Design, calibration, and testing of a laser flare meter

A laser flare meter, insensitive to corneal, lens, and eye background scattering and calibrated by measurements and theoretical modeling, is reported. Calibration measurements and theoretical calculations of light scattering from albumin solutions were found to agree within the limits of error. The results from in vivo measurements of normal eyes of different ages agreed well with normal protein content of aqueous humor. A special aperture design was used to reduce the unwanted background scattering resulting in signal-to-background ratios between 1:1 and 1:3 for normal eyes. Moderately cataractous eyes, with increased scattering from the lens, could be measured with sufficient accuracy. The reproducibility was measured to be ~ 12%. We studied how the flare is affected by sex, right/left eye, eye color, time of day, pupillary dilation, and an intraocular pressure measurement. No differences of practical importance were found.