Scanning electron microscopy of human corneal lenticules at variable corneal depths in small incision lenticule extraction cases

Abstract

Purpose The aim of this study was to evaluate the surface quality of corneal lenticules at variable corneal depths in cases of small incision lenticule extraction using scanning electron microscopy. Patients and methods Forty eyes of 20 myopic patients were included. One eye was randomly assigned for lenticules at 100 µm depth (group I), whereas the other eye was assigned for lenticules at 160 µm depth (group II). The VisuMax femtosecond laser system was used for the procedure. An established scoring system and a new scoring system at higher magnification levels for surface regularity were used. Results The mean overall diameter of the lenticules as seen on electron microscopy was 6.54±0.17 and 6.73±0.20 mm in group I and group II, respectively (P=0.003). In both groups, around 50% of cases showed a smooth surface at ×10 magnification. The mean score was 14.90+1.74 and 13.25+2.77 in group I and group II, respectively (P=0.031). Conclusion The VisuMax femtosecond laser system creates predictable good-quality surface refractive corneal lenticules at superficial depth. Deeper corneal lenticules showed more irregular surfaces, especially at higher magnification levels. Energy settings still need further adjustment to be able to create deeper predictable lenticules in small incision lenticule extraction cases.