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D. Descovich, M.-H. Roy-Gagnon, H. Massé, M. R. Lesk; Heritability of Pulsatile Ocular Measurements, IOP and Choroidal Blood Flow, and of Corneal Hysteresis. Invest. Ophthalmol. Vis. Sci. 2010;51(13):5564.
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© ARVO (1962-2015); The Authors (2016-present)
Pulsatile phenomena in the eye can be used to estimate ocular rigidity using the Freidenwald Equation. We studied the heritability of the ocular IOP pulse amplitude (OPA) and of the pulsatility of choroidal blood flowmetry measurements, as well as the heritability of a direct measure of corneal biomechanical properties, corneal hysteresis.
Measurements were performed on 50 pairs of first-degree relatives (29 parent-offspring and 21 sibling pairs). OPA was determined with the Pascal Dynamic Contour Tonometer. Choroidal blood velocity (VEL), volume (VOL) and flow (FLO) were measured in the sub-foveolar choroid using single-point laser Doppler flowmetry (Oculix). The pulsatility of VEL, VOL and FLO was determined with automated software using, for example, the formula (systolic VEL- diastolic VEL) / systolic VEL. Corneal hysteresis was determined using the Reichert Ocular Response Analyser (ORA). We calculated familial correlation coefficients for each type of relative and overall heritability estimates with the S.A.G.E. and SOLAR software, respectively.
CH showed significant parent-offspring and sibling correlations (0.55 and 0.67, respectively, p<0.01). OPA showed high sibling correlation (0.56, p<0.01) but no parent-offspring correlation even after age adjustment. However, the sibling correlation was mainly driven by an extreme value. No significant heritability could be detected for the pulsatility of choroidal flowmetry measures. For comparison purposes, parent-offspring and sibling correlations were 0.56 and 0.21, respectively for IOP as measured with the Pascal and 0.46 and 0.38 for IOPg measured with the ORA. Heritability estimates will be performed.
As shown previously, corneal hysteresis and IOP measurements are heritable. We found some heritability of OPA, but a larger sample size might be required to confirm this. Pulsatile choroidal flowmetry measurements were not significantly heritable in this sample.
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