Visco-free IOL injection system shows good results in small study

A preloaded injector uses balanced salt solution to provide room in the anterior chamber, capsular bag.

Foldable IOLs can be successfully implanted with a disposable injector using only saline irrigating solution and no ophthalmic viscosurgical devices, according to a study.

Kimiya Shimizu

Kimiya Shimizu, MD, PhD, and colleagues designed and evaluated an IOL implantation device, the KS-VF, that does not use viscoelastics. Instead, the KS-VF uses balanced salt solution to lubricate and maintain space in the anterior chamber during IOL implantation.

The study compared the device with a conventional preloaded IOL injection device using OVD. Lens injection speed and resistance, IOP before and 1 day after surgery and anterior chamber space were evaluated in 11 eyes of 11 patients.

“The use of irrigating solution was not inferior to that of OVD and provided sufficient space in the anterior chamber and capsular bag,” the study authors said.

Dr. Shimizu told Ocular Surgery News that, in his experience, there have been no difficulties using this device and that he might suggest its use in a case of posterior chamber rupture when maintaining the anterior chamber and washout is difficult with an OVD.

The study

Both the KS-VF and the conventional injector (KS-1, STAAR Japan) were preloaded with a +20.5 D folded three-piece silicone IOL. Incision size was 3.2 mm. With the KS-VF injector, the IOL was folded with irrigating solution.

The KS-VF differed from the conventional injector in that the plunger of the KS-VF is hollow. An irrigation and aspiration tube is connected to supply the irrigating solution required for IOL folding and injection.

“The perfusing port of the [visco-free injector] has a universal design and can be connected to most of the connectors on the market,” Dr. Shimizu said, adding that either OVD or perfusing solution could be used to inject a lens with the device.

There were no significant differences between the two devices in terms of injection speed or resistance. For the KS-VF injector, sufficient space for IOL implantation was formed in the anterior chamber and in the capsular bag by the pressure of irrigating solution flowing from the injector, the study authors said. There was a statistically significant IOP increase in the visco-free eyes over the OVD eyes while the capsular bag was filled with irrigating solution (P = .0001). However, IOP levels were within normal range and the elevations were transient, Dr. Shimizu said.

Simple, safe implantation

The study authors said that the possible advantages of using a disposable injector with balanced salt solution rather than OVD include improvements in surgical efficiency, avoidance of postoperative IOP rise from residual OVD and reduced surgical cost. Furthermore, human error is lessened because the damage that can occur to the IOL from manipulation and human handling does not occur.

Furthermore, when the KS-VF injector is removed from the eye, the incision is left to self-seal by hydration, making the surgery simpler.

Because the foldable IOL makes no direct contact with the incision or the operative field, the operative field is cleaner and there is less likelihood of infection. – by Pat Nale

For more information:

Shimizu K, Kobayashi K, Takayama S, Zhaobin G. Preloaded injector for intraocular lens implantation without the use of ophthalmic viscosurgical devices. J Cataract Refract Surg. 2008;34:1157-1160.