www.pacificvision.org     415.922.9500

Volume 2       February 28, 2007

  Eye Health

Once you've had successful refractive surgery and have eliminated or minimized the need for a prescription glasses or contacts, don't forget it's still a good idea to protect your eyes from the sun's ultraviolet (UV) rays. Sunglasses and shade from a hat are great ways to reduce UV exposure while enjoying the outdoors. UV exposure can contribute to premature wrinkles around the eyes, skin cancers and age spots on the eyelids, growths on the surface of the eye such as pinguecula and pterygium, and possible early cataract formation and macular degeneration. A high quality pair of UV blocking sunglasses can be a great investment in your eye health. If you ski or snowboard, the risk of UV exposure is especially high because, in addition to direct exposure, the sun rays also reflect off the snow. Even on cloudy days, you will do well by wearing UV blocking sunglasses or goggles. Of course, they won't have prescription any more!

  What's new in vision correction procedures

As we get older, we may develop cataracts - clouding of our natural lens. Cataracts can be removed and vision can be improved. When we undergo cataract surgery, the cloudy natural lens is replaced with a clear intraocular lens (IOL). Until recently, IOLs were designed to focus at distance only so reading glasses were still required for near vision. New IOLs are now available that provide near vision as well, either with built-in concentric rings that provide the near vision correction (multifocal lens implants) or with flexible hinge design that allows the artificial lens to move in a way that mimics our natural lens movement. Both are exciting options that may provide for a wider range of focusing power to help us see both far and near with minimal reliance on glasses.

  Tech Corner

A photographic technique know as Scheimpflug Imaging was first developed in the early 1900s in Austria to accurately map large landscapes using multiple cameras mounted on floating balloons. The same principle is now being used to accurately map the architecture of the front of the eye. The new Pentacam imaging device uses rotating cameras to take images from 25,000 points of the eye in less than 2 seconds. A map is created with 3 dimensional views of the front of the eye which can be used to evaluate corneal thickness, corneal curvature, and intraocular lens density. Unlike all the other eye imaging devices, the camera in the Pentacam is mounted at the periphery of the cornea, not in the center of the cornea. Therefore, the center of the visual axis (where the vision correction procedures are performed) is not obscured by the camera and can be mapped very accurately. Other imaging devices, with the cameras mounted at the center of the visual axis, don't actually map this region. They simply extrapolate the data from the surrounding area. So, if there is any abnormality in the very center of the visual axis, only the Pentacam will be able to pick it up. With Pentacam, we get the actual data, not the extrapolated one. Pacific Vision Institute is using the advanced technology of the Pentacam to evaluate all patients considering refractive surgery.

  Fun Eye Facts

During World War II, an English ophthalmologist with the Royal Air Force by the name of Harold Ridley (1906-2001) made the observation that fragments of plexiglass from airplane canopies that had logded in the eyes of injured pilots did not trigger a rejection reaction. He used the same plexiglass material to design intra-ocular lens implants for use in cataract and lens surgery. This new technology was revolutionary, eliminating the need for thick post-operative 'cataract glasses'. The first "Ridley Lens" was implanted in the United States in Philadelphia in the 1950s. Although these tiny intraocular lenses have since undergone many generations of refinements, the concept is fundamentally the same as developed by Harold Ridley. Patients have benefited from this miraculous discovery for over 50 years. Sir Howard Ridley was knighted in 2000.

Unsubscribe from this mailing list.