Light scattering and light transmittance in a series of calcified single-piece hydrophilic acrylic intraocular lenses of the same design

PURPOSE: To evaluate light scattering and light transmittance of loflex hydrophilic acrylic intraocular lenses (IOLs) explanted because of clinically significant opacification secondary to calcification. SETTING: John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. DESIGN: Experimental study. METHODS: Seven explanted and 8 control loflex IOLs were studied. Gross and light microscopy of all the IOLs were performed. Light scattering was measured with a Scheimpflug camera, and light transmittance was assessed with a spectrophotometer. Analyses were performed at room temperature in the hydrated state, and findings of the explanted and control IOLs were compared. RESULTS: Light scattering was 219.71 computer compatible tape (CCT) +/- 2.62 (SD) for explanted IOLs and 4.75 +/- 2.50 CCT for controls. The mean light transmittance in the visible light spectrum was 75.94% to 87.25% for explanted IOLs and 97.54% to 98.97% for controls. The most striking finding was variable degrees of light transmittance between 290 nm and 350 nm (ultraviolet-A and B radiation) in the explanted and control IOLs with expiration dates in 2009/2010 but 0% transmittance in this region in all controls with expiration dates in 2011/2012. CONCLUSIONS: Light scattering was extremely high and transmittance was significantly reduced in calcified IOLs. Differences in transmittance observed in the 290 to 350 nm region between IOLs with different expiration dates were related to use of different hydrophilic acrylic raw material suppliers in the manufacture of the IOLs, highlighting the complexity of IOL calcification investigations.