Effect of saline solution immersion on corneal scattering characteristics

The scattering characteristics of the cornea were measured during immersion in various saline concentrations. Initially, scattering was monitored subjectively by spatial frequency thresholds and contrast thresholds on sine wave grids, and by the border enhancement method. Although all three methods responded to corneal scattering changes produced during immersion, the latter method proved to be the most sensitive. The border enhancement method was subsequently applied during immersion of the cornea in various hypotonic and hypertonic saline solutions. Scattering changes were recorded during an immersion period of 1 hr followed by a recovery period of 1/2 hr. As expected, the scattering increased with hypotonicity. However, certain features of the time characteristics of the scattering changes suggest that the effect of the immersion fluid is modified by the tear flow.