X-ray diffraction study of intraocular lenses explanted from eyes with uveitis

ABSTRACT

In some eyes where an intraocular lens [IOL] is implanted, intractable uveitis supervenes some time postoperatively. In order to determine whether structural changes in the polymer substance of these all-polymethylmethacrylate [PMMA] IOLs might contribute to such a chronic inflammatory reaction, we subjected five all-PMMA lenses, explanted at 6 to 12 months after extracapsular cataract surgery from five eyes of children aged between 3 and 9 years, to X-ray diffraction. The results were compared to those obtained by X-ray diffraction of 5 virgin [unused] IOLs of the same material. We found that there was evidence of crystallization within the previously amorphous material of the IOL. The degree of crystallization was greater, the longer the lens had remained within the eye. Further studies are required before a direct causal relationship between this crystallization and the postoperative chronic uveitis can be established