A Comprehensive Guide to Tinted Lenses

What Are Tinted Lenses?

Tinted lenses are optical lenses that have been treated with a special tinting process that changes the lenses' color and visible light transmission. Through the tinting process, these lenses not only absorb some visible light, reducing glare under strong light conditions, but also enhance visual contrast. Furthermore, tinted lenses can flexibly choose colors and color densities according to personal preferences or specific purposes, further enhancing the aesthetics of the wearer.

Tint Density of Tinted Lenses

The tint density of a spectacle lens affects its light transmittance, which is the percentage of visible light passing through. The International Organization for Standardization (ISO) has established a standard that classifies the transmission percentages of tinted lenses into five categories, from category 0 to category 4, making it easy for consumers and manufacturers to select and evaluate.

How Are Lenses Tinted?

1. Tinting of Glass Lenses

Glass materials exhibit coloring effects when mixed with metal oxides that have special absorption properties. For example, adding cobalt and copper can produce a blue color, and adding cerium can produce a green color. These tinting techniques are commonly used in the mass production of non-prescription (plano) sunglass lenses or protective eyewear lenses. Additionally, light-colored materials such as brown, gray, green, or pink are also commonly used to produce refractive correction lenses.

However, there is currently relatively little demand for tinted glass materials. This is primarily because the central thickness differs from the edge thickness in nearsighted or farsighted lenses, resulting in an inconsistent color depth across the lens surface. The higher the refractive power, the more pronounced this color difference becomes.

2. Tinting of Resin Lenses

Resin material has excellent dyeing characteristics, which gives resin lenses great flexibility in the tinting process. Through specific tinting techniques, resin lenses can present a rich variety of colors to meet diverse aesthetic demands. Furthermore, the plasticity of the resin material makes the tinting process easier to control, thereby achieving precise color effects. Therefore, resin lenses have broad application prospects in the field of coloring.

2.1 Dyeing Principle

Resin lenses can withstand high temperatures up to 150℃. In the temperature range of 80~90℃, the molecular gaps in the resin lens gradually expand after being heated. At this time, the dye particles in the water can enter these gaps and color the lens. As the lens cools, the molecular gaps contract, and the color is fixed, thus completing the dyeing process.

2.2 Dyeing Solution and Equipment

The dyeing solution is a mixture of the dyeing agents and accelerators. The dyeing agents usually come in colors such as yellow, brown, pink, green, blue, and gray. The accelerators, also known as surfactants, can reduce the surface tension of the dye, thereby speeding up the process of the resin lens being wetted by the dyeing agents.

The preparation process should strictly follow the instructions to ensure the best coloring result. The dyeing agent and accelerator should be mixed at a specific ratio.

There are many types of dyeing equipment. For simple setups, a small aluminum pot and a heater can be used, while standard optician’s dyeing equipment is an electric heat-based dye bath.

2.3 Dyeing Methods

In the dyeing methods, the steps, effect control, and color blending are particularly important. Color blending needs to be carried out according to practical requirements, by adjusting the proportion and concentration of dyeing agents to achieve the ideal color effect.

• Three primary and secondary colors: The three primary colors are red, yellow, and blue. They can be mixed to form colors like orange, green, and purple.

• Tertiary Colors and Complementary Colors: Tertiary colors can be obtained by mixing a primary and a secondary color, while complementary colors are pairs of colors that are directly opposite each other on the color wheel with sharp contrast.

• Mixed Dyeing Techniques: When dyeing mixed colors, the dyeing sequence should follow the principles of color science to ensure the ideal presentation of color effects.

• Production of Gradient Tinted Lenses: Lenses are automatically dyed by a lens-lifting mechanism (up-and-down movement) to control the gradient change in color.

• Tint Density: The tint density of the lenses can be adjusted by varying the immersion time, dye concentration and bath temperature.

2.4 Fade Treatment

Fading agents are used to adjust the tinting results of lenses. When the tinting result is ideal, for example, the color is too dark or unevenly distributed, the tinted lenses can be faded in a pre-configured fading agent solution at a temperature maintained at 80-90 °C.

Colors of Tinted Lenses

1. Choosing the Right Color

The color matching of tinted lenses mainly relies on the three primary colors: red, yellow, and blue. Color selection needs to consider these primary colors and should be suitable for the personal needs; for instance, brown is often suitable for nearsighted individuals. Gray, brown, and green tinted lenses are the most common in the market, and the choice is mainly based on personal preference. At the same time, the condition of refractive error and the environment in which they are used will also have an impact on color selection.

1.1 Gray Tinted Lenses

They can absorb infrared light and 98% ultraviolet rays. The biggest advantage is that they allow natural colors to appear in their truest form, while effectively reducing light intensity. Gray color is a popular choice for outdoor activities like fishing and driving. Its neutral color provides comfort on both cloudy and sunny days.

1.2 Brown or Amber Tinted Lenses

These tints absorb 100% of UV rays, filter out a lot of blue light, and improve visual contrast and clarity. Therefore, they are ideal for outdoor activities that require depth perception, like golfing, fishing or driving. Wearers of these lenses will feel comfortable in sunny conditions and they will notice an enhanced contrast against green landscapes and blue skies. However, they should not be used in dimly lit or cloudy conditions.

1.3 Blue Tinted Lenses

You can choose blue tinted lenses for a trip to the beach. The blue color filters out the light blue color reflected from the sea and the sky. The lenses effectively prevent reflections from surfaces such as snow, making them excellent on foggy or misty days.

However, avoid using blue color when driving because it will make the driver unable to distinguish traffic signals.

1.4 Green Tinted Lenses

Green tinted lenses can effectively absorb infrared rays and 99% of ultraviolet radiation. They increase the amount of green light reaching the eyes, which is suitable for people with eye strain. Green tinted lenses can absorb red light and can be used as safety goggles for gas welding, electric welding, etc.

1.5 Yellow Tinted Lenses

Yellow tinted lenses, also known as night driving glasses, can absorb 100% of UV light while allowing infrared light and 83% of visible light to pass through the lens. Their primary advantage lies in absorbing the majority of blue light, making objects appear clearer and improving contrast.

In addition to the typical tinted lenses mentioned above, there are other colors available, such as red, purple, etc. Furthermore, there are gradient tints, double-gradient tints, and therapeutic tints specifically designed for medical purposes. In summary, Lens tinting offers a spectrum of colors. You must consider your daily activities and the environment in which you will wear them when choosing tinted lenses.

2. Color Rendition

When selecting tinted lenses, the color rendition index (CRI) is a crucial consideration. It determines whether objects retain their true color when viewed through tinted lenses.

Different tinted lenses exhibit varying color rendition performance. Generally, grey and green lenses show better color rendition performance, uniformly transmitting visible light across all wavelengths under daylight conditions. However, some tinted lenses, such as rose-tinted lenses, may reduce the green and blue color saturation in certain objects, resulting in a visual shift towards a "warmer tone".

Classification of Tinted Lenses

Based on color and function, tinted lenses can be divided into the following categories:

Solid Tinted Lenses:

These are tinted lenses with a single, uniform color. This type of lens can effectively block UV rays from the sun, efficiently reducing eye fatigue and glare.

Gradient Tinted Lenses:

The lenses gradually darken from top to bottom. The lightest area can reduce eye strain, while the darkest area prevents irritation from strong sunlight. This type of lenses is suitable for use during outdoor activities, driving, and traveling.

Mirror Tinted Lenses:

These lenses with a metallic reflective film on the surface have a significant sunglass effect. They can reflect most of the sunlight, reducing overstimulation of the eyes by strong light.

Matte Tinted Lenses:

The lens surface presents a matte effect, which can effectively reduce strong light and reflections, enhancing vision clarity. They are suitable for extended use on cloudy days or indoors.

Clear Tinted Lenses:

The lenses are transparent but have a dyeing effect to prevent damage to the eyes caused by blue light from indoor lighting or computer screens, making them suitable for use in the office or while studying.

Care Tips for Tinted Lenses

1. Avoid exposing lenses to high temperatures (such as car dashboards, heating sides), humidity (such as bathrooms), and direct sunlight to prevent pigment aging and lens deformation.

2. Harsh cleaning agents like ammonia and alcohol are prohibited to avoid damaging the lens coating; It is recommended to wipe with a special glasses cleaning solution and a soft cleaning cloth (such as a microfiber or suede cloth), and wipe in one direction to avoid scratches caused by rubbing back and forth.

3. Do not scratch patterns or text onto the lens surface, and do not touch the lenses with hard objects like fingernails or keys, as this prevents the coating from peeling off or the pigment from being damaged.

4. When not in use for a long time, the lenses should be placed in a special glasses case (with soft padding inside) and kept in a dry and ventilated place to avoid discoloration due to moisture or deformation due to pressure.

FAQs

1. Tinted Lenses or Photochromic Lenses, Which One Should I Choose?

Photochromic lenses are not tinted lenses, but rather a special type of lens that automatically darkens when exposed to ultraviolet light and reverts to a clear state once the UV rays disappear. The lenses contain specialized molecules (often silver halide or naphthopyran compounds) that react to UV light.

Tinted lenses and photochromic lenses are both good eyewear choices for sun protection.

The choice depends on your specific visual needs and lifestyle.

2. Can I Get My Prescription Glasses Tinted?

Yes, you can absolutely get your prescription lenses tinted!  Getting your glasses tinted is one of the most common ways to transform your everyday prescription glasses into a pair of functional and stylish prescription sunglasses.

For that, you should seek help from our opticians or optometrists. Please note that you may need to replace your lenses with new ones rather than tinting your existing corrective lenses.

3. Will Lens Coatings Affect Tint Outcomes?

Yes, they will. Depending on how the lenses are made and the type of coating, some lenses may not be tinted. This depends on the manufacturer's lens material and whether the lens is a finished product that has not been cut or a finished product that has undergone surface treatment.