Hydrated hydrophilic lenses of three different manufacturers (Griffen, Kontur, and Bausch and Lomb) were prepared for scanning electron microscopy utilizing air drying, freeze drying, and critical point drying techniques. Air dried lenses demonstrated artifacts analogous to those commonly seen in soft biological tissues when prepared in this manner. The freeze and critical point dried specimens showed better preservation of surface detail. Surfaces did not appear to have a porous architecture and no pores were seen at magnifications to 36,000 times. Surfaces of two of the lenses demonstrated conspicuous polishing marks which appeared to predispose to the adherence of debris, following wearing and cleaning. Pseudomonas aeruginosa was noted on the posterior surface of one lens. Varying the tonicity of the hydrating solution appeared to have little effect on the surface morphology of the lenses.
Matas BR, Spencer WH, Hayes TL. Scanning Electron Microscopy of Hydrophilic Contact Lenses. Arch Ophthalmol. 1972;88(3):287-295. doi:10.1001/archopht.1972.01000030289014