Your eye health is a vital aspect of your overall health. It’s crucial to make an informed decision about which contacts to buy. If you’re considering getting contact lenses, there are a few things you need to know.
This guide will answer common questions and help you find comfortable, healthy, and clear vision.
*Disclaimer: This guide doesn't replace the advice of an eye doctor. Rely on a qualified eye care professional for personalized information and recommendations.
Schedule a Contact Lens Fitting
During the eye exam, an eye doctor (optometrist or ophthalmologist) will check your eye's overall health. They will also do the following:
- Determine your eye prescription
- Test how your eyes work together
- Check the fluid pressure in your eyes
- Check to see if you have any eye infections or conditions
An eye exam is not enough to determine your contact lens prescription. Your eye doctor will need to perform a contact lens exam for this. They may measure:
- Your corneal curvature
- Pupil or iris size
- Tear film quality
These measurements will help your eye doctor determine whether or not you should wear contact lenses. They will also discuss your lifestyle to determine a healthy wear and replacement schedule. Many eye doctors will then give you a free trial pair of contacts to test out for a week or two.
Your eye doctor’s recommendations are the best source of information for which type and brand of contact lens or other eyewear to purchase.
Contact Lens Prescriptions
A valid contact lens prescription is required to buy contact lenses. Contact lens and glasses prescriptions are different.
Glasses rest about 12mm from your eyes, whereas contacts are placed directly on your eyes. This means the strengths of the prescription may differ.
Example of a Contact Lens Prescription
Example of an Eyeglasses Prescription
The two types of prescriptions contain some of the same information. Though these may refer to the same prescription elements, the numbers may differ depending on the device.
OD stands for oculus dexter for both prescriptions and refers to the right eye. OS stands for oculus sinister and refers to the left eye.
You'll also see the following prescription elements:
POWER (PWR) or SPHERE (SPH)
POWER (PWR) or SPHERE (SPH) is on both types of prescriptions. It's your prescription's refractive power (commonly called “strength”). The larger the number, the stronger the prescription.
- (+) indicates farsightedness correction
- (-) indicates nearsightedness correction
Cylinder (CYL) and AXIS
Cylinder (CYL) and AXIS are measurements for people with astigmatism. They appear on both prescriptions but only have a number if the person has astigmatism.
- CYL measures the amount of astigmatism correction
- AXIS measures the direction of astigmatism correction
B.C. stands for base curve and measures the curvature of the inside of a contact lens. The number is usually between 8 and 10. It should match the curvature of your eye to achieve maximum comfort and fit.
DIA represents the diameter of the lens or width from edge to edge. This number is usually between 13 and 15 mm (smaller for rigid gas-permeable lenses). It determines where the contact sits on your eye.
You’ll receive separate prescriptions for your eyeglasses and contact lenses. Be sure to ask your eye doctor for a copy of each especially if you purchase contacts or glasses online.
Types of Contacts
Different types of contact lenses are suitable for different needs and preferences. The types of contact lenses are as follows:
1. Hard (Rigid Gas-Permeable, or RGP)
Rigid gas-permeable contact lenses are less popular than soft lenses, though some people still prefer them. They are custom-shaped to the person’s eye shape, which may provide sharper vision.
They are more durable and last longer (typically 1-2 years). RGP lenses move on your eye with each blink, allowing oxygen and tears under the lens.
2. Soft Contact Lenses
Soft contact lenses are much more common than RGP lenses. Most people find the silicone hydrogel material of soft lenses more comfortable.
There are a wide variety of soft lenses available. Each type will have a specific wear and replacement schedule, so you can find one that fits your needs and lifestyle.
3. Toric Lenses
Toric lenses are a special type of contacts for people with astigmatism. They have a slightly different shape to take the misshapen cornea into account.
4. Multifocal Contact Lenses
Multifocal contact lenses are available for people with presbyopia. They can replace bifocal or multifocal eyeglasses.
Wear Routines and Replacement Schedules
Soft contact lenses all come with recommended wear routines. These, combined with your eye doctor’s personalized directions, will make up your wear and replacement schedule.
These are the standard types of soft lenses and the amount of time they're safe to wear:
Daily Disposable Lenses
Daily disposable lenses are worn for 1 day and then discarded. They are rising in popularity due to their convenience and safety. With dailies, you don’t need a contact case or solution. You simply throw them away at the end of the day.
Daily lenses negate the risk of build-up. They are also very popular among people with dry eyes.
Weekly or Bi-Weekly Lenses
Depending on your eyes, weekly or bi-weekly lenses get replaced every week or two. They offer a balance of convenience and comfort. The popular Acuvue Oasys lenses are an example of bi-weekly lenses.
Monthly Contact Lenses
Monthly contact lenses must be replaced 30 days after opening. They are the most cost-effective type of soft lenses. However, they do require more cleaning and maintenance than daily disposables.
Extended Wear Contacts
Extended wear contacts are U.S. Food and Drug Administration (FDA)-approved for overnight wear. Most are approved for 7 days and 6 nights, while Air Optix Night & Day lenses are approved for 30 days and nights of continuous wear.
Not everyone can wear the lenses for extended wear. Approximately 80% of people can wear contacts during the day and at night.
Always follow the eye care professional’s recommended lens wear, care, and replacement schedule. Overnight wear of contact lenses has been shown to increase the risk of certain serious contact lens–related complications.
Buying Contacts Online
Buying contacts online is simple, safe, and convenient (and often cheaper) if you’ve had a professional contact lens fitting beforehand.
If you have never worn contacts, see an eye doctor before you order contacts online. They will perform an eye exam and fitting, give you pointers, and help you put your contacts in for the first time.
However, once you know what contact lens brand works best for you, purchasing contacts online can be more convenient and cost-effective than visiting your eye doctor to order. Many sites allow you to buy contact lenses online as a one-time purchase or sign up for a subscription.
Contact lenses are one of the most common treatments for refractive errors. Various types of contact lenses are available, and you must consider all your choices to find the best one for you. Consulting with your eye doctor is the best way to ensure the safety and efficacy of your contact lenses.
Frequently Asked Questions
Can I sleep in my contact lenses?
Only certain contacts are FDA-approved for extended wear. Most extended-wear brands are only approved for 6 nights of continuous wear, while some are approved for up to 30 days/nights.
If your contacts are not approved for continuous wear, you should never sleep in them. It could seriously damage your eyes. Also, not all contact lens wearers are eligible for extended-wear contacts.
How many hours a day can you wear contact lenses?
Most people can wear contacts comfortably for up to 14 to 16 hours daily. However, many eye care professionals recommend wearing contacts for no more than 12 hours a day. Follow any advice from your eye doctor.
Can I swim or shower in my contact lenses?
No, the FDA states that contact lenses should never be exposed to any water. This includes tap, bottled, distilled, lake, or ocean water. Water contains countless microorganisms that can cause eye infections, irritation, and even corneal ulcers.
In this article
Best Places to Buy Contacts
1-800 Contacts is our #1 recommendation to buy contacts online.
GlassesUSA has a huge selection of contacts, glasses, & sunglasses.
Best Places to Buy Glasses
Warby Parker has stylish, high-quality frames at affordable prices.
Liingo Eyewear is another great option to buy glasses online.
Best on a Budget
EyeBuyDirect has a wide variety of budget frames starting at $6.