Send to

Choose Destination
See comment in PubMed Commons below
Invest Ophthalmol Vis Sci. 2001 Feb;42(2):333-9.

Normal human keratocyte density and corneal thickness measurement by using confocal microscopy in vivo.

Author information

  • 1Department of Ophthalmology, Mayo Clinic and Mayo Foundation, Rochester, Minnesota, USA.



To quantify keratocyte density according to stromal region and subject age and to measure the thickness of the normal human cornea and its layers in vivo.


Seventy normal corneas of 70 subjects were examined by confocal microscopy (contact lens wearers were excluded). Ages of subjects ranged from 12 to 80 years, with 10 subjects per decade. Images were recorded by continuously focusing the optical section through the full-thickness central cornea. Two independent human observers manually identified bright objects (keratocyte nuclei) against a dark background to quantify keratocyte density. This method was validated histologically in three human corneas. Thickness measurements were obtained by plotting mean reflected light intensity in images against corneal depth, and calculating distances between intensity peaks that corresponded to corneal layers.


Full-thickness central keratocyte density was 20,522 +/- 2,981 cells/mm(3) (mean +/- SD, n = 69). The number of keratocytes in a full-thickness column of central stroma, which had a cross-sectional area of 1 mm(2), was 9624 +/- 1385 cells. Keratocyte density was highest in the anterior 10% of the stroma. Full-thickness keratocyte density was correlated with age (r = -0.62, P < 0.001), decreasing 0.45% per year. Central corneal thickness was 563.0 +/- 31.1 microm (mean +/- SD) and central epithelial thickness was 48.6 +/- 5.1 microm.


This is the first study to quantify regional keratocyte density comprehensively in vivo across a broad age range of normal human subjects. The method was acceptable to both subject and observer, and may prove useful for quantifying keratocyte density in patients with corneal disorders or after corneal surgery.

[PubMed - indexed for MEDLINE]
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Silverchair Information Systems
    Loading ...
    Support Center