Release and elimination of methylmethacrylate monomer after intraocular lens implantation.

The potential for certain constituents in intraocular lenses, such as monomer methylmethacrylate (MMM), to induce toxic effects after intraocular implantation not only depends on their toxic potency, but also on the characteristics of their release, accumulation, and elimination from the aqueous humor. A mathematical estimation taking these factors into account shows that for a lens mass of approximately 15 mg, the concentration of MMM in the aqueous humor amounts to about 10(-4) of the respective concentration in the lens, but that value is maintained for several weeks. Therefore, experiments to test the chemical toxicity of MMM or similar lens compounds in eyes must not only take into account the actual concentration limit but also the time of exposure to the substance.