TECHNIQUES ORIGINALLY developed to help telescopes see distant objects more clearly are now being used to allow microscopes to get a better view. The methods used are similar whether you are looking at a distant galaxy or the cells at the back of the human eye.
The research field is known as “adaptive optics” and a session at the American Association for the Advancement of Science meeting heard how it is giving us a better view of our “microcosmos”. The session was organised by Chris Dainty, professor of applied physics at NUI Galway and Science Foundation Ireland principal investigator.
“Applied optics is a technique for removing distortion from images and optical beams to produce a sharper image,” he said. It was not about getting a better lens to look through, it meant the use of active methods to enhance the result. Prof Dainty likened it to taking the distortions out of a potato crisp and flattening out all the contours without breaking the crisp.
In astronomy it means reducing the distortion caused when looking through our atmosphere but soon other researchers began to see the benefits, he said. “Adaptive optics has hundreds of other potential applications that could be developed.”
One example was its use in producing very clear images of retinal cells at the back of the eye, said professor of ophthalmology Joseph Carroll of the Medical College of Wisconsin, Milwaukee. In this case the liquid inside the eye causes distortions that adaptive optics can clear up. The technology had delivered “a new era of ophthalmic imagining”, he said.
People with eye diseases such as glaucoma experience retinal cell death but don’t notice until half of the cells are destroyed, he said. “With adaptive optics it is now possible to detect the loss of a single cell.” This can give a much earlier warning of slowly advancing eye disease.
Another use is improving the images from microscopes when studying cells and biological samples, said Dr Eric Betzig of the Howard Hughes Medical Institute in Virginia. He wants to use it to image brain cells but without adaptive optics the instruments can’t see more than a few cells deep.
The light coming back from the tissues “gets scrambled”, leading to a “messy image”. It was like trying to get a clear image of a star from behind a cloud, he said. The goal was to develop techniques to allow microscopes resolve images of much deeper tissues, but to remain sharp.