12-Month Outcomes of Small Incision Lenticule Extraction With Proper Head Positioning but No Reference Marking for the Correction of Astigmatism.

PURPOSE: To investigate the 12-month outcomes of small incision lenticule extraction (SMILE) with proper head positioning but no reference marking for correcting astigmatism. METHODS: This was a retrospective cohort study of 3,541 patients (5,953 eyes) who underwent SMILE between July 2010 and April 2021. Patient positioning on the treatment bed was meticulously done in every patient to avoid face turn, head tilt, and chin-up or chin-down posture. The corrected distance visual acuity (CDVA), uncorrected distance visual acuity (UDVA), manifest refraction, astigmatic outcomes, and adverse events were evaluated at 1, 3, and 12 months postoperatively. RESULTS: The mean preoperative manifest spherical equivalent and manifest cylinder were -5.15 ± 2.24 diopters (D) (range: -0.13 to -12.88 D) and -1.00 ± 0.77 D (range: -0.25 and -6.00 D), respectively. Of all eyes, 88.4% and 98.6% had the spherical equivalent within ±0.50 and ±1.00 D of emmetropia at 12 months. The percentage of eyes with UDVA of 20/20 or better was 92.5%. Six eyes (0.1%) lost two or more lines of CDVA at the 12-month visit. The predictability of cylinder correction was excellent, with 88.1% within ±0.50 D and 98.9% within ± 1.00 D of astigmatism correction at 12 months. The mean correction index (CI) at 12 months was 1.09 ± 0.45 (range: 0.17 to 4.99), indicating a slight astigmatism overcorrection. The high cylinder group tended to have undercorrection with greater residual astigmatism, whereas the low cylinder group was likely to have overcorrection with lesser residual astigmatism (P < .001). No serious adverse events were observed. CONCLUSIONS: SMILE with proper head positioning but no reference marking produces safe, efficient, predictable, and stable outcomes for astigmatism correction over a 12-month period. [J Refract Surg. 2023;39(10):683-692.].

Safety and efficacy of VisuMax® circle patterns for flap creation and enhancement following small incision lenticule extraction.

BACKGROUND: The purpose of this case series is to evaluate the safety and efficacy of VisuMax® Circle patterns in eyes that have undergone small incision lenticule extraction, thus creating a flap to perform an enhancement procedure or residual lenticule extraction. METHODS: This prospective, single center, case study series evaluated the use of a VisuMax® Circle pattern to create a corneal flap following small incision lenticule extraction. Patients were treated and followed at TRSC International LASIK Center (Bangkok, Thailand) for 3 months to assess the efficacy and safety of the procedure. Efficacy was determined by the surgeon's ability to lift the created corneal flap. RESULTS: The study enrolled 28 eyes. Twenty-seven underwent the VisuMax® Circle pattern procedure for refractive enhancement, and one for residual lenticule extraction. In 100 % of cases (28 eyes) the lifting of the flap was possible, as planned. In all cases of refractive enhancement (27 eyes) by laser in situ keratomileusis (LASIK), the exposure of the stromal bed was sufficient for the necessary excimer laser ablation. No eyes lost two or more Snellen lines of corrected distance visual acuity (CDVA) and no procedure or flap-related complications or serious adverse events occurred. CONCLUSIONS: This initial case series demonstrates that VisuMax® Circle pattern is efficacious and a suitable method to create a corneal flap for enhancement, following small incision lenticule extraction.

Efficacy, predictability and safety of small incision lenticule extraction (SMILE).

BACKGROUND: The purpose of this case series is to report the one-year outcomes of small incision lenticule extraction (SMILE) using the VisuMax® femtosecond laser. METHODS: Two hundred and six patients were recruited for this retrospective, single center study at TRSC International LASIK Center in Bangkok, Thailand. Patients underwent SMILE, whereby an intrastromal lenticule was cut using a femtosecond laser and then manually extracted without the need for flap creation. Outcome measures included refraction, visual acuity and contrast sensitivity evaluation. Patients were treated and followed for one year. RESULTS: SMILE for the correction of low to high myopia was performed on 347 eyes of 206 patients. The mean preoperative spherical equivalent was -4.96 ± 1.88 diopters (D). On the first day following surgery, for eyes with a plano target refraction (99.14 % of all eyes), uncorrected distance visual acuity (UDVA) was 20/20 or better in 90 % of eyes. At the one week postoperative exam, the mean spherical equivalent was 0.01 ± 0.36 D and UDVA was 20/20 or better in 84 % of eyes. After one year follow-up, no eyes showed loss of 2 or more lines of visual acuity and 31 % of eyes gained one or more lines. The photopic contrast sensitivity of SMILE treated eyes at 12 and 18 cycles per degree (cpd) improved from 1.59 and 0.94 preoperatively to 1.6 and 0.98, respectively, after one year. CONCLUSIONS: In this series, SMILE using the VisuMax® femtosecond laser demonstrated that after one year it is an effective, predictable and safe minimally invasive corneal refractive procedure.

Spherical aberration from myopic excimer laser ablation for aspheric and non-aspheric profiles.

PURPOSE: To evaluate the difference in the spherical aberration (SA) induced by an aspheric and a non-aspheric myopic ablation profile with the MEL80 excimer laser (Carl Zeiss Meditec). METHODS: This was a prospective randomized paired-eye controlled study of 15 patients (30 eyes) who underwent LASIK using the Hansatome microkeratome (160 µm) (Bausch & Lomb) and the MEL80 using a 6 mm optical zone. For each patient, one eye was treated with an aspheric (Aberration Smart Ablation [ASA]) profile and the other eye was treated with a non-aspheric (Tissue Saving Ablation [TSA]) profile, assigned at random. Patients were measured before and 3 months after LASIK with the wavefront supported custom ablation aberrometer (Carl Zeiss Meditec), and SA was measured with an analysis zone of 3 to 7 mm in 0.5 mm intervals. The area under the curve of SA plotted against analysis zone (RAWS) was calculated. RESULTS: The mean spherical equivalent refraction was -2.43 ± 1.53 D for the ASA group and -2.54 ± 1.47 D for the TSA group (p = 0.87). There was a statistically significant increase in SA for an analysis zone of 6.0 to 7.0 mm for the ASA group and for an analysis zone of 4.5 to 7.0 mm for the TSA group. At the 6 mm zone, the increase in SA was 0.032 in the ASA group and 0.069 in the TSA group. The induction of SA per diopter was 0.024 µm/D in the ASA group and 0.035 µm/D in the TSA group. The RAWS parameter increased by 34.8% in the ASA group and 74.4% in the TSA group. CONCLUSIONS: There was less induction of SA in myopic LASIK with an aspheric ablation profile than with a non-aspheric ablation profile.

Intraoperative perception and sensation in laser in situ keratomileusis (LASIK).

PURPOSE: To investigate intraoperative perception and sensation during Laser in situ Keratomileusis (LASIK). PATIENTS AND METHOD: Sixty patients with uneventful LASIK were included. All procedures were performed by one surgeon with one technique. Any patient with intra-operative complications was excluded. The patients were asked to fill in the subjective evaluation form regarding their perception and sensation during the operation. RESULTS: Twenty-nine patients (48%) reported no pain and twenty-six patients (43%) reported no burning sensation during the surgery. Nineteen patients (32%) reported no light perception during the suction period of microkeratome. There was no correlation between duration of the suction and no light perception (R2 0.01). Thirty-four patients (56%) reported no trouble in maintaining visual fixation at the red light during the laser treatment. Ten patients (16%) reported they could clearly see the movement during the surgery and 5 out of 10 patients (50% of 16%) reported visual frightening. Fifty cases (84%) reported no visual frightening during the surgery after reassurance of the visual experience by the surgeon before the surgery. CONCLUSIONS: Patients undergoing LASIK may experience different visual perceptions. Reassurance of the intraoperative perception and sensation before the surgery can reduce the visual frightening.