If your contact lenses correct your distance vision fully, you choose reading glasses the same way anyone else would: based on your age and the strength needed to bring close-up text into focus. Your contacts handle the nearsightedness or farsightedness, so the reading glasses only need to add magnification for up-close work. Most people start around +1.00 and work up from there as they age.
Why You Need Readers Over Contacts
The issue is presbyopia, the gradual loss of close-up focusing ability that starts in your early 40s. Your eye’s internal lens stiffens over time, making it harder to shift focus from far to near. Contact lenses correct your distance vision, but they don’t fix this age-related change. The result: you can see across the room perfectly, but a menu or phone screen turns into a blur.
Reading glasses worn over contacts act as a simple magnifier for near tasks. Because your contacts already bring your distance vision to essentially zero correction needed, the reading glasses you pick up at a drugstore work just as they would for someone with naturally good distance vision.
Strength by Age
Presbyopia is progressive, so the strength you need increases predictably over about two decades:
- Ages 40 to 45: +1.00 to +1.25 diopters. You’ll notice difficulty with fine print in dim lighting first.
- Ages 46 to 55: +1.50 to +2.00 diopters. Reading at arm’s length becomes a habit because standard distance feels blurry.
- Ages 56 and older: +2.25 to +3.00 or higher. Close work without magnification is essentially impossible.
These ranges are averages. Two 50-year-olds can easily need different strengths, and your dominant eye may differ slightly from your non-dominant eye. The age chart gets you in the right neighborhood, but a simple test narrows it down.
How to Find Your Exact Strength
Put your contact lenses in first, then grab a printed diopter test card (available free online) or head to a drugstore display. Hold the card or a book at 14 inches from your eyes, which is standard reading distance. Try the lowest strength readers, starting at +1.00, and work upward in +0.25 steps until the text looks sharp without effort. The correct pair should make reading feel natural and relaxed, not strained or overly magnified.
A common mistake is grabbing the strongest pair that makes text look large and crisp. Stronger is not better. You want the lowest strength that lets you read comfortably at 14 inches. Going higher than necessary forces your eye muscles to work against the extra magnification, which leads to problems quickly.
Computer Screens Need a Lower Strength
Reading glasses are calibrated for about 14 to 16 inches, the distance you’d hold a book. A computer screen sits farther away, typically 20 to 28 inches, so full-strength readers will over-correct and strain your eyes. The general rule is to subtract 0.50 to 1.00 diopters from your reading power for screen work.
If your screen is on the closer end (around 20 to 24 inches), subtract about 0.50. If it’s farther out (24 to 28 inches), subtract 0.75 to 1.00. In practice, that looks like this: someone who reads books comfortably with +2.00 readers would want +1.25 to +1.50 for computer use. Keeping a separate, weaker pair at your desk saves you from the headaches and neck strain that come from leaning in toward the monitor.
Signs Your Strength Is Wrong
The wrong reading glasses create symptoms fast, often within 15 to 20 minutes. If the strength is too high, you’ll notice headaches that feel like they start behind your eyes or across your forehead. A “swimmy” or dizzy sensation when you move your head is another classic sign of over-correction. Some people feel a pulling or burning sensation in the eyes, or mild nausea when shifting focus from the page to something across the room.
Too-weak glasses produce a different pattern. You’ll find yourself holding material unusually close or squinting to sharpen the text. Eye fatigue builds more slowly but doesn’t go away. Over time, your neck and shoulders tense up from the awkward positions you adopt to compensate. If you’re experiencing any of these issues, try stepping up or down by +0.25 before assuming something else is wrong.
Alternatives to Wearing Readers Over Contacts
If pulling out reading glasses every time you check your phone feels like a hassle, there are contact lens options designed to handle both distance and near vision in a single lens.
Multifocal Contact Lenses
These lenses have concentric zones for distance and near vision built into the same lens. Your brain learns to use the appropriate zone depending on where you’re looking. They eliminate the need for readers entirely for most tasks. The trade-off is some loss of visual sharpness. Many wearers notice mild halos around lights at night, ghosting of images, or slightly reduced contrast. These effects depend on pupil size and lighting conditions, so they bother some people more than others.
Monovision
With monovision, your dominant eye wears a contact lens set for distance and your non-dominant eye wears one set for near. It’s simpler and cheaper than multifocals, and fitting is straightforward. The downside is reduced depth perception, since your two eyes are focused at different distances. This can be an issue for driving at night, sports, or any task where judging distance matters. Higher reading-strength needs make the imbalance between eyes more noticeable.
Both multifocal and monovision lenses involve visual compromises that reading glasses don’t. Readers over contacts give you the sharpest possible vision at every distance, just not all at the same time. It comes down to whether convenience or optical quality matters more to you. Many people try multifocals or monovision for daily life and keep a pair of readers in the nightstand for extended reading sessions where clarity matters most.
Keeping Your Strength Current
Presbyopia progresses steadily until your early to mid-60s, when it typically plateaus. During that 20-year window, expect to bump up your reading strength every two to four years. If text that was comfortable six months ago now feels slightly soft, you’ve likely moved up by +0.25 or +0.50. There’s no harm in retesting with a diopter card whenever things start to feel off. Your contact lens prescription for distance vision, meanwhile, follows its own trajectory and should be evaluated separately at regular eye exams.