Abstract
Purpose: :
The present study is a continuation of the subcutaneous implantation study evaluating intraocular lens (IOL) calcification, which the author presented at ARVO 2006. The goal of the continued analysis was to determine whether the calcium and phosphorus deposits were only on the surface of the IOLs or if they were embedded in the IOLs.
Methods: :
Commercial IOLs were implanted subcutaneously in New Zealand White rabbits for 70 ± 2 days per Buchen et. al., 2001. Hydrophilic IOLs included the Akreos Adapt and Fit, Acri.Smart, ThinOptX, Rayner 570C, and Hydro view IOLs. Hydrophobic IOLs included the acrylic AR40e IOL; and the silicone Clariflex IOL. After explantation, scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDX) analysis, the samples were subjected to atomic force microscopy (AFM) to determine the surface profile and topography.
Results: :
AFM analysis of selected hydrophilic IOLs demonstrated a change in surface topography of up to 2.55 µm in depth with "multi-nucleated" calcium and phosphorus structures ranging in diameter from 5 to 60 µm. Analysis revealed no signs of calcification in the hydrophobic acrylic or silicone IOLs.
Conclusions: :
In the study presented at ARVO 2006, 5 of 6 hydrophilic IOLs showed obvious signs of calcification as demonstrated by SEM and EDX analysis. The current analysis demonstrates that the presence of calcium and phosphorus in the hydrophilic IOLs is not only a surface phenomenon. AFM demonstrates that the calcium and phosphorus structures are embedded in the IOLs.
Keywords: intraocular lens • calcium