Experimental study on the proliferation of cells over plastic lens implants with or without glow discharge treatment
Ohira, A.; Oshima, K.; Yamanaka, A.; Goto, H.; Nakamae, K.
Nippon Ganka Gakkai Zasshi 90(12): 1591-1597
1986
ISSN/ISBN: 0029-0203 PMID: 3825787 Document Number: 285197
Numerous ideas for lens designs or materials have been considered for resolving the complications of lens implantation. However, very little research has been done on the surface condition of the material, especially the wetability. This report describes the wettability of the lens implant surface and its influence on the tissue of the eye. We treated the usual PMMA lenses with glow discharge to impart an enhanced hydrophilic surface, and implanted them in domestic rabbit eyes. The lenses were removed from the eyes after several intervals, and the conditions of cell contact and proliferation were examined. As a control, the same type of lenses, but without treatment, and with a hydrophobic surface, were examined in the same manner. Distinct cell proliferation was first observed on the 233 days after implantation. The largest number of the cells were recognized 277 days after implantation, and then the cell number gradually decreased as the time passed. After 1853 days, the lens were totally encapsulated by the collagenous membrane; however, the lens remained clear. The cells on the lens with a hydrophilic surface had a slender spindle-shape with a monolayer arrangement on the surface. On the hydrophobic lens surface the cells had a polygonal appearance with a rough arrangement in pile-like clusters. This experiment proved that IOLs with greater wettability have better compatibility to cell contact and proliferation. On the hydrophobic surface of the lens, fibroblast-like cells were arranged in monolayers, and the monolayer cell sheet on the surface did not disturb the clarity of the lens. Collagenous membrane which may be formed by fibroblasts remained after the cells decreased. Self-limiting cell proliferation followed by hypocellular membrane formation on the surface is similar to encapsulation of foreign material in vital tissue. Encapsulation of IOL was completed several years after implantation even on the lens with a hydrophobic surface. Therefore, there was no apparent intraocular inflammation that might obscure vision during the process. The membrane would provide good fixation of the IOL due to its biological mechanism. It may shield the lens from surrounding conditions, and may act as a barrier against the risk of immune reactions or biodegradation.