Photochromic Lenses: Transitions Gen S vs HOYA Sensity vs Shamir

A customer walks in, smiles a little awkwardly and asks: "those glasses that darken by themselves — do they actually work?". It is one of the most common questions we hear, and the short answer is "yes, but it depends what you want". Photochromic lenses have changed a lot in recent years — what we saw on our parents has nothing to do with today's generation.

At Eye-Shop we work with three ranges: Transitions Gen S from Essilor, HOYA Sensity and Shamir Transitions. All are serious options, but each has its own strengths. In this article we compare them as they really are — not as the marketing puts it.

What a photochromic lens is

In a nutshell: an optical lens with molecules that change structure when hit by ultraviolet light. Walk out into the sun and those molecules "darken", so the lens goes dark like a sunglass. Step indoors and the UV disappears, they return to their original state and the lens becomes clear again.

Two things to know from the start. First, the transition is not instant — a few seconds to darken fully and a couple of minutes to clear. Second, performance is affected by temperature: in the cold they darken more and faster, in the heat less. That is the physics of the molecules, not a defect.

Transitions Gen S — Essilor's new generation

Transitions is essentially synonymous with the words "photochromic lens" — like Pampers with nappies. Gen S is their newest range and the real revolution is speed. As the company officially states, the lens reaches category 3 darkness within 25 seconds and returns to fully clear in under 2 minutes.

For perspective: the previous Gen 8 needed 4 to 6 minutes to clear. That meant if you went out, in, and out again within a short time, your lens "couldn't keep up". With Gen S that doesn't happen — it changes almost at the pace of your own stride.

Gen S comes in 8 colours: the three classics (grey, brown, graphite green) and five style options — sapphire, amethyst, amber, emerald and the new ruby. It's not just fashion: the lens colour really affects colour rendering and contrast. Graphite green is the safest choice for neutral colour, brown gives warmer tones and contrast, while the coloured options are more of a statement.

Where Gen S does not solve the problem is the car. Like all classic photochromics, it needs UV to activate and the windscreen blocks it. If you drive a lot and definitely want Transitions, the range you want is XTRActive — it is activated by visible light too, not just UV, so it darkens inside the car as well.

HOYA Sensity — stability in every season

HOYA has chosen a different strategy: instead of chasing outright speed, it focuses on stability and consistency. They call it Stabilight Technology, and the promise is that the lens performs the same whether it is February or July — which for a warm climate matters more than it seems.

The Sensity range is not a single product — it's a family of four. Sensity 2 is the core all-rounder for everyday photochromic use. It darkens in 30-40 seconds and clears about 42% faster than the first generation. It comes in three colours: silver grey, bronze brown and emerald green.

Sensity Fast is the racing version — up to 45% faster fade-back than the quickest competitors, according to HOYA. Sensity Shine has a subtle built-in mirror coating that stays even when the lens goes clear indoors — a more fashion approach. And Sensity Dark, the counterpart to Transitions XTRActive: it darkens behind the windscreen too. If you are at the wheel for many hours and want a photochromic, this is the range we'll discuss.

The whole Sensity family is 100% UV and has blue-light protection. It is compatible with all HOYA lens types — single-vision, backside progressives, iD designs — and with their existing anti-reflective coatings. That flexibility is one reason Sensity is a favourite for high or complex prescriptions.

Shamir Transitions Gen S — same photochromic, different lens design

Shamir is known for its high-design progressive lenses. In photochromics it does not develop its own technology — and it doesn't need to. Transitions Optical supplies exactly the same raw material to both Essilor and Shamir. So when we say Shamir Transitions Gen S, we mean the same photochromic technology as Essilor Transitions Gen S, but on a different lens design.

What that means in practice: it darkens in the same time (~25 seconds to Cat 3), clears in the same time (under 2 minutes) and has the same colour palette. There is also a Shamir Transitions XTRActive version that — like Essilor's — is activated by visible light and darkens behind the windscreen. So for anyone who wants photochromic + driving, Shamir covers the same scenario.

So where is the difference? In the lens. Shamir runs a whole range of progressive designs at different levels: Shamir Intelligence is the flagship — the most recent, personalised design with the widest field and minimal edge distortion. Below it sits Shamir Autograph III, the previous generation but still an excellent free-form choice. At the more accessible end are Shamir Spectrum, older technology but reliable. The Transitions Gen S photochromic property can be applied to all of the above.

Side-by-side comparison

	Essilor Transitions Gen S	HOYA Sensity 2	Shamir Transitions Gen S
Darkening speed	~25 s (Cat 3)	30-40 s	~25 s (Cat 3)
Fade-back speed	< 2 min	~2 min	< 2 min
Colours	8	3 (Sensity 2)	8
100% UV	Yes	Yes	Yes
Blue-light filter	Yes	Yes	Yes
Heat/cold stability	Good	Stabilight (very good)	Good
In-car version	XTRActive	Sensity Dark	XTRActive
Progressive performance	With Varilux	With Hoyalux iD	Shamir Intelligence / Autograph III / Spectrum

Note: Essilor Transitions Gen S and Shamir Transitions Gen S use the same Transitions Optical photochromic technology. Their difference is the type of progressive lens it is applied to.

How much they cost

Prices for photochromics depend on three things: the range, the lens type (single-vision or progressive) and the refractive index (if you want a thinner lens for a high prescription). As a general reference point:

Range	Single-vision	Progressive
HOYA Sensity 2	€90-€180	€200-€380
HOYA Sensity Dark	€130-€220	€250-€430
Shamir Transitions	€110-€200	€230-€420
Transitions Gen S	€140-€240	€280-€480
Transitions XTRActive	€160-€260	€300-€520

Prices are indicative, without discounts and without the frame. They are finalised after checking your prescription and choosing coatings (anti-reflective, anti-glare, etc.). Eye-Shop runs periodic offers and interest-free instalments.

Which range for whom

There is no "best" — there is the one that suits your day. If you spend a lot of time in the car, the conversation ends with Transitions XTRActive or HOYA Sensity Dark. Classic photochromics will not cover you at the wheel, however fast they change in other conditions.

For those who want outright speed — in and out of buildings all day, constantly changing conditions — Transitions Gen S is the clear winner. The 2-minute fade-back versus 4-6 for Gen 8 (and similar times for most competitors) is a noticeable everyday difference.

If you live somewhere with big temperature swings — mountains in winter, beach in summer — HOYA Sensity with Stabilight Technology gives you a more consistent experience all year. You won't feel that "they don't darken enough in summer".

For progressive glasses, and especially for those who have tried various progressive ranges without finding their fit, Shamir Transitions Gen S is a strong proposition. You get the same photochromic performance as Essilor (same Transitions Optical raw material) on a Shamir lens design — considered among the most well-balanced progressives on the market. See our guide to Shamir Autograph Intelligence.

And if you want a statement colour — ruby, amethyst, sapphire — and aesthetics matter beyond function, Gen S has the richest palette.

Photochromic or separate prescription sunglasses?

The debate that never ends in the shop. There's no single answer. Photochromics are one pair for everything and therefore more practical. Separate prescription sunglasses give better colour rendering, can be polarized and are designed from scratch as sunglasses — with the right shapes and proper coverage around the eye.

From experience: people who spend serious time outdoors (beach, fishing, sailing, cycling, skiing) almost always end up with the second pair. Those with a more indoor daily life who just want protection when they step out find photochromics more convenient.

Photochromic and polarized

Many ask if there is a photochromic that is also polarized. The short answer: there is, but it is relatively rare and expensive. Transitions XTRActive Polarized and the Vantage range are Transitions' main options for photochromic + polarized. The polarisation activates progressively as the lens darkens — so you don't have a constant 100% polarisation. Who it's worth it for: if you definitely want one pair but drive or are near water, yes. Otherwise a separate polarized sunglass gives a cleaner result.

For the whole night-driving question, see our article on the best glasses for night driving.