LOW SPATIAL-CONTRAST SENSITIVITY IN DRY EYES

Purpose. Blurred vision in keratoconjunctivitis sicca eyes could be th e result of the loss of the glossy surface of the tear film because of changes in composition or thickness irregularities, Spatial-contrast sensitivity in keratoconjunctivitis sicca and normal control eyes was rested before and after a tear substitute. Methods, Three different gr oups of subjects were enrolled. one group of dry eyes with nonsignific ant signs of epithelial disease (n = 12), the second group of dry eye positive with 1% Bengal rose staining of the cornea and of the conjunc tiva (12 = is), and a third of normal eyes as control group (n = 15). Ln all the 45 eyes, spatial-contrast sensitivity was tested under the best correction by means of the Vistech Multivision Contrast Tester 80 00 (Vistech Consultants, Dayton, OH, U.S.A.) before and 15 min after t he instillation of a 0.4% Na-hyaluronate tear substitute without prese rvatives. Results. A significant decrease of spacial-contrast sensitiv ity ranging from 35 to 70% was present in keratoconjunctivitis sicca e yes compared with a third group of age-matched normal eyes used as con trol. The spatial-contrast sensitivity was significantly lower also in the presence of preserved corneal surface. The addition of a tear sub stitute improved spatial contrast-sensitivity thresholds in all groups . Conclusion. Tear-film disease can affect the transfer function of mo dulation of the ocular surface.