[Is the decrease in corneal endothelial cell density in relation to age linear?]

Corneal endothelial cell density is an important factor in maintaining corneal transparency. It is generally assumed that corneal endothelial cell density continuously decreases from birth.

On healthy eyes of 191 subjects, images of the endothelium were taken using a specular endothelial microscope. Statistical analyses were done on corneal endothelial cell density, polymegatism and proportion of hexagonal cells in relation to age.

Extrapolated endothelial cell density at birth was 2957 cells/mm2. Using linear regression, the calculated annual cell loss was 7.58 cells/mm2. With age, polymegatism is increasing and the proportion of hexagonal cells is decreasing. Based on our data, the decrease in corneal endothelial cell density can be described in two different time periods: from birth until 35 years of age, endothelial cell density is considerably and continuously decreasing; after this corneal endothelial cell density is decreasing at a much slower rate.

Our data suggest that changes in the structure of the corneal endothelium are different in the first three decades of life compared to later decades. Reasons for this could be mechanical and physical influences, changing biochemical properties of the cornea and aqueous humor, or the embryological origin of the endothelium. This observation shows that age generally is not a deciding factor for intraocular surgeries.