Structure and function of the corneal endothelium in diabetes mellitus type I and type II
L. I. Larsson, W. M. Bourne, J. M. Pach and R. F. Brubaker
Department of Ophthalmology, Mayo Clinic, Rochester, Minn., USA.
OBJECTIVE: To measure and compare corneal endothelial morphologic
characteristics and function in subjects with diabetes mellitus types I and
II. DESIGN: Forty-nine patients with diabetes mellitus type I and 60
patients with diabetes mellitus type II were recruited from the active
practice of the Mayo Clinic, Rochester, Minn. Thirty-one normal subjects,
divided by age into two overlapping groups of 20 each, served as controls.
Corneal endothelial permeability and corneal autofluorescence were measured
by fluorophotometry. Central corneal endothelial photographs were taken
with a wide-field specular microscope, which also measured the corneal
thickness. RESULTS: Neither the type I nor the type II diabetics differed
from their controls in endothelial permeability and endothelial cell
density. The type I diabetics had polymegethism, pleomorphism, increased
corneal thickness, and increased corneal autofluorescence compared with
their controls. Similar measured values were found in the type II
diabetics, but they did not differ significantly from those of their
age-matched controls. The type II diabetics were older than the type I
diabetics, and the older control group showed changes similar to those seen
in the diabetics; these changes were presumably associated with aging. The
severity of retinopathy was significantly correlated only with corneal
autofluorescence. CONCLUSION: The corneas of patients with type I diabetes
mellitus exhibit abnormalities in endothelial cell morphologic
characteristics and corneal autofluorescence. The changes resemble those
that occur with aging in normal subjects, making them difficult to discern
as abnormal in type II diabetics, who are usually older. We found no
abnormalities in endothelial permeability in either type I or type II
diabetics.
