DOES THE DEPTH OF THE FOVEOLA CHANGE WITH AGE? MEASURMENTS WITH THE HEIDELBERG RETINA TOMOGRAPH (HRT)
N.E. Akbariyeh, P. Janknecht
The macular reflex diminishes with age. We hypothesized that the depth of the foveola might explain this phenomenon.
Patients, Methods: We examined 44 eyes of 44 normal subjects (mean age: 47 ± 20y). The foveola of each subject was scanned with the HRT (20 degree field, 1 mm scan depth, contour line radius 0.5 mm centered on the foveola). The median of the parameter "maximum depth" was plotted against the subjects age.
Results: The depth of the foveola increases with age up to 40y (subjects 10y to 20y: 0.041 mm; subjects 20 to 30y: 0.045 mm; subjects 30 to 40y: 0,040mm; subjects 40 to 50y 0,05mm). It then decreases until the age of 60y (0,033mm). Thereafter, the depth of the foveola stays more or less constant (0,035 mm). These changes are statistically significant (polynomial regression, p=0,0105).
Conclusion: The HRT data show that the depth of the foveola diminishes with age as does the foveal reflex. Our explanation for this is as follows: the foveola is a concave mirror the radius r of which is the foveolas depth. A concave mirror has a focal point at r/2. So, as the depth of the foveola decreases, the focal point moves towards the surface of the retina and becomes less pronounced.
Univ.-Augenklinik Freiburg, Kilianstr.5, D-79106 Freiburg