Clinical tear analysis using laser diffraction.

A diagnostic method has been developed to analyze tear specimens from patients with red eyes, using the technique of laser diffraction. After proper tear sample preparation, presence of a diffraction halo produced by the tear specimen indicates presence of an external ocular inflammation and helps rule out such conditions as glaucoma, iritis and episcleritis. Measurement of the size of the halo pattern may also be used to give information as to the concentration of cells in the tear sample.