Significant corneal swelling was observed during eight hours of corneal contact lens wear in 12 volunteers successful in wearing the initial lenses prescribed. Following one week of daily wear, average increase in corneal thickness was 0.024 mm. Significant change in average corneal thickness occurred also at two to three weeks, six to eight weeks, and six months. Incidence of significant corneal swelling during eight hours of contact lens wear decreased with increasing periods of daily wear. Epithelial edema accompanied corneal swelling in ten of 20 eyes, decreased more rapidly than corneal swelling, and disappeared before corneal thickness had returned to baseline value. There was frequent association between corneal swelling and decreased oxygen uptake of the cornea following eight hours of wear. No simultaneous change was observed in average tear osmolarity with an increase in average corneal thickness.
Farris RL, Kubota Z, Mishima S. Epithelial Decompensation With Corneal Contact Lens Wear. Arch Ophthalmol. 1971;85(6):651-660. doi:10.1001/archopht.1971.00990050653002