Central corneal thickness and corneal hysteresis during corneal swelling induced by contact lens wear with eye closure

center dot PURPOSE: To determine if corneal hysteresis (CH) was associated with increased central corneal thickness (CCT) induced by wearing soft contact lenses during eye closure. center dot DESIGN: A prospective laboratory investigation. center dot METHODS: CCT was measured with a modified optical coherence tomography (OCT), and CH was measured with a Reichert Ocular Response Analyzer (ORA) [Reichert Ophthalmic Instruments, Depew, New York, USA]. The ORA also determined values for intraocular pressure (IOP), corneal compensated IOP (IOPcc), and corneal resistance factor (CRF). One randomly selected eye of 20 non-contact lens wearers (four males and 16 females, age 19.7 +/- 1.1 years) was patched during three hours of soft contact lens wear. Measurements were made before lens insertion, immediately upon removal, and every 20 minutes thereafter for 100 minutes. center dot RESULTS: Immediately after contact lens removal, CCT was increased by 13.1 +/- 2.2% (mean t +/-) compared with baseline (post hoc, P = .001). After 100 minutes, it remained elevated by 2.4 +/- 1.6% (post hoc, P = .001). However, there were no significant differences of CH at any time after lens wear (analysis of variance [ANOVA], P = .9). Immediately after lens removal, there were significant increases in IOP (post hoc, P = .003) and corneal resistance factor (CRF) (post-hoc, P = .015), but not in IOPcc (post hoc, P = .07). After lens wear, there were significant but weak correlations between the percentage change of CCT (CCT%) and IOP (r = 0.32, P = .001) and IOPcc (r = 0.29, P = .001). However, there was no significant correlation between CCT% and CH (r = 0.07, P = .458). center dot CONCLUSION: CH as measured by ORA was not associated with corneal swelling induced by soft contact lens wear in this study group.