Comparative clinical trial of AMO Vitrax and Healon use in extracapsular cataract extraction

Clinical Comparison of the Performance of Two Marketed Ophthalmic Viscoelastic Devices (OVDs): The Bacterially Derived Healon PRO OVD and Animal-Derived Healon OVD

This clinical investigation compared the clinical performance of two marketed ophthalmic viscoelastic devices (OVDs): the bacterially derived Healon PRO OVD (test) and the animal-derived Healon OVD (control) under normal use conditions during cataract removal and lens implantation. This prospective, multicenter, randomized, parallel, participant/evaluator masked, postmarket investigation enrolled 139 subjects (170 eyes), 116 (143 eyes) of which were treated (73 test; 70 control group). Both test and control OVDs were used, at a minimum, to inflate the anterior chamber and protect the endothelium prior to cataract extraction according to the standard procedure. The surgeon completed a postsurgery OVD clinical performance questionnaire, and intraocular pressure (IOP) was measured before surgery and at the 1 day postoperative visit with Goldmann applanation tonometry. Any IOP measurement of 30 mmHg or higher was considered a “spike” and recorded as a study-specific, serious adverse event. The bacterially derived Healon PRO OVD was found to be statistically noninferior to the overall clinical performance of the animal-derived Healon OVD control; thus, the primary hypothesis was satisfied. There were no statistically significant differences between OVD groups for any of the additional endpoints relating to IOP changes or to safety, thus satisfying additional hypotheses. The Healon PRO OVD showed statistically significant improvements in surgeon ratings for ease of injectability, transparency/visibility, and ease of IOL placement. The safety profile was also similar between OVD groups with regards to serious and/or device-related adverse events, as well as medical and lens findings. The results of this clinical investigation support the safety and effectiveness of the bacterially derived, currently marketed Healon PRO OVD and indicate that the intraocular surgical performance was similar between the two OVDs.

Safety of hydroimplantation: a foldable intraocular lens implantation without the use of an ophthalmic viscosurgical device

PURPOSE

To compare the safety of a single-piece, foldable intraocular lens (IOL) hydroimplantation with that of a standard implantation using an ophthalmic viscosurgical device (OVD).

METHODS

One hundred consecutive patients with bilateral age-related cataract surgery were enrolled into a prospective double-blind study. Each patient's first eye was randomly assigned to a standard implantation technique with an OVD or the hydroimplantation technique, while the fellow eye received the opposite technique. The main outcomes measured were endothelial cell loss, postoperative changes of intraocular pressure (IOP), and the frequency of complications.

RESULTS

The reduction of endothelial cell density 1 month and 6 months after the surgery was 9.76% ± 13.5%, 10.7% ± 12.6%, respectively, in group A (OVD) and 9.07% ± 12.7%, 9.13% ± 13.7%, respectively, in group B (hydroimplantation). The differences were not statistically significant. The mean IOP 2 hours after surgery was 10.19 ± 6.78 mm Hg in group A and 9.92 ± 7.01 mm Hg in group B. Twenty-four hours and 1 month after surgery, the mean IOP was 14.52 ± 5.59 mm Hg and 13.21 ± 3.5 mm Hg, respectively, in group A, and 15.45 ± 5.77 mm Hg and 13.1 ± 3.44 mm Hg, respectively, in group B. The differences between groups A and B were not statistically significant.

CONCLUSIONS

The hydroimplantation technique is a safe technique for single-piece foldable IOL implantation. There was no increase in intraoperative and postoperative complications compared with the standard implantation technique using an OVD.

Combined panretinal photocoagulation and cataract surgery in a patient with diabetes mellitus

A case is presented whereby a simple method of applying indirect laser during cataract surgery in the presence of retinal and iris neovascularization is described. The method involves placing an infusion cannula into the anterior chamber following standard phacoemulsification and soft lens matter removal. The main section is then sutured and indirect laser is delivered to the far retinal periphery with gentle manipulation of the eye. Successful delivery of indirect panretinal photocoagulation despite inadvertent vitreous loss in this case demonstrates the advantages of its use. Other advantages, including its use in previously vitrectomized eyes and allowing manipulation/indentation of the eye, control of bleeding, and better visualization, are discussed.

The influence of viscoelastic substances on the corneal endothelial cell population during cataract surgery: a prospective study of cohesive and dispersive viscoelastics

PURPOSE

To compare the ability of cohesive and dispersive ophthalmic viscoelastic devices (OVDs) to protect the corneal endothelium following in-the-bag phacoemulsification with implantation of a foldable posterior chamber intraocular lens (IOL).

METHODS

In a prospective single-masked randomized study, 60 eyes of 60 cataract patients were assigned to three groups of 20 patients each, according to which OVD was used: Celoftal, Vitrax or Healon. The corneal response to surgery was evaluated by measuring the endothelial cell loss, the variation in mean cell area of the endothelial cells (CV), the frequency of hexagonal cells, and the central corneal thickness. Data were recorded preoperatively and 3 months postoperatively.

RESULTS

Preoperatively, no significant difference was observed in cell count, CV, hexagonal pattern or pachymetry among groups. Postoperatively, all three groups had a significant decrease in cell count, but the decrease was significantly less in the Vitrax group (6.97%) than in the Celoftal (18.03%) and Healon groups (18.46%). No changes in CV, hexagonality or corneal thickness were observed within any of the three groups or among the groups. There was an equal and significant increase in visual acuity.

CONCLUSIONS

Phacoemulsification with implantation of a posterior chamber lens is known to affect the density and morphology of corneal endothelial cells. Viscoelastics facilitate cataract surgery and protect the corneal endothelium during the procedure. Choosing a dispersive hyaluronate OVD during the phaco procedure may allow for protection of the endothelial cells while suppressing the formation of free radicals. This may be the reason for the superior protective effect on the corneal endothelial cells of Vitrax compared with Celoftal and Healon.

The effect of alginate and hyaluronate on the viability and function of immunoisolated neonatal rat islets

Recent observations suggest that the extracellular matrix plays a role as regards the viability and morphological integrity in long-term culture of Langerhans islets. For the present study we encapsulated neonatal rat islets without extracellular matrix (WEM), with alginate solution (AL) and with hyaluronate solution (HY) into cuprophane hollow fibers. Function was tested after week 1 and 5. The insulin release of WEM encapsulated islets decreased significantly during the culture period. In contrast to this, AL and HY embedded islets had stable secretion values throughout the whole cultivation. Histological examination confirmed that viability of HY and of AL embedded islets differed significantly from that of WEM encapsulated islets. Furthermore, HY seems to be a more advantageous environment to immunoisolated islets than AL. Both the insulin secretion values and the viability of HY embedded islets were higher than of AL embedded islets. We conclude that an extracellular matrix is important for immunoisolated islets, to maintain their function and morphological integrity and that HY is especially suitable for this application.