LA VISC is a low to medium viscosity HPMC based ophthalmic surgical solution. It is a good choice for routine cataract surgery.
It's adhesive properties cause it to coat tissues, and help in the protection of the endothelial cells.
LA VISC lubricates the implant, instruments and tissues. It is also well suited for the manipulation of the eye's interior structures.
LA VISC is isotonic, non pyrogenic and noninflamatory. LA VISC has good flow characteristics.
LA VISC uses the same proprietary polymer as LA GEL, which consist of extremely long molecules. This makes LA VISC slightly more viscous than regular HPMC solutions while having a significantly lower concentration of HPMC. Therefore there is less HPMC to be metabolized, causing lower post operative pressure spikes.
LA VISC is as easy to remove from the eye as any other HPMC based viscoelastic.
LA VISC can also be used externally during retinal surgery to optically couple contact lenses to the cornea in the sterile field.
LA VISC provides good lubrication between injectors and foldable IOLs.
LA VISC, like all other viscoelastics, has to be removed from the eye at the end of surgery.
About the HPMC
Hydroxypropylmethylcellulose (HPMC) is a polymer, consisting of repetitive groups of molecules in a chain. The first generation viscoelastics, used the commercially available, medical grade HPMC, with molecular weights of 30,000 - 50,000 Daltons, which resulted in a low viscosity (3,000 -5,000 cps). Many of these materials were sold unfiltered.
LA LABS, the manufacturer of LA VISC, LA GEL and LA LON, developed a way to increase the size of these molecules and with it, the length of the molecular chains. The friction between the longer molecules is larger, causing a higher viscosity in solution.
Having control of the molecular size allows adjustment of the viscosity over a wide range. Based on market research, the viscosity of 8,000 cps has been chosen for LA VISC, to provide a similar, but slightly improved feel for our most economic product.
Protection vs. easy removal
The protection of the tissues is made possible by the adhesive properties of a viscoelastic and is a direct benefit to the patient. Easy removability is due to non adhesive properties and is a benefit to the surgeon - indirectly also to the patient.
It is impossible to have a material which possesses both of these characteristics. LA VISC is designed to adhere and to protect, which is especially beneficial during phaco procedures.
For the lens implantation phase of the surgery, we recommend a cohesive, easy to remove sodium hyaluronate based solution like LA LON.