Blue light, anti-glare, high index: what is worth paying for

Worth it for most people

Anti-reflective (anti-glare). A coating on the lens surface that stops light bouncing off it. You notice it at night, when oncoming headlights lose their halos, and in photos, where your eyes stop disappearing behind a reflection. It also makes screens easier to look at by cutting the reflection of the room behind you. Of all the add-ons, this is the one that changes how the glasses work, and it is in our progressive basket for that reason.

Anti-scratch. A hard coating that keeps the lens surface from picking up fine scratches from cleaning and pockets. It is cheap, often included, and in every basket we price. If a retailer charges for it, pay.

Depends on your prescription

Lens index. Index is a measure of how much a material bends light. A higher index bends more, so the lens can be thinner for the same prescription. The standard 1.50 lens is fine for mild prescriptions. As the prescription gets stronger, the edges of a minus lens get thick and the center of a plus lens gets heavy, and a higher index fixes that.

Prescription (strongest sphere)	Index to consider
up to about ±2.00	1.50 standard, or polycarbonate for impact resistance
about ±2.00 to ±4.00	1.57 to 1.61
about ±4.00 to ±6.00	1.67
above about ±6.00	1.74

Frame size matters as much as the number: a wide frame shows thick edges that a small frame hides. If you are near a boundary and like big frames, go up an index.

Polycarbonate or Trivex. Impact-resistant materials that are the default for children, safety glasses and sport. They are also light, which helps with strong plus prescriptions. For adults with mild prescriptions in ordinary frames, standard lenses are fine.

Optional

Blue-light filter. A coating or lens tint that absorbs part of the blue end of the spectrum. The claim is reduced eye strain and better sleep. Ophthalmology bodies have found no evidence that the blue light from screens harms the eye, and strain from screens is mostly from reduced blinking and holding one focus for hours. The filter does no harm and some people prefer the slight warmth it gives; treat it as a preference you pay for, not a correction.

Photochromic. Lenses that darken outdoors and clear indoors. Convenient if you move between the two a lot and do not want to carry sunglasses. They respond to ultraviolet light, so most do not darken much behind a car windshield, and they take a minute or so to clear when you come inside.

UV protection. Worth having, and now built into almost every lens material at no extra cost. If a retailer charges for it as a separate line, check that it is not already included.

Tints and mirrors. Cosmetic, or for sunglasses. Pay for them if you want the look.

Premium progressive designs. Progressives come in tiers, with the pricier designs offering a wider clear zone and less distortion at the edges. First-time progressive wearers often do better with a mid-tier design than the cheapest. This is the one place where a lens upgrade changes comfort a lot, and it is why our progressive basket uses the retailer’s standard design rather than the entry one.

What to do at checkout

Add anti-reflective. Confirm anti-scratch is included. Choose the index from the table above. Skip the rest unless you want it. The total you reach is the number to compare against our table, which prices the plain pair so you can see how much each retailer’s add-ons cost on top.