Dislocation, decentration concerns for foldable IOLs,survey finds

San Francisco-The most common complicationsinvolving foldable IOLs and requiringexplantation showed little changeover the past 2 years, according to an annualsurvey sent to members of the AmericanSociety of Cataract and RefractiveSurgery (ASCRS) and the European Societyof Cataract and Refractive Surgeons(ESCRS).

Of those surgeons who received theform, 117 surgeons responded. The investigatorstook into consideration the designof the IOLs (one-piece plate-type IOLs,one-piece IOLs with haptics, three-piece IOLs, and multifocals) and the IOL materials(silicone, hydrophobic acrylic, hydrophilicacrylic, and collamers).

“With plate-type silicone IOLs, dislocation/decentration occurred even morecommonly-in more than 90% of casesrequiring explantation.”The three-piece hydrophobic acrylicIOLs have a mix of complications associatedwith them; however, decentration/dislocationare the reasons that about 48% ofthe IOLs are explanted. Incorrect lenspower, glare, and optical aberrations areother reasons that occur less frequentlywith that IOL type.

The one-piece acrylicIOLs with haptics also are associated witha mix of complications,with incorrect lenspower, decentration, and dislocation themost common reasons for explantation.

The hydrophilic acrylic IOLs and theone-piece hydrogel IOLs are in a class bythemselves, in that they are associated withdifferent complications compared with theothers.

Calcification or damage to the IOLin the three-piece designs is the most commonreason that these lenses are removed.The one-piece hydrogel IOLs sustain damage,because, Dr.Mamalis explained, theselenses are more fragile than the others.The complications with multifocal siliconeIOLs are about evenlysplit between dislocation/decentrationand incorrect lenspower.

In commenting onthese findings, Dr. Mamalissaid that preoperatively thereis a substantial loss of visualacuity in many of these patients.“The important thing isthat when we look at the visualacuity after the IOL hasbeen explanted, the results areusually very good,” Dr. Mamalissaid.

“Most of the patients have goodvision, with the exception of some withthe hydrophobic acrylic IOLs. The reasonfor decreased vision postoperatively inthese patients was unclear.“Dislocation/decentration are by far themost common reasons for removing foldableIOLs in the most recent survey,” hesaid. “That was followed by incorrect lenspower and damage to the IOL necessitatingremoval.”

Disturbing trends

Investigators have noticed some continuingand disturbing trends over the 8 yearsof this survey, but also some differences.“Because the three-piece silicone IOLshave been evaluated in all of the surveys,when we looked at them we found that therate of dislocation/decentration has increasedmarkedly,”Dr.Mamalis pointed out.“The other complications, such as damageto the IOL and incorrect lens power, havebeen decreasing with time.”The three-piece hydrophobic acrylic IOLsare showing a similar trend with an increasein the rate of dislocation/decentration withtime.

Glare, incorrect lens power, and visualaberrations have decreased somewhat.Glare and optical aberrations were complaintswith the early hydrophobic lenses,but the incidence of these complications isdecreasing.With the one-piece plate siliconeIOLs, dislocation/decentration are alsoslowly increasing with each survey.