Design and performance of a new ophthalmic instrument for dynamic light-scattering measurements in the human eye

A new optical instrument for in vivo dynamic light-scattering measurements in the human eye is described. The instrument is based on the well-known dynamic light-scattering technique. Results can be obtained from the anterior as well as the posterior segment with high spatial resolution and sensitivity. This instrument allows, to our knowledge for the first time, in vivo measurements of dynamic light scattering to be performed in the vitreous. Interesting performance is obtained using single-mode optical fibers to guide the excitation and the scattered light resulting in a modular, compact system with high-beam quality and electrical insulation of the patient. The instrument demonstrates good safety characteristics (the optical power impinging the patient’s eye is 36 times below the maximum laser power at the cornea, recommended for intrapupil exposure by ANSI standard). To demonstrate the possible clinical use of this technique, in vivo measurements were made and the results compared with the known eye pathologies.