Endothelial cell density of the cornea during rigid gas permeable contact lens wear

To determine the influence of a daily wear rigid gas permeable (RGP) high DK lens (CIBA Vision Persecon92E, Dk=92 x 10(-11)) on corneal endothelial cell density (ECD).

A prospective longitudinal, follow-up study was conducted. Variations in corneal ECD during the first year were reported. For this purpose, the endothelium of 97 eyes of 57 unadapted subjects were compared by specular microscopy before and after 1 week (n= 74), 1 month (n=67), 3 months (n=51), and 1 year (n=23) of wearing contact lenses.

There was a significant decrease in cell density vs age (r=-0.28, P=0.005). ECD significantly increased 1 week (3.6%) (P=0.001), 1 month (3.6%) (P=-0.003), and 3 months (4.5%) (P=0.003) after contact lens wear. One year after the lens fitting, a similar but not significant increase was found. While ECD increase was insignificant with initially high ECD subjects (>2700 cells/mm2), subjects with low ECD initially (<2700 cells/mm2) showed a significant increase in ECD in all time intervals.

In the 1 week RGP contact lens wearing period, the endotheliums with low ECD probably adapted to a new oxygen environment by cell migration or mitotic activity. The increased ECD was perhaps related to the daily wear schedule in which the oxygen partial pressure was sufficient.