3-D X-ray computed tomography in the analyses of intraocular lenses explanted because of postoperative opacification

Purpose: To use X-ray computed tomography (CT) –which describes the acquisition and reconstruction of 2-dimensional X-ray transmission images to create a 3D representation of a specimen –in the analyses of intraocular lenses (IOLs) explanted because of optical opacification occurring postoperatively. Setting: John A. Moran Eye Center, and Utah Nanofab, University of Utah, Salt Lake City, Utah. Design: Laboratory study. Methods: A hydrophilic acrylic and a silicone lens (the latter from an eye with asteroid hyalosis) explanted because of postoperative calcification, as well as a poly(methyl methacrylate) (PMMA) lens explanted because of snowflake degeneration underwent analysis under gross and light microscopy. Then, they were attached to an appropriate support and scanned under a Zeiss Xradia Versa X-ray microscope. After data acquisition, data segmentation was performed with a commercially available program to separate image data into components. Results: Morphology, size/volume, and specific location of calcified deposits on the surface or within the substance of explanted IOLs could be demonstrated by X-ray CT within the entire volume of each lens with high contrast and resolution. The PMMA lens showed multiple spaces/fissures in relation to Nd:YAG pitting of the optic, and what appeared to be sheets of delaminated PMMA material at different levels within the optic substance. Conclusions: The key benefit of X-ray CT is that it can be performed without physically sectioning the specimen. This preliminary study demonstrates that this technology can be potentially useful in the imaging and analyses of explanted, opacified lenses.