Variations in corneal biomechanical parameters and central corneal thickness during the menstrual cycle Yakov Goldich, MD, Yaniv Barkana, MD, Eran Pras, MD, Alexander Fish, PhD, Yossi Mandel, MD, Ami Hirsh, MD, Nir Tsur, MSc, Yair Morad, MD, Isaac Avni, MD, David Zadok, MD PURPOSE: To assess variations in the biomechanical properties and central corneal thickness (CCT) throughout the female menstrual cycle. SETTING: Department of Ophthalmology, Assaf Harofeh Medical Center, Zerifin Israel. DESIGN: Case series. METHODS: Young healthy women were prospectively recruited. Every participant was assessed at the beginning of the menstrual cycle, at ovulation, and at the end of the cycle. At every time point, corneal hysteresis (CH) and the corneal resistance factor (CRF) were measured with the Ocular Re- sponse Analyzer and the CCT was measured with an ultrasonic pachymeter. RESULTS: Twenty-two eyes of 22 women (mean age 19.5 years G 1.5 [SD]) were included. The CH was statistically significantly decreased at ovulation (10.1 mm Hg) compared with the beginning (11.1 mm Hg, P<.001) and the end (11.4 mm Hg, P<.001) of the cycle. The CRF was also signifi- cantly decreased at ovulation (9.8 mm Hg) compared with the beginning (10.6 mm Hg, P<.001) and the end (10.5 mm Hg, P<.001) of the cycle. The central cornea was thinnest at the beginning (535 mm) and statistically significantly thicker at ovulation (542 mm, P<.001) and at the end of the menstrual cycle (543 mm, P<.001). CONCLUSIONS: The CCT and biomechanical parameters significantly varied during the menstrual cycle. The CH and CRF were temporarily decreased at ovulation. The cornea was thinnest at the be- ginning and thicker at ovulation and at the end of the cycle. Such corneal changes may be important to consider during screening of candidates for laser refractive surgery. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned. J Cataract Refract Surg 2011; 37:1507–1511 Q 2011 ASCRS and ESCRS The cornea of women can be influenced by hormonal changes that occur during the monthly menstrual cy- cle. Indeed, cyclic variations in corneal topography and corneal thickness have been described. 1–3 These changes are probably driven by the direct interaction of sex hormones with sex hormone receptors located in the human cornea. 4,5 The Ocular Response Analyzer (ORA) (Reichert, Inc.) can be used to assess in vivo corneal biomechanical properties, which are presented by 2 parametersdcor- neal hysteresis (CH) and the corneal resistance factor (CRF). Incorporation of this device into the screening process of laser refractive candidates was recently pro- posed. 6 Conceptually, aggregate analysis of these bio- mechanical parameters together with corneal thickness and topographic characteristics can be used for improv- ing screening for corneal ectasia before performing laser refractive surgery. It has been shown that examination of young healthy women at different time points during the menstrual cycle may yield varying results of corneal pachymetry and topography due to their cyclic fluctua- tions. 1–3 Behavior of ORA parameters during the menstrual cycle has not been described. The aim of our study was to evaluate whether there is a variation in corneal biomechanical properties measured by ORA during the menstrual cycle. SUBJECTS AND METHODS Young healthy women were prospectively recruited from among the service staff of the Assaf Harofeh Medical Center. Q 2011 ASCRS and ESCRS Published by Elsevier Inc. 0886-3350/$ - see front matter 1507 doi:10.1016/j.jcrs.2011.03.038 ARTICLE Downloaded for Anonymous User (n/a) at MACHBA- Bar Ilan University from ClinicalKey.com by Elsevier on April 30, 2019. For personal use only. No other uses without permission. Copyright ©2019. Elsevier Inc. All rights reserved.