Study links hydrophilic acrylic IOL opacification with calcium phosphate crystallite deposition

The authors of this laboratory study examined 30 hydrophilic acrylic IOLs explanted due to gradual opacification and reduced visual acuity to learn more about the causes of lens opacification. The explanted IOLs, which came from 29 patients implanted with them between one and 12 years earlier, were studied using scanning electron microscopy equipped with a microanalysis probe, confocal microscopy, X-ray diffraction and Fourier transform infrared for the identification of the substances involved in the opacified lenses.

The results indicated that calcium phosphate crystallite deposition may be responsible for lens opacification. Aqueous humor analysis showed supersaturation of octacalcium phosphate and hydroxyapatite, the predominant crystalline deposit form responsible for lens opacification. The authors said that calcium phosphate aqueous humor supersaturation may be related to IOL opacification, although the exact mechanisms of this process remain unknown.

Calcium from residual cataractous lens material and inadequate cortex cleaning from the capsular bag may increase the likelihood of calcium deposit formation, the results also suggested. The authors noted that some materials used to make IOLs may promote calcium phosphate formation on the lens surface or interior.

A related article in the same journal issue recommended a multidisciplinary approach to the further investigation of hydrophilic acrylic IOL calcification.