Size variability and fitting of 30-gauge thin-wall needles and 3-piece intraocular lens haptics for the flanged intrascleral fixation technique

Purpose: To assess the diameter of different 30-gauge thin-wall needles and 3-piece intraocular lens (IOL) haptics readily used for the flanged-haptic intrascleral fixation technique. Setting: Hanusch Hospital, Vienna, Austria. Design: Laboratory investigation. Methods: 5 30-gauge thin-wall needles and 5 3-piece IOLs were assessed. An upright light microscopy was used for measurements. The inner and outer diameters of the needles and the end thickness of the haptics were analyzed and compared for haptic fitting into the needle. Results: Among the needles, the inner diameter of the T-lab needle was significantly wider compared with all the others (mean 209.3 ± 8.0 μm, P < .001), followed by TSK (194.8 ± 5.0 μm), MST (194.7 ± 5.8 μm), Sterimedix (187.5 ± 9.0 μm) and significantly narrower Meso-relle (mean 178.7 ± 7.0 μm, P < .05). The outer diameter of the T-lab needle was significantly larger of all (mean 316.0 ± 2.0 μm, P < .001). Concerning the IOLs, the AvanseePreset Kowa's haptic was significantly thinner (mean 127.2 ± 0.7 μm) than all the others, such as the TecnisZA900 Johnson & Johnson (143.5 ± 3.1 μm), the CTLucia202 Zeiss (143.8 ± 1.3 μm), and the AcrysofMA60AC Alcon (143.9 ± 1.4 μm). The only haptic that was thicker than all the others assessed was that of SensarAR40 Johnson & Johnson (170.7 ± 1.7 μm, P < .001). Conclusions: Most of the analyzed haptics would fit into most of the measured needles, with the exception of the Sensar AR40 in combination with the Meso-relle or Sterimedix needles. The combination of a larger needle lumen and a thinner haptic could result in more ease of insertion during surgery. If the dimensions of the needle and IOL haptics used are unknown, we recommend trying insertion before beginning surgery.