Impact of scleral tunnel length on the position of intraocular lenses in flanged intrascleral haptic fixation.

PURPOSE: To investigate the effect of scleral tunnel length on the effective lens position and tilt of the intraocular lens (IOL) in flanged intrascleral haptic fixation (ISHF) using anterior segment optical coherence tomography (AS-OCT). SETTING: Tertiary institution. DESIGN: Retrospective case-control study. METHODS: This study included 55 and 42 eyes that underwent ISHF with 1.0 and 2.0 mm scleral tunnels, respectively. 23 eyes that underwent sutured fixation were used as a control. The anterior chamber depth (ACD), scleral tunnel length, incident angle of haptic, and tilting of optic were analyzed using AS-OCT. RESULTS: The mean postoperative ACD, vertical tilt angle, and spherical equivalent of the 1.0 mm were 5.27 ± 0.39 mm, 6.04 ± 4.87 degrees, and 0.38 ± 1.03 diopters, respectively. The ACD and vertical tilt angle of the 1.0 mm were larger than those of the others ( P < .001 and P < .05, respectively), and the postoperative spherical equivalent was more hyperopic ( P < .05). The 2.0 mm exhibited a lower frequency of tilting greater than 7 degrees. The intereye difference in ACD between in-the-bag fixation and ISHF of the 1.0 mm tunnel was significantly greater than that in the 2.0 mm tunnel ( P < .05). The 1.0 mm tunnel had a significantly larger incident angle and a longer tunnel length ( P < .001, respectively) and showed a greater difference in the tunnel length on both sides ( P < .05). CONCLUSIONS: A shorter tunnel yielded a more unstable IOL position, greater variation in angle and tunnel length, and longer ACD during ISHF. An exact 2.0 mm tunnel must be created on both sides to achieve a stable and predictable IOL position.

Temporary Pupil Occlusion and Retrolenticular Air Bubble Injection for Descemet Membrane Endothelial Keratoplasty in Vitrectomized Unicameral Eyes.

PURPOSE: The aim of this study was to describe a surgical method that can be easily and safely performed during Descemet membrane endothelial keratoplasty in patients who had previously undergone pars plana vitrectomy with transscleral fixation of the intraocular lens. METHODS: This report reviewed 2 Descemet membrane endothelial keratoplasty procedures performed in patients with vitrectomized unicameral eyes. The proposed technique is characterized by the temporary suture of the pupillary aperture to block the forward flow of vitreous humor and prevent the abrupt loss of air tamponade due to backward movement of the air bubble into the vitreous cavity. At the same time, another air bubble is injected behind the scleral-fixated intraocular lens to induce forward movement of the iris-intraocular lens diaphragm through buoyancy. Thus, the depth of the anterior chamber is reduced, allowing easier unscrolling of the Descemet membrane endothelial keratoplasty lenticule. RESULTS: Pupil closure and buoyancy of the air bubble allow the anterior chamber to be separated from the inflow of vitreous cavity fluid and maintained adequately shallow. During the keratoplasty, the graft is then easily unscrolled without the support of the capsular diaphragm. Postoperatively, the air bubble is maintained in the anterior chamber for a sufficient period. Nd:YAG laser suture lysis is performed after complete absorption of the air bubble during outpatient follow-up. CONCLUSIONS: Temporary pupil occlusion and retrolenticular air bubble injection provide a stable surgical approach in challenging cases of postvitrectomized unicameral eyes.