Opacification of artificial intraocular lens: An electron microscopic study

This paper describes the usefulness of electron microscopy in the investiga tion of the cause of opacification of an intraocular artificial lens (IOL), which affected both the anterior and posterior surfaces of the IOL. The ex planted lenses were remarkably similar and were uniformly opaque, with "ret iculated" surfaces under dissecting and ordinary light microscopes, TEM sho wed that the surfaces of the explanted lenses were irregular, and there was a layer of electron-dense granular deposits that extended to a depth of ap proximately 5 mum into the lens substance, SEM showed a "cerebriform" lens surface with elevated areas alternating with depressed crevices, which corr esponded nicely to the TEM appearance, Energy-dispersive x-ray analysis sho wed that the deposit was composed of calcium, oxygen, and phosphorus, which was later shown to be calcium hydroxyapatite by x-ray diffraction study. E lectron microscopy has proven to be an essential tool in the investigation of the cause of this mysterious outbreak of opacification of the surfaces o f the artificial lenses. Apart from directly visualizing the lens surfaces in a 2- and 3-dimensional manner, it also provides information on the eleme ntal composition of the deposit. Such findings enable the clinicians and ma nufacturer to search for the underlying pathogenesis of the abnormal calciu m hydroxyapatite crystals deposit.