With the newest contact lens designs and materials available today, our Optometrist are able to fit patients who may not have had success wearing contact lenses in the past. Whether due to poor vision, astigmatism, comfort issues, or dry eyes there are many more choices in contact lens materials to meet those challenges.
There are several types of Contact lenses but only a thorough examination of your eyes AND your lifestyle will reveal the answer.
A few examples of Contact lenses are:
The shortest replacement schedule is single use (daily disposable) lenses, which are disposed of each night. These may be best for patients with ocular allergies or other conditions, because it limits deposits of antigens and protein. Single use lenses are also useful for people who use contacts infrequently, or for purposes (e.g. swimming or other sporting activities) where losing a lens is likely.
Two-week Replacement Disposables
The main advantage of wearing disposable lenses is that you put a fresh pair of lenses in your eyes every two weeks. Another advantage is ease of care with multipurpose solutions.
One-month Replacement Disposables
Similar to two-week replacement lenses but you throw them out every 30 days.
Conventional Contact Lenses
These are the original soft contact lenses. It is recommended these lenses be replaced on a yearly basis. Conventional lenses are more care intensive than disposable lenses.
Color Contact Lenses
Certain soft contact lenses come in colors to either enhance your eye color or completely change it.
Toric for Astigmatism
Toric lenses are made from the same materials as regular contact lenses but have a few extra characteristics:
They correct for both spherical and cylindrical aberration.
They may have a specific 'top' and 'bottom', as they are not symmetrical around their center and must not be rotated. Lenses must be designed to maintain their orientation regardless of eye movement. Often lenses are thicker at the bottom and this thicker zone is pushed down by the upper eyelid during blinking to allow the lens to rotate into the correct position (with this thicker zone at the 6 o'clock position on the eye). Toric lenses are usually marked with tiny striations to assist their fitting.
They are usually more expensive to produce than non-toric lenses.
Bifocal Contact Lenses
Multifocal soft contact lenses are more complex to manufacture and require more skill to fit. All soft bifocal contact lenses are considered "simultaneous vision" because both far and near vision corrections are presented simultaneously to the retina, regardless of the position of the eye. Of course, only one correction is correct, the incorrect correction causes blur. Commonly these are designed with distance correction in the center of the lens and near correction in the periphery, or vice versa..
In an initial exam, the Optometrist will examine your eyes to determine if you can wear contact lenses. Your prescription and the curvature of your eye are measured and the doctor will discuss any special needs you may have. The doctor will then determine the type of contact lenses that best fit your eyes and provide you with the most accurate vision while ensuring that your eyes remain healthy with the lenses. If trial lenses are available in the office, you may be able to go home with lenses the same day. However, if your prescription or curvature warrant, contact lenses may need to be ordered and a contact lens fitting appointment scheduled when the lenses arrive.
When the lenses are ready, a fitting examination is scheduled as a practice session for you to try your new lenses and to become adept at lens insertion and removal. The doctor will also look at the lenses on your eyes and determine if any changes need to be made. If the lenses fit well and you are seeing well with them, a checkup exam is scheduled 1 week after the practice session. If new lenses are ordered, we will schedule a dispensing appointment when those lenses arrive.
Seeing 20/20 isn’t the only reason for a contact lens exam. Since the eye is a sensitive organ, it is susceptible to irritations that may be caused by contact lens wear. Problems that are undetectable to you can develop into more serious conditions. It is vital to your eye health to make sure that your contact lenses fit properly and are allowing enough oxygen to reach the cells of the cornea. During the annual contact lens exam, your eye care professional evaluates the condition of the lenses and can tell if any changes are warranted in the lenses’ fitting.
There are two main reasons why you should not swim or shower with your contact lenses – possible loss of the lenses and, most importantly, contamination of the lenses. Underwater, contact lenses may be washed out of your eye, or above water a small wave or splash may take the lens with it. Contact lenses, especially the soft variety, will absorb any chemicals or germs in the water. They will then stay in or on the lens for several hours, irritating the eyes and possibly causing infection.
The deciding factor for whether a child should wear contact lenses should be that child’s maturity level. Children of all ages can tolerate contact lenses well, but they must be responsible for the care of the lenses. Parents should make that judgment based on the child’s personal hygiene habits and their ability to perform household chores.
These lenses were the original contact lenses made several decades ago from a plastic called PMMA. For a long time they were the only kind of lens but they are seldom used anymore as they have several drawbacks and have been superseded by “rigid” lenses. Rigid, or gas permeable, lenses are similar to hard lenses in design and appearance, however as the name suggests, the material they are made of is permeable to gases.
Soft lenses are slightly larger and more flexible than rigid or hard lenses. Soft lenses are made of materials which soak up water, and it is this uptake of water that allows oxygen to transfer to the cornea. Soft lens material itself is impermeable, so the oxygen is transmitted via the water.
In order to maintain optimal eye health and comfort, it is important to adhere to the wearing schedule prescribed by your Optometrist.
The two-weeks timeframe refers to 14 days of wear. If you are wearing lenses only two to three days per week, the lenses may last longer then two weeks.
Extended lens wearers may have an increased risk for corneal infections and corneal ulcers, primarily due to poor care and cleaning of the lenses, tear film instability, and bacterial stagnation. Corneal neovascularization has historically been a common complication of extended lens wear, though this does not appear to be a problem with silicone hydrogel extended wear. The most common complication of extended lens use is conjunctivitis, usually allergic or giant papillary conjunctivitis (GPC), sometimes associated with a poorly fitting contact lens.