EyeWorld Asia-Pacific December 2014 Issue

25 EWAP CATARACT/IOL December 2014 by Tony Realini, MD, MPH What causes IOL implant opacification and glistenings? These complications can be frustrating for both the surgeon and the patient P erhaps this has happened to you. You’ve examined the cataract patient and deemed her an ideal candidate for surgery, selected the appropriate IOL, and performed the surgery without complications. The patient is thrilled, and so are you. Until glistenings—or worse, frank opacification—of the IOL appear in the postoperative period. We assume that the IOLs we implant will stay clear for the patient’s lifetime, but this is not always the case. When these late complications do occur, they can be frustrating for both the surgeon and the patient. Glistenings Glistenings have been reported since the introduction of acrylic IOLs and are fairly common. The prevailing theory of their formation is that small voids in the IOL during manufacture become filled with fluid after implantation, likely facilitated by the change from room temperature to the higher temperature inside the eye. These voids may be potential spaces prior to implantation and cannot be seen until after surgery. “These fluid-filled microvacuoles within the IOLs have been reported since the 1990s,” said Lémy Agbessi, MD , Bordeaux, France. “Their impact on visual function remains controversial.” Most studies have failed to demonstrate negative effects on visual acuity outcomes. Dr. Agbessi conducted a study to evaluate the impact of glistenings on visual function. Her group reviewed the records of patients undergoing cataract surgery with implantation of a hydrophilic acrylic multifocal IOL. “Glistenings occurred in 65% of the IOLs,” she said. Her study included 102 eyes of 51 patients who developed glistenings postoperatively. Of these, 32% were graded as mild, 21% as moderate, and 47% as severe, using image analysis software on slit lamp photographs. When they compared mean distance and near visual acuity across these severity groups, no differences were observed. Likewise, Dr. Agbessi said, reading speed, aberrometry, and contrast sensitivity were comparable between groups as well. The only difference observed was in glare severity, which was statistically significantly worse in the eyes with severe glistenings compared to the mild and moderate glistenings groups (p=0.01). Glare was assessed by patient report using the National Eye Institute Refractive Error Quality of Life instrument. “The only predictor of glistenings was IOL power,” Dr. Agbessi said. Glistening severity increased with increasing lens power (p=0.04), she explained. Neither time from surgery nor any demographic attributes of patients correlated with the development or severity of glistening. Opacification Far worse than glistenings is the rare occurrence of frank IOL opacification. This complication has been reported with both modern foldable IOLs and even older PMMA IOLs. It appears to be most common, however, with hydrophilic acrylic IOLs. Wei Ni, MD , Beijing, China, recently conducted a histological study of 6 hydrophilic acrylic IOLs A study has shown that glistenings occurred in 65% of IOLs following cataract surgery. Source: Karl Brasse, MD continued on page 26