The Influence of Hormonal Changes During Pregnancy on Corneal Biomechanics in Humans

Study Overview
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Brief Summary
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The intraocular pressure in the human bulbus requires that the wall of the eye shows a certain (bio)mechanical strength. The human cornea represents the anterior portion of this wall. Since several years, there is a growing interest in the ophthalmological community for identifying factors modulating the biomechanical stability of the human cornea. Reasons are twofold: advances in keratoconus research and the increasing numbers of refractive laser surgery procedures with (correspondingly) increasing numbers of complications due to non-respecting the limits of corneal biomechanics. There is evidence that oestrogen, but also thyroïd hormone changes have a major impact on corneal biomechanics. A number of recent observational studies have reported on keratoconus and refractive laser surgery patients with decompensating biomechanics during pregnancy. Both hormones also show physiological changes during pregnancy and little is known about the impact of these physiological changes on the human cornea. The aim of this study is to establish baseline values for physiological changes in the human cornea during pregnancy.

Official Title
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Influence of Pregnancy-related Hormonal Fluctuations on Corneal Biomechanics in Humans

Conditions
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Pregnancy

Intervention / Treatment
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* Device: Ocular Response Analyzer
* Device: Scheimpflug measurement
* Other: Blood sample


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Older than 18 years Pregnancy confirmed by echography Before gestation week 14 Exclusion Criteria: Pre-existing corneal disease Previous eye surgery Inability to understand the nature of the study Patient with legal guardian

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Device: Ocular Response Analyzer|To measure corneal biomechanics, specifically corneal hysteresis (CH) and the Corneal Resistance Factor (CRF). The devise measures in a non-contact manner, by analyzing the deformation of the cornea upon a defined pulse of air.|
|Device: Scheimpflug measurement|A Scheimpflug camera will be used in a non-contact manner to assess topographical data from the anterior and posterior corneal surface as well as detailed data on corneal thickness.|
|Other: Blood sample|A blood sample will be taken at 6 months after surgery to determine the levels of several hormones. The blood needed to détermine hormone levels during pregnancy will be acquired during the routine examinations that are performed during pregnancy. Here, blood is taken routinely and an additional volume is taken for the purpose of this study.|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Correlate oestradiol and TSH plasma changes with changes in corneal CRF and CH and topographical changes | 3 examinations during pregnancy (gestation week 10-14, 20-26, and 36-40) and one visit at 6 months after pregnancy | 15 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Cornea, biomechanics, pregnancy, keratoconus, refractive surgery