The efficiency of X-ray microanalysis in low-vacuum scanning electron microscope: deposition of calcium on the surface of implanted hydrogel intraocular lens (IOL).

To examine the calcification of implanted hydrogel IOL by X-ray microanalysis, we compared conventional transmission electron microscopy (TEM) with low-vacuum scanning electron microscopy (SEM). We also compared metal coating with non metal coating in low-vacuum SEM. Calcification of IOL showed deposits which were located in the superficial substance of lens. In conventional TEM and X-ray microanalysis, calcium, phosphate and silicon were detected in the deposits. In low-vacuum SEM, the deposits detected in metal coating were calcium, phosphorus, sodium and magnesium, but not silicon. However, in non metal coating, the deposits contained not only calcium, phosphorus, silicon, sodium and magnesium, but also fluoride, aluminum and argentums. It was concluded that in conventional TEM where a specimen is fixed and dehydrated in ethanol, various elements leak out. On the other hand, when a specimen is coated with carbon and gold palladium for SEM, light elements might not be detected in X-ray microanalysis. Low-vacuum SEM preparation does not need metal coating and low-vacuum SEM appears to provide a highly efficient method for X-ray microanalysis.