| Part IInvestigation Of Layered Human Retinal Cell With Excimer Laser Cutting Technique And Comparaing To Photos Taken By The Adaptive Optic SystemAimsTo investigate the distribution of human retinal cells layer by layer using laser cutting technique along with eccentricity , in order to provide histological certification for what was observed by the optic adaptive system.Methods1) 20 human eye caps with the cornea removed by trephine were investigated. 18 of them were fixed in 4% polyformaldehyde and remaining 2 efixed in 10% neural formaldehyde for 1-4 weeks. Then the retinal mounts were prepared according to the method provided by Curcio in 1987.2)The central part of the retinal mounts were observed with the differential interference contrast microscope.At first the inner segments of photoreceptors were observed. Six samples in the region of fovea were taken and the samples overlapped each other in part. Then the residual retina was observed along its horizontal axiae. lmm from the foveoea , the interval for each sample was 300/xm, and from then on up to the peripheral the interval was increased to every lmm.3) When the observation of inner segment has been completed, the retina was cut with 193nm excimer laser using PTK model with different depth. When the photoreceptors faced up, the depth of cut was 50um,70um,90um,110um,when the ganglion cell faced up,the depth was 40um,60um,80um,130um,160um. 4). The thickness of the remainder retina was observed with OCT. 5). The livers of 2 healthy SD mouse were fixed into 10% neural formaldehyde for 48hrs, then cut them into two pieces with the size of 12x 12x4mm. Put the residual retina after laser cutting inside 2 pieces of liver, mounted the whole specimen with paraffin wax, and made slice up. Then stained them with HE. Then the slices were observed with light microscope to investigate the relationship between the laser parameter applied and thickness of the remainder retina.6). According to the method applying for the previous step, the posterior polar of the retina was cut with the same laser, the depth is 90um. Then the remainder retina were stained with haematoxylin to observe the outer nucleus layer using the samemethod indicated in step 2. When the observation of the layer was finished, turned the mount over put the retinal ganglion cell up and cut with laser with depth of 40um to obvserve the ganglion cell layer. When this was completed cutting with laser was continued until 160um was reached to observe inner nucleus layer.7). Counted the number of cells m. At the foveaoa , the size of sample window was selected with the highest peak density. As to the other positions, the counting window on the photo were all at the size of 50x70um. When the cells located at the edge of the frame, only the cells on the edge of left and superior werecounted not for that on the edge of inferior right.Results1.The thickness of the reminder retina after laser cutting were measured by OCT. Some of the mounts showed no change in thickness as comparaed to edgiacent retina. Thinner was found in others. When the parameter of depth was 60um, the retina only show 20-40um thinner, when the depth was 90um, the retina show 40-60um thinner, big deviation was present.2.When looked at the slices, when the photoreceptor layer was up with the cutting depth of 60-80um, part of inner segment of the photoreceptor were left in all mounts. When ganglion cell was up with the depth of 40um, part of nerve fiber layer were left, when the depth was 160um, large variation among the thickness of the remainder retina existed. Some specimens were damaged and it is difficult to stain and observe them. There were no dislocation and dispersion of the cells, no morphology change.3.Inner segment of the cones: 1) High peak cell density in a small area in the foveaoa, ranges from 134000/mm2 to 267000/mm2, average was 198090/mm2. 2) Then it decreases steeply. At the eccentricity of lmm, the density decreased to 21466/mm . 3)High variation among individuals was existed at the foveaola, where...
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