[Needles used in ocular microsurgery: comparative study using scanning electron microscopy].
The use of microsurgical sutures of various types reveals noticeable differences in the ease of penetration of needles into ocular tissues. In order to try to specify these variations, we have examined different needles used in ophthalmology with a scanning electron microscope: CU 1, CU 5 ( Alcon ), LE 1 (Davis Geck), GS 9, GS 17 (Ethicon), SSC Dm 122 (T ubinger material). The examination was performed on new, unused needles and after having been passed through a cornea five times. Studies on new needles showed certain structural variations. Although the tips had a more or less sharp stem, the edge varied from completely regular to notched. The needle surfaces varied from a very smooth appearance to fluted . After use, the examination reveals the presence of cellular debris. No irregularity was caused by contact with surgical instruments. Comparisons between the imprint and the electron micrographic appearance showed that penetration is clearly better with needles having fluted edges and surfaces.