Incidence and risk factors of late in-the-bag intraocular lens dislocation: evaluation of 140 eyes between 1992 and 2012

Abstract

Purpose: To identify risk factors for late in-the-bag intraocular lens (IOL) dislocation and estimate the incidence of this condition over a 21-year period.

Setting: Department of Ophthalmology, County Hospital of Värmland, Karlstad, Sweden.

Design: Retrospective cohort study and nested case-control study.

Methods: The medical records of eyes operated on for late in-the-bag IOL dislocation between 1992 and 2012 were reviewed. The annual incidence and cumulative risk were calculated.

Results: Of 140 eyes whose records were reviewed, 123 qualified for comparison (24 variables) with an equal number in a control group. The annual incidence varied between 0.00% and 0.08%. An increasing trend was found (P < .001). The cumulative risk 5, 10, 15, and 20 years after cataract extraction was 0.09%, 0.55%, 1.00%, and 1.00%, respectively, and was significantly higher (P < .001) in eyes that had cataract surgery between 2002 and 2012 than in those operated on between 1992 and 2001 (0.89% versus 0.39% at 10 years postoperatively) (P < .001). Calendar time (date) of dislocation was positively correlated with the duration of preceding pseudophakia (P = .005). Phacoemulsification time was longer in eyes with dislocation than in control eyes (P < .001). Other identified risk factors were pseudoexfoliation, zonular dehiscence, pseudophacodonesis, and increased axial length.

Conclusions: The increasing number of late in-the-bag IOL dislocations cannot be explained by the growing pseudophakic population only. The increase in the incidence was due primarily to the longer duration of pseudophakia in the population and to a greater dislocation risk with recent cataract surgery. The increase in life expectancy played a minor role. Long phacoemulsification time was a risk factor for dislocation.

Financial disclosure: No author has a financial or proprietary interest in any material or method mentioned.