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Picking eyeglass frames that look right is tough enough. Then you have to choose lenses and coatings. Those decisions are key to how well you’ll see and how much you’ll spend. Americans shell out an average of $275 after insurance for new glasses, and most of that money is for lenses, not frames.

You can’t always rely on salespeople, who may work on commission, to guide you. But Consumer Reports’ expert steps will help.

Looking at lenses

The two best-selling lenses are the most basic ones: the CR-39 and the polycarbonate, both plastic. (Few people now use glass, which is heavy and breakable.)

If you have a single-vision prescription (glasses to see far away or close up), you can generally get by with CR-39 lenses. They can be inexpensive — Consumer Reports found them for $29 to $149 — but they can look thick if you need stronger prescriptions. A more durable, thinner, lighter and more popular option is polycarbonate lenses, which were found for $9 to $205. (Some retailers occasionally offer lenses free of charge as part of packages.)

If you need glasses to see both near and far, lens choices get more complex. Here are four, along with their national average costs:

Progressives ($260) provide a smooth, gradual change in lens strength for seeing well at any distance. Consider them if you need glasses for distance and reading and if you find the split screen of bifocals or trifocals uncomfortable. Pricier than bifocals ($105), progressives can take days to weeks to get accustomed to if they’re made with CR-39 or polycarbonate materials.

High-definition lenses ($310 for progressives) offer sharper vision and better peripheral vision than basic lenses. You may opt for them if you have more-complex visual problems such as cataracts or corneal scars.

High-index lenses ($150 for single-vision, $350 for progressives) are quite thin and light, but unlike other thin lenses, they work for even the strongest prescriptions.

Trivex lenses ($200 for single-vision, $400 for progressives) are extremely resistant to impacts and scratches. They can be useful if you wear rimless or semi-rimless frames, or if you’re hard on glasses.

Coatings to consider

Lens coatings are meant to protect your eyes from light or increase lens durability. Five common treatments to know about:

Anti-scratch coating —generally a good idea for all — comes with 95 percent of plastic lenses. Check the warranty; retailers such as Warby Parker will replace at no charge lenses that get scratched in the first year after purchase.

Anti-reflective coating ($50 to $100), often bundled with high-index and high-definition lenses, used to be smudge-prone and hard to clean, but it now has anti-smudge/anti-fog technology. If you have trouble seeing properly when on a computer, when driving or at night, consider them.

Ultraviolet protection ($20 to $100) is a good idea for most people because the sun’s UV rays may boost the risk of cataracts. Most lenses come with this coating; make sure yours do.

Photochromic coating ($50 to $150) darkens in sunlight and shields you from UV rays. It’s helpful if you’d rather not carry separate sunglasses.

Blue-light-blocking coatings ($30 to $180) are said to reduce exposure to computer screens’ LED light. (Some studies suggest that overexposure can damage the retina and increase the risk of age-related macular degeneration and cataracts.) But there’s “no strong evidence that blue light affects the retina in any way we have to be worried about,” says Neil Bressler, chief of the retina division at the Johns Hopkins Wilmer Eye Institute. The orange or yellow tints may give you the perception that the tint is soothing to your eyes when you’re on a computer, but there is no strong evidence that you need them for eye health or safety.

Four ways to save money

Ask your optician for a discount. “Prices are not set in stone,” says Steve Kodey, senior director of industry research for the Vision Council, a trade organization.

Have costs broken down. Lenses and coatings are often bundled together. A listing of prices will help you see where you can shave costs

Find out about cheaper alternatives. Some lenses and coatings are available in less expensive generic forms.

Check online prices. Kodey says that many optical shops are inclined to match those prices. If your optician is not, check the big-box stores. At Costco, a pair of high-definition progressive lenses with anti-reflective coating and UV protection costs $130; at Walmart, the price is $255.

Copyright 2016. Consumers Union of United States Inc.

For further guidance, go to www.ConsumerReports.org/Health, where more detailed information, including CR’s ratings of prescription drugs, treatments, hospitals and healthy-living products, is available to subscribers.