Contact Lens FAQ
Are there bifocal lenses for astigmatism?
Yes. There are various contact lenses available for patients who need reading glasses and have astigmatism. Proclear Toric Multifocals now are available for once monthly replacement which is great for patients who suffer from dry eye or heavily deposited lenses.
What do you mean by "Measuring the corneal shape"?
Several methods of measuring the shape of the cornea have developed over the years including the most widely used today -- corneal topography. A once popular method, keratometry and other procedures generally provide only a qualitative evaluation of the corneal shape. With the introduction of computer assisted topographical analysis, an eye doctor can get quantifiable data and a reasonably accurate visualization of corneal shape. A corneal topographer is a lighted bowl with a pattern of concentric rings inside it. The patient is seated at the instrument with forehead braced against a bar where an image of the eyes is taken. There is no discomfort associated with this procedure. The computer analyzes the image to produce a color coded readout of the cornea's shape. The colors are used to represent the contours of the eye, much like a topographic map represents elevations of the land. This information is used among other things to determine the base curve and diameter of your contact lenses prescription.
What is "base curve"?
Base Curve (BC) is a measure of the curvature of the contact lens. This helps it fit your cornea more comfortably since some corneas are "steeper" or "flatter" than others. The higher the Base Curve number the "flatter" the curvature of the cornea.
How do you determine the diameter for contact lenses?
A properly fitted contact lens needs to fit over the corneal area of the eye. Therefore the diameter of your cornea determines the diameter of your contact lens. If the lenses are of insufficient diameter part of the light entering your eye would be focused by two lenses (the contact and your eye's lens) and part of the light would be focused by only one lens (your eye's) resulting in blurring and distortions.
What does "evaluating the vision" entail for contact lenses?
A routine eye exam consists of a number of procedures that are performed to determine the shape, visual acuity and health of your eyes. Although these tests are performed in various orders depending on your eye doctors preferences they usually consist of a corneal topography, a glaucoma test, a retinoscopy, a refraction test, a cover test, and a dilation of the pupil followed by a slit-lamp examination of the back eye structure. For more information see our routine eye examination service.
How do you know when a contact lens fits?
Once your eyes are measured for contact lenses the doctor must determine what material, base curve and diameter lens to use for the best vision, comfort and health of the eyes. The doctor places the contact lenses on the eyes and examines them using the biomicroscope to determine if the contact lenses are fitting the eye properly.
Soft contact lenses must be centered on the cornea and move about one to two millimeters every time the eye blinks. If the contact lens does not move with each blink it can cause oxygen deprivation to the corneal tissue. Over time this will result in corneal swelling (edema) and a possible reduction of visual acuity. If the contact lens moves too much this can cause an irritation or inflammation and usually results in an uncomfortable feeling when on the eye.
Gas permeable contact lenses should center on the cornea after the eye blinks. The lens should move two to three millimeters every time the eye blinks. A special dye is inserted onto the eye to ensure a constant exchange of tears after each blink. A gas permeable contact lens that is not fitting well could cause corneal scarring.
Over time the initial contact lenses prescribed may need to be changed to ensure corneal health. This is why contact lenses need to be evaluated on an annual basis to determine if the lenses are fitting properly.
I can't stand anything near my eye, can I ever wear contact lenses?
That is a concern expressed by a number of patients, but with proper training and practice you can learn to overcome this inhibition. The eye has a natural "defense" when anything approaches close to the eye which results in an involuntary closure of the eyelid. With training, this involuntary reaction can be controlled. First we teach you to touch you eye with just your fingertip. We ask you to practice in front of a mirror until you are comfortable with this procedure and grow accustom to the presence of something "in your eye". Once you have acclimated to this, in our office we work with you to place a contact in your eye for the first time. Under this controlled situation you will quickly feel comfortable with putting the contacts in yourself.
What is covered in contact lens follow up appointments?
Contact lens follow up appointments are essential to ensure the health of the eyes will not be compromised by wearing the contact lenses. The office visit includes a history of how long the contact lenses are in the eyes, whether or not the lenses are kept in at night, what contact lens solutions are being used and how often the lenses are being replaced. The vision is then tested to make sure the lens is not altering the best corrected vision. The biomicroscope is used to look at the contacts while on the eyes to determine the position and movement. The tissue is also examined for swelling, allergic reactions to the lens, scarring and engorged blood vessels.
If a problem is discovered at any point of the follow up appointment, it is addressed by either changing the type of contact lens, the wearing schedule or the contact lens solutions used to clean the lenses.
Can contacts correct presbyopia?
Yes, if it is the bifocal or multifocal contact lenses of today. A commonly used contact lens design for people with presbyopia is the concentric bifocal pattern. In this type of contact lens, the near correction is in a small circle at the center of the lens, surrounded by a much larger circle containing the distance correction. Alternatively, the distance correction can be placed in the center, with the near prescription in the outer ring. Progressive contacts can provide good vision for intermediate tasks such as computer screen use. Progressives have a gradually transitioning power for smoother vision transitions at all distances.
Can contacts correct astigmatism?
Years ago this wasn't true but advancements in contact lens technologies means that Astigmatism can be corrected not only with eyeglasses but also with contact lenses. Many people with astigmatism believe that only rigid gas permeable (RGPs) contact lenses can correct astigmatism but this is also no longer true. Now there are soft lens designs called toric contact lenses that can correct astigmatism and may also contain a prescription for nearsightedness or farsightedness if you need it as well. While soft torics work well for many people, if you have severe astigmatism, you'll likely do better with RGP contacts or eyeglasses.
Do they have bi-focal contact lenses?
Bifocal lenses are usually prescribed for those of us who have presbyopia. Bi-focal contact lenses come in all types, RPG, disposable, frequent replacement, or even daily wear. Like eyeglasses, bi-focal contact lenses have two powers in the same lens: one for close and the other for distance. There are different lens designs including aspheric, concentric, and translating. The translating lenses have the near power at the bottom of the lens which is flat thus preventing it from rotating when you blink. Other versions have the bottom weighted more than the top to keep the proper alignment.
Concentric lenses have and inner ring and an outer ring, either of which can be for distance or near. The aspheric design has both prescriptions very near the center of the lens. With progressive contact lens the distance and near rings are blended together at their edges to soften the transition. This is effective for mild presbyopics.
Can I order my contacts through you and will they cost more?
Yes you can order your contact lenses from us whether or not you are a patient of ours. We have provided an eye care store personalized just for you. Your prescriptions are retained in a private area under the "My Prescriptions" tab. Just login with your email id and password that you gave the office when you visited. Our prices are very competitive if you order a years supply of contact lenses from us. If you are not a patient of ours, you can still place an order with us but stepping through our easy to use process. As part of this process, you will create your login and password and you can save you order in your own "My Prescriptions" area as well. Before we place your order, we will need a confirmation of your prescription to make sure that you are ordering the correct lens.
What is the difference between daily wear, extended wear, and disposable contact lenses?
The terms Daily wear and Extended wear refer to how long you can wear a contact lens. If a contact lens is designated daily wear then it must be removed before retiring for the evening. You cannot sleep with them in your eyes. Extended wear contacts may be worn while sleeping. See sleeping in my contacts. Extended wear contacts have different lengths of time that they can be continuously worn, usually 7 days or 30 days. Contact us if you are unsure as to which type of lens you have before attempting to sleep with contacts in your eyes.
Disposable, Frequent replacement, and Reusable contact lenses refer to the frequency with which the lenses need to be replaced with a new pair of lenses. The term disposable refers to contact lenses that need replacement at least every two weeks. Daily Wear, Weekly, and 14 day designations are common for disposable lenses. Frequent replacement lenses are usually replaced monthly or quarterly depending on the brand. And what used to be the more traditional reusable lenses are replaced every six months or more.
You will be asked to sign an informed consent as part of your contact lens examination which will explain the specifics for you particular situation.
Can I sleep with my contacts in?
That depends on the type of contacts the doctor has prescribed for you. A source of confusion is the difference between the replacement cycle for a contact lens and the wearing schedule. The former refers to how often a contact lens needs to be replaced with an brand new lens. This cycle varies depending on the type of contact lens you wear. See differences in lens types. The later, or wearing schedule, refers to how long you can keep the lens in the eye before having to remove it for eye health reasons. Daily wear designations means that you remove them at night and extended wear means you can sleep with them in the eye. Make sure though that you do not exceed the extended wear specification designated by the lens manufacturer.
Wearing lenses at night provides and opportunity for potentially harmful bacteria and other organisms to grow under your lenses, especially in the low oxygen conditions experienced at night. Therefore sleeping in contact lenses is not recommended. The risk of eye infection, ulceration and possible loss of vision is increased dramatically when lenses are left in the eye overnight. Long term wear of overnight contact lenses causes swelling of the corneal tissue, new blood vessel growth and possible intolerance to contact lenses. If you decide to sleep in your contact lenses it is imperative that you do not wear them longer than the specified schedule. You also should consider having your eyes checked more frequently to assess any damage that overnight contact lens wear may be causing. If you have any doubts, please call us before sleeping in your lenses.
Can I lose my contact behind my eye?
No. The tissue membrane called the conjunctiva prevents this from happening. The conjunctiva attached to the side walls of the eye socket and the eyelid, preventing anything from "getting lost in the back of the eye". Even though you cannot lose a lens, it sometimes appears that way as lenses migrate under the eyelid and become difficult to locate. Soft lens may even roll up and hard lens may adhere to the conjunctiva because of suction. If any of these situations happen to you, flush your eye with water or saline and the lens should float free. In the case of a lens adhering by suction, try to move the lens while gently pressing on one edge. If that doesn't work, try to very gently lift up an edge to break the suction or go see your eye doctor. They will be able to remove it by suctioning it (like a tiny vacuum cleaner) from the conjunctiva. If this happens repeatedly, the contact is most likely not fitted correctly and should be replaced.
Can I use my reading glasses with my contacts in?
Yes, you can use reading glasses on top of your contact lens prescription but why would you want to do that when there are so many good contact len alternatives. See "Do they make bi-focal contact lenses."
Can anyone wear contact lenses?
No, not everyone is a good candidate for contact lenses. Besides medical reasons there are environmental, cost, and suitability factors that should be considered. There are medical conditions such as the type or severity of vision problems, shape of your eyes, corneal irregularities, dry eyes, allergies, and certain medical disorders such as diabetes or glaucoma, that make you an unsuitable candidate for contact lenses. Other considerations include the ability to manipulate contact lenses and environmental factors such as working in a very dry or windy atmosphere or where there is a lot of dust in the air also makes it difficult to wear contacts.
Immature children may not be good candidates since wearing contacts requires compliance with specific instructions concerning how many hours they can be worn and how they must be cleaned, handled, and stored. Not adhering to instructions puts the wearer at risk for eye injury and infection. And finally cost is a factor. Contacts are generally more expensive than eyeglasses. A pair of glasses can last many years, but contact lenses must be replaced more frequently. Contact lenses must be disinfected at regular intervals, requiring solutions and equipment that adds considerably to the cost of ownership. So given all these factors, are you a good candidate for contact lenses? If you want more information contact us with specific questions and we will try to answer your concerns.
Can I have my contact lens prescription filled anywhere?
If you are an established patient and have a written prescription for contact lenses then you can order your contacts anywhere. Check out our EYE STORE to order your contact lenses. If you are a first time patient of ours, then we require you to order your first years supply of contact lenses from us. This ensures that you receive the proper follow-up care that is so important to making sure that your contact lenses are fitting properly.
I've heard my contacts referred to as RGP contacts. What does RGP mean?
RGP stands for Rigid Gas Permeable. These are the modern version of the original hard contact lens. Introduced in the 1980's, RPG is a comparatively new contact lens technology. They are permeable to oxygen, even more so than most "soft" contact lenses, allowing oxygen to reach the eye and therefore offer greater comfort. They offer better visual acuity, are very durable, are easy to clean, and because they don't contain water they do not attract lipids (fats) and proteins the way soft contact lens do. They can last year if properly cared for and thus are very economical to own. They are quite useful for people with astigmatism and presbyopia as the rigid nature of the lens provide better acuity. They also make an excellent material for bifocal contact lenses. The downside is that they require an adjustment period unlike soft contact lens.
What is the difference between spherical and aspherical contact lenses?
Aspherical lenses are also used to improve the optical quality of an image by focusing the image at a single plane. With a spherical lens, light passing through the edge of the lens doesn't share the same focal plane as the one for light passing through the center of the lens. This is because spherical lenses tend to reflect light more strongly at the edges than in the lens center, thus focusing light in different planes. The effect is more pronounced the more area of the lens that is used such as in low light conditions when the iris aperture is much larger.
This focusing error is known as "spherical aberration". Aspherical lenses correct this optical defect: by constructing the lens with different lens radii (a spherical lens has only one radius r or curvature) thus alleviating the stronger bending of light at the edges.
Why am I charged an additional amount for contact lens services?
A comprehensive eye examination includes determining the prescription for eyeglasses, checking the visual acuity of the eyes for reading and other specialized tasks and examining the eyes for possible diseases including cataracts, glaucoma and macular degeneration. There is a fee for these tests that is separate from the tests that need to be done for contact lens wearers.
A contact lens examination requires asking additional history questions, measuring the eye for contact lenses, evaluating the vision with the contact lenses and ensuring properly fitting lenses using the biomicroscope. Since these tests require expertise, additional equipment and time there is a fee for these services.
Can I apply cosmetics while wearing my contacts?
Contact lenses should be put on before applying any cosmetics. It is always important that hands have been cleaned with an oil-free soap. At the end of the day remove contact lenses first before removing makeup. Never use oily makeup near your eyes, because it tends to travel as the warmth of your body melts it down. Avoid liquid or powdered eyeliner, so close to the eye , flaking is a real danger. If you line your eyes, use eye pencil only outside the upper lash line. Use powdered eye shadow instead of liquid or cream if powder gets in your eye, your tears will wash it out more readily than oil-based preparations.
Aerosol products such as hairspray and deodorant should be used prior to lens insertion If you must use these products when contacts are in, keep eyes closed and then leave the area since the spray will still be circulating in the air.
Can I swim in my contacts?
Contact lenses are not recommended to be worn while swimming or participating in water sports unless goggles or a swim mask is worn. One reason is to prevent loss of a contact lens. The second reason is to prevent water from getting on the contact lens. If water touches the contact lens there is an increased risk of eye infection, ulceration and possible loss of vision.
If you decide to swim with your contact lenses, remove them afterwards and disinfect in your contact lens care system.
Why do my eyes feel dry when I use my computer or read a lot?
Contact lenses are most comfortable when there is a constant replacement of tears over the lenses. While working at a computer or reading for extended periods of time people tend to blink less than normal. For this reason, your eye may dry out and your contact lenses become uncomfortable. It is recommended to instill a rewetting agent (eye drops) to each eye before you begin working on the computer and as needed thereafter. Remember to blink often and give yourself frequent breaks to alleviate eyestrain.
How do allergies affect contacts?
Contact lenses make eye allergies worse. This is because the contact lens acts like a sponge and holds the eye allergens in the contact lens instead of them being washed away by the tears. If you suffer from eye allergies due to the environment, it is recommended to wear your glasses during times when your eyes are especially bothersome. Prescription eye drops may also be used to alleviate the discomfort.
Occasionally you may develop an allergy to contact lens cleaning solutions. If you feel that your contact lenses are uncomfortable, please let us know so that we can determine the problem.
Occasionally you may develop an allergy to contact lens cleaning solutions. If you feel that your contact lenses are uncomfortable, please let us know so that we can determine the problem.
Should I wear my contacts if my eyes are red?
A red eye is caused by an irritation, an infection, an injury or an allergy. Contact lenses should be removed immediately if a red eye is present. Keeping the contact lens in the eye may actually make the condition worse. That is why it is important to have a pair of eyeglasses in the current prescription and in a style you would feel comfortable being seen in public. Call our office immediately so that proper treatment can be initiated at once.
Can I wear my contact lenses while playing sports?
Contact lenses are ideal for sports because they provide unlimited peripheral vision and are not able to be knocked off the eye like regular eyeglasses. It is important to consider wearing eye protection over the contact lenses to protect the eyeball and surrounding structures from injury. Too many times we hear of someone suffering a retinal detachment or loss of an eye due to a sports related injury.
My contacts feel uncomfortable, what should I do?
If your contact lenses are not feeling comfortable than you must evaluate if there is something you are doing to cause the discomfort such as: using the wrong solution to clean the contacts, not cleaning the contacts, not washing your hands prior to insertion or removal, using soap containing lotion to wash your hands, sleeping with your contact lenses, not replacing your contact lenses at the specified time, wearing your contact lenses too long throughout the day or placing a contact lens on the eye that is torn. If you feel your contact lenses are uncomfortable and none of the above possibilities exist call our office immediately
How do I care for my contact lenses?
As the contact lenses become more comfortable and familiar to you, it is easy to become complacent about caring for the lenses. Washing your hands prior to insertion and removal is critical to keeping lenses clean. Many times patients will not properly rinse the contact lenses prior to insertion and/or after removing them for the day. Now contact lens care solutions recommend that you rub the lens for 10 seconds on each side to remove bacteria and debris.
It is also important to discard old solution daily. Rinse case thoroughly with hot tap water and allow the case to air dry. Do not use saliva or tap water to store your contact lenses. Do not use plain saline to disinfect your lenses it is not strong enough. Others may forget to keep track of when to discard their disposable lenses. It is important to remember that the serious problems can occur if the lenses are not cared for properly.
If at any time you have any problems or questions regarding your contacts and your eyes please call our office.