Supernormal Vision: A Focus on Adaptive Optics Improves Images of the Eye and Boosts Vision

By Wu, Corinna | Science News, November 15, 1997 | Go to article overview

Supernormal Vision: A Focus on Adaptive Optics Improves Images of the Eye and Boosts Vision


Wu, Corinna, Science News


Anyone who grew up reading comic books may recall the advertisement that always graced the back pages, touting weird and wonderful gizmos designed to appeal to fun-loving youngsters. In one classic ad, a crew-cut boy sporting horn-rimmed "X-ray specs" stares gleefully at the bones in his hand. With the specs, the ad promised, mere mortals could acquire the super-vision of Superman.

Most people with failing eyesight are satisfied just to have glasses or contact lenses that can keep their vision within the 20/20 range. One group of researchers, however, has developed a technology that can endow people with a new kind of supernormal vision. Following the tradition of binoculars' helping people to observe distant objects and night vision goggles' allowing them to see in the dark, the most recent technology enables the human eye to detect finer detail than is ordinarily possible.

At a seminar sponsored by Research to Prevent Blindness and held in Los Angeles in September, vision scientist David R. Williams of the University of Rochester in New York explained the approach that he and his group have taken. They have embraced the technique of adaptive optics, originally designed to sharpen images from military surveillance devices and astronomical telescopes. As applied to the human eye, the system allows people to see at high resolution, but it also works in reverse, allowing researchers to capture extraordinarily detailed images of the eye's retina.

That, in fact, is the group's main goal. Clear, detailed images of the retina could improve the diagnosis, understanding, and treatment of diseases such as glaucoma and age-related macular degeneration, both of which can cause blindness. As part of their adaptive optics system, Williams and his group also have adopted a new way of measuring the eye's imperfections that could help to improve the performance of contact lenses and allow more accurate assessment of corrective eye surgery.

Williams and his colleagues recently obtained the clearest pictures yet of individual cells in the retina, an achievement that Howard C. Howland of Cornell University calls "spectacular." The retina acts as the eye's movie screen, receiving a projected image of the ever-changing world. Light entering the eye hits not a white, reflective surface, but a carpet of rods and cones--two kinds of photoreceptor cells that serve different purposes. Rods detect dim light and are needed for peripheral vision, while cones function in bright light and are responsible for color vision. Cone cells come in red, blue, and green types, the names indicating their color sensitivities.

"Spatial arrangement and relative numbers [of rods and cones] are not well characterized in the human retina," says Williams. So far, most studies have been done in excised eyes, not in living people, Howland adds. To take a picture of the intact retina, a researcher has to send a flash of light into the eye, then record the light that bounces off the retina with a camera.

The same imperfections in the eye's cornea and lens that reduce visual acuity, however, also warp retinal images obtained in this way, limiting their resolution. "If you had a perfect eye, the light would come out parallel," says Williams, and could be focused into an undistorted image of the retina.

Many common vision problems, such as myopia and astigmatism, are caused by aberrations in, the shape of the eye that are easy to correct with eyeglass lenses. Other aberrations are harder to deal with, both in improving a person's vision and in examining the eye.

Several years ago, the Rochester group found a solution for dealing with such troublesome distortions when they examine eyes: They do a trick with mirrors. The researchers can direct the light leaving an eye onto a deformable mirror--the key to adaptive optics--and correct for any aberration, thereby producing the highest quality images of the retina ever seen (SN: 10/8/94, p. …

The rest of this article is only available to active members of Questia

Sign up now for a free, 1-day trial and receive full access to:

  • Questia's entire collection
  • Automatic bibliography creation
  • More helpful research tools like notes, citations, and highlights
  • Ad-free environment

Already a member? Log in now.

Notes for this article

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
One moment ...
Default project is now your active project.
Project items

Items saved from this article

This article has been saved
Highlights (0)
Some of your highlights are legacy items.

Highlights saved before July 30, 2012 will not be displayed on their respective source pages.

You can easily re-create the highlights by opening the book page or article, selecting the text, and clicking “Highlight.”

Citations (0)
Some of your citations are legacy items.

Any citation created before July 30, 2012 will labeled as a “Cited page.” New citations will be saved as cited passages, pages or articles.

We also added the ability to view new citations from your projects or the book or article where you created them.

Notes (0)
Bookmarks (0)

You have no saved items from this article

Project items include:
  • Saved book/article
  • Highlights
  • Quotes/citations
  • Notes
  • Bookmarks
Notes
Cite this article

Cited article

Style
Citations are available only to our active members.
Sign up now to cite pages or passages in MLA, APA and Chicago citation styles.

(Einhorn, 1992, p. 25)

(Einhorn 25)

1

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Cited article

Supernormal Vision: A Focus on Adaptive Optics Improves Images of the Eye and Boosts Vision
Settings

Settings

Typeface
Text size Smaller Larger Reset View mode
Search within

Search within this article

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

Full screen

matching results for page

Cited passage

Style
Citations are available only to our active members.
Sign up now to cite pages or passages in MLA, APA and Chicago citation styles.

"Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn, 1992, p. 25).

"Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

"Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences."1

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Cited passage

Welcome to the new Questia Reader

The Questia Reader has been updated to provide you with an even better online reading experience.  It is now 100% Responsive, which means you can read our books and articles on any sized device you wish.  All of your favorite tools like notes, highlights, and citations are still here, but the way you select text has been updated to be easier to use, especially on touchscreen devices.  Here's how:

1. Click or tap the first word you want to select.
2. Click or tap the last word you want to select.

OK, got it!

Thanks for trying Questia!

Please continue trying out our research tools, but please note, full functionality is available only to our active members.

Your work will be lost once you leave this Web page.

For full access in an ad-free environment, sign up now for a FREE, 1-day trial.

Already a member? Log in now.