Observation on the tilt and decentration of multifocal intraocular lens with optic capture in Berger space for pediatric cataract.

PURPOSE: This study aimed to observe the tilt and decentration of multifocal intraocular lens (IOL) with optic capture in Berger space within 2 years after pediatric cataract surgery. METHODS: This is a prospective observational study. The implantation of multifocal IOL (Tecnis ZMB00) with optic capture in Berger space was performed on 33 patients (48 eyes) with pediatric cataract at Qingdao Eye Hospital. Tilt and decentration of IOL was measured using Scheimpflug system (Pentacam) at 1 month and 2 years postoperatively. RESULTS: All the multifocal IOLs were successfully implanted in Berger space with optic capture and no visually significant complications were detected during the follow-up. The mean tilt of IOLs was 2.779° ± 0.950° in the vertical plane and 2.399° ± 0.898° in the horizontal plane at 1 month postoperatively, and the mean length of the decentration was 0.207 ± 0.081 mm in vertical plane and 0.211 ± 0.090 mm in the horizontal plane. Compared with 1 month after surgery, the angle of tilt decreased by a mean of 0.192° and decentration increased by a mean of 0.014 mm at the vertical meridian at 2 years postoperatively (P = 0.37 and P = 0.27, respectively), meanwhile, tilt increased by 0.265° and decentration increased by 0.012 mm at the horizontal meridian (P = 0.11 and P = 0.22, respectively). CONCLUSIONS: The follow-up results suggest the tilt and decentration of multifocal IOL implantation with optic capture in Berger space remain stable in an acceptable range within 2 years after cataract surgery in children above the age of 5. TRIAL REGISTRATION: The study was approved by the Ethics Committee of Qingdao Eye Hospital, and registered on Chinese Clinical Trial Registry (ChiCTR identifier: 1900023155).

Applying Information Gain to Explore Factors Affecting Small-Incision Lenticule Extraction: A Multicenter Retrospective Study.

Purpose: This retrospective study aimed to identify the key factors influencing postoperative refraction after small-incision lenticule extraction (SMILE) using information gain. Methods: This study comprised 2,350 eyes of 1,200 patients who underwent SMILE using a Visumax 500-kHz femtosecond laser (Carl Zeiss Meditec AG) in three ophthalmic centers: Tianjin Eye Hospital (center A), Jinan Mingshui Eye Hospital (center B), and Qingdao Eye Hospital (center C). Anterior segment features, including corneal curvature and central corneal thickness (CCT), were obtained from Pentacam HR (Oculus, Wetzlar, Germany). Information gain was calculated to analyze the importance of features affecting postoperative refraction. Results: Preoperative and postoperative mean spherical equivalent (SE) refraction were -5.00 (-6.13, -3.88) D and 0.00 (-0.25, 0.13) D, respectively. None of the patients lost more than two lines of corrected distance visual acuity. The safety index was 1.32 ± 0.24, 1.03 ± 0.08, and 1.13 ± 0.16 in centers A, B, and C, respectively. The efficacy index was 1.31 ± 0.25, 1.02 ± 0.08, and 1.13 ± 0.17 in centers A, B, and C, respectively. At least 95% of the eyes were within ±1.00 D of the attempted correction. Postoperative refraction was related to preoperative spherical diopter refraction (r = 0.369, p < 0.001), preoperative SE (r = 0.364, p < 0.001), maximum lenticule thickness (r = -0.311, p < 0.001), preoperative uncorrected distance visual acuity (r = 0.164, p < 0.001), residual stromal thickness (r = 0.139, p < 0.001), preoperative mean anterior corneal curvature (r = -0.127, p < 0.001), preoperative flattest anterior corneal curvature (r = -0.122, p < 0.001), nomogram (r = -0.100, p < 0.001) and preoperative CCT (r = -0.058, p = 0.005). Conclusions: SMILE was considered a safe and effective procedure for correcting myopia. Based on information gain, postoperative refraction was influenced by preoperative mean anterior corneal curvature, CCT, refraction, and residual stromal thickness.

Comparison of clinical results between trans-PRK and femtosecond LASIK for correction of high myopia.

BACKGROUND: To compare the clinical outcomes of transepithelial photorefractive keratectomy (TPRK) with femtosecond laser-assisted in situ keratomileusis (FS-LASIK) for correction of high myopia. METHODS: In this prospective, non-randomised, cohort study, 85 eyes of 46 patients treated with TPRK and 80 eyes of 42 patients treated with FS-LASIK were included. All eyes were highly myopic (spherical equivalent refraction <- 6.00 diopters). Both TPRK and FS-LASIK were performed by Schwind Amaris 750S excimer laser. Visual acuity, refraction, corneal high order aberration (HOA) and other variables were analyzed before and at 1, 3, 6, 12 months after surgery. RESULTS: At 12 months after surgery, uncorrected logMAR distance visual acuity (UDVA) in the TPRK and FS-LASIK groups was - 0.04 ± 0.04 and - 0.01 ± 0.08, respectively (P = 0.039). Corrected logMAR distance visual acuity (CDVA) was - 0.06 ± 0.05 and - 0.04 ± 0.05 in both groups (P = 0.621). For UDVA, 86% of eyes in the TPRK group and 80% in the FS-LASIK group remained unchanged or improved one or more logMAR lines (P = 0.314), compared to preoperative CDVA. For CDVA, 97% of eyes in the TPRK group and 90% in the FS-LASIK group remained unchanged or improved one or more lines (P = 0.096), compared to preoperative CDVA. Spherical equivalent refraction was - 0.05 ± 0.39 and - 0.26 ± 0.47 in both groups (P = 0.030). 87% of eyes in the TPRK group and 73% in the FS-LASIK group achieved ±0.50 D target refraction (P = 0.019). All 85 eyes (100%) in the TPRK group and 75 eyes (92%) in the FS-LASIK group were within ±1.00 D of target (P = 0.003). Root mean square (RMS) of corneal total HOA and vertical coma in the TPRK group were lower compared with the FS-LASIK group (P < 0.001 for both variables). CONCLUSIONS: TPRK and FS-LASIK showed good safety, efficacy and predictability for correction of high myopia. Clinical outcomes of TPRK were slightly better than FS-LASIK.

Six modes of corneal topography for evaluation of ablation zones after small-incision lenticule extraction and femtosecond laser-assisted in situ keratomileusis.

PURPOSE: To evaluate the ablation zone diameter (AZD) using six modes of corneal topography after small-incision lenticule extraction (SMILE) and femtosecond laser-assisted in situ keratomileusis (FS-LASIK) for myopia and to compare the programmed and postoperative AZDs METHODS: This retrospective comparative study included 86 right eyes in 86 patients who underwent SMILE or FS-LASIK at the Shandong Eye Institute between June 2016 and August 2017. Data were collected preoperatively and at 1, 3, and 6 months postoperatively using the Pentacam system. The AZD was determined using six modes of corneal topography: postoperative axial curvature topography (PACT), postoperative tangential curvature topography (PTCT), difference-axial curvature topography (DACT), difference-tangential curvature topography (DTCT), postoperative front elevation topography (PFET), and difference-corneal thickness topography (DCTT). The difference between the programmed and postoperative AZDs was compared between the groups of two surgical procedures. RESULTS: At 3 months, the AZDs measured by PTCT, DTCT, and PFET after SMILE showed a significant decrease, while the AZD by DACT revealed an increase (P < 0.001), and the AZDs measured by PACT, PTCT, DACT, DTCT, PFET, and DCTT after FS-LASIK were all significantly decreased (P < 0.001), as compared with the programmed ablation zone values. The AZDs measured by DACT and DTCT after 3 months were larger in the SMILE group (P < 0.001); likewise, the differences between the programmed and postoperative AZDs were lower in the SMILE group (P < 0.001). Furthermore, PACT, PTCT, DACT, DTCT, and PFET indicated acceptable inter-observer reliability (ICC > 0.75). CONCLUSIONS: In the treatment of myopia, the achieved topographic ablation zones after FS-LASIK were smaller than the theoretically designed ones. The AZDs after SMILE were larger than those after FS-LASIK, with an equivalent programmed value. The DACT may be more suitable for measuring postoperative ablation zones in clinic with clearer borders and favorable repeatability. This method may be potential for the measurement of ablation zones and further research on the visual quality after refractive surgery.