Materials glossary / Lens coating
Photochromic lens
On the label: Photochromic · Lens coating
What it is
A lens that darkens in UV light and clears indoors (Transitions is a brand); slow to clear in cold, and does not darken much behind a car windscreen, which blocks UV.
Lens coatings: Layers applied to a lens: anti-reflective, mirror, polarizing film, photochromic dye, scratch-resistant hard coat.
Wikidata: Optical lenses that darken on exposure to certain wavelengths of light. Q2737181 →
In the research
365 PubMed papers mention it with jewelry, allergy, eyewear or UV; the three most recent:
- Multifunctional CNF-Based Composite with Photochromic and Upconversion Luminescence Properties for Advanced Anticounterfeiting Applications · ACS omega, 2026
- A Wide-Band-Gap Pyromellitic Diimide-Based Coordination Polymer for Selective and Visual Detection of Ultraviolet Rays · Inorganic chemistry, 2026
- Investigation of photochromic films containing Na(8)Al(6)Si(6)O(24)(Br,S)(2) · Dalton transactions (Cambridge, England : 2003), 2026
A paper is a paper, not a verdict: titles are listed so you can read them, and a study on one fabric or one filter says little about the piece in your hand.
Pieces whose listing names it
4 on the siteMatched from the words in the supplier's listing; the full material line is on each product page.
Made in the USA
Made in the USA
Made in the USA
Made in the USA
Other lens coatings
Clasp & Lens describes materials from the public record and does not appraise, grade or test pieces; what a listing states is the supplier's statement. If a piece causes a rash, take it off; a reaction that spreads or blisters is a doctor's question, and sunglasses are no substitute for impact-rated eye protection where that is required.