Changes in contrast sensitivity during the first hour of soft lens wear.

Changes in contrast sensitivity were monitored immediately before, during, and after 1 hour's soft lens wear. Soft lenses of three different center thicknesses, 0.03, 0.07, and 0.12 mm, were used. Results demonstrated a gradual reduction in contrast sensitivity during wear, with a faster but not instantaneous recovery after removal. An increase in soft lens center thickness caused a more pronounced loss of contrast sensitivity, with a slower recovery. The implications of this research on the various reasons put forward for the impairment of the contrast sensitivity function by soft lenses are discussed.