Switching from glasses to contacts starts with a contact lens fitting, a separate appointment from your regular eye exam. You can’t use your glasses prescription for contacts because the lenses sit in different places, so you’ll need a new evaluation before you can make the switch. The process is straightforward, and most people adapt to soft contacts within a few days to two weeks.
Why You Need a Separate Prescription
Glasses sit about 12 millimeters away from your eyes. Contacts rest directly on the surface. That gap changes the lens power needed to correct your vision, and your eye doctor has to calculate the difference (called vertex distance) to get your contact lens prescription right. The adjustment is more noticeable if you have a stronger prescription. Someone with mild nearsightedness might see nearly identical numbers on both prescriptions, while someone with a strong prescription could see a meaningful difference in lens power.
Beyond power, contacts also require measurements that glasses don’t. Your cornea has a specific curvature, and the lens needs to match it so it stays centered, moves slightly when you blink, and doesn’t pinch or slide around. A lens that’s too tight restricts oxygen to the cornea; one that’s too loose shifts out of position and blurs your vision.
What Happens at a Contact Lens Fitting
The fitting usually takes one appointment, sometimes two. Your eye doctor will measure the curvature of your cornea using a device called a keratometer, evaluate your tear film to check for dryness, and assess the overall health of your eye’s surface. These measurements determine the base curve and diameter of your lenses.
From there, you’ll be given a pair of trial lenses matched to your prescription and corneal shape. You’ll wear them in the office for a short period, then your doctor will examine how the lenses sit on your eyes, checking their movement, alignment, and whether your eyes are responding well. If the fit isn’t right, you’ll try a different lens. Once everything looks good, you’ll get a prescription and, in most cases, a starter supply to take home.
Many offices also include a training session where a technician walks you through putting lenses in and taking them out. Don’t feel embarrassed if this takes a while. Almost everyone fumbles with it the first few times.
How to Put Contacts In and Take Them Out
Wash your hands thoroughly with soap and water before touching your lenses, then dry them with a lint-free cloth. Avoid soaps with heavy fragrances or oils, which can transfer to the lens surface and irritate your eyes. Always start with the same eye each time so you never mix up your left and right lenses.
To insert a soft lens, place it on the tip of your index finger and make sure it’s not inside out. A correctly oriented lens looks like a smooth bowl; an inverted one flares out slightly at the edges. Pull your lower eyelid down with your middle finger, look up, and gently place the lens on the lower white part of your eye. Then look down and close your eye for a moment. The lens will center itself. If it feels wrong or your vision is off, the lens may be flipped. Remove it, rinse with fresh solution, and try again.
Removal follows a similar routine. Look up, pull down your lower lid with your middle finger, and use your index finger and thumb to gently pinch the lens off the surface of your eye. Use the pads of your fingers, never your fingernails.
Choosing Between Daily and Monthly Lenses
The two most common options are daily disposables (you wear a fresh pair each day and throw them out at night) and monthly lenses (you clean and store the same pair for up to 30 days). Each has trade-offs.
- Daily disposables are the lowest-maintenance option. Because you start with a sterile lens every morning, the risk of infection is lower. They tend to be thinner, which can feel more comfortable, especially if your eyes run dry. The downside is cost: you’re buying roughly 730 individual lenses a year instead of 24.
- Monthly lenses cost less upfront but require daily cleaning, a lens case, and solution. Skipping cleaning or wearing them past their replacement schedule allows protein and bacteria to build up, which increases the chance of redness, irritation, and infection.
Both types are now widely available in silicone hydrogel, a material that lets significantly more oxygen reach the cornea than older hydrogel lenses. If comfort or dryness is a concern, silicone hydrogel is generally the better material to look for regardless of which schedule you choose.
Annual costs for contacts typically range from $250 to $750 depending on brand and wear schedule, plus the cost of solution and supplies for monthly lenses. For comparison, a pair of prescription glasses usually runs $200 to $600 or more, but lasts longer before replacement.
What the First Two Weeks Feel Like
Most people adjust to soft contacts within a few days, though it can take up to two weeks. During that window, a few temporary sensations are normal. Your eyes may water more than usual or feel mildly irritated, as if something is sitting on them (because something is). You might blink more frequently. Some people notice slightly blurry vision right after insertion, which often clears up as the lens settles and your tear film stabilizes.
Eye fatigue is also common in the first week, especially if you’re wearing lenses for a full day right away. Your doctor may suggest building up wear time gradually, starting with four to six hours a day and adding an hour or two each day until your eyes are comfortable for a full stretch.
Rigid gas-permeable lenses, which are less common but offer very sharp vision, take longer to get used to. Expect a few weeks of adaptation rather than a few days. Multifocal contacts, designed for people who need both distance and reading correction, can also require several weeks. Some glare around lights at night is typical during that period.
Keeping Your Lenses and Eyes Healthy
The single biggest risk with contacts is infection, and the single biggest cause of infection is poor hygiene. A serious corneal infection called microbial keratitis occurs at a rate of about 0.52 per 10,000 wearers per year for daily disposable users, but that rate jumps to 2.52 per 10,000 for people who sleep in extended-wear lenses. In other words, sleeping in your contacts roughly quintuples the risk.
If you use monthly or biweekly lenses, follow these habits:
- Never top off old solution. Dump out the old solution, rub and rinse the case with fresh solution, and let it air-dry upside down with the caps off after each use.
- Replace your case at least every three months. Old cases harbor bacterial biofilms that no amount of rinsing will fully remove.
- Never rinse lenses or cases with tap water. Water carries microorganisms, including acanthamoeba, that can cause severe infections.
- Stick to your replacement schedule. A two-week lens worn for a month accumulates deposits that increase irritation and infection risk.
Contacts for Kids and Teens
There’s no strict minimum age for contacts. The FDA has approved lenses for children as young as 8 to 12 for specific purposes, including slowing the progression of nearsightedness. The more relevant question is maturity: can the child reliably wash their hands, follow a cleaning routine, and avoid sleeping in lenses? If your child already handles personal hygiene responsibilities consistently, they’re likely ready. Many optometrists fit children in daily disposables specifically because there’s no cleaning step to skip.