Comparison of protective efficacy in different molecular weight of sodium hyaluronates on the corneal endothelium during phacoemulsification

Purpose.In cataract surgery, sodium hyaluronate(Na-HA) is used not only to maintain the anterior chamber but also to protect ocular tissue such as the corneal endothelium. We compared the protective effects of different molecular weights of Na-HA during phacoemulsification(PEA). Methods.78 postmortem porcine eyes and Na-HA of three different molecular weights labeled with fluorescenct amine (FA-HA) were used: 42×10⁴(group A) , 113×10⁴(group B), and 167×10⁴(group C). 500 μ1 of Na-HA was injected into the anterior chamber and irrigation and aspiration (I/A) or PEA was performed. To measure the endothelial damage, the cornea was dissected at the limbus, and using 0.25% trypan blue, the stained area, i.e., the damaged area was analysed using a video system (Pias LA-555). To evaluate the amount of FA-HA binding to the corneal endothelium, the corneal section was digested by acetate buffer, including 0.25% actinase, fluorescence was measured. Results. Following I/A, a mean area of staining(mm²) was 0.008± 0.016 in group A (4 eyes), 0.00± 0.00 in group B (4 eyes) and C (4 eyes). Following PEA, a mean area of staining (mm²) was 0.364 ± 0.328 in group A (4 eyes), 0.428± 0.841 in group B (4 eyes) and 0.074± 0.086 in group C (4 eyes). The average amount of residual FA-HA (μ g/mg dry Wt.) after PEA was 0.386+ 0.959 in group A(8 eyes), 23.9± 5.66 in group B(7 eyes), and 3.59± 1.38 in group C(7 eyes). The residual level in group B was statistically greater than the other groups (P<0.01). Conclusion Compared with different molecular weight of Na-HA, the residual level of Na-HA after PEA was significantly different, however, the protective effect was not clinically different.