Essilor^® Anti-Fatigue^™ lenses

Lexicon

Accommodation

The eye’s ability to bring images into focus, like a camera lens.

Addition

Difference in correction between far and near vision.

Ametropia

Eyesight disorders that prevent a clear image from forming on the retina, with the exception of age-related presbyopia. Myopia, Hypermetropia and Astigmatism are all forms of Ametropia.

Astigmatism

An anomaly most often due to an irregularity in the curvature of the cornea, resulting in a distorted view of objects. The astigmatic has imprecise near vision. He doesn’t clearly perceive contrasts between horizontal, vertical and oblique lines. Astigmatism can combine with other visual disorders like myopia, hypermetropia or presbyopia.

Field of vision

The area or extent of physical space visible to an immobile eye.

Diopter

A unit of optical measure; the value of a visual defect like that of the corrective lens or contact lens.

Dispersion

A light beam that passes through a lens is made up of several wavelengths. When passing through a lens, not all wavelengths are refracted in the same way: short wavelengths (blue) are more deviated than long wavelengths.

Emmetropia

The opposite of Ametropia and the privilege of those whose eyes have had no optical defects prior to the appearance of presbyopia.

Hypermetropia

Also farsightedness, a defect of vision in which the image is focused on a point behind the retina. The person is able to focus on objects in the distance, but not on close objects.

Myopia (or nearsightedness)

An eyesight disorder in which the distance between the cornea and the retina is too great. The eye is “too long”. The image forms in front of the retina rather than directly on it. A person with myopia sees badly in far vision but well in near vision.

Presbyopia

An eyesight disorder due to the aging of the crystalline lens which thickens over time. As the lens becomes more rigid, it changes shape less easily and the subject sees increasingly less clearly in near vision. Presbyopia spares no one over the age of forty.

Treatment of lenses

• - Non-scratch: Hardening varnish that protects from scratches.
• - Anti-reflecting: Thin coating is applied to the surface of the lens to eliminate glare from light, improving visual comfort and aestheticism.
• - Stain repellent: Thin coating that protects lenses from stains and makes them easier to clean.
• - Photochromic: Ability of a mineral or organic lens to darken or lighten depending on the luminosity.
• - Polarizing: Effective treatment against stray reflection and glare for the wearer.