Downtown Eyewear Kelowna's Premium Optical Store: Glossary

Near Vision
Distance Vision
Continuous Vision From Near To Far
High Index
Aspheric Lenses
Anti Reflection
Scratch Coat
Transition Lenses
Short-Sightedness (Myopia)
Long-Sightedness (Hyperopic)
Astigmatism

Near vision and distance vision

From the age of 40, most people start to suffer from deterioration in vision for near work a (very natural process). To be able to understand, it is important to know how sharp sight works: the crystalline lens within the eye changes shape depending on the distance of the object being viewed. This lens elasticity deteriorates with age (Presbiopia). First signs of Presbiopia are when reading, you tend to hold your book or newspaper further and further away. In this case, reading glasses for a sharp vision area of around 40 cm may be the solution. For other applications, progressive lenses would be more comfortable.

Continuous vision from near to far

Many manufacturers of progressive lenses have been developing new technologies, materials and manufacturing techniques. It is the optician's responsibility to select the best product for the needs of his client, thereby providing the optimum visual experience. The right progressive lens choice equals uncompromising aesthetics and a quality of vision, which comes very close to the natural visual process. An experienced optician not only takes your prescription into account, but also the very personal data of your face and of the frame you have chosen. There are hundreds of progressive lenses on the market today and most Big Box optical stores use the lens that is best for them and not necessarily what is best for their clients. Ask questions.

High Index

Index is an optical term defining in numerical terms, the density of a transparent medium. Normal plastic (CR:39 ) has an index of 1.52, any index higher than that, in layman's terms is considered high index. In reality though, there are many optical lens materials that vary in density from 1.52 to 1.9 index. The optician takes the time to understand the client's needs. Makes the appropriate suggestions and assumes the responsibility for the successful assembly of the frame, prescription, lens materials and cost at a level that is acceptable to the client.

Aspheric Lenses

These new lenses provide special visual and cosmetic benefits for stronger corrections and increase edge to edge clarity. Flatter than conventional lenses, aspheric lenses reduce the "bulgy" appearance of strong plus lenses (far-sighted corrections) and improve the appearance of finished eyewear.

Near-sighted persons also benefit from thinner, lighter weight glasses when the lenses are aspheric. Aspheric lenses are positioned closer to the face so there is less eye magnification with farsighted corrections and less "small eyes" look with nearsighted corrections. Aspheric lenses can be ordered in high index materials for the ultimate attractive thin lenses.

Anti reflection

Anti reflection coating is in reality many coatings, each one designed to eliminate the reflection of a single wavelength of light. The more layers an Anti reflection coating has, the better it is. Most premium quality lenses have a superior scratch coat as a base followed by as many as 32 individual antireflection layers including a UV filter then finally a highly viscose layer that makes the finished lens much easier to keep clean.

Scratch Coat

Scratch coat is a form of liquid polymer applied to the surface of a plastic lens that increases the viscosity of its surface. It therefore assumes that abrasives would slide off rather than dig in and create scratches. The smoothest of these coatings is called (TD 11) and warranties against scratching for 2 years.

Progressive Lenses

Continuous vision from near to far.

Transition Lenses

Transition Lenses change from clear to dark in the presence of ultraviolet light, and block 100% of harmful UV rays. Innovative photo chromic technologies have produced unparallelled lens performance in nearly every lens design and material, including bifocals, trifocals, progressives, and standard and high index materials. These lenses provide visual quality, visual comfort and convenient protection with these performance features:

As clear as regular clear lenses indoors
Even clearer with an anti-reflective coating
As dark as sunglasses outside in bright light
Fast to activate
Fast to fade back
Block 100% of harmful UV rays
Reduce the effects of glare
Reduce eye fatigue
Offer the right tint at the right time in changing light

The single downfall of Transition Lenses is that while driving the windshield effectively filters out the UV radiation, which would normally cause the lens to darken.

Short-Sightedness (Myopia)

People with this condition can see clearly up close but not at a distance. Your eye care practitioner will prescribe a concave or "minus" lens which will redirect the light rays so that they are properly focused on the retina.

Long-Sightedness (Hyperopic)

Long-sighted individuals see better at a distance than close up and sometimes experience difficulty bringing their vision into sharp, clear focus for reading and other close-up activities. Long-sightedness can be very successfully treated with a convex or "plus" lens prescription.

Astigmatism

This condition is characterised by an irregularly shaped cornea, causing light images to focus on two separate points in the eye. The effect is similar to the distorted reflection in a fun-house mirror.

Downtown Eyewear 547 Bernard Avenue Kelowna, BC V1Y 6N9 (250) 763-2020
Testimonials Frames Lenses Specials/Features Glossary Products Contact Home	Glossary Near Vision Distance Vision Continuous Vision From Near To Far High Index Aspheric Lenses Anti Reflection Scratch Coat Transition Lenses Short-Sightedness (Myopia) Long-Sightedness (Hyperopic) Astigmatism Near vision and distance vision From the age of 40, most people start to suffer from deterioration in vision for near work a (very natural process). To be able to understand, it is important to know how sharp sight works: the crystalline lens within the eye changes shape depending on the distance of the object being viewed. This lens elasticity deteriorates with age (Presbiopia). First signs of Presbiopia are when reading, you tend to hold your book or newspaper further and further away. In this case, reading glasses for a sharp vision area of around 40 cm may be the solution. For other applications, progressive lenses would be more comfortable. Continuous vision from near to far Many manufacturers of progressive lenses have been developing new technologies, materials and manufacturing techniques. It is the optician's responsibility to select the best product for the needs of his client, thereby providing the optimum visual experience. The right progressive lens choice equals uncompromising aesthetics and a quality of vision, which comes very close to the natural visual process. An experienced optician not only takes your prescription into account, but also the very personal data of your face and of the frame you have chosen. There are hundreds of progressive lenses on the market today and most Big Box optical stores use the lens that is best for them and not necessarily what is best for their clients. Ask questions. High Index Index is an optical term defining in numerical terms, the density of a transparent medium. Normal plastic (CR:39 ) has an index of 1.52, any index higher than that, in layman's terms is considered high index. In reality though, there are many optical lens materials that vary in density from 1.52 to 1.9 index. The optician takes the time to understand the client's needs. Makes the appropriate suggestions and assumes the responsibility for the successful assembly of the frame, prescription, lens materials and cost at a level that is acceptable to the client. Aspheric Lenses These new lenses provide special visual and cosmetic benefits for stronger corrections and increase edge to edge clarity. Flatter than conventional lenses, aspheric lenses reduce the "bulgy" appearance of strong plus lenses (far-sighted corrections) and improve the appearance of finished eyewear. Near-sighted persons also benefit from thinner, lighter weight glasses when the lenses are aspheric. Aspheric lenses are positioned closer to the face so there is less eye magnification with farsighted corrections and less "small eyes" look with nearsighted corrections. Aspheric lenses can be ordered in high index materials for the ultimate attractive thin lenses. Anti reflection Anti reflection coating is in reality many coatings, each one designed to eliminate the reflection of a single wavelength of light. The more layers an Anti reflection coating has, the better it is. Most premium quality lenses have a superior scratch coat as a base followed by as many as 32 individual antireflection layers including a UV filter then finally a highly viscose layer that makes the finished lens much easier to keep clean. Scratch Coat Scratch coat is a form of liquid polymer applied to the surface of a plastic lens that increases the viscosity of its surface. It therefore assumes that abrasives would slide off rather than dig in and create scratches. The smoothest of these coatings is called (TD 11) and warranties against scratching for 2 years. Progressive Lenses Continuous vision from near to far. Transition Lenses Transition Lenses change from clear to dark in the presence of ultraviolet light, and block 100% of harmful UV rays. Innovative photo chromic technologies have produced unparallelled lens performance in nearly every lens design and material, including bifocals, trifocals, progressives, and standard and high index materials. These lenses provide visual quality, visual comfort and convenient protection with these performance features: As clear as regular clear lenses indoors Even clearer with an anti-reflective coating As dark as sunglasses outside in bright light Fast to activate Fast to fade back Block 100% of harmful UV rays Reduce the effects of glare Reduce eye fatigue Offer the right tint at the right time in changing light The single downfall of Transition Lenses is that while driving the windshield effectively filters out the UV radiation, which would normally cause the lens to darken. Short-Sightedness (Myopia) People with this condition can see clearly up close but not at a distance. Your eye care practitioner will prescribe a concave or "minus" lens which will redirect the light rays so that they are properly focused on the retina. Long-Sightedness (Hyperopic) Long-sighted individuals see better at a distance than close up and sometimes experience difficulty bringing their vision into sharp, clear focus for reading and other close-up activities. Long-sightedness can be very successfully treated with a convex or "plus" lens prescription. Astigmatism This condition is characterised by an irregularly shaped cornea, causing light images to focus on two separate points in the eye. The effect is similar to the distorted reflection in a fun-house mirror. You can contact Randall at or just stop in at the store.