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D. Epstein, E. Albe, P. Vinciguerra; Intra- and Postoperative Ocular Response Analyzer Findings in Keratoconic Eyes Undergoing Cross Linking. Invest. Ophthalmol. Vis. Sci. 2008;49(13):4351. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
To analyze the biomechanical properties of keratoconic corneas before Corneal Cross Linking (CCL), after epithelial removal and after CCL at one and six months follow-up, as measured by the Ocular Response Analyzer (ORA).
Prospective, non randomized clinical controlled study including 24 patients undergoing Riboflavin/UVA CCL and examined by means of ORA and Pentacam pachymetry at each time point in both eyes.
Mean corneal hysteresis (CH) changed from 9.68 at baseline, to 10.32 after epithelial removal, to 15.18 immediately after cross linking, to 11.48 at 1 month follow-up and 10.25 six months after CCL, a difference that was not statistically significant from baseline (P>0.05). Mean corneal resistance factor (CRF) changed from 9.05 at baseline, to 9.42 after epithelial removal, to 14.15 immediately after cross linking, to 12.53 at 1 month follow-up and 11.13 six months after CCL, a difference that was not statistically significant from baseline (P>0.05). Comparison of corneal-compensated intraocular pressure (IOPcc) measurements and Goldman correlated intraocular pressure (IOPg) measurements before CCL and at 12 months showed no significant changes (P>0.05).Mean baseline thinnest cornea point (TCP) and total corneal volume (TCV) were 454.80±26.63 µm and 56.17±2.24 mm3 respectively and 419.53±33.36 µm and 55.62±2.50 mm3 at 12 months, a difference that was statistically significant (P<0.05). A significant correlation between TCP and CH was found before CCL and at 6 months (P<0.05). Also, a significant correlation between TCV and both CH and CRF was found before CCL and at 6 months(P<0.05). No significant correlation was found between TCP and IOPcc at 6 months(P>0.05).
Intraoperative evaluation showed no significant changes in CH and CRF after epithelial removal and a statistical significant difference in CH and CRF soon after CCL. At 6 months, CCL does not induce any change in intraocular pressure as measured by ORA. CCL induces a significant reduction in corneal thickness and total corneal volume. A significant correlation was found between corneal thickness and CH and CRF in keratoconic eyes before and after CCL.
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