How Contact Lenses Work

Contact lenses work like magic! These tiny lenses are worn directly on the eye to correct vision without having to wear eyeglasses. Many people prefer to wear contacts because they provide excellent vision correction, offer better side vision than glasses and are available in various types and materials. 

To gain an even greater appreciation for contact lenses, here are some facts about how they work. 

Understanding How Contacts Work 

Contact lenses work similarly to eyeglasses. They refract and refocus light to help you see better. The difference is that they sit on the tear film layer on the surface of the cornea rather than over your eyes. Also, because they stick to the tear fluid, they move naturally with your eyes. This keeps the lenses feeling comfortable and natural for much of the day. 

Lenses work differently depending on the type of refractive error you have. For example, when light rays focus too early within the eye, you are said to be nearsighted. To correct this problem, your contact lenses diverge light rays and reduce the eye’s focusing power. 

On the other hand, if you are farsighted, this means your eye doesn’t have enough focusing power. When you wear contacts, the lenses converge light rays to increase focusing power. Now you can see clearly. 

Like eyeglasses, contact lenses are expressed in diopters (D). Lens powers that correct nearsightedness start with a minus (-) sign, whereas lens powers that correct farsightedness start with a plus (+) sign. Almost all nearsighted people can wear contact lenses no matter how high their prescription is. Some laboratories make contact lenses up to -30.00 diopters! 

Why are Contact Lenses So Thin? 

It’s amazing to see how thin contact lenses are compared to eyeglasses, but there is a reason for this. Contact lenses rest directly on the eye. Glasses are worn about 12 millimeters away from the eye’s surface so they need to be bigger. Plus, eyeglasses must be thicker and more durable so they do not break on impact. 

Keep in mind that there are different types of contact lenses, and some are thinner than others. For instance, daily lenses are typically very thin and have a high water content. Monthly lenses are a bit thicker because they need to be more durable and long lasting. This thickness also prevents them from drying out. 

How Often Should I Update My Contact Prescription? 

Most contact prescriptions are good for about 1 year. Prescriptions are only made to last this long because your retina doctor wants to see you! A lot can change in a year, including your prescription. This can put extra strain on your eyes. To be on the safe side, ophthalmologists generally want to see their refractive patients every year. 

It’s amazing what a small piece of silicone can do for your vision! Thanks to contact lenses, you can enjoy crystal clear vision, great confidence and all-day-long comfort!