Dislocation, decentration top reasons for IOL explantation

January 1, 2006

Lisbon, Portugal—The results of the 7th annual survey on foldable IOLs indicate that dislocation and decentration are the most common reasons for lens explantation, with incorrect lens power the next most important factor.

Nick Mamalis, MD, reported the results of the survey, which was conducted by the American Society of Cataract and Refractive Surgery (ASCRS) and the European Society of Cataract and Refractive Surgeons (ESCRS), at the recent ESCRS annual meeting in Lisbon, Portugal.

The survey questionnaire considered the patient signs and symptoms; type of IOL that was removed; preoperative and postoperative visual acuity; and the complications that led to removal. The IOLs considered were the one-piece plate type, one-piece IOLs with haptics, three-piece IOLs, and multifocal IOLs. The IOL materials were silicone, hydrophilic acrylic, and hydrophobic acrylic, Dr. Mamalis explained. He is the director of the Intermountain Ocular Research Center, and professor, Moran Eye Center, Department of Ophthalmology, University of Utah, Salt Lake City.

The most common problems that precipitated removal of three-piece silicone IOLs were, in descending order, dislocation/decentration, incorrect lens power, glare, and visual aberrations.

The plate silicone IOLs were "overwhelmingly" explanted because of dislocation and decentration.

For hydrophilic acrylic IOLs, however, the major complication was calcification. For multifocal silicone IOLs, glare and optical aberrations were the primary reasons for removal, Dr. Mamalis reported.

"I can summarize the findings by saying that dislocation and decentration were the most common reasons for explanation followed by incorrect lens power. Calcification in this survey applied exclusively to hydrophilic acrylic IOLs on the surface and within the substance of the lens itself. Glare and optical aberrations were seen with all types of lenses. IOL damage upon insertion is being seen less frequently, as surgeons and nurses become more skilled at loading and injecting the implants," Dr. Mamalis said.

The key point to consider is the way in which the complications can be avoided, he emphasized.

"First, there is no substitute for adhering to excellent surgical technique. Continuous curvilinear capsulorhexis with capsular bag fixation of the IOL should decrease the problems with decentration and dislocation.

"Work is ongoing on technologies for more accurate measurement to choose the IOL power. We need ongoing vigilance about new IOL materials as they are developed," Dr. Mamalis said.

This study is ongoing. Complications with IOLs can be reported on the ASCRS and ESCRS Web sites.