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 isdescribed. The instrument is based on the well-known dynamic light-scattering technique. Resultscan be obtained from the anterior as well as the posterior segment with high spatial resolution andsensitivity. This instrument allows, to our knowledge for the first time, in vivo measurements ofdynamic light scattering to be performed in the vitreous. Interesting performance is obtained usingsingle-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 instrumentdemonstrates good safety characteristics ~the optical power impinging the patient’s eye is 36 timesbelow the maximum laser power at the cornea, recommended for intrapupil exposure by ANSIstandard!. To demonstrate the possible clinical use of this technique, in vivo measurements weremade and the results compared with the known eye pathologies.