Lasers in your eye

There’s a certain irony to be found in the relationship between lasers and the human eye. While lasers can permanently blind someone, they can also restore or improve sight. In fact ophthalmology represents one of the most successful therapeutic applications of lasers-currently accounting for roughly one-third of all medical-therapy lasers sold (see www.laserfocusworld.com/articles/245112)-and is probably most familiar to the layperson in the guise of photorefractive surgery techniques like LASIK. Recent and probably less familiar research is now exploring the role of the eye as a window . . . not necessarily to the soul as it’s often been described, but at least to the brain. By applying noninvasive laser-based spectroscopic techniques to detect and measure a newly discovered biomarker in the fluid of the eye, researchers hope to develop a clinical screening system for diagnosis and management of neurodegenerative diseases such as Alzheimer’s (see p. 73).

The ongoing quest to “drill down” into the materials and tissue that make up the world around us has driven continuing advances in detection and measurement technologies. From finding and tracking the biomarkers mentioned above, to colossal enhancements in the sensitivity and resolution that can be achieved in imaging, metrology, and analytical methods, these advances have opened up entirely new, and previously invisible, vistas. In one example, the sensitivity benefits of surface-enhanced Raman scattering are driving a resurgence of an “old” technique with promising new potential in clinical and life-science applications (see p. 109). In another, a novel interferometric metrology system enables improved process control during asphere manufacturing (see p. 93). And in a third example, improving the speed and spatial resolution of multiphoton and confocal scanning microscopies will allow seeing finer detail, while enabling the study of cellular processes on their native timescales (see p. 85).