Lens Parameters Research Articles

Sensitive HPLC Method to Support Pre-formulation Studies and to Determine Critical Quality Attributes of Therapeutic Contact Lenses Containing Dorzolamide Hydrochloride

Background: Dorzolamide hydrochloride (DRZ) is a carbonic anhydrase inhibitor used to treat glaucoma and ocular hypertension. Drug-eluting contact lenses, such as Acuvue Theravision ™ with Ketotifen, offer improved drug delivery and reduced side effects compared to eye drops. Drug-loaded nanoparticle-loaded contact lenses can sustain drug release and enhance comfort for extended wear. Objective: High buffer concentration and low pH increase the risk of damage to silica-bonded columns. Therapeutic contact lenses face challenges related to critical lens parameters, including the estimation of drug incorporation and release due to interference of lens matrix leaching. There is currently no analytical method available for estimating DRZ in contact lenses. Method: The HPLC method, which was developed and validated using ICH Q2 (R1) criteria, used a C18 column (250 mm × 4.6 mm, 5 μm) as a stationary phase and methanol:water (70:30 v/v) as the mobile phase. The detecting wavelength was 253 nm. Moreover, to support the efficiency of the developed method, the marketed formulation of DRZ eye drops, drug purity, and loading in contact lenses were analysed. The method was also employed to determine the Critical Quality Attributes (CQAs) of therapeutic contact lenses and drug release and drug leaching during the sterilization process. Result: The developed HPLC method shows Rt for DRZ at 2.881 minutes with good linearity (r2 > 0.998) between 2-32μg/mL, precision (RSD < 2%), accuracy (Recovery > 99.5%), sensitivity, and specificity for quantifying DRZ in marketed formulations and therapeutic contact lenses. The developed method is devoid of any buffer or modifier in the mobile phase, making it safer for the stationary phase. This method mitigates the interference of lens matrix leaching, which induces an overestimation of DRZ. All the result for therapeutic contact lenses was found to be closely aligned with theoretically expected results, confirming the reliability of the developed HPLC method for therapeutic contact lenses. Conclusion: This method is specific, accurate, and precise for quantifying DRZ in commercial formulations and newly developed therapeutic contact lenses. It effectively evaluates the critical quality attributes of these lenses, demonstrating their reliability for assessing their performance and ensuring quality in therapeutic applications.

Revisiting the effect of lens mass models in cosmological applications of strong gravitational lensing

Abstract Strong gravitational lens system catalogues are typically used to constrain a combination of cosmological and empirical power-law lens mass model parameters, often introducing additional empirical parameters and constraints from high resolution imagery. We investigate these lens models using Bayesian methods through a novel alternative that treats spatial curvature via the non-FLRW timescape cosmology. We apply Markov Chain Monte Carlo methods using the catalogue of 161 lens systems of Chen et al. (2019) in order to constrain both lens and cosmological parameters for: (i) the standard ΛCDM model with zero spatial curvature; and (ii) the timescape model. We then generate large mock data sets to further investigate the choice of cosmology on fitting simple power-law lens models. In agreement with previous results, we find that in combination with single isothermal sphere parameters, models with zero FLRW spatial curvature fit better as the free parameter approaches an unphysical empty universe, ΩM0 → 0. By contrast, the timescape cosmology is found to prefer parameter values in which its cosmological parameter, the present void fraction, is driven to fv0 → 0.73 and closely matches values that best fit independent cosmological data sets: supernovae Ia distances and the cosmic microwave background. This conclusion holds for a large range of seed values fv0 ∈ {0.1, 0.9}, and for timescape fits to both timescape and FLRW mocks. Regardless of cosmology, unphysical estimates of the distance ratios given from power-law lens models result in poor goodness of fit. With larger datasets soon available, separation of cosmology and lens models must be addressed.

Assessing Transducer Parameters for Accurate Medium Sound Speed Estimation and Image Reconstruction.

The influence of the transducer lens on image reconstruction is often overlooked. Lenses usually exhibit a lower sound speed than soft biological tissues. In academic research, the exact lens sound speed and thickness are typically unknown. Here, we present a simple and nondestructive method to characterize the lens sound speed and thickness as well as the time to peak of the round-trip ultrasound waveform, another key parameter for optimal image reconstruction. We applied our method to three transducers with center frequencies of 2.5, 7.5, and 15 MHz. We estimated the three parameters with an element-by-element transmission sequence that records internal reflections within the lens. We validated the retrieved parameters using an autofocusing approach that estimates sound speed in water. We show that the combination of our parameters estimation method with two-layer ray tracing outperforms standard image reconstruction. For all transducers, we successfully improved the accuracy of medium sound speed estimation, spatial resolution, and contrast. The proposed method is simple and robust and provides an accurate estimation of the transducer lens parameters and the time to peak of the ultrasound waveform, which leads to improved ultrasound image quality.

Stereo Bi-Telecentric Phase-Measuring Deflectometry.

Replacing the endocentric lenses in traditional Phase-Measuring Deflectometry (PMD) with bi-telecentric lenses can reduce the number of parameters to be optimized during the calibration process, which can effectively increase both measurement precision and efficiency. Consequently, the low distortion characteristics of bi-telecentric PMD contribute to improved measurement accuracy. However, the calibration of the extrinsic parameters of bi-telecentric lenses requires the help of a micro-positioning stage. Using a micro-positioning stage for the calibration of external parameters can result in an excessively cumbersome and time-consuming calibration process. Thus, this study proposes a holistic and flexible calibration solution for which only one flat mirror in three poses is needed. In order to obtain accurate measurement results, the calibration residuals are utilized to construct the inverse distortion map through bicubic Hermite interpolation in order to obtain accurate anchor positioning result. The calibrated stereo bi-telecentric PMD can achieve 3.5 μm (Peak-to-Valley value) accuracy within 100 mm (Width) × 100 mm (Height) × 200 mm (Depth) domain for various surfaces. This allows the obtaining of reliable measurement results without restricting the placement of the surface under test.

Influence of Contact Lens Parameters on Cornea: Biomechanical Analysis.

This study presents a finite element analysis to model ocular biomechanics and the interactions between the human eye and contact lenses in the closed-eye condition. The closed-eye state, where the eyelids are fully shut, presents challenges for experimental measurements due to the invasive nature of accessing and analysing the contact lens and corneal interface, making simulation tools valuable for accurate characterisation. The primary objective of this study was to examine how CLs fold and twist and their impact on the cornea when the eye is closed. The secondary aim of this study was to assess how crucial contact lens parameters (Young's modulus, base curve, and diameter) influence corneal stress distribution and the overall fit of the lens on the eye. The findings show that increasing Young's modulus significantly reduces corneal stress and promotes uniform stress distribution, making it the most influential factor for wearer comfort and safety. While base curve and diameter variations primarily affect contact area, their impact on stress distribution is minimal. This research provides insights for improving contact lens design and enhancing safety for contact lens wearers.

Description of a new method to calculate the equator of the crystalline lens using AS-OCT images: Accuracy in non-dilated measurements.

To establish a methodology for objectively estimating the Lens Equatorial Plane (LEP) from clinical images, comparing LEP with dilated versus non-dilated pupils. A cohort of 91 eyes from 60 patients undergoing preoperative assessments for cataract surgery was evaluated. Anterior Segment Optical Coherence Tomography (AS-OCT) images were analysed under conditions of pharmacologically induced pupil dilation versus a non-dilated pupil. Geometrical parameters, including LEP, intersection diameter (ID), lens thickness (LT), anterior and posterior lens thickness were automatically calculated by applying standard image processing techniques to clinical AS-OCT images. Significant differences in lens parameters, including LEP, were observed between dilated and non-dilated conditions (all p < 0.001). A strong linear correlation was found across all geometrical variables under both conditions (r[LEP] = 0.64, r[ID] = 0.78, r[LT] = 0.99, all p < 0.001); enabling reliable correction of these differences. The study introduces an objective methodology for LEP calculation, emphasising the need to consider the eye's physiological state during preoperative measurements. Incorporating LEP into future intraocular lens (IOL) power calculation formulas and replacing the habitual effective lens position may potentially improve the accuracy of IOL power estimation and thus postoperative visual outcomes.

Effect of lighting conditions on implantable collamer lens vault: Influence of anterior chamber and lens parameters

PurposeTo investigate the change in the vault of the implantable collamer lens (ICL) under dark-to-light conditions and its association with anterior chamber and lens parameters in patients undergoing ICL surgery. MethodsIn 76 eyes from 40 patients, preoperative anterior chamber volume (ACV), pupil diameter (PD), anterior chamber angle, central corneal thickness (CCT), white-to-white (WTW), lens thickness (LT), axial length (AL), spherical equivalent (SE) and patient's age were collected. Postoperative vault, PD and LT were measured under dark and light conditions using anterior segment optical coherence tomography (CASIA2; TOMEY, Japan), and changes and lens displacement under dark-to-light conditions were calculated. Mixed-effects models were used to analyze the correlation between the vault change and the anterior chamber and lens parameters of all subjects and the high-vault subgroup. ResultsThe vault under light condition (648.36 ± 304.47 μm) was significantly smaller compared to the vault under dark condition (708.89 ± 316.15 μm). In all patients, vault change increased with the increase of age, lens displacement and PD change; and increased with the decrease of ACV, LT change and baseline vault (under dark condition). In the high-vault subgroup, vault change increased with the increase of CCT, lens displacement and PD change; and increased with the decrease of ACV. ConclusionsICL vault changes significantly from dark to light, influenced by age, ACV, PD change, LT change, lens displacement, and baseline vault. A higher baseline vault is correlated with a larger LT change, affecting the levels of accommodation under dark-to-light transition.

International trends in prescribing silicone hydrogel contact lenses for daily wear (2000–2023): An update

PurposeIntroduced around the turn of the 21st century, silicone hydrogel contact lenses alleviated hypoxic anterior eye complications due to their high oxygen transmissibility. The purpose of this work is to update earlier surveys by describing international trends in silicone hydrogel daily wear contact lens fitting between 2000 and 2023. MethodAn annual contact lens prescribing survey was sent to eye care practitioners in up to 71 countries between 2000 and 2023. Data relating to 260,144 daily wear soft contact lens fits undertaken in 20 countries returning reliable longitudinal data were analysed in respect of silicone hydrogel daily wear contact lens fitting. ResultsThere has been a dramatic increase in silicone hydrogel daily wear lens fits (p < 0.0001), increasing from 2.8 % of all daily wear soft lens fits in 2000 to 73.7 % in 2023. Of all daily wear soft contact lenses prescribed to males, 44.6 % were silicone hydrogel lenses, compared with 43.5 % for females (p = 0.0146). The mean age of those wearing silicone hydrogel daily wear lenses was 32.0 ± 14.5 years, compared to 30.4 ± 13.6 years for those wearing daily wear hydrogel lenses (p < 0.0001). Between 2019–2023, the average percentage of fits was – (a) material type: silicone hydrogel – 73 %; mid-water content hydrogels – 13 %; high water content hydrogels – 9 %; and low water content hydrogels – 5 %, and (b) lens design: spherical – 44 %, toric – 32 %, multifocal – 17 %, monovision – 4 %, and ‘other’ – 3 %. ConclusionThe dramatic increase in silicone hydrogel contact lens prescribing for daily wear has been commensurate with the introduction of multiple lens brands and an ongoing expansion of lens designs, parameters and replacement frequency options. The balance between silicone hydrogel and hydrogel lens prescribing is perhaps starting to approach an equilibrium.

Fast phase matching based on order partition with sub-pixel accuracy

Structured light is a method of 3D imaging that involves projecting a sequence of striped or structured patterns onto a target scene and then, based on the warping of stripes across a target surface, a camera can reconstruct the target. For practical reasons relating to changing lens parameters for the projector, binocular structured light improves over monocular structured by performing triangulation between two cameras, using the striped patterns to solve the correspondence matching problem; however, the speed at which these correspondences are found is still an active area of research. And in this paper, we propose a fast-matching algorithm that enhances phase labeling and introduces the concept of triangle plane interpolation based on linear interpolation. The experimental results demonstrate that our method achieves a noticeable speed improvement in computational efficiency and a stable improvement in accuracy as compared to the phase matching along epipolar line pointwisely based on look-up tables.

Frequency Shift in Binary Microlensing

Abstract Gravitational microlensing with binary lensing is one of the channels for detecting exoplanets. Due to the degeneracy of the lens parameters for the binary microlensing, additional features such as parallax and finite-size effects need to identify the lens parameters. The frequency-shift effect as the relativistic analogy of the gravity assist for the photons, is an extra observation that provides additional constraint between the lens parameters . In this work, we extend the application of the frequency shift effect to binary microlensing and derive the frequency shift during the lensing and caustic crossing. The frequency shift for the binary lens is of the order of Δν/ν ∼ 10−12. We also investigate the feasibility of detecting this effect by employing Cross-Correlation methods .

Large-depth-range 3D measurement based on optimized multi-focal projection system

High-speed and large-depth-range 3D measurement technology is of great importance in a variety of fields. Conventional binary defocusing methods can achieve high measurement speed, but their depth range is limited because the defocusing effect is insufficient near the focal plane in the ordinary projection system. To address this problem, we propose an optimized multi-focal projection system by introducing a cylindrical lens with optimal parameter configuration. Compared to traditional methods, the proposed method could overcome the constraint of defocusing region to obtain high-quality sinusoidal fringe patterns over large depth range without sacrificing the measurement speed. In this paper, the principle of multi-focal projection system and the related scheme of parameter configuration are presented in order to illustrate the role of the cylindrical lens and system parameters on modulating the distribution of defocusing kernel and removing the limitations of defocusing region. Experimental results show that the proposed multi-focal projection system with optimal parameter configuration increased the depth range from 150 mm to 725 mm over the conventional single-focal system, achieving greater depth range and better measurement results.

GLANCE – Gravitational Lensing Authenticator using Non-modelled Cross-correlation Exploration of Gravitational Wave Signals

ABSTRACT Gravitational lensing is the phenomenon where the presence of matter (called a lens) bends the path of light-like trajectories travelling nearby. Similar to the geometric optics limit of electromagnetic waves, gravitational lensing of gravitational waves (GWs) can occur in geometric optics condition when GW wavelength is much smaller than the Schwarzschild radius of the lens, that is, $\lambda _{\mathrm{ GW}} \ll$R$^{\rm s}_{\rm lens}$. This is known as the strong lensing regime for which a multiple-image system with different magnifications and phase shifts is formed. We developed GLANCE, Gravitational Lensing Authenticator using Non-modelled Cross-correlation Exploration, a novel technique to detect strongly lensed GW signals. We demonstrate that cross-correlation between two noisy reconstruction of polarized GW signals shows a non-zero value when the signals are lensed counterparts. The relative strength between the signal cross-correlation and noise cross-correlation can quantify the significance of the event(s) being lensed. Since lensing biases the inference of source parameters, primarily the luminosity distance, a joint parameter estimation of the source and lens-induced parameters is incorporated using a Bayesian framework. We applied GLANCE to synthetic strong lensing data and showed that it can detect lensed GW signals and correctly constrain the injected source and lens parameters, even when one of the signals is below match-filtered threshold signal-to-noise ratio. This demonstrates GLANCE’s capability as a robust detection technique for strongly lensed GW signals and can distinguish between lensed and unlensed events.

The effect of lens and fitting characteristics upon scleral lens centration.

To quantify the impact of varying central fluid reservoir depth, lens thickness/mass and the addition of a peripheral fenestration upon scleral lens centration. 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. 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. 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, massor the addition of a single peripheral fenestration did not substantially affect lens centration.

Visual outcome in Keratoconus with spherical rigid gas permeable contact lens

Introduction: Keratoconus is a bileteral asymetric progressive ecteria of cornea commonly associated with vernal keratoconjunctivitis and Atopic dermatitis. Rigid gas permeable (RGP) contact lens is the first choice for refractive correction in keratoconic eyes. The visual outcome in Keratoconus with spherical RGP contact lens along with the mean age of presentation, gender predominance, ethnicity, associated conditions, refractive error and corneal astigmatism was evaluated. Methods: The records of the Keratoconus patients attending cornea and contact lens clinic for last 6 years were reviewed and analyzed using SPSS-14 software. Data on laterality, race, age, gender, refractive error, visual acuity (VA), associated conditions and contact lens parameters were obtained. A total of 22 patients with 38 keratoconic eyes were included in the study. Results: The mean age of Keratoconus presentation was 18.11 ± 4.45 years. Sixteen cases (72.73 %) were bilateral; 6 (27.27 %) were unilateral. Mean uncorrected visual acuity (UCVA) was 0.86 ± 0.40 Log MAR. Mean spectacle visual acuity was 0.54 ± 0.38 Log MAR. Mean visual acuity with spherical RGP contact lenses was 0.08 ± 0.14 Log MAR. The difference between mean spectacle visual acuity and mean VA with spherical RGP contact lens was statistically significant (p &lt; 0.001). Conclusion: In all stages of Keratoconus, improvement in visual acuity with spherical RGP contact lens was highly significant.

Development and evaluation of a deep neural network model for orthokeratology lens fitting.

To optimise the precision and efficacy of orthokeratology, this investigation evaluated a deep neural network (DNN) model for lens fitting. The objective was to refine the standardisation of fitting procedures and curtail subjective evaluations, thereby augmenting patient safety in the context of increasing global myopia. A retrospective study of successful orthokeratology treatment was conducted on 266 patients, with 449 eyes being analysed. A DNN model with an 80%-20% training-validation split predicted lens parameters (curvature, power and diameter) using corneal topography and refractive indices. The model featured two hidden layers for precision. The DNN model achieved mean absolute errors of 0.21 D for alignment curvature (AC), 0.19 D for target power (TP) and 0.02 mm for lens diameter (LD), with R2 values of 0.97, 0.95 and 0.91, respectively. Accuracy decreased for myopia of less than 1.00 D, astigmatism exceeding 2.00 D and corneal curvatures >45.00 D. Approximately, 2% of cases with unique physiological characteristics showed notable prediction variances. While exhibiting high accuracy, the DNN model's limitations in specifying myopia, cylinder power and corneal curvature cases highlight the need for algorithmic refinement and clinical validation in orthokeratology practice.

Performance Analysis and Design Considerations of the Near-Field-Focused Rotman Lens Antennas

This study investigates the application of Rotman lens antennas in the near field. The design equations of these antennas have been derived in the near field and demonstrated to be highly effective. By considering specific examples, the shapes of the inner surfaces of these lens antennas have been analyzed and discussed, revealing how practically realizable lens surfaces can be designed. As these Rotman lenses are perfect at only three points in the near field, they exhibit phase errors at other points along a line connecting the three near-field focal points, resulting in deterioration of the near-field patterns. It has been shown that by selecting the lens parameters appropriately, these phase errors can be kept to a minimum, causing only minimal beam deterioration. Compared to far-field-focused Rotman lens antennas, near-field-focused Rotman lens antennas achieve significantly higher power levels, having 3.8 to 6.3 dB improvement for different beams of a 17-element array. The study has demonstrated the potential of Rotman lenses as multiple beamforming antennas for near-field applications.

Mini-Scleral Lens: An Effective Mode of Visual Rehabilitation in Eyes With Resolved Hydrops.

To evaluate the visual outcome of mini-scleral contact lenses (MSLs) in keratoconus following the resolution of acute hydrops. This was a prospective observational case series of patients of healed hydrops in keratoconus fitted with an MSL (Keracare, Acculens, Lakewood, CO) who were managed for acute hydrops medically or surgically at least 3 months prior. Uncorrected visual acuity, best spectacles-corrected visual acuity, best lens-corrected visual acuity, topographic indices, keratometric indices, contact lens parameters, and ocular aberrometric changes were evaluated. All patients were followed up for at least 3 months. Eighteen eyes of 17 patients were included in the analysis. The mean post-hydrops topographic values of the eyes included flat keratometric value (K1) 64.93±10.88 (range 44.30-93.40) diopters (D), steep keratometric value (K2) 70.41±10.92 D (range 45.8-98.6 D), and Kmax of 79.53±17.73 D (range 50-130.2). The final mini-scleral lens's mean dioptric power was -8.56±3.96 D (range -18 to -4). Visual acuity significantly improved from post-hydrops resolution uncorrected visual acuity of 1.5±0.71 logMAR to 0.79±0.18 logMAR best spectacles-corrected visual acuity to 0.27±0.01 logMAR best lens-corrected visual acuity ( P -value <0.0001). Similarly, there was considerable improvement in corneal aberrometric values after wearing an MSL. At the 3-month follow-up, 15 patients (16 eyes) were compliant to contact lens use with a minimum of 6 to 8 hr daily while two patients (2 eyes) were poorly compliant. A MSL is a valuable option for visual rehabilitation in keratoconus following the resolution of acute hydrops.

Enhancing transmission and coupling efficiency in Cassegrain optical systems with four-petal Gaussian beams.

This study investigates the propagation characteristics of four-petal Gaussian beams through Cassegrain optical systems. With the properties of this new type of beam, the problem of masking loss in the Cassegrain optical system can be well solved. Analytical expressions of the optical field for beams after propagating the optical system are derived, considering atmospheric turbulence effects and random jitter on coupling efficiency. Simulation tests explore various factors affecting transmission efficiency. Acceptable axial mounting error tolerance and significant efficiency drops beyond specific communication distances under different turbulence conditions ($C_{n}^{2}$). Achieving over 80${\% }$ coupling efficiency is feasible with specific lens parameters (f = 0.4 - 0.5 mm, receiving position after 4 km) using standardized lenses. This work offers a theoretical model for four-petal Gaussian beams, aiding optical communication design and application, with practical engineering implications.

Thermal lens investigation of the CdSe quantum dots using dual beam z-scan technique

We highlighted on the thermal lens (TL) effect of Cadmium Selenide quantum dots (CdSe QDs) using dual beam z-scan technique. The thermal lens nonlinear optical properties of CdSe QDs were investigated by applying the two CW laser beams (λ = 532 nm and λ = 632.8 nm). The thermal lens parameters of the CdSe solutions, such as: the on-axis phase shift (θ), the thermal diffusivity (D), and thermal diffusion time (tc) were extracted using the theoretical thermal lens model. Our results give new insight into the CdSe QDs dissolved in toluene and are valuable for further development of semiconductor QDs optical devices.

The effect of landing zone toricity on scleral lens fitting characteristics and optics.

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. 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). 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. 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.