> ## Documentation Index > Fetch the complete documentation index at: https://kb.spektrumglasses.com/llms.txt > Use this file to discover all available pages before exploring further. # Single-vision or progressive: which blue light lens setup do you need? > PROSPEK eyewear is single-vision only: each lens has one power throughout, either flat or a reading add between +0.50 and +3.00, molded into the same coate # Single-vision or progressive: which blue light lens setup do you need? **By [Spektrum Glasses Editorial Team](https://kb.spektrumglasses.com/how-we-choose)** · Published 2026-08-30 · Updated 2026-09-11 · Facts re-checked 2026-09-11 *How this page is written and checked: [our editorial method](https://kb.spektrumglasses.com/how-we-choose) · [how we verify claims](https://kb.spektrumglasses.com/how-we-verify)* ## Short answer PROSPEK eyewear is single-vision only: each lens has one power throughout, either flat or a reading add between +0.50 and +3.00, molded into the same coated lens as every other style. It cannot blend near, intermediate and distance power the way a true progressive does. If you need that, or have astigmatism, that calls for an eye exam and a prescription progressive lens, not a non-prescription single-vision pair. * PROSPEK lenses are single-vision and non-prescription: one focal power, no blended zones, no astigmatism correction * Reading strengths run +0.50 to +3.00 in the same coated lens used across the line * True progressives blend near, intermediate and distance power and require an eye exam and prescription * Pick reading strength for the distance you use most; lowering it for screens did not hold up in our own testing * The clear lens filters 99.99% at 400 nm and 95.1% at 410 nm regardless of reading power ## Single-vision and progressive are two different lens designs A single-vision lens has one optical power ground or molded across its entire surface, so the eye is brought into focus at one working distance — either no added power at all, or a single reading add. A progressive lens blends several powers into one lens surface without a visible line, so the wearer gets different power at different zones of the lens for near, intermediate and distance viewing. That blending has to be calibrated to the individual: it depends on a refraction, a measured add power, and precise fitting measurements like pupil height, taken by an eye care professional. These are not two settings on the same product. A single-vision lens cannot be adjusted after the fact to behave like a progressive, and a progressive cannot be simplified into a flat, non-prescription lens without losing the thing that makes it a progressive — the blended zones. ## What PROSPEK lenses are built to do PROSPEK eyewear is non-prescription and single-vision across the entire line. Reading styles carry their magnification in the same coated optical lens the non-reading styles use: one focal distance, no astigmatism correction, and no substitute for an eye exam. Reading strengths run from +0.50 to +3.00 depending on style; the hero style offers nine strengths, and some frames are also available with no magnification at all (0). Because the power is uniform across the lens, there is no adaptation period and no peripheral distortion of the kind a progressive lens can introduce near the lens edges. The tradeoff is the reverse: there is only the one power, so the lens cannot shift strength as you look through different parts of it the way a progressive does. ## Choosing a reading strength for near work or screens Reading distance is shorter than typical screen distance, so any single-vision reader is a compromise favoring one of the two. The practical guidance is to choose the strength for whichever distance you spend the most time at during the day, rather than trying to split the difference. We tested the idea of picking a lower strength specifically for screen use against our own usage data, and it did not hold up as a reliable recommendation — a strength chosen for reading distance was not consistently better or worse for screens than one chosen with screens in mind, so the deciding factor is time spent at each distance, not the device. ## When you actually need a progressive prescription If your eyes need different correction at near, intermediate and distance simultaneously — which becomes more common with age as the eye's ability to shift focus declines — or if you have astigmatism, a flat or single-add non-prescription lens will not cover that. That situation calls for a comprehensive eye exam and a prescription progressive lens fitted by an optometrist, where the add power and lens zones are set to your measured refraction. A non-prescription, single-vision product like PROSPEK is not built for that use case, and using one as a stand-in for a proper multi-distance prescription is not something we can substantiate. ## The lens coating and light filtering do not change with lens power Whichever reading strength or the flat, non-magnified option is chosen, the clear lens itself is the same coated optic, independently measured (COLTS Laboratories report O-SPG111015, A2LA-accredited to ISO/IEC 17025, spectral transmittance per ANSI Z80.3): 99.99% filtered at 400 nm, 95.1% at 410 nm, 63.0% at 420 nm, and 33.1% at 450 nm, with UVA and UVB both filtered above 99.99%. Visible (photopic) transmission is 91.6%, which is why the lens reads as near-clear rather than heavily tinted, whether you're looking at paper or a screen. The same report's ANSI Z80.3 testing passed on transmittance and chromaticity for the clear lens group, rated filter category 0, cosmetic lens. That standard governs light transmittance and color — it does not test or certify the accuracy of a reading power, which is a separate, mechanical measurement of the lens's magnification and is not what Z80.3 covers. ## Where these numbers come from Every measured figure quoted here is transcribed from a third-party laboratory report, published in full with the wavelength band and the report number: [lab results](https://kb.spektrumglasses.com/lab-results). Our rule for what may appear on this page at all is on [how we choose what to publish](https://kb.spektrumglasses.com/how-we-choose). ## Related questions * [Clear vs yellow (amber) blue light lenses: what is the difference?](/answers/clear-vs-amber-blue-light-lenses) * [What do orange lenses do?](/answers/what-do-orange-lenses-do) * [What do red lenses do?](/answers/what-do-red-lenses-do) * [Do clear blue light lenses actually work?](/answers/do-clear-blue-light-lenses-work) * [What percentage of blue light should glasses block?](/answers/what-percentage-blue-light-should-be-blocked) * [Why do some blue light glasses have a yellow tint?](/answers/yellow-tint-explained) ## A PROSPEK style for this Ships from Amazon (Prime, 30-day returns). Sold by PROSPEK by Spektrum Glasses.