Overall winner of ESCrs Video Competition presents challenge to IOL manufacturers

Hiroyuki  Matsushima, Japan, received First Prize overall in this year’s Video Competition for his presentation, “Opacification of intraocular lenses”, which provides an explanation for a recently observed phenomenon wherein IOLs themselves become opacified over time, in some cases to the point that they must be removed and replaced. 

Opacification occurs in both hydrophilic and hydrophobic IOLs. However, the opacification is of a markedly different character in the two types of lenses. 

In hydrophilic IOLs, surface opacity is clearly visible under slit-lamp examination, the fundus is only faintly visible under transillumination and patients tend to complain of poor vision, leaving lens exchange the only option for recovering vision. 

In hydrophilic IOLs, on the other hand, slit-lamp examination shows thin bands of opacity on the front and back of the lens, but the opacification is barely visible under transillumination and the fundus is clearly visible. Moreover, patients tend to complain much less about their vision and lens exchange is seldom necessary. 

When Dr Matsushima and his associates examined the surfaces of explanted opacified lenses with scanning electron microscopy, they observed dense deposits of calcium on the surface of the hydrophilic IOLs, but the surface of the hydrophobic IOL had no deposits. Examination of a cross-section of the hydrophobic lens using a cryogenic FIB scanning electron microscope revealed nanometre-sized water particles distributed widely throughout its outer layers. 

The properties observed in the hydrophobic IOLs suggest that the opacification results from a phenomenon called water phase separation,which in turn results in the supersaturation of the lens material.