Library

Eye Care Topics

The staff of the Center for Eye Care & Surgery present these information topics to help people better understand vision and the health of their eyes. We hope you find the information informative and interesting.

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Glossary

Astigmatism
Astigmatism is blurry vision produced by football-shaped corneas which are too steep in one place and too flat in another. Astigmatic corneas focus light in two different places in the eye, making both near and distance vision a problem.

Best corrected visual acuity (BCVA)
The best possible vision a person can achieve with corrective lenses measured in terms of Snellen lines on an eye chart.

Cornea
The transparent front segment of the eye that covers the iris, pupil and anterior chamber, providing most of the eye's optical power. This is the part of the eye reshaped by laser vision correction.

Diopter
A measurement of the degree to which light converges or diverges; also a measurement of lens refractive power.

"The Fingerprint of Your Vision™"
Because no two eyes are alike, each eye has a unique map, or fingerprint. "The Fingerprint of Your Vision" defines unique characteristics in each individual's vision and is produced by WaveScan® technology.

Hyperopia (Farsightedness)
Also known as farsightedness, is a refractive error in which you see better from a distance than close up. Hyperopia is caused by an eyeball that is too short to focus light on the retina. Light strikes the retina before it can come to a sharp focus.

Myopia (Nearsightedness)
Also known as nearsightedness, is a refractive error in which you see better close up than from a distance. Myopia is caused by an eyeball that is too long to focus light on the retina or a cornea which is too steeply curved. In these cases light focuses instead in front of the retina.

Personal Best Vision
The best possible vision for each individual as corrected by the VISX CustomVue procedure.

Retina
The thin lining at the back of the eye that converts images from the eye's optical system into electronic impulses sent along the optic nerve for transmission to the brain.

Snellen Chart
The chart used to test visual acuity with black letters of various sizes against a white background.

Uncorrected visual acuity (UCVA)
The best possible vision a person can achieve without corrective lenses measured in terms of Snellen lines on an eye chart.

VISX CustomVue Procedure
As shown in a clinical study, WaveScan-driven laser vision correction has the potential to produce better vision than is possible with glasses or contact lenses, and enables the physician to measure and correct unique imperfections in each individual's vision.

VISX STAR S4™ Excimer Laser System
The most advanced laser technology platform available today. The VISX STAR S4 combines Variable Spot Scanning (VSS™) and ActiveTrak® 3-D Active Eye Tracking along with the WaveScan, providing physicians with the best possible treatment options for their patients.

WaveScan Technology
Originally developed for use in high-powered telescopes to reduce distortions in space, now adapted for eyecare. A single beam of infrared laser light is passed into the eye and focused on the retina. The light is then reflected off the retina, passed back through the eye, through a lenslet array to a sensor, and then analyzed from 200 different aspects to create a map of the eye - or fingerprint of vision. This technology uncovers unique characteristics of the eye never measured before using standard methods for glasses and contact lenses.