenses and/or contact lens case because cultures of these may identify the infectious agent. Depending on the cause of the infection, specific antibiotic eyedrops may be required. Rarely, hospitalization is required.

Picture of corneal topography showing astigmatism and the curvature of the cornea. Photo courtesy of Michelle Rhee, MD.

• If you experience irritation, pain, blurred vision, redness, or light sensitivity, immediately remove your contact lenses and reevaluate your symptoms.
• Because you should not wear your contact lenses when experiencing these problems, you should have an up-to-date pair of glasses for these times. With well-fitting contact lenses, you should be able to remove your lenses and see well with your glasses, essentially immediately. Blurred vision, lasting for hours, upon removal of the contacts is usually a sign of poorly fitting contact lenses. If your vision is blurred, with your glasses, when lenses are removed, notify your fitter.

You should examine your contact lenses for any defects. In the case of a torn soft lens or a cracked gas permeable lens, your eye should feel immediately relieved once you remove the lens. If soap or cleaning solution gets in your contact lens case and, in turn, on your lenses, irrigate your eyes with your rinsing solution or tap water if no sterile solution is available. Tap water, especially overseas or in warm climates, may be contaminated with harmful germs. This can cause an extremely painful infection. Then, either discard the lenses or rinse them off multiple times in the storage solution to rid the lenses of the soap.

• When the irritation is from something blowing into the eye, remove the lens and look for a foreign body. The foreign body may be removed with a cotton-tipped applicator or a rolled-up piece of facial tissue. Once removed, your eye should feel immediately relieved of the discomfort.
• If eye drops are prescribed for an infection, you should use these eye drops, usually with the contacts out of your eyes. Ask your doctor whether you should remove your lenses when instilling drops. You should not wear contacts when your eyes are red or irritated.
  • To instill eye drops, hold your head back and chin up. Squeeze one drop out of the bottle. If more than one drop comes out, this will not cause damage to the eye...Do not touch your lashes or eyelids with the dropper. Close your eyes gently so that you do not squeeze the drop out of your eye for about 30 seconds after installation. Do not rub your eyes.

Treatment of contact-lens problems ranges from not wearing your contact lenses for a short time to intensive antibiotic treatment of infections. You may have to wear your glasses for a variable period of time. After the condition is cleared, you might have to be refit with new or different lenses.

If only one eye is affected, you may be advised to discontinue the contact lens in the other eye, as some infections may spread into the uninvolved eye. If the lens is worn out or torn, it must be replaced. With frequent replacement lens wear, you usually have extra lenses at home and can easily replace the lens yourself.

• If a solution incompatibility is suspected, solutions and the care regimen are evaluated, and you may be required to change solutions.
• If the lens is not fitting well, wear of that lens is discontinued. It may be necessary to refit you with new lenses of the same or different material, which may be better tolerated or may provide better vision.
• With infections, antibiotic eyedrops are used. Pills are rarely used because eyedrops are usually more effective.
  • Your eye doctor chooses the eyedrop that is most effective for the particular infection. Eyedrops may need to be used every hour. You might have to be seen every day with more serious infections.
  • With corneal infections, a culture of the infection may be taken to help determine the most effective antibiotic eyedrop. (See figure.)
  • Once the infection is under control, the most superficial layer of the cornea (epithelium) needs to heal. During this time, you may be prescribed a soft contact lens to be used as a bandage, referred to as a bandage contact lens. This can help heal the epithelium and lessen discomfort.
  • On rare occasions, surgical management of the infection may be necessary. Ultimately, if more conservative treatment is not successful, antibiotic injections into the eye or even a corneal transplant may be necessary.

Picture of common culture media for corneal infections. Photo courtesy of Michelle Rhee, MD.

All contact-lens wearers should have an annual follow-up examination. People who wear extended-wear lenses are often seen every three to six months. Remember that extended wear of contact lenses not designed for extended wear increases the risk of a serious eye infection and is not recommended.

These examinations allow the fitter to review the care, wearing, and fit of the lenses. Problems or potential problems may be found at these examinations before they interfere with vision and before the wearer notices them.

• Fitting of contact lenses involves a complete eye examination with measurements of the cornea and selection of appropriate lenses.
• The fitting is not complete until follow-up evaluations confirm the correct fitting of the contact lenses.
• After this, in most states, the fitter must give the contact-lens prescription to the wearer whether or not he or she asks for it.
  • Some people order their lenses by mail order or through local stores. If this is done, it is essential to make sure that the lenses received are exactly the same (same brand, material, base curve, diameter and thickness; see figure) as the lenses that were fit and dispensed. Recognize that some people will have problems that they think might be solved by ordering new lenses, and the cause may actually be an infection or other serious problem. If lenses are ordered by mail, be sure to have your regular follow-up exams.
  • Although mail order is used because of an expectation of a lower price, you should check with your fitter. Your fitter will usually meet or beat the price of the mail-order companies.
  • If lenses are not purchased from the fitter, be sure to have follow-up examinations at the intervals recommended by the fitter.

Wearing correct-fitting lenses, using the correct care regimen, and undergoing periodic follow-up examinations by the fitter should prevent most problems.

• Cleanliness is essential. Do not handle contact lenses without first washing your hands. Contact-lens cases must be cleaned every day by rinsing with a multi-purpose solution and letting them air dry upside down. Always be sure to fully discard the old solution and replace with new solution when storing lenses overnight. They should be replaced at least every three months because they may serve as a culture medium for bacteria and fungi.
• Use of rewetting drops while wearing contact lenses maintains and aids in comfortable wear. These are available over the counter. Typically, these drops are used four times a day.
• Any contact lens wearer must follow the general rules of good hygiene. The wearer must also be motivated and mature enough to follow the instructions for avoidance of problems. For this reason, some fitters will not fit children.
  • Children must be evaluated on a case-by-case basis. More recently, orthokeratology has been gaining traction in the U.S. Orthokeratology is the use of RGPs to wear during sleep to reshape the cornea. Its use is most effective in children because there is an opportunity to limit the amount of myopia (nearsightedness) they develop.
  • In young children (younger than 8-9 years of age), contact lenses are usually prescribed for medical reasons only. For example, after congenital cataract surgery, contact lenses offer essentially normal vision without the use of thick glasses. Parents assume the responsibility for the correct care and wearing of the lenses.
• Different types of lenses have different care routines. In general, lens care involves rinsing of the lenses upon removal, cleaning the lenses, and storing them in a disinfecting solution. Homemade or non-contact-lens saline or solutions should never be used. Only use the solutions that are recommended.
  • The lenses should be worn and discarded as directed. If lenses are to be replaced on a scheduled basis (for example, daily, weekly), it is a false economy and dangerous to try to extend the lenses by replacing them less often.
  • The safest way to wear lenses is to wear them on a daily basis and discard them every day. This avoids the use of solutions and decreases handling. However, it is slightly more expensive, and daily disposable lenses are not available in all prescriptions.
  • Overnight wear of contact lenses is available for certain prescriptions. Although approved by the U.S. Food and Drug Administration (FDA), this is not believed to be safe by many fitters because of the increased rate of infections with extended wear. The authors are advocates of well-fit extended-wear contact lenses (by reliable patients) if they adhere to the rules and are followed correctly).
• Most complications may be eliminated by meticulous wear and care by the wearer and following instructions meticulously as well as getting follow-up examinations by the fitter.
  • It is essential to be examined by your ophthalmologist, optometrist, or other fitter at least once a year and more often if extended wear lenses are worn. Every examination should, at a minimum, include a history as to how the lenses are cared for and to find out if there are any problems. The vision should be checked with the contact lenses, and the lenses should be observed on the eye with the slit lamp (a special microscope used in the office to examine eyes). An evaluation of the vision with glasses (after removing the contact lenses) should also be performed.
  • The examination also includes an examination of the shape of the cornea. No distortion or changes should be present. The cornea, as well as the rest of the eye, should be evaluated and measured, along with an evaluation for the possible presence of any eye diseases, such as glaucoma or cataracts.

In most cases, contact-lens problems are managed with no permanent damage. Usually the patient may return to normal contact-lens use and care.

There is constant research being carried out to develop new lens materials and designs as well as new solutions for care. It is rare to switch a patient to a new lens unless there is a reason for it (for example, a patient may no longer tolerate his or her lenses but will be able to resume lens wear with a new lens type or solution).

For more information on contact lenses, visit the Contact Lens Association of Ophthalmologists at http://www.CLAO.org and http://www.contactlensdocs.com/.