Blurred vision in keratoconjunctivitis sicca eyes could be the 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 tested before and after a tear substitute.
Three different groups of subjects were enrolled: one group of dry eyes with nonsignificant signs of epithelial disease (n = 12), the second group of dry eye positive with 1% Bengal rose staining of the cornea and of the conjunctiva (n = 18), and a third of normal eyes as control group (n = 15). In all the 45 eyes, spatial-contrast sensitivity was tested under the best correction by means of the Vistech Multivision Contrast Tester 8000 (Vistech Consultants, Dayton, OH, U.S.A.) before and 15 min after the instillation of a 0.4% Na-hyaluronate tear substitute without preservatives.
A significant decrease of spatial-contrast sensitivity ranging from 35 to 70% was present in keratoconjunctivitis sicca eyes compared with a third group of age-matched normal eyes used as control. The spatial-contrast sensitivity was significantly lower also in the presence of preserved corneal surface. The addition of a tear substitute improved spatial contrast—sensitivity thresholds in all groups.
Tear-film disease can affect the transfer function of modulation of the ocular surface.
From the Department of Ophthalmology, University of Genoa, Genoa, Italy.
Address correspondence and reprint requests to Dr. M. Rolando, Department of Ophthalmology, University of Genoa, Osp. S. Martino Pad 9, V.le Benedetto XV, 16132 Genoa, Italy.
Submitted December 17, 1997. Revision received February 13, 1998. Accepted February 23, 1998.