SEP 26, 2012
The authors report on three cases in which a distinct type of calcification confined to the pupillary area occurred in hydrophilic IOLs in complicated, traumatized eyes with a history of intraocular gas use.
After explantation, the lenses were examined with environmental scanning electron microscopy imaging and X-ray energy-dispersive spectroscopy.
All three eyes had central areas of IOL opacification over the pupillary zone confined to the anterior IOL surface. Analysis of the lenses showed that opacified areas were composed of calcium and phosphate.
The authors conclude that the areas of opacification in all three IOLs were attributable to calcification. They note that there have been several other recent reports of secondary IOL calcification with similar characteristics. The IOLs in this article and the other similar reports are either Rayner or Bausch and Lomb Akreos IOLs. Both types are hydrophilic polymers with 26 percent water content.
The authors postulate that the presence of intraocular gas in the anterior chamber could induce changes in the surface of the central part of the hydrophilic IOL with the pupil margin limiting the area affected. This may increase the IOL's permeability to protein or other factors that leach into the anterior substance of the IOL and then act as a nidus for dystrophic calcification. Tamponade from the gas could also drive calcium-rich aqueous into the hydrophilic lens, stimulating calcification.
However, they say that further experimental study is needed to clarify the process and confirm the possible role of intraocular gas.