Observation of various biofilm structures using SEM techniques after 72 h incubation. Biofilms in A-C were prepared using the SEM method with critical point drying. Biofilms in D-F were prepared using the SEM method with prolonged sodium hydroxide drying. Etafilcon A: A (500×), B (5000×), D (100×); Omafilcon A: C (2000×), E (500×), F (5000×). Different structural formations appear to cover the contact lens surface: extensive networks consisting of EPS and bacterial cells, mushroom-like structure, clumps and cover layers overlap compact, thick agglomerations of cells which are embedded in a network of EPS.