Have You Chosen the Right Photochromic Lenses?
Photochromic lenses, also known as light-sensitive lenses, work based on the principle of reversible light-color change.
When exposed to light and UV radiation, the lenses darken rapidly to block strong light and absorb ultraviolet rays, while providing neutral absorption of visible light.
When returning to a dark environment, they quickly revert to a clear, colorless state to ensure optimal light transmission.
Therefore, photochromic lenses are suitable for both indoor and outdoor use, protecting your eyes from sunlight, UV rays and glare.
Photochromic lenses are generally available in three colors: gray, brown and green. Gray and brown are the most commonly used.
Gray lenses absorb infrared light and 98% of UV rays. They do not alter the natural color of objects, only reduce brightness, effectively lowering light intensity for a more realistic and natural visual experience.
Brown lenses absorb 100% of UV rays and filter blue light, improving visual contrast and clarity while brightening your vision. They are ideal for wearing in hazy or heavily polluted conditions, making them perfect for drivers.
Like gray lenses, green lenses effectively absorb infrared light and 99% of UV rays. While absorbing light, they maximize the amount of green light reaching your eyes, creating a cool and comfortable feeling—ideal for people with easily fatigued eyes.
| Color | Suitable Scenarios | Features |
| Gray | Driving, outdoor sports | Balanced absorption across all spectra, no color distortion, true visual perception. Ideal for users who prefer natural color reproduction. |
| Brown | Foggy, cloudy days, dusk | Filters blue light, enhances contrast and clarity—an excellent choice for drivers. |
| Yellow | Nighttime, low-light conditions | Filters blue light, improves contrast and low-light vision; commonly known as "night vision lenses". |
| Green | Daily wear, long hours outdoors | Balanced color reproduction, comfortable vision, suitable for all-day use. |
Photochromic lenses fall into two categories: substrate-based photochromic and coating-based photochromic.
1. Substrate-based photochromic lenses
The entire lens darkens when activated. The thicker the lens, the darker it becomes.
2. Coating-based photochromic lenses
The photochromic effect occurs in the coating on the lens surface.
The darkness of the tint is not affected by the thickness of the lens.
There is no absolute "better" choice between the two types of photochromic lenses; each has its own advantages and disadvantages.
- For myopia under 300 degrees, with a difference of less than 50 degrees between both eyes, substrate-based lenses can be chosen.
- For high myopia or a large difference in prescription between eyes, coating-based lenses are a better choice.
- Daily commute / frequent indoor-outdoor switching: Coating-based photochromic lenses are preferred. They feature fast color change (response within 30 seconds) and rapid fading, making them ideal for users who frequently move between indoors and outdoors.
- Plateau/snow / strong-light environments: Substrate-changing glass lenses or high-transmittance resin lenses are recommended. They offer 100% UV400 protection, effectively blocking strong light and reflected glare.
High-quality photochromic lenses darken quickly outdoors under UV light and fade rapidly when back indoors.
Good lenses darken more intensely as UV radiation becomes stronger. Ordinary lenses usually perform less satisfactorily.
For a pair of photochromic lenses (especially coating-based ones), both lenses should show almost the same speed and depth of color change. There should be no situation where one lens is dark and the other is light.
1. If the prescription difference between your two eyes is more than 100 degrees, we recommend coating-based lenses, to avoid uneven color depth caused by different lens thicknesses.
2. If one lens of a pair worn for over a year is damaged and needs replacement, we suggest replacing both lenses together, to avoid inconsistent photochromic performance due to different usage periods.
3. Patients with high eye pressure or glaucoma must NOT wear photochromic lenses or sunglasses.
4. Photochromic lenses darken according to UV intensity, so they may also change color on cloudy days.
5. For drivers: regular photochromic lenses may not darken inside a car, because most modern windshields block UV rays. Some manufacturers have developed car-friendly photochromic technology that allows lenses to darken even inside vehicles.