Abstract
Purpose: :
To analyze the influence of age on corneal thickness in a normal population.
Methods: :
We prospectively recorded the central and peripheral corneal thickness in 500 healthy eyes (including ametropia) from 250 patients aged 9 to 97 years. Corneal thickness, in the central zone and in eight peripheral zones, and the thinnest point were analyzed using Orbscan data. In addition, central corneal thickness was measured using ultrasonic pachymetry. Mirror-image symmetry (enantiomorphism) of the thinnest point of fellow eyes was quantified by an index which was calculated using rectangular coordinates (x,y). The different characteristics of the pachymetry were correlated with age and compared according to 3 age-related groups.
Results: :
Central corneal thickness was correlated with age (r=+0.28 p<0.001) and it significantly increased by 6.2 µm per decade (<30 years: 539µm; 30-60 years: 545µm; >60 years: 572µm p<0.001). The correlation with age was not homogenous for peripheral cornea (r: -0.21 to +0.14). The thinnest zone (inferotemporal) increased by 6.2 µm per decade, whereas the thickest zone (superonasal) decreased by 3.2 µm per decade. The distance between the thinnest point and the apex increased with age (r=0.36 p<0.001; <30 years: 0.72mm; 30-60 years: 0.75mm; >60 years: 1.08mm; p<0.001), while the location of this point remained uneffected by age (p=0.92; inferotemporal: 74%, superotemporal: 15%, inferonasal: 8% and superonasal: 3%). The difference in central pachymetry between fellow eyes increased with age (r=0.21 p=0.001; <30 years: 6.8µm; >60 years: 9.8µm p=0.003:). The enantiomorphism of the thinnest point decreased significantly with age (r=0.40 p<0.001).
Conclusions: :
Central corneal thickness statistically increases with age whereas both the degree of symmetry and enantiomorphism decrease. Finally, most characteristics of corneal thickness are age-related.
Keywords: cornea: clinical science • topography • aging