What Does 20/20 Mean?
Visual Acuity
There's more to good vision than "20/20".
If you're reading this, you're probably familiar with the vision chart that hangs in every optometrist's examining room--the one with a big "E" at the top. Officially known as a Snellen chart, it is the basis for measuring what is known as visual acuity. This quantitative measure of your vision establishes where your vision is placed on a numeric scale. There are also qualitative measures of your vision, such as your ability to perceive subtle contrast changes, especially in low-light situations. Taken together, these quantitative and qualitative measures determine the overall performance of your vision.
Vision Challenges
Many common problems can be identified by the quantitative measurement method described above, including the more familiar ones, like nearsightedness and farsightedness. However, a number of considerations, like contrast sensitivity, also contribute to your vision's performance. Contrast sensitivity is a measure of the ability to discern subtle variations in a visual image. Many everyday visual tasks - recognizing a face, for example - rely more upon contrast sensitivity than the quantitative visual acuity. Problems that patients experience with contrast sensitivity commonly occur in low-light settings. These problems involve a more precise diagnosis which utilizes wavefront mapping of the optical distortions in the eye. Understanding your vision requires taking both the quantitative and qualitative elements into consideration. Since it is possible to possess very good visual acuity yet have poor visual quality, and vice versa, it is important to consider how both concerns may be resolved as you make your decision about laser vision correction.
Visionary Solutions
In the past, one of the biggest drawbacks to conventional laser correction surgery has been its inability to address both the quantitative and qualitative properties of correcting vision. Now, however, the Wavefront Optimized™ technology built into our ALLEGRETTO WAVE® treatments addresses this limitation. At night and in dark conditions, the pupil of the eye expands to permit the maximum amount of light to enter. With an optical zone smaller than the expanded pupil, the troubled patient likely experiences poor night vision or problems with glare and halos around bright objects such as oncoming headlights. ALLEGRETTO WAVE® is able to produce a larger optical zone, virtually eliminating glare and night vision problems associated with older generation lasers.
Visual Results: ALLEGRETTO’S Difference
Approved by the FDA in 2003 as the first new laser in five years, ALLEGRETTO WAVE® has been met with wide acclaim for its superior ability to correct both myopic and hyperopic vision. A growing number of surgical clinics are endorsing the treatment, and the supporting statistics illuminate why:
• More than 98% of patients achieved 20/40 vision one year after treatment. (20/40 is the level of visual acuity required to pass most driving tests).
• 87% of the myopic patients attained 20/20 vision one year after the treatment.
• Nearly 60% of near-sighted patients achieved 20/16 vision after one year of treatment.
• Both near- and far-sighted patients reported an improvement in their reaction to bright lights and night driving glare after ALLEGRETTO WAVE® treatments. In addition, near-sighted patients reported an improvement in sensitivity to light.
• Consistent results are the standard for the ALLEGRETTO WAVE®. More than 90% of patients achieve refraction within 1 diopter of their target correction.