Cell content of tears following overnight wear of a contact lens

Abstract

The cell content of the precorneal tears of eight subjects was sampled following overnight wear of a contact lens in one eye. This was compared with morning samples taken from the other eye, and afternoon samples taken several days later from both eyes.

In the morning the median number of desquamated epithelial cells in the precorneal tears was 62 cells in the lens-wearing eye and 119 cells in the control eye. The difference was not statistically significant. In the afternoon the medians were 18.5 cells in one eye and 7.5 cells in the other. There were relatively few leucocytes in the afternoon, the median was 2 leucocytes in one eye and 9 in the other. In the morning the median was 8,154 leucocytes in the lens-wearing eye and 6,500 in the control eye.

The data show that large numbers of leucocytes are present on the ocular surface during sleep. There was no evidence that the number of leucocytes or the number of epithelial cells was altered by the presence of the contact lens.