A hydrophilic contact lens was fitted on the normal right cornea of ten informed volunteers and worn continuously for ten days. No evidence of an overwearing syndrome was encountered in any of the subjects. Edema and a burning sensation occurred in several subjects, but these symptoms were transient, minor, and self-limited. Some variability in visual acuity was noted and the cause of this finding is discussed. A small increase in total corneal thickness, not exceeding 30%, occurred in all subjects on the first full day of contact lens wear but did not interfere with vision. The cornea stabilized at this new thickness and no further increase occurred during the remainder of the wearing period.
Leibowitz HM, Laing RA. Continuous Wear of Hydrophilic Contact Lenses. Arch Ophthalmol. 1973;89(4):306-310. doi:10.1001/archopht.1973.01000040308010