[Correlation between total aqueous protein concentrations and photon counts in rabbits].

We studied the correlation between photon counts of the aqueous flare and total aqueous protein concentrations in rabbit eyes. After mydriasis, a predetermined volume of the aqueous humor was aspirated and photon counts of the secondary aqueous was measured using a laser flare-cell meter. In vitro measurements of total protein concentrations showed that step-wise changes in withdrawal volume ranging from 50 to 200 microliters induced corresponding rises of the total protein concentrations in the secondary aqueous, with the mean total protein concentrations ranging from 220 to 1980 mg/dl. A ratio of albumin to globulin concentrations (A/G) ranged from 1.0 to 3.6, but they did not show any significant correlation with the aqueous total protein concentrations. The mean photon counts in the secondary aqueous ranged from 40 to 343/msec. A statistical analysis showed that photon counts correlated well with the total protein concentrations. The linear regression equation was X = Y1.07 x 3.33 where X and Y indicate protein concentrations and photon counts, respectively (r = 0.92, p less than 0.001). The regression equation might be used to estimate the total aqueous protein concentrations in laser flare-cell measurements in vivo. The variation of A/G ratio affected the photon count values, and the total protein concentration might be within 3/2 and 1/2 of the estimated value.