[Correlation between laser tyndallometry and protein concentration in the anterior eye chamber]

The laser flare cell meter (LFCM) is introduced as an instrument that quantifies noninvasive anterior chamber protein. The relationship between laser flare measurement and actual protein concentration in vivo and in vitro was assessed. The intensity of light scattering by helium neon laser beam is measured by LFCM and depends on protein concentration and molecular size. Total protein, albumin and transferrin were measured using nephelometry and the Coomassie method. We tested 63 patients undergoing routine cataract surgery. Laser flare measurements were made before surgery. The mean in vivo flare was 8.25 photons/ms, standard deviation 9.57 photons/ms. Before surgery paracentesis was performed in 61 patients. In vitro aqueous flare was 10.55 +/- 7.68) photons/ms. Biochemical analysis showed a mean anterior chamber protein concentration in 51 patients of 33.65 (+/- 27.36) mg/dl, a mean albumin concentration in 38 patients of 15.78 (+/- 11.03) mg/dl, and a mean transferrin concentration in 33 patients of 2.01 (+/- 0.88) mg/dl. Up to a "cell" count of 40/0.075 mm3 there is a statistically significant correlation. Laser flare values compared with biochemical analysis showed for total protein a correlation coefficient of r = 0.695 in vivo and r = 0.753 in vitro. A "cell" count higher than 40/0.075 mm3 produces marked overestimation of protein concentration by laser flare values. There is a statistical significant linear correlation between photon count by LFCM and total aqueous protein concentration by biochemical analysis in vivo and in vitro in normal cataractous eyes.