COMPARATIVE CLINICAL TRIAL WITH TWO VISCOELASTICS (HEALON GV ® AND PROVISC®) Of DIFFERENT VISCOSITY AND MOLECULAR WEIGHT FOR PHACOEMULSIFICATION IN EYES WITH CORNEA GUTTATA
B. Schmidl, U. Mester, N. Anterist
Viscoelastics gained widespread use in actual cataract surgery. Viscoelastics with high molecular weight and high viscosity show superior handling qualities. On the other hand, viscoelastics with low molecular weight and low viscosity seem to have a better endothelial protective effect because of their longer contact to the intraocular structures.
Patients and Method: We compared two hyaluronic acid viscoelastics of different molecular weight (Healon GV® 5 mio., Provisc ® 1,1 mio. Dalton) and viscosity (2 mio. vs 50.000 m Pa·s).
This prospective, randomized, single masked clinical trial was characterised by an intraindividually comparing study design. Within 8 weeks we performed phakoemulsification with IOL-implantation on 30 eyes using Healon GV® and the 30 fellow eyes using Provisc ®. For better demonstrating the endothelial protective function of the viscoelastics only patients with bilateral cornea guttata were included. Central endothelial-cell-counts, corneal thickness, and anterior- chamber-flare were recorded preoperatively and postoperatively at the first and 14th day after surgery.
Result: No differences could be observed between the endothelial-cell-counts in both eyes. In contrast, eyes treated with Provisc® had a statistically significant higher increase of corneal thickness compared to the fellow eyes treated with Healon GV ®. Additionally, transient corneal decompensation was noticed only in three eyes of the Provisc OR-group.
Conclusion: The results indicate no superior protection of the corneal endothelium by viscoelastics with lower viscosity compared to viscoelastics with higher viscosity. The functional impairment of endothelial cells seems to be even stronger using viscoelastics of low viscosity.
Department of Ophthalmology, Bundesknappschaftskrankenhaus, An der Klinik 10 D-66280 Sulzbach/Saar