The optimal molecular weight of dispersive type sodium hyaluronate for the reduction of corneal endothelial damage induced by sonication, irrigation, and aspiration.

PURPOSE The purpose of this study was to investigate the optimal molecular weight of dispersive sodium hyaluronate (Na-HA) for the reduction of corneal endothelial damage induced by sonication, irrigation, and aspiration, using enucleated pig eyes. METHOD The phaco-needle of phacoemulsification and aspiration (PEA) equipment was inserted into the anterior chamber after aqueous humor replacement with a 1% Na-HA solution of various molecular weights (2420 x 10(3), 1460 x 10(3), 1100 x 10(3), 520 x 10(3) or 290 x 10(3)). Then sonication, irrigation, and aspiration were conducted for 60 seconds. The residual rate of Na-HA in the anterior chamber and the damaged area of corneal endothelium were determined using an image analyzer. RESULTS Na-HA with a molecular weight of 1100 x 10(3) gradually disappeared from the anterior chamber after mixing with the irrigating solution, and the damaged area in only the 1100 x 10(3) group was significantly smaller compared with that in the control group. CONCLUSION These results suggest that an optimal molecular weight exists for dispersive hyaluronate applied for the protection of intraocular tissues during PEA. Under the conditions of this study, Na-HA with a molecular weight of 1100 x 10(3) displayed the highest protective efficacy.