Membrane formation on the surface of implanted posterior chamber intraocular lenses

To study the prevention and treatment of the membrane formation on the lens surface after extracapsular cataract extraction (ECCE) with posterior chamber intraocular lens (PCIOL) implantation.

We reviewed the records of 312 cataractous patients that had undergone ECCE with PCIOL implantation between 1989 and 1993. Postoperatively all patients were examined under slit-lamp microscopy. The membrane formation on the surface of PCIOL in pupilar area was divided into four grades. Two membranes of surgical removal were observed under a transmission electron microscopy. One PCIOL of surgical removal was observed under a scanning electron microscopy.

Of 312 patients, 21 had the membrane formation on the surface of the PCIOL postoperatively. The incidence of the membrane formation was 6.7%. Comparisons with cases of senile cataract showed the incidence to be significantly the highest among: 1. patients who had traumatic cataract (P < 0.05); 2. patients with complicated cataract (P < 0.05). Intraoperatively residual lens cortex and rupture of posterior capsule, interval time between the first and second eye operations less than 1 month are the main factors of membrane formation. The ultrastructure in membrane and cytology on the lens surface showed that the membrane on the surface of PCIOLs is usually composed of a cellular protein film and cellular elements, including macrophages, fibroblast-like cells, epithelioid cells, giant cells, fibroblasts and collagen fibrils, etc.

The cellular response on the surface of an implanted PCIOL is a chronic foreign-body inflammatory reaction and the membrane of the surface of implanted PCIOL is a reactive membrane of the foreign-body.