In The Name Of GOD

In The Name Of GOD

CLINICAL SPECULAR MICROSCOPY

F.FazelMD

The corneal specular microscope is a reflected-light 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.

Optic Principles

Optic Principles

Identifies abnormal endothelial structures.

Cell Conformation. Miscellaneous Structures

Qualitative Morphometric Analysis of Specular Images

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 Conformation

Normal corneal endothelium.The endothelium is usually made up of hexagonal, regular, cells which are roughly uniform in shape.

Cell conformation

Miscellaneous Structures

 Polymegathism

Polymegathism refers to variation in cell sizes

Pleomorphism  (also known as polymorphism) refers to variation

in cell shape

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…

Quantitative Morphometric Analysis of Specular Images

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 cell size

Fixed Frame Analysis of Cell Size

Specular Microscopy : Variable Frame Analysis

Endothelial wound healing mechanisms: sloughing & sliding, coalescence, and mitosis(in successful graft rejection only)

In Vivo Findings of Specular Microscopy

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

Aging

350,000 cell / cornea at birth, 3000 - 4000 cell / mm2

at middle age, 2500 cell / mm2

at old age, 2000 cells / mm2

Aging

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.

Clinical Applications

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.

Corneal guttae

Specular microscopy with slit lamp

guttae

Endothelial change after AC IOL implantation

Guttae

Guttata

Graft Rejection

Posterior polymorphous dystrophy

Contact Lens Wear

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).

Summery(important parameters)

First specular microscope

EM-3000 Specular Microscope

Yoji Kushino

TOMEY CORPORATION

★Built in analysis software

1 Cell number

2 Cell Density 　（ pcs/mm ２）

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

EM-3000 Specular Microscope

Thanks For Your Attention