Glossary

Adjustment Period

The time required for your eyes and brain to adapt to new lenses, most commonly varifocals. This phase usually lasts from a few days up to two weeks.

Anti-Fog Coating

Lenses are treated with a specialist coating that helps prevent misting in cold conditions or humid environments.

Anti-Glare Coating

Anti-Glare Coating: Reduces reflections and glare from screens, lighting, and sunlight for clearer vision and less eye strain.

Astigmatism

A refractive condition where light does not focus evenly on the retina, causing blurred or distorted sight. Corrected using toric lens designs.

Axis

The axis value works with the cylinder to correct astigmatism, indicating the orientation of the correction needed. It is measured in degrees between 1 and 180.

Bifocal Lenses

Lenses with two distinct segments for distance and near vision, typically separated by a visible line.

Bifocal Lenses

Lenses with two distinct segments for distance and near vision, typically separated by a visible line.

Blue Light Protection

Coating that reduces blue light from digital devices and artificial lighting, helping reduce eye strain and protect sleep patterns.

Chromatic Aberration

A visual effect where colours appear fringed or blurred because different wavelengths of light focus at different points. Reduced through higher-quality lens materials.

Click & Fit

Lensology’s system for fitting lenses into compatible frames, including Meta and smart glasses, allowing customers to insert lenses themselves without sending frames in.

Coatings

Thin surface layers which are applied to lenses to enhance performance, durability and comfort. Examples include anti-glare, scratch resistance and UV protection.

Cylinder (CYL)

The cylinder value in your prescription corrects astigmatism, working alongside the axis to provide clear, accurate vision.

Digital and Lifestyle Lenses

Special lenses designed for clear vision at close and intermediate distances, ideal for office or screen work.

Distance Vision

The part of a prescription that corrects vision for far-away objects such as road signs or television screens.

Driving Lenses

Specialist lenses designed to reduce glare and enhance clarity on the road, particularly in low-light conditions.

Enhanced Anti-Glare Coating

Adds easy-clean and smudge-repellent properties to standard anti-glare.

Eye Strain

Discomfort or fatigue caused by prolonged visual effort, often linked to screen use or incorrect prescriptions.

Fast Track Service

Priority lens production and faster turnaround for an additional fee.

Fitting Height

A vertical measurement that is required for varifocal and bifocal lenses. Ensures optical zones align correctly within the frame.

Frame Compatibility

An assessment confirming whether existing frames are suitable for new lenses based on size, condition and design.

Glare

Excessive brightness that causes discomfort or reduced visibility. Often minimised through coatings or specialist lens designs.

Half Rimmed Frames

Frames that partially surround the lens, typically along the top edge, requiring specific materials and precise glazing for strength.

Hall of Frame

Lensology’s showcase of customer frames that have been successfully reglazed. Used to demonstrate experience and craftsmanship.

High Index Lenses

Thinner and lighter lenses designed for stronger prescriptions, improving comfort and appearance.

Intermediate Vision

The visual range between distance and near vision. Commonly used for screens, dashboards and workstations.

Lens Index

A measure of how thin and lightweight a lens is. Higher index lenses are thinner and more discreet, ideal for stronger prescriptions.

Lens Material

The substance used to manufacture lenses, such as standard plastic, high-index plastic or polycarbonate.

Lens Replacement

The process of fitting new lenses into existing frames instead of purchasing new glasses.

Lens Replacement (Reglazing)

The process of fitting new lenses into existing frames instead of purchasing new glasses.

Lens Thickness

Refers to how thick or thin lenses appear, influenced by prescription strength, lens index and frame size.

Meta Lenses

Smart glasses developed using Meta technology that integrate features such as cameras, audio and voice control into everyday eyewear. When fitted with prescription lenses, specialist glazing is required to ensure optical accuracy while maintaining the performance and balance of the smart components.

Meta Smart Glasses

Smart glasses developed using Meta technology that integrate features such as cameras, audio and voice control into everyday eyewear. When fitted with prescription lenses, specialist glazing is required to ensure optical accuracy while maintaining the performance and balance of the smart components.

Mirror Coating

Reflective coating applied to sunglass lenses for style and additional glare reduction.

Mirror Finish

Reflective coating applied to sunglass lenses for style and additional glare reduction.

Near Vision

Vision distance used for close-up tasks such as reading or detailed craftwork. Corrected using reading or varifocal lenses.

Non-Prescription Lenses

Lenses without corrective power. Typically used for UV protection (sunglasses), safety glasses, impact resistance, or fashion.

Occupational Lenses

Special lenses designed for clear vision at close and intermediate distances, ideal for office or screen work.

Omni-Vision HD

Lensology’s premium varifocal lens design is engineered for wider viewing areas and smoother transitions between vision zones.

Photochromic Lenses

Lenses that react to ultraviolet light by darkening outdoors and returning to clear indoors.

PhotoFusion X

ZEISS’ advanced photochromic lens technology, designed for faster light adaptation and improved performance.

Polarised Lenses

Sunglass lenses that reduce glare from reflective surfaces such as roads or water. Particularly beneficial for driving and outdoor activities.

Postal Reglazing

Sending your frames by post for reglazing, rather than visiting a physical store.

Prescription

A written specification from an optician detailing the optical power required to correct vision.

Prism

A prescription value used to correct eye alignment issues, helping both eyes work together comfortably.

Pupil Distance (PD)

The measured distance between the centres of your pupils. Crucial for accurate lens positioning.

Pupillary Distance (PD)

The measured distance between the centres of your pupils. Crucial for accurate lens positioning.

Ray-Ban Meta Glasses

A range of smart glasses created in collaboration between Ray-Ban and Meta, combining classic frame styling with built-in technology such as hands-free photo capture, audio playback and voice assistance. Prescription lenses must be precisely fitted to preserve both vision quality and device functionality.

Ray-Ban Smart Glasses

A range of smart glasses created in collaboration between Ray-Ban and Meta, combining classic frame styling with built-in technology such as hands-free photo capture, audio playback and voice assistance. Prescription lenses must be precisely fitted to preserve both vision quality and device functionality.

Reading Lenses

Single-vision lenses designed exclusively for near tasks, such as reading or crafts.

Reglazing

The process of replacing lenses in existing frames rather than buying a completely new pair. Often chosen after prescription changes, lens damage or when upgrading coatings or tints.

Rimless Frames

Frames with no rim around the lenses. These require special glazing and stronger lens materials.

Scratch-Resistant Coating

A protective layer that improves lens durability and helps reduce surface damage from everyday wear.

Single Vision Lenses

Lenses with one prescription for either distance, intermediate (computer), or near (reading) vision.

Smart Glasses

Eyewear that incorporates digital technology, such as cameras, speakers, or connectivity features, alongside traditional lenses. Smart glasses require specialist lens design and fitting to accommodate electronics, sensors and frame construction without compromising comfort or visual performance.

Tinted Lenses

Lenses coloured to reduce brightness and improve comfort in bright conditions.

Transitions® Lenses

Photochromic lenses that darken in sunlight and become clear indoors, adapting to changing light conditions.

ULTIMA Coating

Lensology’s premium coating with anti-glare, scratch resistance, UV block, anti-smudge, and easy-clean features, plus a free upgrade to thinner, lighter lenses.

UV Protection

Lens treatment that blocks harmful ultraviolet radiation to help protect eye health.

Varifocal Lenses

Also known as progressive lenses, these provide multiple focal zones (distance, intermediate, near) in a single lens, allowing seamless vision across all distances.

Visual Comfort

The ability to see clearly and comfortably over extended periods without strain.

Working Distance

The typical distance at which a person performs tasks such as screen work or reading. Used to tailor lens design.