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Are Photochromic Lenses a Help or Hindrance to Eye Health?

In most cases, photochromic lenses are a boon for eye health...

In most cases, photochromic lenses are a boon for eye health. The only exceptions are poorly made lenses that fail to block UV light effectively, potentially causing harm. Let’s explore why this happens by understanding how photochromic lenses work.


Photochromic lenses change color because they contain UV-sensitive materials like silver halide and copper oxide. When exposed to UV light, silver halide breaks down into tiny black particles, darkening the lens. This process is similar to how photographic film works, but it's reversible. When UV light is no longer present, the particles recombine, and the lenses become clear again.

Despite some concerns about dilated pupils allowing more UV light in, choosing high-quality, standard-compliant photochromic lenses alleviates these worries. Let’s break down the impact of light on our eyes and how these lenses can help.


The Impact of Light on Our Eyes

1. Light Sensitivity and Strong Light Exposure


Our eyes constantly adapt to changing light conditions throughout the day. Both natural sunlight and artificial sources like LED lights, flashlights, and screens can cause light sensitivity. In bright light, our eyes squint and pupils contract to reduce light intake. Prolonged exposure to intense light can lead to eye strain, dryness, tearing, muscle spasms, swelling, and dizziness.

2. Harmful Light: UV and Blue Light Exposure

UV light can damage various parts of the eye, including the conjunctiva, cornea, lens, and retina, leading to conditions like pterygium, keratitis, cataracts, macular degeneration, and even ocular melanoma. Everyday sources like LED lights and tanning lamps emit significant amounts of blue light, which also impacts eye health.


Why UV Light Damages Eyes


The cornea contains corneal epithelial cells, and the principle of UV sterilization is to damage the cell nucleus. Therefore, similarly, UV rays can also damage the nuclei of corneal epithelial cells, leading to large-scale shedding of the corneal epithelium. This exposes the nerve endings of the upper and lower epithelium, resulting in severe photophobia and tearing, and sometimes a strong foreign body sensation.


To elaborate further, UV rays act on the water molecules in epithelial cells, causing dissociation of these molecules, which generates a large number of free radicals. These free radicals can attack the cells in various ways, leading to cell death and shedding caused by UV exposure. 


These symptoms peak about 12 hours later. This means that often when you look directly at the sun in summer or are exposed to the sun for a long time, you may only feel slight discomfort in your eyes at that moment. However, in the following week or even longer, you are likely to experience eye discomfort, and this is merely the acute reaction, known as photokeratitis.

UV light’s cell-damaging effects can not only severely impact the cornea, disrupting epithelial cells and causing corneal erosion. This exposure can result in severe photophobia, tearing, and a sensation of foreign bodies in the eye. Chronic UV damage is cumulative and irreversible, contributing to cataracts and other eye problems. High-quality photochromic lenses can mitigate these risks by effectively blocking UV radiation.


Misconceptions About Photochromic Lenses


Some believe photochromic lenses are harmful because substandard coatings might not block UV rays adequately. Also, sudden removal of these lenses in bright light can disrupt the eye’s adjustment process, leading to photokeratitis. However, using high-quality photochromic lenses minimizes these risks and proves beneficial for overall eye health.

Solutions for Light-Induced Eye Strain


For those with vision impairments, traditional sunglasses can be cumbersome and may not match prescription needs well. Photochromic lenses are a convenient solution, adapting to varying light conditions and providing comprehensive UV protection.


Why Choose Photochromic Lenses?


1. Daily Convenience: They seamlessly adapt to changing light conditions.

2. Comprehensive Protection: Blocking over 99% of UVA and UVB rays and harmful blue light.

3. Versatility: Suitable for various environments and activities.


Among the top choices are MaatOptical’s photochromic lenses, known for their advanced technology and superior UV protection.



MaatOptical Photochromic Lenses


MaatOptical employs two production processes to cater to different needs: in-mass photochromic and CB layer coating. The in-mass method, developed in the 1960s, offers stable performance at a lower price. The CB layer coating, or spin-photo method, is a more advanced technology, providing faster response times and better performance.


Production Process


Maat currently adopts two kinds of production processes to meet the needs of different consumer groups.


In-mass photochromic originally was developed by Corning in the 1960s and applied to glass materials, nowadays it is widely used in resin lens production. The principle is mixing photochromic dyes with lens monomer, the biggest advantage is a stable photochromic performance at a lower price, the bands are only mid-index available, and lower responsive speed(both darkening and fading time).


CB layer coating photochromic, also named spin-photo, is considered to be the most advanced photochromic lens production technology nowadays.


Advantages: faster color changing speeding and fading speed, more optional indexes and flexible function selection.


Disadvantage: higher price.


Photochromic Dyes


Photochromic lenses remain clear indoors, while get dark outdoors when exposed to UV light present in sunlight. The major factor of the magic is the photochromic dyes in the lens or on the surface of the lens. After decades of R&D and improvement, Maat has made breakthrough achievements in its self-developed and improved dyes:


1. Faster responsiveness

2. Darkness up to CAT-3 level

3. Stability and consistency in all optional colors

4. Long-service life


Lens Substrate


The lens monomer(major material) is supplied by worldwide brand companies, PPG, Mitsui, KOC, and so on. 


Maat does not produce all the substrate lenses ourselves, we also use a self-developed process to apply patented photochromic dyes or other photochromic materials to our partner’s clear substrate lenses.


UV Protection


Not only do Photochromic lenses react to UV light—but they also protect your eyes from it! It could fully block UVA and UVB rays, reducing the risks of UV-related cataracts and other eye diseases.


Blue Light Filter


A blue light filter is optional in most of our products, we now supply photochromic lenses with two levels of blue light filter, UV410 and UV420.UV410 blue light filter is designed for light office work, an average of 3-4 hours per day in front of the computer.UV420 suits people who work with computers all day long or have higher blue light protection needs.


Transition Speed


Generally, a photochromic lens gets very dark in 30 seconds and fades back to acceptable clarity in 2 minutes. Maat’s self-developed super fast and dark photochromic(Maatlite RapidyTM) lens improved the transition speed by 20%(darkening speed 18.5% faster, fading speed 26% faster)compared with regular In-mass photochromic lenses.


By introducing the latest generation of CB layer coating dyes, the Maat CB2 photochromic lens improved its transition speed without sacrificing any photochromic properties. It’s a breakthrough product in all dimensions.

MaatOptical Product Series


   - Improved color depth by 33%.

   - Darkens to 93.3% within 90 seconds.

   - Fading speed improved, reaching 73.6% clarity within 5 minutes.

   - Can be worn for over 12,000 hours based on internal tests.



   - Maat Lab conducted over 10,000 experiments over three years

   - High resistance to light exposure, temperature, oxidation, and stains.


   - Uses advanced composite bonding technology for a uniform coating.

   - Faster and more uniform color change.



   - Suitable for both near and distance vision.

   - Reduces eye movement and offers comfort, especially for older adults.



   - Fixed curvature on the outer surface for better vision stability.

   - Reduces distortion and provides a wider field of view.

Who Should Use Photochromic Lenses?

Suitable for:

1. Outdoor enthusiasts.

2. People with outdoor jobs.

3. Photography lovers.

4. Vacationers at beaches, snowfields, or tropical climates.

5. Individuals with light sensitivity, especially older adults.

6. Nearsighted individuals needing sunglasses.

Not suitable for:

1. School children, whose visual systems are still developing.

2. Individuals with poor corrected vision.

3. Those with glaucoma or narrow anterior chamber angles.

Keep Your Eyes Safe and Healthy

High-quality photochromic lenses are beneficial for eye health, providing protection against harmful UV and blue light while ensuring comfort and clarity. To truly benefit, choose reputable products from trusted brands like MaatOptical, which combine advanced technology with robust UV protection. This way, you can enjoy the advantages of photochromic lenses and keep your eyes safe and healthy.

Jay Zhang

Jay Zhang, with over 5 years of experience, currently serves as the Sales Manager at JIANGSU MAAT OPTICAL TECHNOLOGY CO LTD. He specializes in research and development, as well as manufacturing, of photochromic lenses with a wide range of optional colors. In his role, Jay excels in marketing, customer-focused service, ensuring service quality, and enhancing the overall customer experience. His expertise lies in the commerce sector, contributing to the success of the company in the dynamic Chinese market since January 2023.

Learn More About Jay Zhang

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