[Opacification of a hydrophilic acrylic intraocular lens after DMEK : A material analysis]

Abstract

Objective: Calcification of a hydrophilic intraocular lens (IOL) is a rare complication. We report on the analysis of an opacified IOL, which was explanted 2 years after Descemet membrane endothelial keratoplasty (DMEK), using light and scanning electron microscopy, X‑ray spectroscopy and investigations on the optical bench.

Methods: In October 2012 a patient with pseudophakic keratopathy and Fuchs endothelial dystrophy underwent DMEK with double rebubbling. Due to primary graft failure the patient underwent penetrating keratoplasty in January 2013. The initial postoperative visual acuity was 0.2. Increasing opacification of the IOL lowered visual acuity down to hand movement, so that in November 2014 the patient underwent IOL replacement. The explanted IOL was first natively examined with an Olympus BX50 light microscope. In addition, image quality was determined on the optical bench. Subsequently, the explanted IOL was divided into two and one half was stained with Alizarin red and von Kossa and examined by light microscopy and the other half was analyzed by scanning electron microscopy. The composition of the deposits was examined by X‑ray spectroscopy.

Results: The macroscopic view showed opacification of the IOL only in the central area of the lens where contact between the IOL and the gas bubble had taken place. Light and scanning electron microscopy revealed numerous fine granular, crystal-like deposits under the anterior IOL surface, which were linearly arranged parallel to the surface. Using energy dispersive X‑ray spectroscopy the deposits were shown to be composed of calcium phosphate. No deposits were detected on the posterior surface.

Conclusion: The cause of the opacification of hydrophilic IOL is not clearly understood; however, the injection of gas/air into the anterior chamber during DMEK appears to increase the risk of IOL opacification by changing the lens surface or by alterations to the blood-aqueous humor barrier. Granular deposits under the anterior IOL surface can cause such a strong decrease in visual acuity that IOL exchange becomes neccessary.

Keywords: Cataract surgery; Descemet stripping endothelial keratoplasty; Intraocular lens; Microscopy; Opacification.