Patient guide
Contact lenses: what a fitting is, the kinds of lenses, and who they suit
A red, painful eye while wearing contact lenses is an emergency. Take the lens out, do not put it back in, and call the same day even if it is mild and only one eye. Bring the lens and the case. Call (609) 246-0236. If the office is closed, or you cannot reach us, go to a hospital emergency room — most have an ophthalmologist on call.
Contact lenses sit on the living surface of the eye, which is why they are medical devices with a prescription, why the prescription is not the same as your glasses, and why a fitting is a real examination rather than a formality. Fitted and worn properly, they are safe and most people love them. Worn carelessly, they are the commonest cause of serious corneal infection in otherwise healthy eyes.
This guide covers what a fitting involves, the kinds of lenses and who each suits, and the few rules that keep them safe.
Why a contact lens prescription is different
A glasses prescription describes lens power at about half an inch from the eye. A contact lens sits on the eye, so the power changes, especially for stronger prescriptions. More than that, a contact lens prescription names a specific lens: its brand and material, its curve, its diameter, and how often it is replaced. Those come from measuring your eye and watching the lens on it, not from a chart. That is the fitting, and it is why a glasses prescription cannot be used to order contact lenses, and why a lens that was perfect for someone else may not fit you at all.
What a fitting involves
- A full eye exam first, including your glasses prescription, the health of the cornea and lids, and the tear film. Dry eye, allergy and lid inflammation are treated before lenses go on an eye, not after, because lenses make all three worse.
- Measurements. The curve and size of the cornea, the size of the pupil, and a map of the corneal shape when there is any irregularity.
- Trial lenses. A lens is chosen, placed on the eye, and assessed after it settles: how it moves with a blink, how it centers, how you see with it, how it feels. Sometimes two or three are tried.
- Teaching, for new wearers: putting lenses in, taking them out, and the care routine, practiced until you can do it yourself. Nobody leaves until they can.
- A follow-up visit, usually one to two weeks later, with the lenses worn for a few hours, to confirm the fit on the eye and finalize the prescription. Then the prescription is yours to fill here or anywhere.
A fitting is a separate service from the eye exam, and a separate fee, because it is separate work. It is more involved for astigmatism, multifocal and specialty lenses than for a simple spherical lens.
The kinds of lenses
- Daily disposables. A fresh lens every morning, thrown away at night. No cleaning, no case, no solution. The lowest rate of serious complications of any soft lens, and the lens we recommend first for most people, for children, and for anyone with allergies.
- Two-week and monthly lenses. Reusable soft lenses, cleaned and stored each night. Cheaper per day; they depend on the care routine being followed.
- Toric lenses, for astigmatism, in daily and reusable forms. They are weighted to stay in the right orientation. Fitting them well is routine here.
- Multifocal lenses, for reading age, which give usable near and distance vision in the same lens. They suit most people who want them, with a short adaptation.
- Lenses approved for overnight wear. A few lenses are approved to be slept in. Even with those, sleeping in lenses raises the infection risk several-fold, and we recommend it only where the reason is strong.
- Rigid gas permeable lenses. Small, firm lenses that give the sharpest vision and correct irregular corneas by letting the tears fill the gap underneath. A few days to get used to; very durable.
- Scleral lenses. Larger rigid lenses that vault over the cornea on a layer of fluid and rest on the white of the eye. The usual choice for keratoconus, corneal scarring, after corneal surgery, and for severe dry eye. Comfortable from the first day for most people.
- Hybrid lenses, a rigid center with a soft skirt, for people who need rigid optics but cannot tolerate a rigid lens.
- Myopia control lenses for children, such as MiSight, which slow the progression of nearsightedness. How myopia management works.
Who contact lenses suit, and who they do not
Most people who want them can wear them, including people with astigmatism, people over forty, and children who are ready for the responsibility. Sport, an active job, a strong prescription that makes glasses heavy or distorting, and a large difference between the two eyes are all good reasons to try.
Lenses are a poor fit for an eye with untreated dry eye or lid inflammation, for someone who cannot or will not follow the care routine, and for anyone who expects to sleep in them without a lens designed for it. Those are usually solvable, and the fitting visit is where they are solved.
The rules that keep lenses safe
Serious infections are uncommon, and almost all of them come from how lenses are worn rather than from the lenses themselves. The habits that matter, in order of importance:
- Do not sleep in lenses unless they were prescribed for it. Naps count. This is the single biggest risk factor.
- Keep water away from lenses. No showers, swimming or hot tubs in lenses, and never rinse a lens or case in tap water. Water carries an organism that causes a rare and devastating infection.
- Replace lenses on schedule, and the case every three months.
- Fresh solution every night, never topped up, in a case left open to dry.
- Wash and dry your hands before touching a lens.
- Keep a current pair of glasses, so a red eye never tempts you to put a lens back in.
- Buy lenses from a seller who asks for your prescription. Decorative and costume lenses sold without one are illegal to sell in the United States and have blinded people.
The full routine is on contact lens safety, the page we give every wearer.
Common questions
Why does my contact lens prescription expire every year?
Federal law sets a minimum of one year, and the eye under a lens changes: the cornea's oxygen supply, the tear film, and the fit itself. The yearly visit checks for early problems you cannot feel, including the small changes in the cornea that precede trouble, and keeps the prescription current so you can order lenses anywhere.
Can I buy my lenses online or somewhere else?
Yes. Once the fitting is complete you receive a copy of the prescription, and the law requires that you can fill it where you choose. Sellers are required to verify it with us, and we respond the same day. What we will not do is sign off a lens that was never fitted on your eye.
At what age can a child wear contact lenses?
There is no fixed age. Children as young as eight wear daily disposables for sport or for myopia control. What matters is whether the child will wash their hands, follow the routine and take a lens out when an eye is red, with a parent keeping an eye on all three.
My eyes feel dry in lenses by the afternoon. Is that normal?
It is common and it is not something to put up with. Often the lens material or replacement schedule is wrong for your tear film, and a different lens solves it. Sometimes there is underlying dry eye or lid inflammation that needs treating first. Mention it; it is one of the most fixable complaints there is.
Does a contact lens fitting go through my vision plan or my medical insurance?
A routine contact lens fitting goes through a vision plan if you have one, usually with a separate allowance or copay for the fitting and for the lenses. A fitting for a medical reason, such as keratoconus or a scarred cornea, is often a medical visit and some plans cover the lenses themselves. Vision plans cover routine eye exams and eyewear; medical plans cover conditions. Many patients carry both and are not sure which applies. Vision plan or medical insurance explains the difference, and a call with your plan details before you book sorts it out beforehand rather than afterwards.
Book a fitting
Book an exam and say you are interested in contact lenses, so time is set aside for the fitting. If you already wear lenses, bring them, and the box or packaging that names them.
Book an exam Call (609) 246-0236
Khoury Eye Care, Hamilton Mall, 4403 Black Horse Pike, Mays Landing.
Sources
The figures and recommendations on this page come from the following. Ask at your visit if you would like a copy of any of them.
- US Food and Drug Administration. Contact lenses: types, risks, and focusing on contact lens safety. fda.gov.
- Federal Trade Commission. The Contact Lens Rule (implementing the Fairness to Contact Lens Consumers Act). 16 CFR Part 315.
- Centers for Disease Control and Prevention. Healthy contact lens wear and care. cdc.gov/contact-lenses.
- Stapleton F, Keay L, Edwards K, et al. The incidence of contact lens-related microbial keratitis in Australia. Ophthalmology. 2008;115(10):1655-1662.
- Stapleton F, Edwards K, Keay L, et al. Risk factors for moderate and severe microbial keratitis in daily wear contact lens users. Ophthalmology. 2012;119(8):1516-1521.