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Increased Corneal Hysteresis After Corneal Collagen Crosslinking

Increased Corneal Hysteresis After Corneal Collagen Crosslinking ImportanceA reliable tool for quantification of the biomechanical status of the cornea in conjunction with corneal collagen crosslinking (CXL) treatment is needed. ObjectiveTo quantify the biomechanical effects of CXL in vivo. Design, Setting, and ParticipantsA prospective, open, case-control study was conducted at the Department of Ophthalmology, Umeå University, Umeå, Sweden. Participants included 28 patients (29 eyes) aged 18 to 28 years with progressive keratoconus and corresponding age- and sex-matched healthy individuals serving as controls. All participants were monitored during a 6-month period between October 13, 2009, and November 5, 2012. Main Outcomes and MeasuresCorneal hysteresis after CXL for keratoconus. ResultsA difference in corneal hysteresis between the control group and the patients with keratoconus was found at baseline, both with an applanation resonance tonometer (ART) and an ocular response analyzer (ORA), at mean (SD) values of –1.09 (1.92) mm Hg (99% CI, –2.26 to 0.07; P = .01) and –2.67 (2.55) mm Hg (99% CI, –4.05 to –1.32; P < .001), respectively. Increased corneal hysteresis was demonstrated with an ART 1 and 6 months after CXL, at 1.2 (2.4) mm Hg (99% CI,–0.1 to 2.5; P = .02) and 1.1 (2.7) mm Hg (99% CI, –0.3 to 2.6; P = .04), respectively, but not with ORA. A decrease in corneal thickness was seen 1 and 6 months after treatment (–24 [26] µm, P < .001; and −11 [21] µm, P = .01, respectively), and a corneal flattening of −0.6 (0.7) diopters was seen at 6 months (P < .001). No significant change in intraocular pressure was identified in patients with keratoconus with any method, except for an increase at 1 month with Goldmann applanation tonometry (P = .005). Conclusions and RelevanceTo our knowledge ART is the first in vivo method able to assess the increased corneal hysteresis after CXL treatment. Given the large-scale use of CXL in modern keratoconus treatment, a tool with this capacity has a great potential value. Refinement of the ART method of measuring and quantifying corneal biomechanical properties will be a subject of further studies. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png JAMA Ophthalmology American Medical Association

Increased Corneal Hysteresis After Corneal Collagen Crosslinking

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References (44)

Publisher
American Medical Association
Copyright
Copyright 2014 American Medical Association. All Rights Reserved. Applicable FARS/DFARS Restrictions Apply to Government Use.
ISSN
2168-6165
eISSN
2168-6173
DOI
10.1001/jamaophthalmol.2014.3029
pmid
25171564
Publisher site
See Article on Publisher Site

Abstract

ImportanceA reliable tool for quantification of the biomechanical status of the cornea in conjunction with corneal collagen crosslinking (CXL) treatment is needed. ObjectiveTo quantify the biomechanical effects of CXL in vivo. Design, Setting, and ParticipantsA prospective, open, case-control study was conducted at the Department of Ophthalmology, Umeå University, Umeå, Sweden. Participants included 28 patients (29 eyes) aged 18 to 28 years with progressive keratoconus and corresponding age- and sex-matched healthy individuals serving as controls. All participants were monitored during a 6-month period between October 13, 2009, and November 5, 2012. Main Outcomes and MeasuresCorneal hysteresis after CXL for keratoconus. ResultsA difference in corneal hysteresis between the control group and the patients with keratoconus was found at baseline, both with an applanation resonance tonometer (ART) and an ocular response analyzer (ORA), at mean (SD) values of –1.09 (1.92) mm Hg (99% CI, –2.26 to 0.07; P = .01) and –2.67 (2.55) mm Hg (99% CI, –4.05 to –1.32; P < .001), respectively. Increased corneal hysteresis was demonstrated with an ART 1 and 6 months after CXL, at 1.2 (2.4) mm Hg (99% CI,–0.1 to 2.5; P = .02) and 1.1 (2.7) mm Hg (99% CI, –0.3 to 2.6; P = .04), respectively, but not with ORA. A decrease in corneal thickness was seen 1 and 6 months after treatment (–24 [26] µm, P < .001; and −11 [21] µm, P = .01, respectively), and a corneal flattening of −0.6 (0.7) diopters was seen at 6 months (P < .001). No significant change in intraocular pressure was identified in patients with keratoconus with any method, except for an increase at 1 month with Goldmann applanation tonometry (P = .005). Conclusions and RelevanceTo our knowledge ART is the first in vivo method able to assess the increased corneal hysteresis after CXL treatment. Given the large-scale use of CXL in modern keratoconus treatment, a tool with this capacity has a great potential value. Refinement of the ART method of measuring and quantifying corneal biomechanical properties will be a subject of further studies.

Journal

JAMA Ophthalmology – American Medical Association

Published: Dec 1, 2014

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