The Optician's Ultimate Guide to Light-Reactive Lenses: Standard Photochromics

The first photochromic lenses appeared in 1964, and quickly drew interest for their unique ability to darken in sunlight and fade back indoors. However, the first generation of photochromic lenses came with cosmetic and functional barriers – two of the largest being that it took them about an hour to fade and they never got fully clear.

Fast forward more than half a century, and the technology has greatly expanded, as have the types of light-reactive lenses available. Reaction speeds, darkness, clarity, and overall aesthetics have all improved greatly, and there are now four different types of light-reactive lenses available: standard, extra reactive, ultra-fast, and polarized.

In part one of this three-part series, we’ll be focusing on standard photochromics, with an emphasis on the technology, benefits, ideal patient, performance expectations, and dispensing. Read through each or jump to a section by clicking one of the buttons below: 

• The Technology
• The Benefits
• The Ideal Patient
• Setting Expectations
• Dispensing Tips

Standard Photochromics: The One that Started it All

Standard photochromics are the original offering in the light-reactive lens category. But, unlike their slower, unsightly predecessors, today’s options have made huge strides in both performance and appearance. Like all light-reactive lenses, standard photochromic lenses provide a variety of great benefits for almost any patient.

But, before we dive into the advances and benefits, let's take a quick look at how standard photochromics work.

How Do Standard Photochromic Lenses Work?

Dye molecules in the lens change structure when UV light strikes them. When UV light is present, the molecules “unfold,” absorbing light and appearing colorful. When the molecules are removed from UV light, they fold back, appearing colorless.

What Are the Benefits of Standard Photochromic Lenses?

While they don’t share all the technological advancements of their extra reactive and ultra-fast brethren, standard light-reactive lenses still provide a long list of great benefits:

Convenience: The major benefit of all light-reactive lenses is convenience. Without having to switch to a pair of sunglasses, wearers can enjoy improved visual comfort and shade their eyes from bright sunlight, UV radiation, and blue light.

Outdoor Comfort: Standard light-reactive lenses soften direct and reflected glare in their darkened, outdoor state, providing comfort and helping to reduce eye strain.

Indoor Clarity: Standard light-reactive lenses get very clear indoors when fully deactivated, offering excellent clarity and visual precision.

100% UV Protection: Light-reactive lenses protect against UV radiation, which can contribute to a variety of eye conditions, including but not limited to pterygium, cataracts, and cancer. And since light-reactive lenses are commonly combined with a patient’s primary pair of glasses, the wearers’ eyes are protected – even if they forget their sunglasses.

Blue Light Filtration: Blue light, which has been linked to digital eye strain, comes from the sun, as well as digital screens and energy-efficient lighting. Standard photochromics provide ​​​​exceptional blue light defense indoors in the clear state and even better defense against blue light from the sun in their darkened outdoor state. This makes them a great choice for everyone from young device users to older patients who ply their trade outdoors.

Who's the Ideal Patient for A Standard Photochromic Lens?

Identifying an ideal candidate for a standard light-reactive lens comes down to getting to know your patient a little more personally. Things you’ll want to consider when determining whether a patient is a photochromic fit, include, but aren't limited to occupation, lifestyle, and location:

Occupation:
Jobs that entail shifting from indoors to extended periods outdoors are great fits because they don’t necessarily require ultra-fast fade-back speed. But, don’t limit your options to outdoor professions. Some examples of occupations that lend themselves to standard light-reactive lenses include: 

• Office Workers: Many office workers are in and out of the office throughout the day, heading to meetings, stretching their legs, or stepping out to grab a bite or a coffee.  The majority of office workers are also exposed to blue light from monitors and devices all day, making a photochromic a great recommendation for relief of digital eye strain.
• Landscaping Professionals: By shielding the eyes from harsh sunlight without impacting visibility, light-reactive lenses allow landscapers to easily read labels, see cut lines, and review plans clearly and comfortably, while shielding their eyes from daily UV exposure.
• Dog walkers: Since dog walkers spend a majority of their day outdoors, they don’t necessarily need the fastest fade-back speed…however, many of them will still opt for it when given the choice.​
• ​Caretakers: Whether tending to children or the elderly, caretakers often find themselves on outings where glare reduction and UV protection are needed. 

Lifestyle:
Lifestyle activities that require a lens built for indoor and outdoor use without the need for ultra-fast fade-back speed benefit from a standard photochromic. Some possible light-reactive lifestyles include:

• Active: Hikers, bikers, runners, and boaters all benefit from a lens that provides outdoor comfort and clarity in addition to UV defense.
• Digital: Anyone on devices for two or more hours a day will benefit from the exceptional blue-light-reducing properties of standard photochromics.  People who play video games (gamers) often spend an extraordinary amount of time in front of a screen.
• Outdoor: Brown photochromic lenses are specifically suited to outdoor activities like fishing, hunting, and golfing because they enhance color and contrast – ideal when you’re trying to find your ball in the rough​.
• ​Educational: From kindergarten to college, students are in and out of the classroom all day, making them perfect candidates for a photochromic. And the blue light reduction is perfect for these heavy computer and mobile device users.

Location:
Areas where UV levels are at their peak are prime locations for a lens built to respond to ultraviolet rays. These areas include:

• Reflective Environments: Areas near water or in the snow result in direct UV exposure from above and reflected UV from below, behind, or to the side.
• High-Altitude Locations: The thinner atmosphere at higher elevations filters out less UV naturally.
• Southern States: Due to their closer proximity to the equator, southern states receive a stronger dose of UV than their neighbors to the north.​

Setting Realistic Expectations Around Standard Photochromic Lenses

Setting realistic expectations about performance sets the stage for a better wearer experience. When it comes to standard light-reactive lenses, here are a few points to mention:

Visual Experience: Many people choose a light-reactive lens thinking they perform like a pair of sunglasses. While they do darken outdoors and provide relief from bright light, the view looking out is quite different. The view through a photochromic is not as dark as a pair of sunglasses. In fact, it feels more like looking through a standard pair of glasses than a dark pair of prescription suns. This is actually beneficial to the wearer as it provides exceptional visual precision and contrast in addition to outdoor comfort.

Fade-Back Speed: Standard light-reactive lenses can take anywhere from seven to 20 minutes to return to clear. Ambient temperature can speed up and slow down fade-back speed, with hotter temperatures resulting in faster fade back and colder temperatures yielding longer lag time from dark to clear.

Outdoor Darkness: Because light-reactive lenses work in direct response to UV exposure, factors that decrease the amount of UV reaching the lens can impact how dark they get outdoors. Examples include:

• ​Time of Day: UV levels are highest from 2 - 4 p.m. They’re lower in the morning and at dusk, which could result in lenses that aren’t quite as dark.
• Time of Year: UV levels are higher in summer and lower in winter, so lens activation may be at a high in summer and take a dip during winter. However, seasonal temperatures play a role in darkness. See the “Temperature” bullet below to learn more.
• Altitude: The atmosphere is thinner at higher altitude and therefore filters less UV. With stronger UV levels, the lenses will get darker. 
• Attire: Hats and visors are designed to shade the face from bright sunlight, so they can prevent lenses from fully activating.
• Weather: UV levels are lower on cloudy days, which can impact how dark the lenses get outdoors.
• Temperature: Photochromics generally get exceptionally dark in colder temperatures and don’t get as dark in extremely hot conditions. 

In-Car Performance: Because standard light-reactive lenses respond only to UV light and most car windows have UV filtration embedded in the windows, these lenses generally won’t work in cars.  

Tips for Dispensing Standard Photochromic Lenses

• Keep the science simple – Your patients aren’t eye care professionals. Don’t confuse them with a lot of technical information or industry jargon. Dark when they need it. Clear when they don’t. That’s about as technical as you need to get.
• Discuss the convenience factor – Convenience is a primary selling point for any type of light-reactive lens. The benefits of indoor clarity, outdoor comfort, and all-around protection in one convenient package is a big draw for a lot of people.
• Offer peace of mind – Standard photochromics deliver 100% outdoor UV protection and targeted blue light filtration in any location. This is a huge benefit to bring up when talking to parents considering light-reactive lenses for their children.
• Get to know your patient’s specific needs – Standard photochromics are a great fit for a number of lifestyles and occupations. Use a lifestyle questionnaire or an in-depth chat to determine if a standard option is the right fit, or whether an extra reactive or fast fade-back lens would be more suitable.
• Explain the unique outdoor performance – While darkening to reduce glare and improve comfort, the view looking out remains crisp and clear with a standard photochromic. This is a huge benefit when comfort and precision outdoors are a necessity.
• Set realistic expectations – Discussing the aforementioned factors that can impact performance up front will result in happier patients down the road.

Wrapping it Up

If ultra-fast fade-back speed and in-car activation aren’t must-haves for your patient, standard light-reactive lenses represent a good value, providing all the other benefits of the light-reactive category.​
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Be sure to read part two in our three-part series: The Optician's Ultimate Guide to Extra Reactive Photochromic Lenses.