The fractional erbium non-ablative laser 1540 beam goes deep into the dermis to heat the collagen to 66 degrees centigrade and promote the growth and production of new collagen to replace the collagen lost in the dermis in the stretch mark. The 1540 also causes collagen shortening which tightens skin. 1540 works down to about 1000 microns deep in the dermis. That is about half of the depth or thickness of the skin.
Viora Refit is an RF frequency device which delivers heat to the very deepest layers of the dermis, deeper than the 1000 microns affected by the Starlux 1540. These deeper layers are where the elasticity of the dermis resides. Thus the Viora adds not only new dermal collagen production but also adds significant skin tightening.
Both of these devices are called fractional because the heat is delivered into small partial areas of the skin instead of the entire skin surface. Because untreated areas of skin are left, the skin does not slough or peel, thus no skin is removed or ablated. Thus the term non-ablative laser and light treatment.
These non-ablative treatments leave the skin intact so that no surface healing is required-no down time, unlike the old time laser resurfacing which required 2-3 weeks for skin healing.