Photochromic Lenses – Why Do You Need Them?

Photochromic lenses, also often referred to as transition lenses, are a type of optical lens that automatically adjust their tint to ambient light. These lenses serve two main purposes, which are to protect the eyes from UV light and to eliminate the need for a separate pair of sunglasses.

While this is the basic explanation of what photochromic lenses are, their actual usage is actually much wider.

Therefore, in this blog post, we will discuss everything you need to know about photochromic lenses, including how they work, their benefits and limitations and more. 

What Are Photochromic Lenses?

The main purpose of photochromic lenses is to adapt the color of the lens to provide eye protection against bright sunlight and make the spectacles multi-purpose and more versatile. These spectacles can be worn with or without a prescription. As per the research by ReFocus Eye Health, photochromic lenses can block 100% of UVA and UVB rays. 

The molecules in the spectacle lenses automatically activate when exposed to UV light. This causes the spectacle lenses to darken automatically, thus shielding the eyes from the brightness of the sunlight. 

A pair of these spectacles works as both regular spectacles and for UV protection. Moreover, these glasses can be worn with or without a prescription.

Grey and brown remain the most conventional colors in which photochromic lenses are available. However, newer shades of blue, green, amber, emerald, and amethyst are also available.

How Photochromic Lenses Work?

When photochromic lenses are exposed to ultraviolet (UV) light, the photochromic molecules, trillions in number, begin to change their structure. As a result, the lenses automatically darken when exposed to UV light and return to clear when the exposure is removed.

The two common materials of photochromic spectacles are plastic and glass. Plastic photochromic lenses are significantly lighter and shatter-resistant. 

Glass photochromic lenses, on the other hand, are significantly heavier. 

Most modern photochromic lenses are made of plastic and have many advanced features that make them more versatile than conventional photochromic lenses. Modern-day photochromic lenses darken in 30-60 seconds and clear in a few minutes once the exposure is removed. For example, the lens will start to darken when you step into sunlight, but it will clear up indoors.

Advantages of Photochromic Lenses

Photochromic lenses provide significant and multiple advantages to the wearer, such as those we have listed below.

• Convenience: With these photochromic lenses, you do not need to switch between indoor and outdoor glasses.

• Eye Comfort: As the photochromic lenses darken automatically according to the light, they help to reduce eye strain by reducing glare, all the while providing better comfort in bright environments. Moreover, some premium photochromic lenses also offer blue light protection.

• UV Protection: Photochromic lenses provide complete eye protection against ultraviolet light as they block 100% of UVA and UVB rays.

• Cost-Effectiveness: While a little higher in cost, these glasses provide a more economical value. This is because a single pair of these glasses can be used outdoors and indoors.

• Aesthetically Pleasing: Modern photochromic lenses are available in various color options, as well as additional indoor tints. 

NEW PRODUCT ALERT: A new innovation from Zeiss® Vision and EssilorLuxottica® in photochromatic lenses with a tint so they have a lighter permanent color all the time and darken when exposed to UV light or Sunlight.  These can also be done in fashionable gradient tints that are darker on the top and gradually become lighter towards the lower part of the lens.

Moreover, they can also be incorporated into your desired frame style.

Limitations to Consider

While photochromic lenses have strong benefits, there are also certain limitations imposed on them. To have a better understanding of these lenses, let's take a closer look at the disadvantages of photochromic glasses.

1. Slower Clearing Indoors: While most modern-day photochromic lenses begin to darken immediately upon UV exposure (sunlight), under certain conditions, the lenses may take up to 60 seconds to achieve peak darkness. However, their reversal can take a little longer. For instance, the lenses may take about 3 to 5 minutes to return to a fully clear state once indoors.

2. Less Effective in Cars: When inside a car, the majority of UV light is blocked by the windshield. Without exposure to these rays, the chemical process does not start and the lenses do not darken. Therefore, most photochromic lenses do not work well while driving.

NEW PRODUCT ALERT: 

Transitions® brand of photochromatic lenses from EssilorLuxottica® have a special range of lenses called the Xtractive® Transitions® that darken to about 20-30% inside a car and achieve the same darkness of their latest generation of Transition® lenses when exposed to direct sunlight or UV radiation.

Another solution for this is the tinted photochromatic lenses mentioned earlier from Zeiss®Vision and EssilorLuxottica® 

1. Not as Dark as Sunglasses: While photochromic lenses can darken and block UV light, they are not as dark as dedicated sunglasses.

2. Temperature Sensitivity: The darkness of photochromic lenses varies based on climatic conditions. For instance, in colder temperatures, the photochromic lenses tend to have a higher darkness compared to warm weather.

3. Degradation in Performance Over Time: Repeated UV exposure can lead to cataracts and macular degeneration. As a result, their transition speed and maximum darkness may be reduced.

Do note that these limitations do not make photochromic lenses inherently bad. These lenses are ideal for people who value adaptability over maximum sun darkness.

Who Should Use Photochromic Lenses?

Photochromic lenses can be worn all day as both indoor and outdoor glasses. Due to their UV protection, they become ideal for candidates such as:

• Prescription Wearers: These lenses completely eliminate the need for prescription wearers to switch between normal and prescription glasses.

• Outdoor Workers and Commuters: The automatic transition of photochromic lenses reduces sudden glare and eye fatigue, making them especially beneficial for outdoor workers and commuters.

• Children: The UV protection of these lenses protects the young and sensitive eyes of children without requiring them to carry separate glasses.

• Frequent Travelers: All those who love travelling will benefit from the constant UV protection and glare reduction provided by photochromic lenses.

• People With Light Sensitivity: Photochromic lenses are ideal for those who experience eye strain and feel uncomfortable in bright lights.

Photochromic Lenses vs Other Options

Below, we have shared a comparison table between photochromic glasses, polarized sunglasses and anti-reflective glasses to help you better understand the differences between these eyewear.

It helps to understand how photochromic lenses compare with polarized sunglasses and anti-reflective glasses.

Photochromic lenses adjust to light automatically, work well both indoors and outdoors, provide UV400 protection, and are screen-friendly. They are best suited for people who constantly move between indoor and outdoor settings, and offer the convenience of one pair doing it all.

Polarized sunglasses do not adjust their tint, are meant only for outdoor use, and also provide UV400 protection, but they are not screen-friendly. They are best suited for people who spend significant time outdoors, and are convenient only for outdoor use.

NEW PRODUCT ALERT:

Under the Xtractive® Transitions® from EssilorLuxottica®, they have photochromic-polarised lenses that become polarised upon darkening.  So indoors, they are non-polarised, almost clear with a 5%-ish tint; inside a car, the lens becomes about 30% dark and semi-polarised; and upon direct sunlight / UV exposure, the lenses achieve peak darkness and become polarised as well. These are the most practical all-purpose lenses.

There are other photochromic polarised options too, but they have a higher residual tint, making them essentially sunglasses in which the tint adjusts from dark to darker.

Anti-reflective treatment for spectacles is more to minimise the reflections from the surface of the spectacle lenses.  The anti-reflective treatment by itself does not adjust the ir tint of the lenses either, but they work well both indoors and outdoors, provide UV protection, and are screen-friendly. However, anti-reflective treatment can be and should be incorporated for all photochromatic lenses.  This will make the lenses more see-through indoors and minimise ghost images of light sources at all times, indoors or outdoors. 

How to Choose Photochromic Lenses

If you are planning to buy photochromic lenses, there are some important factors that you must consider before making the investment.

• Lens Material: Photochromic lenses are primarily made of either mineral glass or organic plastic. Mineral glass is heavier and more fragile, whereas organic plastic is lighter, impact-resistant and has a slightly faster transition.

• Desired Darkening Level: This is one of the most essential factors that you need to consider when buying photochromic lenses. This is because, depending on the material used, the darkening level can differ significantly.

• Speed of Transition: Consider whether you want faster darkening and clearing.

• Driving Needs: If you want a photochromic glass that can provide a high level of darkness while driving, then you may need to look beyond standard lenses.

• Budget: Photochromic lenses fall within a broad price range, and their costs can also differ according to brands and features. However, you can reach out to R. Kumar Opticians to find the perfect pair of glasses for you.

How to Check Photochromic Lenses

In order to check the performance of your photochromic lenses, you can run a simple test.

1. Move the lenses into sunlight and check how long they take to darken.

2. Make sure that the lenses are directly under the sunlight, and not behind a windshield, window, or shade.

3. Come back indoors and see how long the glasses take to clear.

By running this simple test, you will be able to check the transition of the glass. As a result, you will be able to determine whether their level of darkness is suitable for your needs or not.

FAQs

Are photochromic lenses bad for the eyes?

No, photochromic lenses are not bad for the eyes. On the contrary, they provide eye protection from harmful UV rays, all the while ensuring comfort and style.

Are photochromic lenses good for computer work?

While these lenses can be used for computer work, their effectiveness is considerably lower compared to blue-light or screen-specific lenses.

Are photochromic lenses the same as anti-glare lenses?

No, both these lenses are significantly different from one another. Photochromic lenses darken outside, whereas anti-glare lenses reduce reflections.

Final Takeaway

Photochromic lenses are an excellent option for people who want a pair of glasses that adapts to changing lights and provides complete UV protection for the eye. When choosing these glasses, however, be sure to choose a pair that matches your lifestyle, driving habits, temperature conditions and expectations for darkness.

Get professional consultation from R. Kumar Opticians and find the perfect photochromic glasses for you.