Medical Optics a FiO Feature

Using tiny implantable cameras to restore sight, lasers to treat infertility and light to detect malaria are a few of the medical research advances to be discussed during Frontiers in Optics 2007 (FiO), the 91st Annual Meeting of the Optical Society of America. FiO will be held Sept. 16-20 at the Fairmont Hotel in San Jose, Calif., collocated with Laser Science XXIII, the annual meeting of the American Physical Society Division of Laser Science.

At FiO, researchers from the University of Southern California (USC) will present the paper "Intraocular Camera for Retinal Prostheses: Design Constraints Based on Visual Psychophysics," about their work with implanting a tiny camera into the human eye and connecting it to the retina. The ultimate goal of the camera is to provide limited vision to those blinded by diseases that don't completely destroy the retina, such as retinitis pigmentosa and age-related macular degeneration, via a fully implantable retinal prosthetic device.

Current retinal prostheses are designed to be used with an external camera mounted in a pair of glasses, which requires a subject to move his head in order to scan the environment. The miniaturized prototype being developed by the USC team would be directly implantable and would allow for natural eye and head movements.

The researchers also discovered that the minimum system requirements for vision-related tasks was only 625 pixels, compared to the more than a million in a typical computer display. That knowledge helped them to reduce their prototype's size and weight from that of a Tylenol tablet to about one-third the size of a Tic-Tac. Initial tests have been successful, but human FDA trials are still at least two years away.

Scientists from the University of California's Irvine and San Diego campuses will present their research, using laser traps as a sorting technique for sperm in infertility treatments, in the paper "Annular Laser Trap: A Tool for High-Throughput Sperm Sorting and Analysis." The laser trap, consisting of special cone-shaped lenses, a standard lens and a laser, can separate stronger, faster sperm -- sperm more likely to successfully fertilize an egg -- from slower sperm. The technique could improve conception chances via in vitro fertilization and could find wide application in animal husbandry and human fertility treatments. Since X sperm are generally heavier and swim slower than Y sperm, it is also possible to use the technique for gender selection.

In their FiO presentation, "Confocal Polarimetry Measurements of Tissue Infected with Malaria," scientists from the University of Waterloo in Ontario and the University of Murcia in Spain will speak on their new, more accurate and detailed technique to analyze large tissue samples for signs of malaria.

The scientists used a new instrument, a confocal laser scanning Macroscope, capable of imaging much larger tissue samples at a very high resolution. By combining their new technique with the Macroscope, the researchers measured tell-tale changes in the polarization of light reflecting off a sample of infected tissue, since the malaria parasite changes light polarization.

The technique allows large areas to be imaged in a single scan as opposed to the smaller field available with a traditional microscope. The researchers found that not only could this new approach improve the assessment of the severity of malaria cases, but it could also be used to assess tissues affected by other diseases and conditions that interact with polarized light, such as Alzheimer's disease.

Technical sessions presented under the broad FiO topic of "Optics in Biology and Medicine" will include discussions of biosensors, advances in single-molecule biophysics, micro- and nanotechnology for bioengineering, and molecular imaging and microspectroscopy of live cells using immunotargeted nanoparticles.

Also, Stanford University researchers' work with retinal implant technologies and optical brain imaging and mapping in small animals will also be discussed during the Joint FiO/Stanford Photonics Research Center Symposium Monday, Sept. 17.

For more information, visit www.osa.org