You have seen all the ads for buying contacts online. You do not really need contacts, but you love the idea of buying colored contacts or fashion contacts that do fun and unique special effects. Because you do not have a prescription, you are free to purchase your non-prescription contacts from any seller you like, including online sellers. However, there are a few things you should know before you buy any contacts at all.

You Still Need to Know Diameter and Base Curve

To get contacts to fit your eyes properly, an optometrist uses special instruments to measure the diameter of the colored parts of your eyes and their base curve. The base curve is the depth curve of the inside of your lens. It is important to know these two pieces of information so that your contact lenses do not fall out or scratch your corneas. If the lenses are too big, they fall out. If they are too small, they will scratch, itch, and irritate your eyes, making your "fun" contacts not so fun.

Additionally, if you order your contacts online, the online company will ask you for your base curve (BC) numbers and your eye diameters. If you cannot supply these numbers, the company will not complete your order. You can get the proper contact lens fit from an optometrist.

You Need to Understand How Fashion Lenses Work

Fashion contacts are those that give you unusual special effects looks. Solid black demon eyes, milk white eyes, lucky eight-ball eyes; all of these are examples of fashion contacts. They operate very differently from non-prescription colored contacts.

Colored lenses in general only alter the colored parts of your eyes, the irises. These lenses leave a wide open center aperture for your natural lenses to open and close your pupils. Opening and closing your pupils allows light into your eyes and shuts excess light out. The available, non-colored part of any colored or eye color-changing lense is open wider to allow your eyes to naturally adjust to indoor and outdoor light, day or night.

Fashion lenses, on the other hand, tend to occlude more of the lenses's surface areas. As such, the fashion lenses restrict more of the light you are able to take in, which may make it more difficult to see in the dark. If you are going to be wearing fashion lenses after dark (say, for a Halloween party), then be sure to drive more carefully or find a ride to and from events. Click to read more.