Two- and Three-Dimensional Confocal Microscopy of the Eye

Abstract

Confocal microscopy is a technique which permits morphological measurements of ocular tissue which are not possible by other methods (Wilson, 1990). Real-time confocal microscopes permit the observation of living tissue (and Eye Bank eyes) without the use of staining (Lemp et al., 1986). The images are sharp and show high contrast. The confocal microscope provides high resolution, high contrast images of both the cornea and ocular lens. Images are produced without light scatter from the tissue above and below the focal plane of the microscope. The reflected light confocal light images are due to the small differences of refractive index which occurs in the semitransparent ocular tissue. No other ophthalmic optical instrument is capable of imaging the lens capsule, the lens epithelium, or the single lens fibers with the resolution and the contrast provided by confocal microscopes (Koester and Roberts, 1990). The confocal microscope is a new tool for the scientist and the clinician who observes ocular tissue. This chapter discusses a new paradigm to visualize the living eye (Masters, 1990a; Masters and Kino, 1990b). The application of confocal microscopy to image the eye represents a major development in noninvasive optical ophthalmic imaging. The use of confocal microscopy to observe the eye permits the observation and real-time acquisition of optical sections of the cornea and ocular lens (Masters, 1992). The resulting stack of two-dimensional images can be rendered as stereo pairs or reconstructed into a three-dimensional image (Masters, 1991a; Masters and Paddock, 1990b). The three-dimensional image can be further processed for enhanced visualization, segmentation and quantitative image analysis.