POSTOPERATIVE INTRAOCULAR-PRESSURE IN THE FIRST DAYS FOLLOWING THE USE OF HYALURONIC-ACID SOLUTIONS OF DIFFERENT VISCOSITY

Background Viscoelastic substances are used in anterior segment surger y to reduce tissue trauma and endothelial cell loss and to serve as sp ace maintainer. Healon(R)GV (approximate to greater viscosity), a hyal uronic acid product with a ten times higher viscosity than Healon(R), is utilized in complicated procedures (vitreous pressure, flat anterio r chamber, congenital cataracts, etc.) and often in phacoemulsificatio n. Intraocular pressure (IOP) rise following incomplete removal is a k nown problem. Materials and methods A prospective randomized study was performed to evaluate the IOP following cataract surgery with Healon( R) or Healon(R)GV and different removal times (RT). Forty patients (fo rty eyes) having uncomplicated phacoemulsification with foldable silic one posterior chamber lens implantation and identical viscoelastic rem oval technique were assigned to four groups: Healon(R) with 20 or 40 s econds (sec.) RT, Healon(R)GV with 20 or 40 sec. RT. All surgeries wer e performed by the same surgeon using the same technique especially fo r the removal of the viscoelastic. All patients had an identical pre- and postoperative medication. Intraocular pressures were obtained usin g Goldman's applanation tonometry preoperatively, six, 24, 36, and 48 hours postoperatively. Results The IOP follow-up showed no significant difference between the two viscoelastic substances and the two differ ent removal times of 20 and 40 sec. (t-test). In four patients (two of the Healon(R)-groups, two of the Healon(R)GV-groups) the IOP required treatment. On the second postoperative day, the same four patients sh owed IOP lower than 22 mm Hg. The highest mean-IOP (mm Hg) in both Hea lon-groups was obtained at 24 hours postoperatively: 18.5+/-3.9 SD (He alon(R)); 17.3+/-5.9 SD (Healon(R)GV). Conclusion The incidence of pos toperative rise in IOP using high viscosity hyaluronic acid (Healon(R) GV) can be minimized by the applied removal technique. Both viscoelast ics - despite of higher molecular weight and viscosity - can be remove d equally from the anterior chamber following phacoemulsification and posterior chamber lens implantation utilizing IOP as a parameter in vi vo.