For millions of Americans who suffer from vision problems, such as nearsightedness or farsightedness, contact lenses offer an ideal solution. Vision correction is a very common need in the United States and other areas of the world. Approximately 168 million US citizens use some form of corrective devices, such as contact lenses or eyeglasses. In addition, some people wear them for reasons other than vision correction. For instance, professional athletes use them to sharpen their sight when engaged in a sport, while other individuals use them for the purpose of changing their eye color. A person may even acquire contacts to enhance a costume for a party. However, most people obtain such devices to correct their vision. Most consumers receive a prescription from an optometrist and then order their corrective lenses at that time, while others choose to purchase contact lenses online. It is important for all individuals to learn essential facts about corrective devices of this type and how to use them safely.
How Contacts Lenses Work
Contacts are prescription lenses that are worn over the eye. The fact that they make contact with the eye is likely how they acquired their name. They were developed to maintain ocular health and correct refractive errors in those who do not wish to wear eyeglasses. They essentially float on the surface of the cornea in what is called the tear film layer. The obvious advantage is that they are much smaller than eyeglasses and worn directly on the eye, as opposed to resting on the person’s nose and ears. Another benefit of contact lenses over eyeglasses is the fact that the former adapt to eye movement, while eyeglasses remain stationary.
Types of Contacts
As one may suspect, all contacts are not the same. Different types have been designed over the years to meet a variety of purposes. These include monthly or daily contact lenses, as well as those that are disposable. These types cover a broad range of modalities, which is a term that refers to how often they are changed.
Contacts also come in a wide range of diopters. This term refers to the actual shape of the lens, which is essentially the prescription. On all boxes of contacts there are plus or minus signs, followed by numbers, and these codes refer to the shape of the lenses. Different shapes are used to correct different vision problems.
Toric lenses are designed with more weight at the bottom than the top, and these are used to correct a vision problem called astigmatism. Spherical lenses are the same weight around their entire circumference, and are used to correct farsightedness or nearsightedness. This means that lenses are available for essentially any need, including options for those who need multifocal lenses, bifocals or monovision contacts.
Disposable Contact Lenses
Disposable contacts were designed to be worn for a predetermined length of time and then disposed of, hence their name. Disposables are the most frequently purchased contact lenses in the United States. Both consumers and eye care professionals often prefer disposables for their convenience and health benefits alike. Disposable lenses are generally replaced every two weeks or sooner.
Daily contact lenses are typically removed from the eyes nightly and placed in a cleansing solution until the next day. These come in three standard types, which are planned replacement contact lenses that usually last between one and six months, traditional soft contacts, which can be used up to a year if cared for properly, and gas-permeable, rigid lenses, which last over a year in many cases.
Extended Wear Contacts
Extended wear contacts are generally worn continuously for up to a full week. This option became available when silicone hydrogel lenses were invented, which are much more efficient than traditional lenses with regard to letting oxygen through to the eye’s lens. Continuous wear contacts of this type can even be worn up to 30 days without being removed, and these are commonly referred to as monthly contact lenses. Previously, before silicone hydrogel lenses were developed, the primary danger of leaving contacts in too long was depriving the cornea of oxygen. Oxygen is vital to the health of both the eyelids and the blood vessels of the eye.
Extended wear contacts are an ideal option for individuals who have highly active lifestyles or unpredictable schedules. For example, outdoor enthusiasts or even military personnel who are not always able to stop and clean their contacts when necessary often benefit greatly from extended wear models that can be left in place for lengthy amounts of time. This is also the case for shift workers and those who work as emergency technicians in various settings. People with binocular vision irregularities, such as amblyopia, are often given extended wear contacts, as continuous vision correction is usually indicated for such individuals.
Contact lenses offer exceptional benefits to essentially anyone suffering from vision problems. However, because vision varies greatly from one individual to another, an ideal choice for one person may be of little or no benefit to the next. For this reason, those who need corrective lenses should speak to a qualified eye care professional about all his or her alternatives in order to find the best option available.