Laser flare photometry

Abstract

In case of intraocular inflammation, blood-ocular barriers are disrupted allowing serum proteins as well as cells to enter the eye. The normal noninflamed status and the different levels of intraocular inflammation can be observed in the aqueous humor that is visually accessible through the cornea. The two inflammatory parameters obtained by slit-lamp examination are aqueous cells seen as particles identified by backscattering light from the incoming beam and the “Tyndall effect” or flare, an optical phenomenon caused by the backscattering of light by “cloudy matters” of small molecular size, here aqueous proteins, producing a milky beam, described for the first time by Lord John Tyndall in 1869. Efforts were made to establish standardized ways to evaluate the level of inflammation in the anterior chamber, and a grading system was put forward by Hogan, Kimura, and Thygeson at the Proctor Foundation in San Francisco. They established scores from 0 to 4 for both flare and cells that are shown for flare on Table 15.1. This system was used for the last half century because there was no other better alternative.