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Purpose To compare vision-related quality of life (VRQoL) scores and clinical outcomes between small-incision lenticule extraction and laser in situ keratomileusis (LASIK). Setting Singapore National Eye Centre, Singapore. Design Prospective study. Methods Patients had small-incision lenticule extraction using the Visumax 500 kHz femtosecond laser; or LASIK excimer ablation with the Wavelight Allegretto 400 Hz laser. Primary outcomes were 3-month predictability, efficacy, and safety. Secondary outcomes were intraoperative experience, visual symptoms, and VRQoL (validated Quality of Life Impact of Refractive Correction [QIRC] questionnaire) in 25 a subgroup of patients in each group. Following Rasch analysis, "Functional" and "Emotional," QIRC dimensions were analysed separately. Results At 3 months, predictability (82.5% versus 85.3%, ±0.5 diopters attempted correction, P =.453), safety index (1.13 ± 0.19 [SD] versus 1.07 ± 0.16, P = .158), and efficacy index (0.91 ± 0.21 versus 0.97 ± 0.19; P = .002) were found when comparing small-incision lenticule extraction (172 eyes) and LASIK (matched 688 eyes). Intraoperative experience between groups was not statistically different; visual fluctuations ( P = .020) and episodes of visual blurring ( P = .008) were greater after small-incision lenticule extraction than after LASIK at 1 month but not at 3 months. There was no difference in "functional" (66.7 ± 15.7 versus 55.3 ± 22.2, P = .064) and "emotional" (42.7 ± 23.2 versus 37.9 ± 23.8, P = .394) QIRC dimensions between the 2 groups (25 patients in each group) at 3 months. Conclusion The study, 3-month predictability, safety, and VRQL scores were not statistically different between small-incision lenticule extraction and LASIK. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

Purpose To describe the transition and outcomes of 3 refractive lenticule extraction (ReLEx) techniques: femtosecond lenticule extraction (FLEx), small-incision lenticule extraction (SMILE), and pseudo small-incision lenticule extraction. Setting Singapore National Eye Center, Singapore. Design Prospective comparative case series. Methods Refractive lenticule extraction was performed between March 1, 2010, and November 1, 2012, using the Visumax 500 kHz femtosecond laser system. The main outcome measures were the refractive efficacy, predictability, and safety over 12 months. Results The study enrolled 88 eyes. All 3 refractive lenticule extraction techniques yielded good refractive outcomes and stability over 12 months. Three months postoperatively, the mean overall efficacy index of refractive lenticule extraction was 0.89 ± 0.22 (SD), with 95.5% of eyes attaining an uncorrected distance visual acuity (UDVA) of better than 20/40 and 60.2% of better than 20/20. Of all eyes, 95.5% were within ±1.00 diopter (D) and 78.4% within ±0.50 D of the attempted correction. The mean overall safety index was 1.06 ± 0.17. At 3 months, all small-incision lenticule extraction eyes and 96.7% of pseudo small-incision lenticule extraction eyes had a UDVA of 20/40 or better, while femtosecond lenticule extraction eyes had a lower efficacy index (87.0%). However, efficacy was comparable in all 3 groups by 12 months (mean 0.87 ± 0.04 [standard error of the mean]; P = 1.00). Conclusion The efficacy, safety, and predictability profiles of the 3 refractive lenticule extraction techniques were good over a 12-month follow-up. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

Purpose To compare the efficacy, predictability, and safety outcomes of 2 femtosecond laser platforms for flap creation during laser in situ keratomileusis (LASIK) for myopia and myopic astigmatism. Setting Singapore National Eye Centre, Singapore. Design Retrospective case review. Methods In this single-center multisurgeon study, patients had LASIK with flaps created using a Visumax 500 kHz or Intralase 60 kHz femtosecond laser system. Ablation was performed with the Wavelight Allegretto Eye-Q 400 Hz excimer laser in all patients. Preoperative and 3-month postoperative manifest refraction, attempted treatment spherical equivalent (SE), visual acuity, and complications were compared. Results The 500 kHz femtosecond laser group comprised 381 patients (381 eyes) and the 60 kHz femtosecond laser group, 362 patients (362 eyes). Three months postoperatively, the uncorrected distance visual acuity was 20/40 or better in 99.1% of eyes in the 60 kHz laser group and 99.4% of eyes in the 500 kHz laser group ( P =.678). Regarding predictability, 98.6% of eyes and 97.4% of eyes, respectively, were within ±1.0 diopter of the attempted SE correction postoperatively ( P =.228). The safety index was similar in the 60 kHz laser group and the 500 kHz laser group (mean 1.06 ± 0.16 [SD] versus 1.05 ± 0.14) ( P =.321). Conclusion The safety, predictability, and efficacy profiles of the 500 kHz femtosecond platform for LASIK were excellent and comparable to those of the 60 kHz platform. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

Purpose To describe simulated night vision, night-vision symptoms, and refractive outcomes after small-incision lenticule extraction. Setting Tertiary referral eye center, Singapore. Design Prospective case series. Methods All patients had small-incision lenticule extraction using the Visumax 500 kHz femtosecond laser system. The main outcome measure was simulated night vision logMAR corrected distance visual acuity (CDVA) using the super vision test-night vision goggle vision chart at 12 months. Secondary outcomes measures included refractive outcomes (ie, efficacy, predictability, and safety) up to 12 months and vision-related symptoms assessed using a validated questionnaire. Results The study comprised 50 eyes. Overall simulated night vision was not affected (mean CDVA 0.08 logMAR ± 0.1 [SD], P = .67; mean mesopic CDVA −0.02 ± 0.1 logMAR, P = .58) after small-incision lenticule extraction at the 12-month follow-up. In low myopia, simulated night vision improved from preoperatively (mean 0.099 ± 0.07) to 12 months postoperatively (mean 0.006 ± 0.09) (P = .008). Most patients reported mild or no night-vision symptoms 3 months after surgery (score range 1.6 to 2.2). At 12 months, the overall efficacy index was 0.98 ± 0.20, with 100% of eyes attaining an uncorrected visual acuity of 20/40 or better and 86% attaining 20/20 or better. Ninety-four percent eyes were within ±1.0 diopter of the attempted correction, and the overall safety index was 1.17 ± 0.17. Conclusion Small-incision lenticule extraction did not affect simulated night vision or contrast sensitivity, with patients reporting no or mild night-vision symptoms. Financial Disclosure None of the authors has a financial or proprietary interest in any material or method mentioned.

Purpose To evaluate the between-observer (interobserver) and between-instrument (intraobserver) variability in flap thickness measurements after laser in situ keratomileusis (LASIK) using spectral-domain and time-domain anterior segment optical coherence tomography (AS-OCT). Setting Singapore National Eye Centre. Design Evaluation of diagnostic test or technology. Methods Two independent masked observers measured flap thickness 1 month after LASIK using spectral-domain (RTVue) or time-domain (Visante) AS-OCT. The measurements were taken at central (0.0 mm), −1.5 mm, and +1.5 mm locations. Measurements were repeated to assess between-instrument variability. Results There was no statistically significant difference in mean flap thickness between the 2 observers at −1.5 mm, 0.0 mm, and +1.5 mm on spectral-domain AS-OCT and at −1.5 mm and +1.5 mm on time-domain AS-OCT ( P P =.0008). There was stronger interobserver correlation for spectral-domain AS-OCT at −1.5 mm ( r = 0.82), 0.0 mm ( r = 0.88), and +1.5 mm ( r = 0.88) than for time-domain AS-OCT ( r = 0.73, r = 0.62, and r = 0.79, respectively). There was no statistically significant difference in between-instrument measurements. There was stronger between-instrument correlation with spectral-domain AS-OCT than with time-domain AS-OCT at all locations. The mean standard deviation (measure of instrument repeatability) for spectral-domain AS-OCT was 4.19 μm. Conclusion Spectral-domain AS-OCT had closer agreement in between-observer and between-instrument measurements than time-domain AS-OCT and provided more consistent measurements of post-LASIK flap thickness. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

To evaluate and compare (anterior and posterior) corneal parameters obtained by use of 3 corneal topography devices.Tertiary referral eye center, Singapore.Prospective observational study.Corneal measurements were obtained from 30 normal eyes and 40 eyes after Descemet-stripping automated endothelial keratoplasty (DSAEK) with use of the spectral-domain AS-OCT device, Scheimpflug device, and time-domain AS-OCT device. The posterior area analyzed, anterior and posterior keratometric values, keratometric power, and pachymetry were compared.The spectral-domain AS-OCT device was able to capture the highest posterior area analyzed (86.2% ± 6.7%) compared with the Scheimpflug device (56.8% ± 11.9%) and the time-domain AS-OCT device (68.8% ± 12.3%) (P.001). Intra-class coefficients (ICC) indicated strong agreement between devices in anterior keratometry (ICCs between 0.9 to 1.0) in both normal and DSAEK eyes. Agreement was poor to moderate for normal eyes (ICCs between 0.6 to 0.9) but poor in DSAEK eyes (ICCs between 0.60 to 0.7). For corneal pachymetry, agreement was moderate to strong for normal eyes (ICCs between 0.8 to 1.0) but showed poor to moderate agreement in DSAEK eyes (ICCs between 0.5 to 0.8). Vector analysis plots for mean astigmatism values showed greater differences between devices in anterior values compared with posterior values in both groups.Although the agreement between imaging systems was good for anterior corneal topography, posterior corneal topography had moderate agreement in normal eyes and poor agreement in eyes after endothelial keratoplasty.

Purpose To study intraobserver and interobserver reproducibility of corneal topography and aberrometry measurements using a device combining optical coherence tomography (OCT) and a Placido disk (Visante Omni). Setting Singapore National Eye Centre, Singapore. Design Prospective nonrandomized study. Method Measurements of simulated keratometry (K), anterior mean curvature, spherical anterior and posterior elevations, 4.5 mm diameter zone aberrometry (spherical aberration, asphericity, astigmatism), pachymetry, and white-to-white (WTW) diameter were taken in normal right eyes. Mean biases and limits of agreement (LoA) were obtained using Bland-Altman analysis. Results Regarding intraobserver repeatability, the mean biases for simulated K, anterior mean curvature, spherical anterior/posterior elevation, 4.5 mm zone aberrometry, pachymetry, and WTW diameter were not statistically significant ( P > .05). The LoA for the anterior mean curvature measurements were flat K, −3.96 diopters (D) and 4.86 D; steep K, −4.50 D and 4.27 D; mean K, −2.48 D and 2.09 D. The LoA for WTW were −9.90 mm and 8.74 mm. Regarding interobserver reproducibility, the mean biases for simulated K, anterior mean curvature, spherical anterior/posterior elevation, 4.5 mm zone aberrometry, pachymetry, and WTW diameter were not statistically significant ( P > .05). The LoA for anterior mean curvature were flat K, −4.05 D and 4.13 D; steep K, −5.08 D and 3.85 D; mean K, −2.65 D and 2.29 D. The LoA for WTW diameter were −8.79 mm and 8.24 mm. Conclusions The OCT–Placido device had high intraobserver and interobserver clinical reproducibility for measurements of simulated K, 4.5 mm zone aberrometry, pachymetry, and standard anterior/posterior corneal elevation. However, intraobserver and interobserver reproducibility of anterior mean curvature measurements and WTW diameter was lower. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

To compare the efficacy, predictability, and refractive outcomes of laser in situ keratomileusis (LASIK) using 2 femtosecond platforms for flap creation.Multisurgeon single center.Clinical trial.Bilateral femtosecond LASIK was performed using the Wavelight Allegretto Eye-Q 400 Hz excimer laser system. The Visumax femtosecond platform (Group 1) was used to create the LASIK flap in 1 eye, while the Intralase femtosecond platform (Group 2) was used to create the LASIK flap in the contralateral eye. The preoperative, 1-month, and 3-month postoperative visual acuities, refraction, and contrast sensitivity in the 2 groups were compared.The study enrolled 45 patients. Three months after femtosecond LASIK, 79.5% of eyes in Group 1 and 82.1% in Group 2 achieved an uncorrected distance visual acuity of 20/20 (P=.808). The mean efficacy index was 0.97 in Group 1 and 0.98 in Group 2 at 3 months (P=.735); 89.7% of eyes in Group 1 and 84.6% of eyes in Group 2 were within ± 0.50 diopter of emmetropia at 3 months (P=.498). No eye in either group lost more than 2 lines of corrected distance visual acuity. The mean safety index at 3 months was 1.11 in Group 1 and 1.10 in Group 2 (P=.570).The results of LASIK with both femtosecond lasers were similar, and both platforms produced efficacious and predictable LASIK outcomes.No author has a financial or proprietary interest in any material or method mentioned.