A 3-piece hydrophobic acrylic intraocular lens (IOL) was explanted from the left eye of a 68-year-old patient 26 days after implantation because of glistenings that impaired fundus visualization. The effect of the glistenings on the patient's visual function was unknown because of retinal issues. The fluid-filled vacuoles within the IOL optic were different from those described in clinical and experimental studies. They were initially observed 4 days after surgery and were very large. The glistening formation was reproduced experimentally by immersing the explanted IOL in balanced salt solution at 37 degrees C and analyzing the IOL at room temperature for up to 2 weeks. An IOL of the same design was used as a control. Although both IOLs were subjected to the same laboratory conditions, gross and light microscopic analyses confirmed that the pattern of the glistening formation differed between them. Analyses of the explanted IOL and the control IOL under differential scanning calorimetry, as well as by attenuated total reflection Fourier transform infrared spectroscopy, revealed slight differences between the IOLs.