What Are Eyeglasses and How Do You Choose the Right Pair?

Eyeglasses are frames holding prescription lenses that bend light before it reaches your eye, correcting how the eye focuses. Choosing the right pair means matching three things: an accurate prescription, a frame that fits your face and lens power, and lens options suited to how you use them. Target Optical, for example, sells eyeglasses, prescription sunglasses, and contact lenses, with prescription lenses available at 40% off and free shipping on all orders — useful context if you plan to buy online rather than in a store.

What eyeglasses actually do

A lens corrects vision by changing the angle at which light enters your eye so it lands on the retina instead of in front of or behind it. Your prescription describes exactly how much correction each eye needs. The frame's job is to hold those lenses in the right position relative to your pupils — if the frame sits too low, too far out, or tilts, even a correct prescription performs worse.

Reading your eyeglasses prescription

An eyeglasses prescription typically lists values per eye (OD = right, OS = left):

If CYL is blank or zero, you have little or no astigmatism. PD is sometimes omitted from a prescription written for in-store use but is required for online ordering, so ask for it if you plan to buy remotely.

Frames: style, material, and fit

Frame choice is partly taste and partly mechanics.

• Face shape is a styling guide, not a rule: angular frames often balance round faces, rounded frames soften square ones. The more practical test is width — the frame front should roughly match the widest part of your face, and your eyes should sit near the horizontal center of each lens.
• Material affects weight and durability. Acetate (plastic) allows more color and shape variety; metal and titanium frames tend to be lighter and thinner.
• Fit points to check: the frame shouldn't slide when you look down, shouldn't pinch at the temples or nose, and the lenses should sit close enough that your eyelashes don't brush them.

Lens options

• Single vision — one prescription power across the whole lens; the standard choice for most everyday wear.
• Bifocal — two zones with a visible line, for distance plus near vision.
• Progressive — the same idea without a line, with a gradual transition; there's usually an adaptation period.
• Coatings — anti-reflective reduces glare and reflections; scratch-resistant and UV protection are common additions.
• Tints and photochromic — colored lenses for light sensitivity or sunglasses use; photochromic darken in sunlight and clear indoors.

Higher prescriptions generally need thinner, higher-index lens materials to avoid thick edges, which is worth factoring into cost.

Measuring fit and adjusting for comfort

Fit is measured, not guessed. PD centers the lenses over your pupils; optical center height matters too, especially for progressives. If frames arrive uncomfortable, most opticians can adjust nose pads, temple arms, and frame tilt — small tweaks that fix sliding, pressure points, and lenses sitting too high or low.

A practical way to decide

Start with your prescription and PD, then pick a frame width that matches your face, then choose lens type based on how you use your glasses (all-day distance, reading, or both). If you're buying online, confirm the return and adjustment policy before ordering, since fit issues are the most common reason a pair doesn't work out.