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. The retina acts as the eye's movie screen, receiving a projected image of the ever-changing world. 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.
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. 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.