what to look for in new glasses lenses

Nowadays frames are sold almost everywhere, but not powered lenses. The function of spectacle lenses are more significant to a person having refractive error/eye power. They alter the light accordingly and form image onto the retina (which is a screen in our eye that perceives light signal and further sends to brain).

In olden days, spectacle lenses were made out of glass material. Because, they were heavy and fragile, in 19th century, plastic lenses were made. Which makes them more light and not easily breakable. Further, more innovations were made to solve visual problems like glares, fogging, light sensitivity and health problems like macular degeneration and more. 

In this era, its about the quality of image that the lenses should be able to render. It doesn't end at making you able to see distance things but also the level of clarity. There has been lot innovations done to make spectacle lenses so advanced, that almost for any degree of power, clarity could be achieved. 

An optician can help you choose the right spectacle lenses. They know the science of light and how they react to different material. On the basis of your lifestyle and day to day work, they can suggest you, appropriate lenses suiting to your budget.

This one here is just a small guide to make you able to know the lenses that you should choose. Below are the features/properties along with the explanation what each property contributes to.    

Scratch resistive coat:

Scratches on lenses does not let wearer to get a clearer picture of what they are looking at. It can get extremely disturbing while driving, especially at night. Plastic lenses compared to glass, tend to get more scratched. This property (scratch resistance) is very essential for plastic lenses.

Quality of this coating differs over brands. In regular lenses, this coating has the tendency to peel off, which can be observed as small multiple pools on the lens surface. And scratch resistance is low. 

The best scratch resistive coat are provided by premium, well known brands like Zeiss, Essilor and Vision RX. Their coating goes by the name Dura vision platinum, Crizal Rock and Satin Azure uv, respectively. 

Anti-glare coating:

Add on coating over scratch resistance coat on the lenses. This coating helps reduce glare by 25-30%. Wish there was a lens that could reduce 100% glare, probably the research is still going on, on that. 

By reducing glare, it makes the wearer see clearer. Also wearers eyes are seen better through the lenses to others. So when you are trying to take a selfie, your eyes could be visible, clearly to your viewers. 

Night time driving, the glares caused from the vehicles coming in the front, are reduced. 

For higher powers the peripheral thickness of the lenses is very less visible in spectacle frame. 

Hydrophobic coating and smudge resistance coating :

They both come along with anti-glare and scratch resistance coat. 

Hydrophobic coating is to prevent the water droplets staining the spectacle lenses.

Though it is advisable to not touch Spectacle lenses, it sometimes happens by mistake. Why should you not touch the spectacle lenses? The finger prints smudge the lenses. Also, Plastic lenses have tendency to attract dust, so even dust particles stuck onto your fingers, get onto the lens. And then when you run dry cloth, every time you touch the lenses, there is more wear and tear.  

Smudge resistance coat helps in resisting the formation of the fingerprints over the lenses.

Both the coatings come along with scratch resistance and anti-glare coats. 

Blue blocker:

This coating comes along in a combination with anti-glare and scratch resistance. It protects our eyes from blue rays. 

For this era, this is a much required property in a spectacle lens! 

Visible light on a electromagnetic spectrum ranges from 400nm (nano meter) to 700nm. In which, the blue light ranges between 450-485nm.

The digital devices that we use today, emit blue rays. Considering the prolonged usage of computers and mobiles in 20th century, our eyes are getting affected. How? 

Prolonged exposure to blue light from screens can cause symptoms like eye fatigue, dryness, blurred vision, and headaches, often called computer vision syndrome.

Blue light, from digital devices especially at night, suppresses melatonin production (Melatonin is a hormone naturally produced by the pineal gland in the brain, primarily in response to darkness), making it harder to fall asleep and disrupting the circadian rhythm.

The blue rays could give rise to age-related macular degeneration ( which usually affects people aged above 55 or 60) in earlier stages. 

Photochromatic: 

Photochromatic lenses are those which become dark when they are exposed to sun/UV rays. Required for those who are into field works/mostly out in the sun. 

Older photochromatic lenses do not get that dark. Modern photochromatic lenses (Transitions Gen 8 by essilor) have the tendency to become so dark, that wearers eyes won't be visible to others, when standing under the sun and also the response time of the lenses to become dark is less compared to older photochromatic lenses.  

Older photochromatic lenses have only 2 options i.e grey and brown. Modern has 7 colors available i.e grey, brown, Graphite green, Sapphire blue, amber, Emerald, Amethyst purple.

Polarized:

They are powered colored lenses for sunglasses.

Specialized lenses designed to reduce glare caused by light reflecting off surfaces like water, roads, or snow. They have a special chemical coating that filters out horizontal light waves, which are responsible for glare, while allowing vertical light waves to pass through. This improves visual comfort, clarity, and contrast, especially in bright conditions.