[Reduction of cataract by plasma etching of intraocular lenses. An animal experiment study]

We studied if a modification of the silicon intraocular lens (IOL) by plasma etching is able to promote a bonding of the IOL surface and the capsular bag which might inhibit proliferation and migration of lens epithelial cells.

Silicon-disc lenses (90D, Adatomed), as disposable for regular cataract surgery, were used. Their haptic surface was etched via the use of a SO2 plasma, leaving the optic unmodified. The experiments were done on dwarf rabbits to allow for tight apposition of IOL and bag. Nine rabbits underwent extracapsular lensectomy using propofol anaesthesia and phaco/clear cornea surgical technique. Six eyes each received either no, a regular or a modified IOL. After 11 weeks the eyes were enucleated. Capsular bag and IOL were digitized using a flatbed scanner with transparency adapter. The data obtained were calibrated against a densitometric standard. The densities of the various specimen were analyzed quantitatively using self designed software.

In aphacic eyes no significant posterior capsule opacification (PCO) was detectable. In the same time-span the regular IOL had developed a dense, heterogenous PCO. The plasma-treated IOL showed, especially in the central areas, a significant reduction of PCO as compared to untreated IOL.

The reduction of PCO could not be explained by adhesion of the IOL surface and the capsular bag, which would impair migration of lens epithelial cells and thereby PCO. Likewise, lower PCO may be related to improved hydrophilic properties of the surface-modified IOL.