Advances in Cataract Surgery

Majed Alkharashi; Walter J Stark; Yassine J Daoud


Expert Rev Ophthalmol. 2013;8(5):447-456. 

In This Article

Ophthalmic Viscosurgical Devices

Healon (sodium hyaluronate 1%, Abbott Medical Optics Inc. Santa Ana, CA, USA) was the first ophthalmic viscosurgical device (OVD) to be introduced in 1979. Since then, a number of OVDs have been manufactured with varying composition and rheologic behavior. OVDs have variety of uses in ophthalmic surgery which could be summarized in space creation, tissue stabilization and corneal endothelial cell protection.[9] OVDs used to be classified as either dispersive or cohesive.

Dispersive OVDs (e.g., Viscoat, Alcon. Fort Worth, TX, USA) are low in viscosity and molecular mass, have short molecular chain length and require longer aspiration time for complete removal. Typically, dispersives remain in the eye during phacoemulsification to protect the endothelium from turbulent flow.

Cohesive OVDs (e.g., Healon, Abbott Medical Optics Inc.) are typically more viscous; have a higher molecular mass, possess longer chains, result in excellent space maintenance and are easy to remove. Thus, cohesives are used to expand the capsular bag for intraocular lens insertion at the end of cataract surgery.

The introduction of Healon5 (sodium hyaluronate 2.3%) in 1998 heralded a new class of OVDs termed viscoadaptive.[10] Viscoadaptives (e.g., Healon5 and DisCoVisc, Alcon.) behave similar to superviscous cohesives under low shear stress. With change in fluid dynamics, the viscoadaptives fracture freeing pieces to float around in the balanced salt solution. This biphasic nature has resulted in viscoadaptives being referred to as pseudodispersive in ophthalmic surgery because they are well retained in the anterior segment similar to dispersive OVDs.[11]

OVDs have led to dramatic improvement in the safety of cataract surgery and minimized damage to the ocular structures that used to occur previously as a result of cataract surgery. Indeed, OVDs are of the most important advances in cataract surgery.