An optical penetrating adapter for mounting to a surgical portal to permit visualization through the surgical portal includes an adapter member defining a longitudinal axis and having a transparent window adapted to penetrate tissue and to permit visualization therethrough and means for coupling the adapter member to the surgical portal. The transparent window may have various shapes and configurations adapted to penetrate, dissect, resect or separate tissue in a non traumatic manner. Alternatively, the transparent window may incorporate structure such as cutting edges blades, points, etc to pierce, cut or incise tissue.