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Purpose: To explore the potential of crystalline lens decentration and tilt as indicators for screening cataract patients for presbyopia-correcting intraocular lens (IOL) implantation. Methods: Prospective observational study. Patients undergoing phacoemulsification with bifocal (Tecnis ZMB00) or extended depth-of-focus (EDOF) (Tecnis ZXR00) IOL implantation were consecutively enrolled. The decentration and tilt of the crystalline lens and the IOL were quantified through the utilization of swept-source optical coherence tomography (SS-OCT, Casia2). Postoperative visual acuity (VA), contrast sensitivity (CS), objective optical quality, and patient-reported outcomes were assessed at a 3-month follow-up. A LOWESS (LOcally WEighted Scatterplot Smoothing) curve was employed to analyze the changes in VA, CS, and objective optical quality relative to the decentration or tilt of crystalline lenses. A further comparison of visual outcomes was conducted based on the inflection points suggested by the curves. Results: Eighty‑seven patients with ZMB00 IOL and 76 patients with ZXR00 IOL were included. Multiple 6-mm internal aberrations showed a nonlinear increase with greater crystalline lens decentration. The inflection points for the steep increase were observed to be 0.28 mm for the bifocal group and 0.35 mm for the EDOF group. Beyond these points, internal aberrations such as coma increased significantly (all P < 0.01). Patient satisfaction decreased (P < 0.01). Moreover, the bifocal group exhibited a decline in spectacle-independence from 98.67% to 83.33% (P = 0.049), along with a reduction in CS (P < 0.05). Conclusions: The increased decentration of crystalline lenses compromises specific visual quality aspects in eyes implanted with ZMB00 and ZXR00 IOLs, with cut-off values of 0.28 mm and 0.35 mm, respectively. [ABSTRACT FROM AUTHOR]

Introduction: We conducted an evaluation of capsular bag performance of the Clareon CNA0T0 intraocular lens (IOL), focusing on postoperative anterior chamber depth (ACD), IOL tilt, and IOL decentration. Methods: Inclusion criteria were bilateral age-related cataract and the ability to provide informed consent. Exclusion criteria were prior surgeries, combined surgeries, and conditions posing a risk for postoperative capsular bag instability. Preoperative and 8-week postoperative assessments included optical biometry and high-resolution anterior segment optical coherence tomography (OCT). Subjective refraction was conducted only at 8 weeks postoperative visit. Results: In the first analysis, 49 right eyes of 49 patients were included. Mean preoperative and postoperative ACD were 3.10 and 4.69 mm, respectively. Mean preoperative tilt was 4.77°, increasing to 5.06° postoperatively. Preoperative decentration was 0.16 mm, increasing to 0.26 mm postoperatively. Absolute refractive error (ARE) was + 0.31D, with 81% of eyes within ± 0.5D limits. In analysis II (98 eyes of 49 patients), both eyes showed a moderate correlation in IOL tilt (Pearson correlation coefficient: 0.27, p = 0.061) and a low correlation in IOL decentration (Pearson correlation coefficient: 0.02, p = 0.892) and ARE (Spearman: 0.15, p = 305) between right and left eyes of the same patient. Conclusions: The Clareon CNA0T0 IOL demonstrated high mechanical stability, with low postoperative tilt and decentration values, resulting in excellent refractive outcomes and visual acuity. These findings confirm the IOL's high stability within the capsular bag and effectiveness in minimizing postoperative refractive error, requiring only minor A-constant adjustments for optimal cataract surgery outcomes. Trial Registration: NCT06595693. [ABSTRACT FROM AUTHOR]

Objectives: This laboratory study aims to assess the effects of misaligning different trifocal intraocular lenses (IOLs) under varying spectral and corneal spherical aberration (SA) conditions. Methods: With an IOL metrology device under monochromatic and polychromatic conditions, the following models were studied: AT ELANA 841P, AT LISA Tri 839MP, FineVision HP POD F, Acrysof IQ PanOptix, and Tecnis Synergy ZFR00V. The SA was simulated using an aberration-free and average-SA cornea. The modulation transfer function (MTF) was measured at different pupil sizes for the on- and off-axis lens positions. Results: The IOLs exhibited varying responses to decentration up to 1 mm, showing the lowest impact in polychromatic light. The least affected was AT ELANA, with an MTF loss of 15.7% to 28.4% at 50 lp/mm across the studied conditions. It was followed by PanOptix and FineVision, with the MTF loss ranging from 19.1% to 36.0% and from 21.2% to 46.6%. AT LISA showed a more substantial reduction, i.e., 41.2% to 64.8%, but it was still lower than that of Synergy (51.1% to 78.8%). When decentration was induced at a 4.5 mm distance, its effect was more evident in conditions that were closer to each IOL's SA correction. A tilt of 5° had a lesser impact than 1 mm decentration, with the effect being more severe at 4.5 mm. Conclusions: The off-axis position affects the optical quality of trifocal IOLs. Low- rather than high-SA-correcting trifocals perform better under misalignment. In polychromatic light, the impact of misalignment is less evident, suggesting a potential mitigating effect of chromatic aberration. [ABSTRACT FROM AUTHOR]

Background/Objectives: The objective of this study was to examine the trend of treatment zone (TZ) decentration over 12 months of orthokeratology (OK) wear using two Corneal Refractive Therapy (CRT) lens designs: standard (STD) and dual axis (DA). Methods: A prospective, randomized, longitudinal study was conducted at the Optometry Clinic of the Complutense University of Madrid. Subjects were randomly fitted with an STD design or DA design in one of the eyes. Refraction, uncorrected visual acuity (VA), and corneal topography were performed at baseline and after 1 night, 1 week, and 1, 3, 6, and 12 months of lens wear. Subjects requiring lens parameter adjustments or replacements after 3 months were excluded. Decentration was measured by subtracting pre-OK from post-OK tangential curvature maps at each visit, with decentration distance and corneal optical TZ being measured using MATLAB. Correlations between decentration and visual acuity (VA) were also analyzed. Results: A total of 30 healthy children (17 females and 13 males) with a mean age of 12.83 ± 2.42 years (range: 8–17 years) completed all the visits. No statistically significant differences (p > 0.05) were found between lens designs in horizontal, vertical, nor total decentration through the visits. However, for the STD design, horizontal and total decentration increased significantly at the last visit (p < 0.05). For the DA design, no significant differences were found over time (p > 0.05). No correlation was found between decentration and VA. Conclusions: Total decentration in both lens designs was similar throughout one year of follow-up. The standard design tended to decenter horizontally during the last 6 months, while the dual-axis design maintained consistent decentration throughout the year. [ABSTRACT FROM AUTHOR]

Henri Grivois has posited that psychosis involves the subjective experience of oneself as the center or focal point of the world. In this experience, the world that is typically unrelated to oneself becomes incomprehensible, and in its place is the sense that all life events are directly related to oneself or that one is perpetually at the center of all noteworthy activity. We suggest that this experience of centrality can be understood through the lens of the integrated model of metacognition. Specifically, we explore the idea that the metacognitive domain of decentration, or the ability to form ideas about the larger community one is a part of, can be used to operationalize and measure centrality. We propose a three-phase approach to addressing centrality within an integrative psychotherapy focused on subjective and experiential aspects of recovery. These phases focus on the patient's experience of centrality and include (1) inviting the therapist to join one's centrality, (2) acknowledging others as different from oneself, and (3) recognizing alternative perspectives in the world. We provide case examples and explore the metacognitive tasks and potential barriers associated with each phase. [ABSTRACT FROM AUTHOR]

Akshaya L Thananjeyan, Chandra Bala PersonalEyes, Sydney, NSW, AustraliaCorrespondence: Chandra Bala, Personal-Eyes, 2/33 York St, Sydney, NSW, 2000, Australia, Tel +61 88337111, Email bala@personaleyes.com.auPurpose: To assess ocular higher-order aberrations (HOAs) following ray trace guided laser in situ keratomileusis (LASIK).Methods: Retrospective review at a single-site ophthalmology practice. Two hundred and fifty eyes of 250 patients with myopia and astigmatism undergoing ray trace LASIK were randomly reviewed (Wavelight Plus, Alcon). The InnovEyes Sightmap (Alcon) diagnostic device was used for whole-eye wavefront aberrometry, tomography, and biometry assessment preoperatively and 3 months post-operatively. Ocular HOA, ablation decentration, intraoperative pupil size, and pupil tracking were assessed. Intraoperative eye tracking of x and y coordinates were separately averaged to calculate mean and standard deviation of movement along the x-axis and y-axis to assess eye movement.Results: Total HOA RMS (n = 250 eyes) increased marginally from 0.306 ± 0.102 to 0.371 ± 0.135 (p < 0.001) post-operatively. Spherical aberration decreased (0.092 ± 0.112 to 0.056 ± 0.125, p < 0.001). There was no significant difference in preoperative to postoperative vertical coma under − 3D SEQ and horizontal coma under 2D SEQ. In eyes with 4D or more myopia treatment, post-operative vertical and horizontal coma was moderately correlated with the product of ablation depth and vertical and horizontal decentration (R2 0.51, p < 0.001, R2=0.34, p < 0.001, respectively). Multivariate analysis further showed this was correlated to eye movement.Conclusion: Ray trace LASIK results in a minimal increase in total ocular HOA which is statistically but not clinically significant. Spherical aberration decreases. In larger treatments, there is an increase in coma which correlates with vertical and horizontal decentration of ablation, likely due to eye movement during surgery.Keywords: laser in situ keratomileusis, ray trace, higher-order aberration, eye movement, decentration, coma

Abstract Purpose To compare long-term intraocular lens (IOL) decentration and tilt following femtosecond laser-assisted cataract surgery (FLACS) and conventional surgery using swept-source anterior segment ocular coherence tomography (SS-ASOCT). Methods In this retrospective cross-sectional study, all patients underwent FLACS or conventional cataract surgery. Those with a minimum of 12-months follow-up since surgery were included. Patients with surgical complications were excluded. Demographics, preoperative ocular measurements (axial length, anterior chamber depth), and postoperative measurements [corrected distance visual acuity (CDVA), autorefraction, keratometry, IOL type] were collected. Postoperative IOL tilt and decentration were compared using SS-ASOCT between patients with FLACS and conventional cataract surgery. Subgroup analysis was conducted to analyze tilt and decentration by haptic type (single-piece vs. three-piece). Results A total of 188 eyes were included [110 (58.5%) in the FLACS group and 78 (41.5%) in the conventional group]. No differences were observed between the FLACS and conventional groups regarding preoperative parameters. FLACS resulted in less IOL decentration compared to conventional cataract surgery (170 μm vs. 240 μm, p = 0.002). No statistically significant differences were observed between the FLACS and conventional groups in the magnitude and axis of IOL tilt. Both groups had a trend of IOL tilt toward the inferotemporal aspects. Moreover, no difference regarding postoperative CDVA, spherical equivalent, and keratometric astigmatism was observed. Conclusions FLACS resulted in significantly better long-term IOL centration than conventional surgery with manual capsulotomy. No significant difference in IOL tilt or postoperative CDVA was observed between FLACS and conventional cataract surgery.

Purpose: To quantify the impact of varying central fluid reservoir depth, lens thickness/mass and the addition of a peripheral fenestration upon scleral lens centration. Methods: Ten young, healthy adults participated in a series of repeated‐measures experiments involving short‐term (90 min) open eye scleral lens wear. Scleral lens parameters (material, back optic zone radius, diameter, back vertex power and landing zone) were controlled across all experiments, and the central fluid reservoir depth (ranging from 144 to 726 μm), lens thickness (ranging from 150 to 1200 μm), lens mass (101–241 mg) and lens design (with or without a single 0.3 mm peripheral fenestration) were altered systematically. Scleral lens decentration was quantified using over‐topography maps. Results: On average, scleral lens centration varied by <0.10 mm over 90 min of wear. Medium and high initial fluid reservoir conditions resulted in 0.17 mm more temporal and 0.55 mm more inferior lens decentration, compared to the low fluid reservoir depth (p < 0.001). Changes in lens thickness or the addition of a peripheral fenestration did not cause clinically significant changes in centration (<0.10 mm on average) when controlling for fluid reservoir depth. Central fluid reservoir depth was the best predictor of horizontal and vertical lens decentration, explaining 62–73% of the observed variation, compared to 40–44% for lens thickness and mass. Conclusion: Scleral lens decentration remained relatively stable over 90 min of lens wear. A greater initial central fluid reservoir depth resulted in significantly more lens decentration, particularly inferiorly. Large variations in lens thickness, mass or the addition of a single peripheral fenestration did not substantially affect lens centration. [ABSTRACT FROM AUTHOR]

Purpose: To compare long-term intraocular lens (IOL) decentration and tilt following femtosecond laser-assisted cataract surgery (FLACS) and conventional surgery using swept-source anterior segment ocular coherence tomography (SS-ASOCT). Methods: In this retrospective cross-sectional study, all patients underwent FLACS or conventional cataract surgery. Those with a minimum of 12-months follow-up since surgery were included. Patients with surgical complications were excluded. Demographics, preoperative ocular measurements (axial length, anterior chamber depth), and postoperative measurements [corrected distance visual acuity (CDVA), autorefraction, keratometry, IOL type] were collected. Postoperative IOL tilt and decentration were compared using SS-ASOCT between patients with FLACS and conventional cataract surgery. Subgroup analysis was conducted to analyze tilt and decentration by haptic type (single-piece vs. three-piece). Results: A total of 188 eyes were included [110 (58.5%) in the FLACS group and 78 (41.5%) in the conventional group]. No differences were observed between the FLACS and conventional groups regarding preoperative parameters. FLACS resulted in less IOL decentration compared to conventional cataract surgery (170 μm vs. 240 μm, p = 0.002). No statistically significant differences were observed between the FLACS and conventional groups in the magnitude and axis of IOL tilt. Both groups had a trend of IOL tilt toward the inferotemporal aspects. Moreover, no difference regarding postoperative CDVA, spherical equivalent, and keratometric astigmatism was observed. Conclusions: FLACS resulted in significantly better long-term IOL centration than conventional surgery with manual capsulotomy. No significant difference in IOL tilt or postoperative CDVA was observed between FLACS and conventional cataract surgery. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate and compare the effect of decentration and tilt on the optical quality of monofocal and trifocal intraocular lenses (IOL). Methods: Optical quality of a monofocal IOL (AcrySof IQ SN60WF; Alcon Laboratories, Inc., USA) and a trifocal IOL (AcrySof IQ PanOptix; Alcon Laboratories, Inc., USA) was assessed using an in vitro optical bench (OptiSpheric IOL R&D; Trioptics GmbH, Germany). At apertures of 3.0 mm and 4.5 mm, modulation transfer function (MTF) at spatial frequency of 50 lp/mm, MTF curve and the United States Air Force (USAF) resolution test chart of the two IOLs were measured and compared at their focus with different degrees of decentration and tilt. Optical quality at infinity, 60 cm and 40 cm and the through-focus MTF curves were compared when the two IOLs were centered at apertures of 3.0 mm and 4.5 mm. Spectral transmittance of the two IOLs was measured by the UV–visible spectrophotometer (UV 3300 PC; MAPADA, China). Results: The SN60WF and the PanOptix filtered blue light from 400 to 500 nm. Both IOLs at the far focus and the PanOptix at the intermediate focus showed a decrease in optical quality with increasing decentration and tilt. The PanOptix demonstrated enhanced optical quality compared to the previous gradient at the near focus at a decentration range of 0.3–0.7 mm with a 3.0 mm aperture, and 0.5 mm with a 4.5 mm aperture, whereas other conditions exhibited diminished optical quality with increasing decentration and tilt at the focus of both IOLs. When the two IOLs were centered, the SN60WF had better optical quality at infinity, while the PanOptix had better optical quality at 60 cm and 40 cm defocus. The optical quality of the SN60WF exceeded that of the PanOptix at far focus, with a 3 mm aperture decentration up to 0.7 mm and a 4.5 mm aperture decentration up to 0.3 mm; this observation held true for all tilts, irrespective of aperture size. As both decentration and tilt increased, the optical quality of the SN60WF deteriorated more rapidly than that of the PanOptix at the far focal point. Conclusions: The SN60WF showed a decrease in optical quality with increasing decentration and tilt. Optical quality of the PanOptix at the near focus increased in some decentration conditions and decreased in some conditions, while it showed a decrease at the other focuses with increasing decentration. While tilt only had a negative effect on optical quality. When both IOLs were centered, the PanOptix provided a wider range of vision, while the SN60WF provided better far distance vision. At the far focus, the SN60WF has better resistance to tilt than the PanOptix, but the optical quality degrades more quickly when decentered and tilted. [ABSTRACT FROM AUTHOR]

Background: The aim is to investigate induced higher-order aberrations (HOA)s and astigmatism as a result of non-toric ortho-k lens decentration and utilise artificial intelligence (AI) to predict its magnitude and direction. Methods: Medmont E300 Video topographer was used to scan 249 corneas before and after ortho-k wear. Custom-built MATLAB codes extracted topography data and determined lens decentration from the boundary and midpoint of the central flattened treatment zone (TZ). An evaluation was carried out by conducting Zernike polynomial fittings via a computer-coded digital signal processing procedure. Finally, an AI-based machine learning neural network algorithm was developed to predict the direction and magnitude of TZ decentration. Results: Analysis of the first 21 Zernike polynomial coefficients indicate that the four low-order and four higher-order aberration terms were changed significantly by ortho-k wear. While baseline astigmatism was not correlated with lens decentration (R = 0.09), post-ortho-k astigmatism was moderately correlated with decentration (R = 0.38) and the difference in astigmatism (R = 0.3). Decentration was classified into three groups: ≤0.50 mm, reduced astigmatism by −0.9 ± 1 D; 0.5~1 mm, increased astigmatism by 0.8 ± 0.1 D; >1 mm, increased astigmatism by 2.7 ± 1.6 D and over 50% of lenses were decentred >0.5 mm. For lenses decentred >1 mm, 29.8% of right and 42.7% of left lenses decentred temporal-inferiorly and 13.7% of right and 9.4% of left lenses decentred temporal-superiorly. AI-based prediction successfully identified the decentration direction with accuracies of 70.2% for right and 71.8% for left lenses and predicted the magnitude of decentration with root-mean-square (RMS) of 0.31 mm and 0.25 mm for right and left eyes, respectively. Conclusions: Ortho-k lens decentration is common when fitting non-toric ortho-k lenses, resulting in induced HOAs and astigmatism, with the magnitude being related to the amount of decentration. AI-based algorithms can effectively predict decentration, potentially allowing for better control over ortho-k fitting and, thus, preferred clinical outcomes. [ABSTRACT FROM AUTHOR]

Purpose: To assess the possible impact of minor changes in fixation on wavefront measurements as a potential constraint in detecting subtle temporal variations in ocular wavefront error. Methods: Twelve healthy subjects with an average age of 36.3 ± 8.8 were instructed to put their heads in the aberrometer's chin-rest and look at a fixation target that was embedded in the device. The fixation targets were readily observable to the participants without accommodation, thanks to the aberrometer's Badal system. When each eye was staring at the target, its wavefront aberration was recorded three times and then averaged for further analysis. The averaged Zernike coefficients were rescaled to the smallest value of the maximum round pupil found among all eyes (4.41 mm), and this procedure was repeated for each target. Results: Alteration of the fixation targets caused changes to the Zernike coefficients of defocus (C(2,0)), vertical trefoil (C(3,–3)), vertical coma (C(3,–1)), horizontal coma (C(3,1)), oblique trefoil (C(3,3)), primary spherical aberration (C(4,0)), and secondary spherical aberration (C(6,0)), but the changes were not statistically significant. Nevertheless, an alteration in the target's size and shape exhibited a significant correlation across all of the aforementioned coefficients in both eyes (p < 0.05). The total RMS of aberrations and the RMS of the spherical-like aberrations were both lowest while choosing the larger Maltese cross, and the bigger E-letter minimized the RMS of HOA and comatic aberrations. Conclusion: The aberrometric changes occur as a consequence of altering the fixational gaze and are within the range of the changes found after performing a near-vision task, so they might potentially act as a confounding factor when attempting to identify such small variations in the ocular wavefront. Using a smaller E-letter (5 arcmin) as an internal fixation target resulted in the least standard deviation of measurements, fixational stability, and higher accuracy in ocular wavefront measurements. [ABSTRACT FROM AUTHOR]

Abstract Purpose To investigate the repeatability and reproducibility of a new method for centration analysis after small incision lenticule extraction (SMILE) and femtosecond laser-assisted LASIK (FS-LASIK). Methods This study comprised 29 eyes treated with SMILE and 24 with FS-LASIK. Decentrations were analyzed using tangential and pachymetry difference maps respectively. Both difference maps were generated with a Scheimpflug tomographer (Pentacam) for each eye, using preoperative and 3-month postoperative scans. Repeatability and reproducibility were evaluated by calculating the intraclass correlation coefficient (ICC), within-subject standard deviation (Sw), and coefficient of repeatability (CR). Results ICC, Sw, and CR showed good to excellent repeatability in locating the coordinates of the optical zone (OZ) center on both maps, with values ranging from 0.84 to 0.96, 0.03 to 0.13, and 0.08 to 0.36 respectively. The repeatability of the total decentration from the preoperative corneal vertex on the tangential curvature difference maps( $$d_{TC}$$ d TC ) and the pachymetry difference maps( $$d_{PC}$$ d PC ) were moderate and good, respectively. The ICC, Sw, and CR of $$d_{TC}$$ d TC were 0.63, 0.09, and 0.25, respectively. The ICC, Sw, and CR of $$d_{PC}$$ d PC were 0.77, 0.10, and 0.28, respectively. The reproducibility of the OZ center measurements was excellent for the tangential difference maps (ICC $$\ge 0.97$$ ≥ 0.97 ) and good for the pachymetry difference maps (ICC $$\ge$$ ≥ 0.86). ICC, Sw, and CR showed excellent reproducibility of $$d_{TC}$$ d TC , with values of 0.95, 0.03, and 0.08, respectively. ICC, Sw, and CR showed good reproducibility of $$d_{PC}$$ d PC , with values of 0.89, 0.06, and 0.17, respectively. Conclusion The centration analysis method used in this study showed good to excellent repeatability and reproducibility in locating the coordinates of the center of the OZ on the tangential and pachymetry difference maps.

Purpose: To investigate the repeatability and reproducibility of a new method for centration analysis after small incision lenticule extraction (SMILE) and femtosecond laser-assisted LASIK (FS-LASIK). Methods: This study comprised 29 eyes treated with SMILE and 24 with FS-LASIK. Decentrations were analyzed using tangential and pachymetry difference maps respectively. Both difference maps were generated with a Scheimpflug tomographer (Pentacam) for each eye, using preoperative and 3-month postoperative scans. Repeatability and reproducibility were evaluated by calculating the intraclass correlation coefficient (ICC), within-subject standard deviation (Sw), and coefficient of repeatability (CR). Results: ICC, Sw, and CR showed good to excellent repeatability in locating the coordinates of the optical zone (OZ) center on both maps, with values ranging from 0.84 to 0.96, 0.03 to 0.13, and 0.08 to 0.36 respectively. The repeatability of the total decentration from the preoperative corneal vertex on the tangential curvature difference maps( d TC ) and the pachymetry difference maps( d PC ) were moderate and good, respectively. The ICC, Sw, and CR of d TC were 0.63, 0.09, and 0.25, respectively. The ICC, Sw, and CR of d PC were 0.77, 0.10, and 0.28, respectively. The reproducibility of the OZ center measurements was excellent for the tangential difference maps (ICC ≥ 0.97 ) and good for the pachymetry difference maps (ICC ≥ 0.86). ICC, Sw, and CR showed excellent reproducibility of d TC , with values of 0.95, 0.03, and 0.08, respectively. ICC, Sw, and CR showed good reproducibility of d PC , with values of 0.89, 0.06, and 0.17, respectively. Conclusion: The centration analysis method used in this study showed good to excellent repeatability and reproducibility in locating the coordinates of the center of the OZ on the tangential and pachymetry difference maps. [ABSTRACT FROM AUTHOR]

Purpose: The fit and optical performance of a scleral lens is affected by the alignment of the landing zone with the underlying ocular surface. The aim of this research was to quantify the effect of landing zone toricity upon scleral lens fitting characteristics (rotation and decentration) and optics (lens flexure) during short‐term wear. Methods: Scleral lenses with nominal landing zone toricities of 0, 100, 150 and 200 μm were worn in a randomised order by 10 young healthy participants (mean [SD] 24 [7] years) for 30 min, with other lens parameters held constant. Scleral toricity was quantified using a corneo‐scleral profilometer, and lens flexure, rotation, and decentration were quantified using over‐topography during lens wear. Repeated measures analyses were conducted as a function of landing zone toricity and residual scleral toricity (the difference between scleral and lens toricity) for eyes with 'low' magnitude scleral toricity (mean: 96 μm) and 'high' magnitude scleral toricity (mean: 319 μm). Results: Toric landing zones significantly reduced lens flexure (by 0.37 [0.21] D, p < 0.05) and lens rotation (by 20 [24]°, p < 0.05) compared with a spherical landing zone. Horizontal and vertical lens decentration did not vary significantly with landing zone toricity. These trends for flexure, rotation, and decentration were also observed for eyes with 'low' and 'high' magnitude scleral toricity as a function of residual scleral toricity. Conclusion: Landing zones with 100–200 μm toricity significantly reduced lens flexure (by ~62%) and rotation (by ~77%) but not horizontal or vertical lens decentration, compared with a spherical landing zone, when controlling for other confounding variables. The incorporation of a toric landing zone, even for eyes with lower magnitude scleral toricity (~100 μm), may be beneficial, particularly for front surface optical designs. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the relative positions of modern soft contact lenses (SCLs) relative to the limbus/cornea and the pupil. Methods: Sixty images of the anterior eyes of 101 subjects were acquired over 10 s while participants fixated the centre of the camera lens located 33 cm in front of the eye in a well‐lit (300 lux) clinic. Custom validated image analysis software was used to locate the boundaries of the contact lenses, pupils and corneas (limbus). Horizontal and vertical relative positions of the contact lens, pupil and limbus were calculated from the fitted boundaries. Results: The mean (standard deviation) pupil and corneal diameters for all subjects were 3.84 mm, (0.83) and 11.97 mm (0.48), respectively. The mean [95% confidence interval] pupil centre was located 0.28 mm [0.26, 0.30] nasally and 0.07 mm [0.05, 0.10] superiorly to the corneal centre. Consistent with clinical observations, the contact lenses centred accurately relative to the corneal centre both nasally 0.04 mm [0.01, 0.07] and inferiorly −0.01 mm [−0.06, 0.03]. However, regardless of the eye, the contact lens was significantly (p < 0.001) decentred relative to the pupil centre both temporally −0.23 mm [−0.26, −0.20] and inferiorly −0.08 mm [−0.12, −0.04]. Decentration magnitudes were significantly correlated between the right and left eyes. Conclusions: Spherical SCLs centred well on the cornea but temporally and inferiorly from the primary line of sight (pupil centre), due to the differences in the location of the pupil and corneal centres. Contrary to some previous reports, there was no evidence that lens optics or material affected lens centration significantly. [ABSTRACT FROM AUTHOR]

PurposeThis study analyzed the corneal surface shape following overnight orthokeratology with different optical zone diameters.MethodsA total of 82 eyes belonging to 41 myopic children who completed 1 month of the orthokeratology (ortho-k) lens wear at the Eye Hospital of Wenzhou Medical University from January 2022 to January 2023 were retrospectively analyzed. According to the size of the base curve (BC) of ortho-k lens, patients were divided into BC 5.0 and BC 6.0 groups. The changes in decentration distance and corneal refraction of the two groups after the ortho-k lens wear were analyzed. Independent sample t-tests were used to compare these two outcome measures between the two groups.ResultsThe decentration distance of BC 5.0 group (0.37 ± 0.19 mm) was significantly lower than that of BC 6.0 group (0.49 ± 0.25 mm, t = −2.330, p = 0.022). In the BC 5.0 group, the direction of decentration was superonasal in 3 cases, inferonasal in 2 cases, inferotemporal in 21 cases, and superotemporal in 6 cases. In the BC 6.0 group, the direction of decentration was superonasal in 2 cases, inferonasal in 2 cases, inferotemporal in 27 cases, and superotemporal in 19 cases. The optical zone area (8.19 ± 2.96 mm2) and reverse curve zone area (30.05 ± 6.74 mm2) in the BC 5.0 group were significantly lower than in the BC 6.0 group (10.42 ± 2.03 mm2, t = −4.043, p < 0.001; 38.21 ± 4.77 mm2, t = −6.422, p < 0.001). The change in the rate of refraction in the horizontal direction in BC 5.0 group were significant higher than in BC 6.0 group.ConclusionBase curve 5.0 mm ortho-k lens is better positioned than BC 6.0 mm lens. A small BC ortho-k forms a smaller optical zone and reverse curve area, which might get a greater aiameter of alignment curve to facilitate positioning better than the traditional BC lens. In addition, a small BC lens increases positive refraction in the peripheral area, resulting in a greater negative pressure than the traditional BC lens.

Addressing challenges such as centralization, data tampering, and information silos within traditional supply chain transparency frameworks, we leverage the decentralized, immutable, and traceable attributes of blockchain technology. Given the multitude of participating nodes and the extensive volume of tracking data in Manufacturing-as-a-Service (MaaS) supply chains, we initially propose a master-slave multi-chain data storage model tailored for MaaS supply chain transparency. Building upon this, to enhance blockchain performance in this context and address the issues of high communication overhead, low consensus efficiency, and the absence of dynamic mechanisms inherent in the Practical Byzantine Fault Tolerance (PBFT) method, we introduce the Service Quality Scoring Based Practical Byzantine Fault Tolerance (SQS-PBFT) method. By incorporating the service quality scoring model for optimal master node selection, we aim to improve consensus efficiency; through the node tiering mechanism and consensus protocol optimization, we reduce communication costs; and by establishing the dynamic node mechanism for flexible node entry and exit, we enhance system flexibility. Experiments demonstrate that with an increasing number of nodes, the proposed SQS-PBFT method results in about 29.47% lower communication overhead, about 25.11% higher throughput, about 19.98% reduced latency, and about 36.15% reduced malicious behavior, thus offering improved consensus efficiency and serving as a reference for MaaS supply chain transparency.

Purpose: To evaluate the effect of primary posterior continuous curvilinear capsulorrhexis (PPCCC) on the positional stability of IOLs. Methods: This study is a prospective intra-individual comparative randomized controlled trial including 31 patients (62 eyes). Eyes of the same patient were randomly assigned to the PPCCC group (18 right eyes and 13 left eyes) or group without PPCCC (NPCCC group). Eyes in both groups were implanted with a one-piece foldable hydrophobic acrylic IOL via routine cataract surgery. Patients in the PPCCC group underwent additional manual PPCCC before IOL implantation. Examinations were performed 1 day, 1 week, 1 month and 3 months postoperatively. IOL tilt (x, y), decentration (x, y), anterior chamber depth (z) and refractive prediction error data were collected and analyzed with Pentacam. Results: Postoperatively, the range of IOL position change over 3 months in PPCCC group was comparable to NPCCC group, which indicated smaller value in every tilt and decentration index. PPCCC eyes showed comparable tilt and decentration with NPCCC eyes in this study endpoint: mean tilt (x, y), decentration (x, y) and anterior chamber depth (ACD) were 1.04 ± 0.56°, 0.90 ± 0.64°, 0.239 ± 0.140 mm, 0.233 ± 0.133 mm and 4.01 ± 0.32 mm, respectively, in the PPCCC group vs. 1.09 ± 0.76°, 1.10 ± 0.82°, 0.252 ± 0.153 mm, 0.244 ± 0.155 mm and 4.01 ± 0.38 mm, respectively, in the NPCCC group. Refractive prediction error in the PPCCC group demonstrated a mild hyperopic shift vs. the NPCCC group (0.13 ± 0.50 vs. 0.05 ± 0.39; p = 0.208), and corrected distance visual acuity (CDVA) did not differ between the two groups (0.027 ± 0.014 vs. 0.059 ± 0.185; p = 0.377). Conclusions: Comparable IOL tilt, decentration, ACD and refractive prediction error were observed in PPCCC eyes with that underwent routine cataract surgery. Little IOL position fluctuation and good visual acuity were shown in PPCCC group over time. Trail registration: The study was registered at the Chinese Clinical Trial Register Center on May 27th, 2020 (protocol code ChiCTR2000033304, 27/05/2020). [ABSTRACT FROM AUTHOR]

AIM: To evaluate the effect of anterior capsule polishing on visual quality after phacoemulsification.METHODS: Prospective randomized control study. A total of 65 patients(73 eyes)with age-related cataract who underwent phacoemulsification combined with intraocular lens(IOL)implantation in the Emergency General Hospital between November 2021 and June 2022 were included. These patients were randomly assigned to two groups, with one group(anterior polishing group)underwent anterior and posterior capsule polishing(30 cases, 35 eyes), while the other(control group)receive routine posterior capsule polishing(35 cases, 38 eyes). Best corrected visual acuity was observed at 1wk, 1, 3 and 6mo after operation. Area of anterior capsule orifice was measured at 3 and 6mo after operation. Meanwhile, posterior capsular opacification(P score), IOL tilt and decentration were recorded by Pentacam Scheimpflug system. In addition, wavefront aberration, Strehl ratio(SR)of point spread function(PSF)and modulation transfer function(MTF)were evaluated by OPD-Scan Ⅲ.RESULTS: At 1wk, 1, 3 and 6mo after operation, best corrected visual acuity in anterior polishing group is significantly better than that of control group(P0.05). At 3mo follow-up, no significant differences in IOL tilt and wavefront aberration were measured between two groups either(P>0.05). However, IOL tilt [(1.65±0.60)° vs.(2.34±0.43)°, P

Abstract Background To evaluate the influence of decentration of plate-haptic toric intraocular lens (IOLs) on visual quality. Methods This study enrolled 78 eyes of 78 patients. Patients in group A were implanted with toric IOLs, and patients in group B were implanted with monofocal IOLs. All patients were divided into group A1 and B1 (decentration below 0.3 mm) and group A2 and B2 (decentration above 0.3 mm). The uncorrected distance visual acuity (UDVA), best corrected visual acuity (BCVA), modulation transfer function cutoff (MTF cutoff), objective scatter index (OSI), strehl ratio (SR), optical interference and patients’ satisfaction were measured in different pupils at three months postoperatively. The associations between decentration and visual quality were analyzed by Spearman correlation. Results There were no significant differences in UDVA, BCVA, MTF cutoff, OSI, SR, optical interference and patients’ satisfaction among subgroups. The differences in decentration between groups A and B were not statistically significant. In group A2, the total higher order aberrations (tHOAs) at pupil sizes of 3 mm (P = 0.046), 5 mm (P = 0.014), spherical aberrations at pupil sizes of 3 mm (P = 0.011), 4 mm (P = 0.014), 5 mm (P = 0.000), secondary astigmatism at pupil sizes of 3 mm (P = 0.002), 4 mm (P = 0.005) were higher than in group B2. Compared to group A1, group A2 had higher spherical aberrations at pupil sizes of 4 mm (P = 0.042), 5 mm (P = 0.001), 6 mm (P = 0.038), secondary astigmatism at pupil sizes of 3 mm (P = 0.013), 4 mm (P = 0.005), 6 mm (P = 0.013). Group B2 has higher coma and secondary astigmatism than group B1 at 6-mm pupil (P = 0.014, P = 0.045). Significant positive correlations were found between spherical aberrations and the decentration of group A1 and A2 at 6-mm pupils. Conclusion The decentration above 0.3 mm negatively affected visual quality due to increased tHOAs, spherical aberrations, coma and secondary astigmatism aberrations, the influence become larger with increasing pupil diameter. And toric IOLs are more affected by decentration than monofocal IOLs.

Abstract Background To compare the outcomes of sutured transscleral fixation and sutureless intrascleral fixation for the treatment of a dislocated intraocular lens (IOL). Methods Thirty-five eyes of 35 patients who required IOL repositioning surgery due to IOL dislocation were included in this retrospective study. Sixteen eyes underwent two-point sutured transscleral fixation, eight eyes underwent one-point sutured transscleral fixation, and 11 eyes underwent sutureless intrascleral IOL fixation. The patients were followed for ≥ 12 months after repositioning surgery, and their postoperative outcomes were recorded and analyzed. Results The major cause of IOL dislocation was ocular blunt trauma (19/35, 54.3%). The mean corrected distance visual acuity (CDVA) improved significantly after IOL repositioning (P = 0.022). The mean postoperative change in endothelial cell density (ECD) was − 4.5%. There were no significant differences in the changes in CDVA or ECD among the three groups with different repositioning techniques (both P > 0.1). The mean vertical tilt of the IOLs in all enrolled patients was significantly greater than the horizontal value (P = 0.001). The vertical tilt was greater in the two-point scleral fixation group than that in the sutureless intrascleral fixation group (P = 0.048). The mean decentration values in the one-point scleral fixation group in the horizontal and vertical directions were greater than those in the other two groups (all P

Purpose: To assess the possible impact of minor changes in fixation on wavefront measurements as a potential constraint in detecting subtle temporal variations in ocular wavefront error. Methods: Twelve healthy subjects with an average age of 36.3 ± 8.8 were instructed to put their heads in the aberrometer’s chin-rest and look at a fixation target that was embedded in the device. The fixation targets were readily observable to the participants without accommodation, thanks to the aberrometer’s Badal system. When each eye was staring at the target, its wavefront aberration was recorded three times and then averaged for further analysis. The averaged Zernike coefficients were rescaled to the smallest value of the maximum round pupil found among all eyes (4.41 mm), and this procedure was repeated for each target. Results: Alteration of the fixation targets caused changes to the Zernike coefficients of defocus (C(2,0)), vertical trefoil (C(3,–3)), vertical coma (C(3,–1)), horizontal coma (C(3,1)), oblique trefoil (C(3,3)), primary spherical aberration (C(4,0)), and secondary spherical aberration (C(6,0)), but the changes were not statistically significant. Nevertheless, an alteration in the target’s size and shape exhibited a significant correlation across all of the aforementioned coefficients in both eyes (p < 0.05). The total RMS of aberrations and the RMS of the spherical-like aberrations were both lowest while choosing the larger Maltese cross, and the bigger E-letter minimized the RMS of HOA and comatic aberrations. Conclusion: The aberrometric changes occur as a consequence of altering the fixational gaze and are within the range of the changes found after performing a near-vision task, so they might potentially act as a confounding factor when attempting to identify such small variations in the ocular wavefront. Using a smaller E-letter (5 arcmin) as an internal fixation target resulted in the least standard deviation of measurements, fixational stability, and higher accuracy in ocular wavefront measurements.

Lens dislocation is a significant complication after cataract surgery. Scleral fixation of 3-piece intraocular lens provides favorable visual outcome and can spare patients the need for lens exchange. Two patients presented with dislocated 3-piece lenses implanted over 10 years earlier. Both patients underwent pars plana vitrectomy and dropped lens rescue with scleral fixation. Postoperatively, the lens optic was found flipped nearly 90° at the optic-haptic junctions secondary to fluid-air exchange performed during vitrectomy. Both patients underwent intraocular lens exchange with a four point sclera fixated lens. Our study found that air tamponade is better avoided during rescue of old dislocated 3-piece lens implants. Intraocular lens exchange is preferred, when possible, to avoid complications associated with old dislocated lenses. Larger studies are needed to determine the effect of time on dislocated lens implants materials. [ABSTRACT FROM AUTHOR]

Abstract Background Quick contrast sensitivity function (qCSF) method is an advanced quick method for contrast sensitivity function (CSF) evaluation. This study evaluated the contrast sensitivity (CS) of eyes undergoing cataract surgery with multifocal intraocular lens (IOL) implantation and its tolerance to IOL tilt and IOL decentration using the qCSF method. Methods Patients undergoing uneventful phacoemulsification and a trifocal IOL (Zeiss AT LISA tri 839MP, Carl Zeiss, Germany) or an extended depth-of-focus (EDOF) IOL (Tecnis Symfony ZXR00, Johnson & Johnsons, USA) implantation were included. Monocular contrast sensitivity was measured using the qCSF method at one month post-surgery. IOL tilt and decentration were measured using an optical aberrometer (OPD-Scan III, NIDEK, Japan). Results Seventy-two patients/eyes with the 839MP IOL and 64 patients/eyes with the ZXR00 IOL were included. Area under the log CSF (AULCSF) and CS acuity did not differ significantly between the two groups. The ZXR00 IOL group showed better CS at 1 cpd (1.137 ± 0.164 vs. 1.030 ± 0.183 logCS) and 1.5 cpd (1.163 ± 0.163 vs. 1.071 ± 0.161 logCS), while the 839MP IOL group had better CS at 6 cpd (0.855 ± 0.187 vs. 0.735 ± 0.363 logCS). In the 839MP IOL group, all CSF metrics were negatively correlated with IOL tilt (all P 0.05). Among myopic eyes, fewer CSF metrics were negatively correlated with IOL tilt in the ZXR00 IOL group than in the 839MP IOL group. No significant correlation was found between CSF metrics and IOL decentration. Conclusions The ZXR00 and the 839MP IOL groups presented comparable CSF. CS was negatively correlated with IOL tilt, instead of decentration in multifocal IOLs, particularly among myopic eyes. The ZXR00 IOL had better tolerance to IOL tilt in myopic eyes.

Background and Aims: Induced prismatic effects due to poor fitting spectacle frames is a common problem, seen in most of the spectacle wearers and this improper fitting is often due to optical center demarcation on lenses and this error causes asthenopic symptoms and diplopia. However, these errors are most common in developing countries due to lack of awareness, hence a standardized regulation is required. The current study aimed to estimate the amount of prismatic effect that is induced due to the decentration of an optical center in ophthalmic lens. Methods: A quantitative cross‐sectional study was conducted in single vision spectacle wearers (N = 120) with a mean age of 25 ± 5 years. The pupillometric evaluation was performed to mark the pupil center on the spectacle lens. A lensometry evaluation was done to mark the optic center of the spectacle lens. A comparison was made to note whether the optic center is aligned with pupillary center. Objective assessment was performed through Prentice's rule (P = cF) and subjective symptoms were assessed through a validated visual comfort questionnaire. Results: In this sample, around 57% of the individual with single vision glasses were not looking through the optic center and experiencing induced prismatic effect of −0.7 to 0.6 prism diopter, with mean decentration of 3.5 mm. Forty percent of the individuals with misaligned optic center showed asthenopic symptoms and visual discomfort. Conclusion: Optometrist should check quality of dispensing and visual performance before handing over the newly dispensed glasses to the patients. [ABSTRACT FROM AUTHOR]

Background: To evaluate the influence of decentration of plate-haptic toric intraocular lens (IOLs) on visual quality. Methods: This study enrolled 78 eyes of 78 patients. Patients in group A were implanted with toric IOLs, and patients in group B were implanted with monofocal IOLs. All patients were divided into group A1 and B1 (decentration below 0.3 mm) and group A2 and B2 (decentration above 0.3 mm). The uncorrected distance visual acuity (UDVA), best corrected visual acuity (BCVA), modulation transfer function cutoff (MTF cutoff), objective scatter index (OSI), strehl ratio (SR), optical interference and patients' satisfaction were measured in different pupils at three months postoperatively. The associations between decentration and visual quality were analyzed by Spearman correlation. Results: There were no significant differences in UDVA, BCVA, MTF cutoff, OSI, SR, optical interference and patients' satisfaction among subgroups. The differences in decentration between groups A and B were not statistically significant. In group A2, the total higher order aberrations (tHOAs) at pupil sizes of 3 mm (P = 0.046), 5 mm (P = 0.014), spherical aberrations at pupil sizes of 3 mm (P = 0.011), 4 mm (P = 0.014), 5 mm (P = 0.000), secondary astigmatism at pupil sizes of 3 mm (P = 0.002), 4 mm (P = 0.005) were higher than in group B2. Compared to group A1, group A2 had higher spherical aberrations at pupil sizes of 4 mm (P = 0.042), 5 mm (P = 0.001), 6 mm (P = 0.038), secondary astigmatism at pupil sizes of 3 mm (P = 0.013), 4 mm (P = 0.005), 6 mm (P = 0.013). Group B2 has higher coma and secondary astigmatism than group B1 at 6-mm pupil (P = 0.014, P = 0.045). Significant positive correlations were found between spherical aberrations and the decentration of group A1 and A2 at 6-mm pupils. Conclusion: The decentration above 0.3 mm negatively affected visual quality due to increased tHOAs, spherical aberrations, coma and secondary astigmatism aberrations, the influence become larger with increasing pupil diameter. And toric IOLs are more affected by decentration than monofocal IOLs. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to evaluate the short‐term effects of peripheral gradient high‐addition multifocal soft contact lenses (MFSCLs) and orthokeratology (Ortho‐K lenses) on visual performance in myopic children. Methods: Thirty myopic children participated in this prospective study. Each participant wore different sets of lenses in the following sequence: single‐vision spectacles (SVSPs) as a control, MFSCLs and Ortho‐K lenses. Ocular aberrations, topography, high‐contrast visual acuity (HCVA), low‐contrast visual acuity (LCVA) and accommodation of the right eye were measured with each type of correction on a different day. Results: Compared with SVSPs, high‐addition MFSCLs and Ortho‐K lenses significantly increased all items of aberrations (all p < 0.05) except trefoil (p = 0.17). MFSCLs induced less coma, root mean square of the third‐order aberration (RMS3) and higher order aberrations than Ortho‐K lenses (all p < 0.05). No significant difference in HCVA was found across the three correction types (F = 1.19, p = 0.39). In terms of LCVA, MFSCLs performed significantly poorer than SVSPs (difference, 0.16 logMAR; p = 0.001) and slightly worse than Ortho‐K lenses (difference, 0.08 logMAR; p = 0.35). No significant difference in decentration was found between the two types of contact lenses, and no associations were observed between decentration and visual acuity at both high‐ and low‐contrast levels (all p > 0.05). For MFSCLs, decentration was positively related to coma (r = 0.43, p = 0.02) and RMS3 (r = 0.44, p = 0.02), which was not the case for Ortho‐K lenses. Accommodative facility was worse with MFSCLs than Ortho‐K lenses (p = 0.001). Conclusion: Multifocal soft contact lenses differed from Ortho‐K lenses in aberration profile and LCVA, although decentration was similar. Decentration <1 mm had minimal influence on both HCVA and LCVA for either type of correction, but significantly increased third‐order aberrations for MFSCLs, but not Ortho‐K lenses. [ABSTRACT FROM AUTHOR]

Background: To compare the outcomes of sutured transscleral fixation and sutureless intrascleral fixation for the treatment of a dislocated intraocular lens (IOL). Methods: Thirty-five eyes of 35 patients who required IOL repositioning surgery due to IOL dislocation were included in this retrospective study. Sixteen eyes underwent two-point sutured transscleral fixation, eight eyes underwent one-point sutured transscleral fixation, and 11 eyes underwent sutureless intrascleral IOL fixation. The patients were followed for ≥ 12 months after repositioning surgery, and their postoperative outcomes were recorded and analyzed. Results: The major cause of IOL dislocation was ocular blunt trauma (19/35, 54.3%). The mean corrected distance visual acuity (CDVA) improved significantly after IOL repositioning (P = 0.022). The mean postoperative change in endothelial cell density (ECD) was − 4.5%. There were no significant differences in the changes in CDVA or ECD among the three groups with different repositioning techniques (both P > 0.1). The mean vertical tilt of the IOLs in all enrolled patients was significantly greater than the horizontal value (P = 0.001). The vertical tilt was greater in the two-point scleral fixation group than that in the sutureless intrascleral fixation group (P = 0.048). The mean decentration values in the one-point scleral fixation group in the horizontal and vertical directions were greater than those in the other two groups (all P < 0.01). Conclusion: All three IOL repositioning techniques resulted in favorable ocular prognosis. [ABSTRACT FROM AUTHOR]

With the development of refractive cataract surgery,Toric intraocular lens(Toric IOL)has been widely used as a functional IOL in the clinical practice. The implantation of Toric IOL in cataract patients can effectively correct preoperative corneal astigmatism and reduce postoperative residual astigmatism, thus obtaining better uncorrected visual acuity and visual quality. Mild decentration, tilt and rotation of Toric IOL do not cause significant subjective discomfort in patients. However, a certain degree of decentration, tilt and rotation of Toric IOL can increase astigmatism and higher-order aberration, resulting in decreased visual acuity and visual quality. Based on relevant results at home and abroad, this article reviewed the influence of the decentration, tilt and rotation of Toric IOL on visual quality at both basic and clinical levels and discussed the existing problems and prospects.

AIM: To investigate the correlation between postoperative lens decentration and tilt and visual quality in eyes implanted with aspherical intraocular lens(IOL)by using a new anterior segment swept-source optical coherence tomography(OCT)CASIA2.METHODS: An observational study. A total of 90 eyes of 62 participants who underwent age-related cataract surgery at 1mo were included. Using CASIA2 by an experienced examiner, IOL tilt and decentration were obtained three consecutive times after mydriasis and the vector mean values were calculated. Double-pass optical quality analysis system(OQAS)and wavefront aberration instrument KR-1W were used for the visual quality measurements, including the total high-order aberration(tHOA), spherical aberration(SA), Coma, objective scatter index(OSI), modulation transfer function cut off frequency(MTF cut off)and Strehl ratio(SR)at 4 and 6mm pupil diameter.RESULTS: IOL decentration was positively correlated with SA(r=0.347, P=0.001)and OSI(r=0.343, P=0.002)at 4mm pupil diameter, and it was negatively correlated with MTF cut off(r=-0.244, P=0.032). There was no significant correlation between IOL decentration and tHOA, Coma and SR. IOL tilt was negatively correlated with MTF cut off(r=0.-345, P=0.002)and SR(r=-0.256, P=0.023)at 4mm pupil diameter, but it was not correlated with tHOA, SA, Coma and OSI. There were no significant correlations between the IOL decentration and tilt and tHOA, SA, Coma, MTF cut off and SR at 6mm pupil diameter.CONCLUSION: After aspherical IOL implantation in age-related cataract patients, IOL decentration was weakly correlated with SA at 4mm pupil diameter, while decentration and tilt were not significantly correlated with other higher-order aberrations. The decentration and tilt were weakly correlated with OSI value and MTF cut off value of the visual quality parameters. The results suggest that clinicians should pay more attention to higher-order aberrations and visual quality during precise cataract surgery.

Abstract Background and Aims Induced prismatic effects due to poor fitting spectacle frames is a common problem, seen in most of the spectacle wearers and this improper fitting is often due to optical center demarcation on lenses and this error causes asthenopic symptoms and diplopia. However, these errors are most common in developing countries due to lack of awareness, hence a standardized regulation is required. The current study aimed to estimate the amount of prismatic effect that is induced due to the decentration of an optical center in ophthalmic lens. Methods A quantitative cross‐sectional study was conducted in single vision spectacle wearers (N = 120) with a mean age of 25 ± 5 years. The pupillometric evaluation was performed to mark the pupil center on the spectacle lens. A lensometry evaluation was done to mark the optic center of the spectacle lens. A comparison was made to note whether the optic center is aligned with pupillary center. Objective assessment was performed through Prentice's rule (P = cF) and subjective symptoms were assessed through a validated visual comfort questionnaire. Results In this sample, around 57% of the individual with single vision glasses were not looking through the optic center and experiencing induced prismatic effect of −0.7 to 0.6 prism diopter, with mean decentration of 3.5 mm. Forty percent of the individuals with misaligned optic center showed asthenopic symptoms and visual discomfort. Conclusion Optometrist should check quality of dispensing and visual performance before handing over the newly dispensed glasses to the patients.

Objective To develop an automatic and objective quantification algorithm based on corneal topography to evaluate the orthokeratology (Ortho-K) lens fitting. Methods K-means algorithm was used to analyze the defocus ring of corneal topography and fit the most suitable ellipse on the defocusing region of corneal topography combining with weighted least squares method. The decentration distance was defined as the distance between the pupil center and the center of ellipse. Corneal topography images from 200 eyes (100 patients) were used to evaluate the accuracy and repeatability of the algorithm. Results The decentration distance was calculated using this automatic algorithm. One hundred and fourteen eyes (57%) had mild decentration, 75 eyes (37.5%) had moderate decentration and 11 eyes (5.5%) had severe decentration after wearing Ortho-K lenses. Compared with manual evaluation, the automatic algorithm showed higher accuracy and better repeatability. Conclusions Using K-means combining with weighted least squares algorithm, an objective and accurate algorithm was developed to evaluate Ortho-K fitting and could be used as an useful quantitative analysis tool for future clinical practice and research. [ABSTRACT FROM AUTHOR]

Purpose: We aimed to investigate misalignment (tilt and decentration) and rotational stability of the implantable collamer lens V4c 6 months after implantation and to explore the potential risk factors associated with postoperative misalignment and rotation. Methods: A total of 36 eyes of 36 patients with high myopia and myopic astigmatism who underwent implantable collamer lens V4c implantation were included in this study. Tilt, decentration, and rotation of the implantable collamer lens were assessed postoperatively at l week, 1 month, 3 months, and 6 months. Correlation analysis was used to identify the potential risk factors for implantable collamer lens tilt, decentration, and rotation at 6 months postoperatively. Higher-order aberration was measured to evaluate the effect of implantable collamer lens misalignment on visual quality at pupil diameters of 4.0 mm and 6.0 mm. Results: The tilt and decentration at the last follow-up were 2.43 ± 1.35° and 0.278 ± 0.160 mm, respectively. There was a significant positive correlation between tilt and decentration (r = 0.31, P = 0.046). No significant correlation was detected between implantable collamer lens decentration and internal higher-order aberrations (P > 0.05). The degree of implantable collamer lens rotation (3.11 ± 2.00°) was significantly associated with the vault (r = − 0.422, P = 0.01), while it was positively associated with the preoperative anterior chamber depth (r = 0.36, P = 0.034). No significant correlation was found between postoperative astigmatism and rotation (r = − 0.07, P = 0.351). Conclusions: The implantable collamer lens V4c provides relatively stable misalignment and rotation after implantation. The ICL lens vault is a potential risk factor for postoperative implantable collamer lens rotation. The absolute value of decentration and tilt was relatively small, which showed no correlation with internal higher-order aberration in short-term observation. [ABSTRACT FROM AUTHOR]

Abstract Background The central hole of the Visian Implantable Collamer Lens (ICL V4c) provides a reference to observe its tilt or decentration. This study aimed to investigate the tilt and decentration effects of ICL V4c on visual quality after implantation. Methods A total of 135 eyes from 69 patients who underwent ICL V4c implantation were included in this study. Evaluation of uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and aberrations were performed 6-months postoperatively. The anterior segment parameters were collected using CASIA2 anterior segment-optical coherence tomography, tilt and decentration of ICL V4c were analyzed using MATLAB software. All patients received questionnaires to investigate the visual quality postoperatively. Results The safety and effectiveness were 1.18 ± 0.17 and 1.11 ± 0.18, respectively. No significant changes were observed regarding higher-order and spherical aberrations after the operation; however, coma and trefoil significantly increased compared to preoperative values. The average total decentration and tilt was 0.21 ± 0.12 mm and 2.54 ± 1.00°, respectively. Horizontal, vertical, and total values of tilt and decentration were not significantly associated with postoperative CDVA, UDVA, and aberrations. The most common visual symptom was halo, and 97.04% of patients had a satisfaction score ≥ 8. The total or horizontal tilt was significantly positively correlated with the frequency, severity, and bothersome scores from the questionnaires. Conclusions ICL V4c implantation can obtain high visual quality and patient satisfaction. Although the degree of tilt and decentration after ICL V4c implantation was small, a positive effect on subjective visual quality was observed.

Abstract Background Information on the centration and tilt of iris-claw intraocular lenses (IC-IOLs) is limited. In this study, we tested the capacity of an anterior segment optical coherence tomography (AS-OCT) instrument to measure decentration and tilt of anterior and posterior IC-IOLs through an integrated software. Methods The present observational, cross-sectional study was conducted at University Eye Clinic of Parma (Parma, Italy). The CASIA2 swept-source AS-OCT (Tomey Corp.) was used to measure the tilt and decentration of posterior and anterior IC-IOLs in patients implanted at least 6 months in advance. After failure with full-automation, semi-manual IOL tracing was applied. In-the-bag (IB) contralateral IOLs, when present, were measured automatically. The Bland-Altman method was used to evaluate the agreement between repeated measurements (2 images for each study eye). The amount and direction of tilt and decentration were recorded and plotted into polar charts for evaluation. Results A total of 21 patients were included: 14 with posterior and 7 with anterior IC-IOL fixation. In 17 eyes (81%), the AS-OCT provided a repeatable measurement of tilt and decentration. All contralateral eyes with IB IOL were automatically measured. The median decentration was 0.67 mm, 0.24 mm, and 0.24 mm in posterior IC-IOLs, anterior IC-IOLs, and IB IOLs group, respectively. The median tilt was 5.0°, 5.6°, and 5.6° for posterior IC-IOLs, anterior IC-IOLs, and IB IOLs, respectively. Tilt direction was mainly temporal, while decentration was inferior-temporal with posterior IC-IOLs and scattered with anterior IC-IOLs and IB IOLs. Conclusions The semi-manual tracing function of the CASIA2 AS-OCT provides repeatable and affordable measurements of the decentration and tilt of IC-IOLs in both the anterior and posterior chamber. Data from the former group were similar to the IB group.

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Objective: To study the effect of treatment zone (TZ) decentration on axial length growth (ALG) in adolescents after wearing the orthokeratology lenses (OK lenses). Materials and methods: This retrospective clinical study selected 251 adolescents who were fitted OK lenses at the Clinical College of Ophthalmology, Tianjin Medical University (Tianjin, China) from January 2018-December 2018 and wore them continuously for >12 months. The age of the subjects was 8-15 years, spherical equivalent (SE): -1.00 to -5.00 diopter (D), and astigmatism ≥ 1.50 D. The corneal topography were recorded at baseline and 1-, 6-, and 12-month visits, and the axial length (AL) were recorded at baseline and 6-, 12-month visits. The data of the right eye were collected for statistical analysis. Results: The subjects were divided into three groups according to the decentration distance of the TZ after wearing lenses for 1 month: 56 cases in the mild (<0.5 mm), 110 in the moderate (0.5-1.0 mm), and 85 in the severe decentration group (>1.0 mm). A significant difference was detected in the ALG between the three groups after wearing lenses for 6 and 12 months (F = 10.223, P < 0.001; F = 13.380, P < 0.001, respectively). Among these, the 6- and 12-month ALG of the mild decentration group was significantly higher than that of the other two groups. Multivariable linear regression analysis showed that age, baseline SE, and 1-month decentration distance associated with the 12-month ALG (P < 0.001, P < 0.001, and P = 0.001, respectively). Conclusion: The decentration of the TZ of the OK lens affected the growth of the AL in adolescents, i.e., the greater the decentration, the slower the ALG. [ABSTRACT FROM AUTHOR]

Purpose: To investigate whether the treatment zone (TZ) decentration in orthokeratology (OK) lenses affects retinal expansion in Chinese children with myopia. Methods: Children aged 8 to 13 years (n = 30) were assessed over 13 months comprising 12 months of OK lens wear followed by discontinuation of lens wear for 1 month. Corneal topography was measured at 0, 1, 3, 6, 9, 12 and 13 months. TZ decentration of the OK lens was calculated, and subjects were subdivided into a small decentration group (group S) and a large decentration group (group L) based on the median value of the weighted average decentration (dave). Central axial length (AL) and peripheral eye lengths (PELs) at the central retina, as well as 10°, 20° and 30° nasally and temporally were measured at 0 and 13 months under cycloplegia. Second‐order polynomial (y = ax2 + bx + c) and linear fits (y = Kx + B) were applied to the peripheral relative eye length (PREL), and the coefficients 'a' and 'K' were used to describe the shape of the eye. Results: Mean AL growth for one year was 0.28 ± 0.17 mm. In a multiple linear regression model, AL elongation was related to the baseline age (β = −0.41, p = 0.01) and the dave (β = −0.37, p = 0.03) (R2 = 0.34, p = 0.002). When compared with smaller dave (0.45 ± 0.15 mm), a larger dave (0.89 ± 0.17 mm) was associated with slower ocular growth (central: 0.20 ± 0.13 mm vs. 0.35 ± 0.17 mm, p = 0.009; 10° nasal: 0.26 ± 0.18 mm vs. 0.45 ± 0.21 mm, p = 0.02; 10° temporal: 0.17 ± 0.14 mm vs. 0.32 ± 0.19 mm, p = 0.02) and more oblate retina shape ('a': −0.13 ± 0.02 vs. −0.14 ± 0.02, p = 0.02; Knasal: 0.35 ± 0.11 vs. 0.39 ± 0.09, p = 0.02; Ktemporal: −0.42 ± 0.08 vs. −0.46 ± 0.08, p = 0.004). Conclusions: Greater TZ decentration with the use of OK lenses was associated with slower axial growth and a more oblate retinal shape. TZ decentration caused local defocusing changes, which may inhibit myopic progression. These findings may have important implications for improving optical designs for myopia control. [ABSTRACT FROM AUTHOR]

Yuan Ning,1 Yushuang Shao,1 Jiangyue Zhao,1 Jinsong Zhang,1 Mingwu Wang,2 Yu Qin1 1Department of Ophthalmology, The Fourth Affiliated Hospital of China Medical University, Eye Hospital of China Medical University, Key Lens Research Laboratory of Liaoning Province, Shenyang, 110005, People’s Republic of China; 2Department of Ophthalmology and Vision Science, The University of Arizona College of Medicine, Tucson, Arizona, 85711-1824, USACorrespondence: Yu QinDepartment of Ophthalmology, The Fourth Affiliated Hospital of China Medical University, Eye Hospital of China Medical University, Key Lens Research Laboratory of Liaoning Province, No. 11 Xinhua Road, Heping District, Shenyang, 110005, People’s Republic of ChinaTel +86 24 62035015Fax +86 24 62035015Email yuqin_3620@163.comObjective: The aim of the present study was to evaluate the stability of four different types of aspheric intraocular lenses (IOLs) after implantation.Methods: This retrospective study included 124 eyes implanted with four different types of aspheric IOLs including a one-piece four-loop fixed hydrophilic acrylic IOL, a one-piece flat fixed acrylic IOL, a one-piece two-loop fixed acrylic IOL, and a three-piece two-loop fixed silicone IOL. IOL decentration, tilt, and ocular coma‐like aberration (coma) at one-week, one-month, three-month, and one-year time points were evaluated postoperatively.Results: IOL decentration, tilt, and coma in the AO, 36A, IQ, and KS-AiN implantation groups were statistically significantly different one week and one year postoperatively (p < 0.01). There were significant differences between each of the pairs of groups (p < 0.01), except for coma between the AO and 36A implantation groups one week postoperatively (p > 0.05). When comparing the different time points (ie, one week, one month, three months, and one year postoperatively), IOL decentration, tilt, and coma were significantly different in each group (p < 0.05). IOL decentration, tilt, and coma in each group increased over the period from one week to one year postoperatively. A positive linear correlation was observed between IOL decentration or tilt and coma one year postoperatively (p < 0.01).Conclusion: One-piece multi-point fixed acrylic IOLs demonstrate better stability when compared with three-piece two-point fixed silicone IOLs. IOL decentration, tilt, and coma increase gradually over time. Ocular coma‐like aberrations are influenced by the stability of IOLs.Keywords: stability, aspheric intraocular lens, IOL, decentration, tilt, coma

Copyright of Journal of Chongqing University of Posts & Telecommunications (Natural Science Edition) is the property of Chongqing University of Posts & Telecommunications and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: The central hole of the Visian Implantable Collamer Lens (ICL V4c) provides a reference to observe its tilt or decentration. This study aimed to investigate the tilt and decentration effects of ICL V4c on visual quality after implantation.Methods: A total of 135 eyes from 69 patients who underwent ICL V4c implantation were included in this study. Evaluation of uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and aberrations were performed 6-months postoperatively. The anterior segment parameters were collected using CASIA2 anterior segment-optical coherence tomography, tilt and decentration of ICL V4c were analyzed using MATLAB software. All patients received questionnaires to investigate the visual quality postoperatively.Results: The safety and effectiveness were 1.18 ± 0.17 and 1.11 ± 0.18, respectively. No significant changes were observed regarding higher-order and spherical aberrations after the operation; however, coma and trefoil significantly increased compared to preoperative values. The average total decentration and tilt was 0.21 ± 0.12 mm and 2.54 ± 1.00°, respectively. Horizontal, vertical, and total values of tilt and decentration were not significantly associated with postoperative CDVA, UDVA, and aberrations. The most common visual symptom was halo, and 97.04% of patients had a satisfaction score ≥ 8. The total or horizontal tilt was significantly positively correlated with the frequency, severity, and bothersome scores from the questionnaires.Conclusions: ICL V4c implantation can obtain high visual quality and patient satisfaction. Although the degree of tilt and decentration after ICL V4c implantation was small, a positive effect on subjective visual quality was observed. [ABSTRACT FROM AUTHOR]