Lens that is resistant to shattering or splintering. Polycarbonate is the most impact resistant lens material making it very safe to wear.


Vertical heterophora in which one eye tends to deviate downwards relative to the other. This can be differentiated from Hyperphoria in the other eye only by evidence of paresis or paralysis of elevating.


An actual deviation of the z-axes in the vertical meridian.


Tendency of one eye to deviate upward.


Farsighted (difficulty seeing up close).

High Luster Edge Polish

Edge of lens is polished from a cloudy appearance to a clear transparent edge.

High-index Lenses

An alternative. choice to plastic lenses. High-Index lenses are comprised of a dense material, resulting in thinner and lighter lenses than those produced from plastic. High- Index lenses are especially useful to those with strong prescriptions, creating eyeglasses that are comfortable to wear without the awkward look of thick lenses. HI 1.74 refers to a lens with a refraction index of 1.74 and is the thinnest lens offered. A HI 1.67 lens has a refraction index of 1.67.

HD Progressive Lenses

See Lens, HD progressive lenses.

Gradient Coat

A lens coating that is darker at the top of the lens, fading to lighter at the bottom.


A disease caused by high pressure in the eye. When pressure gets too high, it blocks circulation to the retina and retinal tissue, resulting in a loss of vision and, in severe cases, blindness. Glaucoma is usually controlled by eye drops.

Laser treatment is sometimes necessary when eye drops fail.


Colloquial name for eyeglasses.

Glass Photochromic Lenses

See Lens, Glass photochromic.

Glass or Plastic Lenses

Plastic has replaced glass as the material used in eyewear due to its high impact resistance and cost efficiency. We still do administer and offer glass lenses if medically necessary.


Using both eyes together (referred to as normal when both eyes work together).

Full-spectrum Lens

An ophthalmic lens made from a plastic that transmits approximately 90% of ultraviolet light. (A conventional plastic lens transmits only 10%.)


A component of an ophthalmic frame typically consisting of a bridge and eyewires.

Free-form Lenses

See Lens, HD progressive lenses.


A book that is published quarterly and lists every frame manufactured along with a price list that all doctors use to establish UCR for frames.

Frame, Rimless

A type of frame that provides no, or only partial, peripheral support for the lenses.

Frame, Dress Ophthalmic

A frame for prescription or corrective lenses, intended for ordinary use in correcting or improving vision. Such a frame is not intended for occupational or safety use.

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