Calcification of intraocular hydrogel lens: evidence of dystrophic calcification

Abstract

This study confirms and extends the previous reports of five cases of calcification of hydrogel intraocular lenses. The exact mechanism of calcification remains obscure but evidence suggesting cell-mediated dystrophic calcification of the lens surface is presented. Further study is required to monitor the incidence and development of this phenomenon.

Microscopic and spectroscopic investigation of an explanted opacified intraocular lens

“…Our findings confirm that the grains deposited on the central part of the intraocular lens contain hydroxyapatite and this could be due to calcification of the remnants of degenerate epithelial cells associated with the lens surface [9]. Because it was demonstrated that lens epithelial cells can act as phagocytes, i.e.…”

“…The size and shape of the deposited grains suggest, to some extent, a similarity with cells. It was already considered the possibility that these depositions represent dystrophic calcification of the remnants of degenerate epithelial cells associated with the lens surface [9]. With respect to this, we could explain the relatively high nitrogen content determined by XPS in the calcified grains.…”

“…Even though the exact mechanism of calcification was not identified, it was shown that the calcification of the lens surface is a cellmediated process and the deposits are associated with what appear to be traces of cellular material including basement membrane and plasmalemma [9].…”

“…Many papers reported that the calcification takes place on or within the lenses, or both [7], or just beneath the surface [8][9][10], and several mechanisms were proposed to explain the experimental observations on explanted intraocular lenses [10,11]. Notwithstanding the relatively high number of studies, the processes contributing to opacification are still under debate.…”

Spectral analysis and comparison of mineral deposits forming in opacified intraocular lens and senile cataractous lens

“…Although the exact cause of opacification and/or calcification for both samples is yet unknown, several factors may be proposed as follows: (1) oxidative stress in the cell-mediated mechanism such as peroxidative reactions within the cellular matrix of the lens tissues; (2) patient's associated conditions including the age, medical history, risk factors and aetiology, clinical features, pathogenesis, prognosis and treatment; (3) production processes of the lens manufacturer during polymer selection, component, manufacturing techniques and processes, and packaging; (4) surgical settings and techniques of clinicians and adjuvants used; (5) environmental and other internal factors [37][38][39][40][41].…”