Small-incision lenticule extraction (SMILE) is currently one of the preferred techniques for the management of myopia and myopic astigmatism. However, complications have been described for SMILE, with suction loss being one of the most frequently encountered intraoperatively.1 Several strategies for the management of suction loss during SMILE have been described.2–4 In this study, we present a case of suction loss during SMILE successfully managed by creating only a small incision using CIRCLE software (Carl Zeiss Meditec AG). To our knowledge, this is the first report describing the use of CIRCLE software without cap-to-flap conversion for the management of suction loss during SMILE.
A 26-year-old woman presented to our institute for correction of her refractive error. Uncorrected (UDVA) and corrected distance visual acuities were counting fingers and 20/20 in both eyes, respectively (manifest refraction −3.50 −0.50 × 180 in the right eye and −4.00 in the left eye). Slitlamp and fundus examinations were unremarkable. Corneal topography (Sirius Tomograph and Corneal Topographer, CSO) was within normal limits; keratometry readings (flat K/steep K) were 43.57/44.90 diopters (D) and 43.48/44.61 D in the right eye and the left eye, respectively. Corneal thickness was 556 μm and 535 μm in the right eye and the left eye, respectively. SMILE was planned for correction of her refractive error in both eyes.
The procedure was performed by V.P.K. under sterile conditions and topical anesthesia using the 500 kHz VisuMax femtosecond laser platform (Carl Zeiss Meditec AG). The patient's right eye was well centered and docked, and suction was started. Targeted lenticule and cap diameters in the right eye were 6.50 mm and 7.50 mm, respectively. The intended cap thickness was 120 μm. The 3 mm (46-degree) wide small incision was planned at 90 degrees (Figure 1, A). The lenticule interface and side cuts were successfully completed. Toward the end of cap interface cut, unstable suction resulting in intrusion of conjunctival tissue within the contact interface was noted. Laser application was continued and completed because there was no loss of contact between the corneal surface and the suction glass. The cap interface was successfully formed, but the small incision was not created. During manual dissection, the surgeon confirmed that femtosecond laser application was ineffective in creating the small incision. Because laser delivery was complete, it was not possible to use the restart treatment module of the software. We decided to use CIRCLE software to create only the small incision without converting the cap to a flap. The lamellar cut was created at the same depth of 120 μm as original cap thickness using CIRCLE software (“D” pattern). To create a 50-degree wide (3.2 mm) small incision, a 310-degree hinge (20.83 mm) was designed. The hinge was positioned at 290 degrees in such a way that the new small incision would not coincide with the previous SMILE incision at 90 degrees; thus, the new incision was created superotemporally at 110 degrees (Figure 1, B). Manual lenticule dissection and extraction were then performed uneventfully (see Video, http://links.lww.com/JRS/A97). SMILE treatment of the left eye was uneventful.
On the first postoperative day, the UDVA was 20/20. Corneal topography showed a regular postoperative curvature map (40.31/41.33 D) with a well-centered treatment (Figure 2). Slitlamp examination and anterior segment optical coherence tomography (Cirrus HD-OCT Model 500, Carl Zeiss Meditec AG) showed a regular and clear corneal stromal interface (Figures 3 and 4). The UDVA was found to be stable during the 3-month follow-up.
SMILE is a flapless lenticule extraction technique currently used for correction of myopia and myopic astigmatism. In SMILE, intrastromal lenticule is created using the femtosecond laser and manually extracted through a small incision, avoiding the flap-related complications. Nevertheless, several other complications of SMILE can occur; one of the main intraoperative complications is suction loss.1 Several approaches for the management of suction loss during SMILE have been described depending on the stage at which suction loss is encountered.2–4 Reinstein et al. have described a comprehensive decision tree for the management of suction loss during different stages of SMILE, depending on the type of eye movements, suction stability grading, and progress of the femtosecond laser cutting.3 Liu et al. reported the clinical results of suction loss during SMILE managed by different retreatment modalities to be comparable with the outcome in fellow eyes that underwent uneventful SMILE.4
In our case, suction loss occurred at the end of cap interface cut, resulting in conjunctival tissue intrusion within the contact interface. Although cap interface cut was successfully completed, the small incision was not created because of overlying conjunctival tissue. Because the laser was completely delivered, restart treatment module of the software could not be used. Various retreatment options such as conversion to surface ablation or thin-flap laser in situ keratomileusis were considered. However, because creation of the cap and lenticule interfaces had been completed, the only concern was to gain access to the formed lenticule.
CIRCLE software, originally indicated as a tool for enhancement after SMILE, allows conversion of SMILE cap into a flap, thus providing access to the interface.5–7 Ganesh et al. and Reinstein et al. have demonstrated the use of CIRCLE software for the management of complicated lenticule dissection during SMILE surgery.8,9 Converting the cap to a flap using CIRCLE software could have been an option in our case to gain access to the lenticule. However, this alters the flapless SMILE procedure to a flap-assisted femtosecond lenticule extraction procedure. Hence, in our case, we used CIRCLE software only for the creation of small incision without converting the cap to a flap. CIRCLE was planned in a new manner to create a 50-degree wide small incision with a 310-degree hinge. Our main goal was to complete the flapless SMILE procedure avoiding cap-to-flap conversion and, thus, the possible complications and disadvantages of a flap. SMILE is devoid of flap-related complications and has less postoperative dry eye with minimal loss of corneal sensitivity when compared with femtosecond laser–assisted in situ keratomileusis.10
To our knowledge, this is the first report that describes the successful use of CIRCLE software for small incision creation alone as a management strategy for suction loss in SMILE. This unique approach of using CIRCLE software without cap-to-flap conversion in similar scenarios seems to be safe, resulting in a favorable outcome.
WHAT WAS KNOWN
- Numerous strategies have been described for the management of suction loss during small-incision lenticule extraction (SMILE), such as restart SMILE treatment or conversion to thin-flap laser in situ keratomileusis.
- CIRCLE software, apart from its indication for enhancement, can be used therapeutically after complicated SMILE surgery.
WHAT THIS PAPER ADDS
- Suction loss during SMILE was successfully managed by using CIRCLE software without converting the SMILE cap to a flap. Creation of only the small incision using CIRCLE software allowed completion of the flapless SMILE procedure after suction loss.
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