Glossary of terms

Don’t know the difference between “progressive” or “polycarbonate” when faced with eyecare decisions? We can explain. Click below for easy definitions of terms.

For comprehensive information on vision care and eye health issues, visit the B.C. Association of Optometrist’s website.

Anti-reflective coating: Used to decrease glare seen by a patient, as well as reflections. This coating prevents night and computer glare.

Common vision problems: Here are some examples: amblyopia, astigmatism, cataracts, glaucoma, hyperopia, macular degeneration, myopia, presbyopia and retinitis pigmentosa. See your doctor of optometry for information on how to treat these problems.

Computer vision syndrome: Symptoms include: eye strain, headaches, blurred vision, dry or irritated eyes, neck and back pain, sensitivity to light and double vision or “after images.” It can be caused by poor lighting, improper viewing distance or minor vision problems not diagnosed previously.

Face shield: Used to protect the face from corrosive chemicals, blood or potentially infectious diseases, but doesn’t protect an eye from heavy impact.

Flat-top bifocals: Designed for the wearer to see distance through the upper portion of the lens, while the lower is used for normal reading distance.

Glass: Recommended for those who easily scratch lenses, glass also has excellent optical quality. Glass, however, is not recommended for safety wear, as it shatters easily.

High-Index: A thinner and lighter lens, good for far-sighted patients who, in the past, had to wear thick, heavy lenses.

Photogray/photobrown: Glass lens that darkens in sunlight, activated by UV radiation. They are available in grey or brown.

Photochromism: In-depth treatment enables the lens to darken in brighter light and become clear in the shade.

Plastic: Lighter and more protective than glass, plastic lenses have similar optical properties. They are inert to chemicals and less breakable than glass, but are not as strong as polycarbonate lenses.

Polarized: Lenses that block light reflected from horizontal surfaces such as water, canceling glare. Polarized lenses are available in a variety of colours.

Polycarbonate: Stronger than comparable glass and plastic lenses, polycarbonates are excellent for safety. However, these lenses scratch easily and have poorer optical properties than glass or plastic.

Progressive: Multi-focal lenses with correction areas that blend invisibly into one another. This design is the most natural for near, far and all distances in between.

Safety glasses: Industrial-strength glasses that protect the wearer from flying particles, and to some degree, hazardous materials.

Safety goggles: Provide complete nose to ear frontal protection from airborne debris, and can be worn over regular glasses.

Scratch resistant coating: An applied lens coating that prevents excessive scratches on lenses.

Side shields: Attachments for the sides of safety glasses recommended for anyone who does woodworking or grinding.

Smart Seg: A progressive lens in a half moon format.

Smudge proofing: A water-repellent topcoat is applied to prevent dirt deposits on the lens, making it easier to clean.

Task-specific eyewear
: Specialty safety eyewear worn by employees doing specific jobs, such as working with lasers or radiation.

Transitions: A plastic lens similar to photogray. Popular due to its ability to lighten and darken quickly, and weighs less than its glass counterpart.

Trifocals: Multi-focal lenses with lines that provide three fields of vision – near vision, distance vision and intermediate vision.

Ultraviolet (UV) coating: A coating put on lenses worn outside that blocks 99 to 100 per cent of the sun’s UV rays. It can also help reduce the risk of cataracts.

Unifocal, or single vision lenses: Identical correction regardless of vision distance.

  • Find an OVP optometrist

    Click the link above to search for doctor of optometry who participates in the Occupational Vision Plan Program through our Find a Doctor Search.

    Please select the city or postal code and then select the program ‘Occupational Vision Plan’.