Optical Terms
Vision is clear and sharp when the eye is able to focus images correctly onto the retina. If your vision causes the image to "miss the target" on the retina, lenses can help the eyes to function normally. As we age, most of us require some sort of visual correction.
Farsightedness or Hyperopia
Is a common vision problem, affecting about a fourth of the population. People with hyperopia can see distant objects very well, but have difficulty seeing objects that are up close. This vision problem occurs when light rays entering the eye focus behind the retina, rather than directly on it. The eyeball of a farsighted person is shorter than normal.
Nearsightedness or Myopia
Is a vision problem experienced by up to about one-third of the population. Nearsighted people have difficulty reading highway signs and seeing other objects at a distance, but can see for up-close tasks such as reading or sewing. Myopic people often have headaches or eyestrain, and might squint or feel fatigued when driving or playing sports.
Astigmatism
Occurs when an irregular cornea causes images not to reach a sharp focal point. Vision is distorted in some directions more than others and the perceived image has a doubled edge.
Presbyopia
Is a hardening of the lens in the eye occurs as a natural aging process usually after age 40. The result is decreasing ability to focus clearly on reading material and close-up objects.
Solutions:
- Bifocals - The gradual decrease in ability of the eye to focus is a natural part of the aging process. Bifocals contain two prescriptions for correcting vision at different distances. Bifocals aid both near and far vision, with a visible line dividing the two areas of power prescription.
- Trifocals - Trifocals are prescribed to aid near, far and middle distance seeing. The trifocal lens design has three distinct areas of power to be used, with visible lines dividing the three distinct areas of power prescription.
- Blended Multi "focals" - These lenses have two focal corrections without the noticeable lines. The area that fuses the two powers together is unusable area.
- Progressive No Lines - Advanced technology allows these lenses to gradually change in power from the distance segment to the near vision segment. Your specific prescription is ground from a series of custom lens designs and powers.
- Single Vision - One focal distance is required for your eyes to make adjustments at differing focal distances.
