Transcript Clinical Specular Microscopy

F.Fazel
MD
The corneal specular microscope is a reflectedlight microscope that projects light onto the
cornea and images the light reflected from an
optical interface of the corneal tissue, most
typically the interface between the corneal
endothelium and the aqueous humor.
 Although specular microscopes have been used
primarily to evaluate the corneal endothelium,
the corneal epithelium and stroma as well as the
crystalline lens can also be visualized and
evaluated.

Identifies abnormal endothelial
structures.
 Cell Conformation.
 Miscellaneous Structures



The central endothelial cells of young people with
normal eyes are hexagonal and approximately the same
size; the distribution of cell area is approximately
Normal (Gaussian). With age, the average cell area
increases, the cellular pattern becomes distinctly
pleomorphic, and the cell size distribution becomes
skewed toward larger cell areas. In young people with
normal eyes the cell side lengths are all roughly equal.
In older individuals, the side lengths lose this regularity
and one sees an increasing variation.
As in the case with changes in endothelial cell size,
alterations in shape have not been directly related to
changes in the physiologic function of the affected cells.
cell size (cell area or cell density).
 polymegathism (variation of cell size such as
coefficient of variation of mean cell area).
 pleomorphism (variation of cell shape such as
percent of hexagonal cells or coefficient of
variation of cell shape).
 Etc…

mean cell area .
 cell density or cell count.
 Cell area has been expressed in units of µm²
per cell and cell density in units of cells per
mm².


Endothelial wound healing mechanisms:
sloughing & sliding, coalescence, and
mitosis(in successful graft rejection
only)
Mean cell size is150-350 micrm2
 From birth to adolescence the cell density
decreases rapidly.
 From age 20 through approximately age 50,
endothelial cell density seems to be relatively
stable.
 . After the age of 60, cell density decreases
significantly in most people

350,000 cell / cornea
 at birth, 3000 - 4000 cell / mm2
 at middle age, 2500 cell / mm2
 at old age, 2000 cells / mm2

In EDC between 300-700 cll per mm2 corneal
edema ocures.
 Cell loss 0%-30% in anterior segmen surgery.
 At least EDC of 1000-1200 is needed for safe
AC surgery.
 Polymorphism and polymegatism above 0.40
or hexagonal shape less than 50% is abnormal
and risk.


Cornea guttate, characteristic for Fuch’s
endothelial dystrophy, are focal accumulations
of collagen on the posterior surface of
Descemet's membrane that apparently are
formed by stressed or abnormal endothelial
cells; they appear as warts or excrescences of
Descemet's membrane and can easily be seen
with specular microscopy. Cornea guttate also
occur as a result of aging and corneal
inflammation.
Density
 Polymegathism:Coefficient of variation(mean
cell area/standard deviation of mean cell
area)normally less than 0.30.
 Percentage of hexagonal cell.
 Pleomorphism(cell shape).

Yoji Kushino
TOMEY CORPORATION
★Built in analysis software
1 Cell number
2 Cell Density （pcs/mm２）
3 Cell area （Average、maximum、minimum）
4 Standard deviation
5 Coefficient of variation
6 Histogram(Cell area and cell stroke count)
7 Percentage of hexagon cell
8 Topography map