In The Name Of GOD
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Transcript of 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