Written and maintained by CASRAI Editorial Board
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Single vision lenses have one lens correction across the whole lens, so they help you see either close up or far away, not both. The American Academy of Ophthalmology (AAO) describes single-vision glasses this way, and contrasts them with bifocal, trifocal and progressive lenses, which put more than one correction in a lens. In the United States, every eyeglass lens, single vision included, must also meet the FDA impact-resistance rule in 21 CFR 801.410. This guide is general product information, not medical advice and not a reading of anyone’s prescription.
Definition and scope
A single vision lens has a single optical correction. The AAO states that “single-vision glasses have a lens designed to help you see either close up or far away” (AAO, Eyeglasses: How to Choose Glasses for Vision Correction, checked 2026-10-30). That is the whole definition: the term describes how many corrections a lens carries, not what the lens is made of or what it is coated with.
The AAO also notes that people who wear single-vision eyeglasses for distance and need reading glasses for near work are among those who may consider progressive lenses (AAO, Pros and Cons of Progressive Lenses, checked 2026-10-30). In other words, a single pair of single vision glasses serves one distance.
Single-vision vs bifocal, trifocal and progressive lenses
The AAO describes the four common lens types by how corrections are arranged. The table uses the AAO’s own wording.
| Lens type | What the AAO says about the correction |
|---|---|
| Single vision | One lens design to help you see either close up or far away |
| Bifocal | Corrects for reading on the bottom and distance on the top |
| Trifocal | Lenses with three different lens corrections |
| Progressive | A smooth transition instead of visible dividing lines between zones |
The AAO adds that computer glasses are a subset of progressives that devote more space to intermediate distances. Source: AAO, Pros and Cons of Progressive Lenses, checked 2026-10-30.
For a plain-language look at reading-only correction, see the CASRAI guide on reading glasses strength charts.
Do single-vision lenses work for reading and distance?
One lens corrects one distance. Per the AAO, a single-vision lens is designed for either close up or far away. Bifocal, trifocal and progressive designs, described above, put more than one correction in a lens. Questions about a specific person belong with their eye care professional.
Material and coating are separate choices from lens type
Lens type (how many corrections) is independent of lens material and coatings. The AAO lists these as separate attributes that can apply to a lens (AAO, Eyeglasses, checked 2026-10-30):
- Polycarbonate: “highly impact resistant.”
- High index: “thin, lightweight, plastic lenses.”
- Anti-reflective coating: reduces glare.
- UV coating: “helps to protect your eyes from the sun’s harmful radiation.”
So “single vision” on an order or spec sheet answers only the correction question. Material and coating still need to be stated separately.
Where it matters for labs, clinics and supply decisions
Are single-vision lenses covered by the FDA impact-resistance rule?
Yes. 21 CFR 801.410 requires eyeglass and sunglass lenses to be impact-resistant, and it does not exempt single vision lenses (text checked 2026-10-30 as mirrored at Cornell LII; the official eCFR is the controlling source). Key points of the rule:
- Lenses may be glass, plastic or laminated, provided they pass the impact test (paragraph (c)(1)).
- The test drops a 5/8-inch steel ball, about 0.56 ounce, from 50 inches onto the lens, striking within a 5/8-inch circle at the geometric center (paragraph (d)(2)).
- Each finished impact-resistant glass lens for prescription use must be individually tested; other lens types may be batch-sampled (paragraph (c)(3)).
- The one exception applies where a physician or optometrist finds that impact-resistant lenses will not fulfil the patient’s visual requirements. Other lenses are then directed in writing, and the patient is notified in writing.
A short spec checklist for a single-vision order
Drawn only from the sources above, a single-vision lens description has four parts that should each be stated: the single correction and its intended distance (near or far), the lens material (for example polycarbonate or high index), any coatings (anti-reflective, UV), and compliance with the 21 CFR 801.410 impact rule. Where the use is protective eyewear, see the CASRAI guide on prescription safety glasses and ANSI standards, and for clinic stocking context the optometry clinic supply checklist.
Common misunderstandings
- “Single vision means distance only.” No. The AAO says single-vision lenses are designed for close up or far away; which one depends on the lens.
- “Single vision is a material.” No. Polycarbonate and high index are materials; single vision is a correction layout.
- “The impact rule only covers safety glasses.” No. 21 CFR 801.410 covers eyeglass and sunglass lenses generally.
- “Contact lenses and eyeglass lens types are interchangeable terms.” They are different products. For contact lens materials see contact lens materials.
FAQ
What are single vision lenses?
Lenses with one correction, designed to help you see either close up or far away (AAO, checked 2026-10-30).
How are they different from progressive lenses?
Progressives provide a smooth transition between zones with no visible dividing lines, while a single-vision lens has one correction.
Do single-vision lenses have to be impact-resistant?
Yes, under 21 CFR 801.410, apart from the written exception for cases where a physician or optometrist finds impact-resistant lenses will not meet the patient’s visual requirements.
Sources
- American Academy of Ophthalmology, Eyeglasses: How to Choose Glasses for Vision Correction, checked 2026-10-30.
- American Academy of Ophthalmology, Pros and Cons of Progressive Lenses, checked 2026-10-30.
- U.S. FDA, 21 CFR 801.410, Use of impact-resistant lenses in eyeglasses and sunglasses, text checked 2026-10-30 at Cornell LII.
