Dispersive OVD a surgical aid in cataract extraction

Take-home

A newly approved dispersive ophthalmic viscosurgical device (Healon EndoCoat, Abbott Medical Optics) was found in a recent study to be comparable to another device with regard to the incidence of IOP spikes and change in endothelial cell count.

New Product Focus By Roger F. Steinert, MD; Special to Ophthalmology Times

Irvine, CA-A dispersive ophthalmic viscosurgical device (OVD) (Healon EndoCoat, Abbott Medical Optics) is safe and effective for routine cataract surgery.

A recent study conducted by my colleague, Toby Tyson, MD, and I found the newly approved OVD to be comparable to another agent (Viscoat, Alcon Laboratories) with regard to the incidence of IOP spikes and change in endothelial cell count (ECC).

This multicenter, double-masked, randomized, parallel-group comparison included 400 patients from 11 sites who underwent cataract extraction. All patients were followed from the preoperative examination until 3 months postoperatively, and were observed for incidence of postoperative IOP spikes (30 mm Hg or more), endothelial cell loss, and other complications.

Safe and effective

Uncorrected and best-corrected distance visual acuities were clinically comparable between the two groups. All eyes in both groups achieved 20/40 or better best-corrected visual acuity postoperatively, with comparable uncorrected visual acuity in both groups. The mean percent change in ECC from the preoperative exam to 3 months postoperatively showed a greater loss of endothelial cells for Viscoat (–7%) compared with Healon EndoCoat (–4.7%). The difference was statistically significant.

There was no difference in complications and adverse events between the two groups, and no unanticipated adverse events were reported at any point during the study. However, the percentage of subjects with surgical complications was statistically lower for the Healon EndoCoat group (3%) compared with the Viscoat group (8%).

The safety data included the viscoelastic removal time and the ease of viscoelastic removal. The mean removal time for Healon EndoCoat was 149.1 seconds (range: 60 to 300), compared to 133.7 seconds (60 to 454) for Viscoat.

For the Healon EndoCoat group, viscoelastic removal was easy in 3.5% of cases, average in 63% of cases, difficult in 33% of cases, and very difficult in 0.5% of cases. In the Viscoat group, viscoelastic removal was easy in 4.5% of cases, average in 71% of cases, difficult in 24.5% of cases, and very difficult in 0% of cases.

At 6 hours after surgery, 7.5% of eyes in the Healon EndoCoat group and 6.1% of eyes in the Viscoat group experienced IOP spikes of 30 mm Hg or more. The cumulative incidence over the 3-month postoperative period was 10.6% in the Healon group and 7.6% in the Viscoat group. These differences were not statistically significant.

Other benefits

This new OVD is based on the same formulation as the older Vitrax II (formerly marketed outside the United States). However, it has several key advancements.

First, it offers a smaller (25 gauge) cannula, a cannula guard, 0.85 ml of product in a 1-ml syringe, and improved ergonomics, including a larger backstop and thumb rest. The large volume avoids the need to open a second syringe in more challenging cases, such as phacoemulsification of dense nuclei.

The OVD is an important addition to cataract surgeons’ armamentarium because it is truly a dispersive. It is 3% sodium hyaluronate, and it can be used alone or in combination with another cohesive viscoelastic. The goal is to provide maximal endothelial protection throughout the phaco procedure. In comparison, Viscoat does not flow smoothly into the eye to cover and protect the surfaces, and visualization with chondroitin sulfate is universally known to be a problem.

Overall, the new device is a very valuable tool. It has all the characteristics of dispersive viscoelastic stability, retention, and protection, and it works well when used in combination with another OVD. It has a high level of ocular clarity throughout the surgical procedure.

Roger F. Steinert, MD, is the Irving H. Leopold Professor and Chair of Ophthalmology, professor of biomedical engineering, and director of the Gavin Herbert Eye Institute at the University of California, Irvine. Drs. Steinert and Tyson are consultants to Abbott Medical Optics.