Purchase this article with an account.
O. Touzeau, E. Costantini, T. Gaujoux, E. Basli, R. Kopito, L. Laroche, V. M. Borderie; Optical and Geometric Symmetry Between Fellow Corneas. Invest. Ophthalmol. Vis. Sci. 2009;50(13):5090.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To assess symmetry between fellow corneas in a normal population
Both corneas of 300 patients were prospectively analyzed by means of Orbscan topography and ultrasonic pachymetry. The enantiomorphism (mirror-image symmetry) of directional data (i.e., astigmatism axis, location of the thinnest point) was quantified by indices which were calculated using rectangular coordinates (x,y).
Fellow corneas showed no significant differences (p>0.05) and strong correlation (r≥0.90 p<0.001) for pachymetry and for main optical and geometric properties of the anterior corneal surface. Central ultrasonic pachymetry showed the smallest difference between fellow eyes (1.2% or 6.6 µm) and the strongest correlation (r=0.97 p<0.001). The difference between fellow eyes increased with age (r≥0.23 p<0.001) Corneal astigmatism showed higher enantiomorphism than ocular (subjective) astigmatism (difference between mirror symmetry = 17° vs 27° p<0.001). The degree of enantiomorphism of astigmatism increased significantly with the magnitude of astigmatism (r=0.43 p<0.001). Corneal thickness showed a high degree of enantiomorphism: the location of the thinnest point was in the same quadrant for both eyes in 85% of cases. The degree of enantiomorphism of the cornea decreased significantly with age (pachymetry: r=0.44 p<0.001; astigmatism: r=0.21 p<0.001). Posterior corneal data showed weaker correlation with the fellow cornea (r≤0.72 p<0.001) than did the anterior corneal data.
The human cornea exhibits a high degree of symmetry and enantiomorphism with the fellow eye for the main geometric and optical properties. However, the symmetry between fellow eyes decreases with aging.
This PDF is available to Subscribers Only