Search

Objective: This study aimed to explore corneal curvature changes following strabismus surgery using a quadric surface fitting model to address ocular misalignment. Material and Methods: In this prospective cross-sectional study, 54 completed cases (84 eyes) of patients aged 6-60 years old (mean 10 years old) undergoing horizontal rectus muscle surgery were examined using placidobased keratometry with the Oculus Keratograph 5M system. Data on corneal curvature were collected one week preoperatively, and again one week, one month, and three months post-operation. Asphericity in the vertical meridian (Qy) and horizontal meridian (Qx), and surgically induced astigmatism (SIA) were calculated. Results: The 84 eyes included were categorized into three groups: horizontal muscle surgeries, oblique muscle surgery, and combined horizontal and oblique muscle surgeries. Significant corneal prolation (steep central, flat peripheral) was revealed in the vertical meridian (Qy) at 3 months postoperatively for lateral rectus (LR) recession in the first group (p < 0.001), and the mean SIA was 0.45 D (95% CI: 0.35-0.56 D). A similar effect was seen in the vertical meridian of the third group (p < 0.01), with a mean SIA at 3 months of 0.27 D (95% CI: 0.23-0.32 D). Conclusion: Lateral rectus muscle recession induces corneal vertical prolation for up to 3 months post-operation. Surgeons are thus advised to re-evaluate refraction and defer contact lens refitting, refractive surgery, and intraocular lens calculations for at least 3 months after the procedure. [ABSTRACT FROM AUTHOR]

We previously proposed that the optical centroid efficiency (OCE) might be a preferred figure-of-merit to the enclosed energy of a rectangular pixel (EOD) for an instrument subject to unpredictable environmental jitter and alignment conditions. Here we follow the same symbols for the corresponding quantities, particularly the width of the pixel as being equal to 2d. Here we analyze the performance of the OCE vs. the EOD for the three Seidel primary aberrations of an optical component: spherical, coma, and astigmatism, plus defocus. We show that the OCE has an approximate U-shape when graphed against the EOD, for the aberrations ranging from 0 to 1.25λ. We conclude that for pixels larger than 2d = 3λF/#, a small pixel will feature better performance when expecting jitter, misalignment, and other environmental and unpredictable conditions. When evaluating the performance of low-aberration instruments in dynamic and unpredictable environments, the choice of the lager pixel 2d = 7λF/# might be advantageous. Its selection will result in the deterioration of image resolution. [ABSTRACT FROM AUTHOR]

AIM: To compare the effective optical zone(EOZ)and corneal high order aberrations(HOAs)after small incision lenticule extraction(SMILE)among low, moderate, and high myopic patients.METHODS:A total of 134 patients who had undergone SMILE at the Second People's Hospital of Foshan from February 2019 to February 2021 were recruited, with all right eyes enrolled. The patients were divided into low myopia group(SE >-3.00 D), moderate myopia group(-6.00 D< SE ≤-3.00 D), and high myopia group(SE ≤-6.00 D)according to the spherical equivalent(SE). The total HOA(tHOA), spherical aberration, coma, and EOZ were measured by Pentacam preoperatively and 1 mo postoperatively, and differences in tHOA, spherical aberration, coma, and EOZ among the three groups were analyzed.RESULTS: EOZ was smaller than programmed EOZ in all groups at 1 mo after SMILE. With the increase in corrected refractive error, the EOZ decreased further(P0.05). The tHOA, spherical aberration and coma increased with corrected refractive errors; the difference in tHOA and spherical aberration was statistically significant among the three groups(all P0.05).CONCLUSION: With the increase of the refractive power corrected by surgery, the postoperative EOZ reduced more after surgery, and the HOA of the cornea is increased; corneal HOA increases at 1 mo after SMILE.

Purpose: To compare the objective visual quality of moderate-to-high myopia corrected by small incision lenticule extraction (SMILE) and transepithelial photorefractive keratectomy (TransPRK) at a 1,050-Hz ablation frequency, assisted by Smart-Pulse technology (SCHWIND eye-tech-solutions). Methods: This study involved 123 patients (123 eyes) with moderate-to-high myopia between July 2020 and January 2021. They were categorized into the SMILE group (67 patients, 67 eyes) and the TransPRK group (56 patients, 56 eyes). Follow-ups were conducted at 6 months postoperatively to record the logarithm of the minimum angle of resolution visual acuity, and the Strehl ratio and higher order aberrations were measured using the Sirius anterior segment analysis device (SCHWIND eye-tech-solutions) under a 6-mm pupil diameter at various postoperative intervals. Results: At 1 week and 1 month postoperatively, the uncorrected distance visual acuity (UDVA) in the SMILE group was superior to that in the TransPRK group (P <.05 for both). At 1 week and 1 month postoperatively, the Strehl ratio value in the SMILE group was higher than that in the TransPRK group (P <.05 for both). At 1, 3, and 6 months postoperatively, coma was greater in the SMILE group than in the TransPRK group (P <.05 for all). Spherical aberrations were lower in the SMILE group than in the TransPRK group at 3 and 6 months postoperatively (P <.05). At 6 months postoperatively, UDVA was −0.09 ± 0.08 and −0.11 ± 0.05 logMAR in the SMILE and TransPRK groups, respectively, which exceeded their preoperative corrected distance visual acuity of −0.05 ± 0.04 and −0.09 ± 0.08 logMAR (all P <.001). Compared with preoperative values, the Strehl ratio, total higher order, coma, and spherical aberration differences were significantly increased postoperatively in both groups (all P <.001). Conclusions: Both surgical methods improved UDVA and each had its advantages. The visual quality of SMILE was superior at 1 week and 1 month postoperatively (Strehl ratio values were higher than those of the TransPRK group), and its spherical aberration was lower than that of the TransPRK group at 3 and 6 months; TransPRK with SmartPulse technology with a 1,050-Hz ablation frequency showed that coma was significantly lower than that of the SMILE group at 1, 3, and 6 months postoperatively. [J Refract Surg. 2024;40(7):e490–e498.] [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the optical and aberrometric outcomes of an enhanced monofocal intraocular lens (ISOPure) compared with those of a standard monofocal lens (MicroPure) having the same platform and material. Methods: A prospective, comparative and randomised clinical study. A total of 28 eyes of 28 patients were randomly assigned to either group. Monocular visual acuity (VA) was measured at distance and intermediate under photopic and mesopic conditions. Aberrometry was analysed for 3.0‐, 4.0‐, 4.5‐ and 5.0 mm pupils. The contrast sensitivity defocus curve was measured for 3.0‐ and 4.5‐mm pupils, while the modulation transfer function (MTF) and Strehl ratio (SR) were assessed with a double‐pass system. All measurements were performed monocularly 3 months after surgery. Results: No significant differences were found for distance VA. Under photopic conditions, intermediate VA was better with the ISOPure lens, while no significant differences were found between the lenses under mesopic conditions. Internal and total aberrations were higher for the ISOPure lens. No significant differences were found for corneal aberrations. Additionally, both the contrast sensitivity defocus curve and optical quality showed similar behaviour for each lens, with the MTF cut‐off frequency exceeding 30 c/deg in both cases. Conclusion: The isofocal ISOPure lens enhanced intermediate VA without affecting distance VA under photopic conditions. Moreover, there were no significant differences in visual quality between the ISOPure and MicroPure lenses, despite the former exhibiting higher internal and total aberrations than the monofocal model. [ABSTRACT FROM AUTHOR]

Abstract Background An enhanced monofocal intraocular lenses (IOLs) (Tecnis Eyhance ICB00 and Tecnis Eyhance Toric DIU) has been developed to enhance intermediate vision while avoiding the disadvantages of multifocal IOLs. Although many studies have demonstrated the improvement of intermediate visual acuity with enhanced monofocal IOLs, it is not known specifically for which patients these IOLs should be recommended or avoided. In this study, we aim to find out which ocular parameters affect vision performance and photic phenomenon of ICB00 or DIU at different distances. Methods Patients who underwent cataract surgery with ICB00 or DIU, performed by a single surgeon, were included. Before surgery, the patients’ age, gender, axial length, anterior chamber depth, spherical aberration Z (4,0), vertical coma, horizontal coma, angle kappa (κ), angle alpha (α), and other ocular parameters were investigated. One month after surgery, uncorrected near visual acuity (UNVA at 40 cm), uncorrected intermediate visual acuity (UIVA at 66 cm), uncorrected distance logMAR visual acuity (UDVA), IOL decentration, and quality of vision (QoV) questionnaires were conducted. Results A total of 43 patients (58 eyes) were included. The results of the univariate linear regression analyses showed a negative correlation between spherical aberration and logMAR UNVA and UIVA (p = 0.003, β=-0.51 and p = 0.018, β=-0.23, respectively) and a positive correlation between angle α and logMAR UIVA (p = 0.036, β = 0.19). Deeper anterior chamber depth (ACD) was associated with poorer total QoV (p = 0.018, β = 14.43), particularly in glare, halo, blur, and fluctuation perception. A higher degree of IOL decentration tended to decrease UNVA and UIVA (Pearson correlation coefficient, r = 0.336 and r = 0.221, respectively); however, no significant effect was observed on UDVA (Pearson correlation coefficient, r = 0.042). Conclusions In enhanced monofocal IOLs, a higher level of spherical aberration is associated with better performance in UNVA and UIVA, whereas a larger angle α has a negative impact. A deeper ACD negatively affects the QoV.

Background: An enhanced monofocal intraocular lenses (IOLs) (Tecnis Eyhance ICB00 and Tecnis Eyhance Toric DIU) has been developed to enhance intermediate vision while avoiding the disadvantages of multifocal IOLs. Although many studies have demonstrated the improvement of intermediate visual acuity with enhanced monofocal IOLs, it is not known specifically for which patients these IOLs should be recommended or avoided. In this study, we aim to find out which ocular parameters affect vision performance and photic phenomenon of ICB00 or DIU at different distances. Methods: Patients who underwent cataract surgery with ICB00 or DIU, performed by a single surgeon, were included. Before surgery, the patients' age, gender, axial length, anterior chamber depth, spherical aberration Z (4,0), vertical coma, horizontal coma, angle kappa (κ), angle alpha (α), and other ocular parameters were investigated. One month after surgery, uncorrected near visual acuity (UNVA at 40 cm), uncorrected intermediate visual acuity (UIVA at 66 cm), uncorrected distance logMAR visual acuity (UDVA), IOL decentration, and quality of vision (QoV) questionnaires were conducted. Results: A total of 43 patients (58 eyes) were included. The results of the univariate linear regression analyses showed a negative correlation between spherical aberration and logMAR UNVA and UIVA (p = 0.003, β=-0.51 and p = 0.018, β=-0.23, respectively) and a positive correlation between angle α and logMAR UIVA (p = 0.036, β = 0.19). Deeper anterior chamber depth (ACD) was associated with poorer total QoV (p = 0.018, β = 14.43), particularly in glare, halo, blur, and fluctuation perception. A higher degree of IOL decentration tended to decrease UNVA and UIVA (Pearson correlation coefficient, r = 0.336 and r = 0.221, respectively); however, no significant effect was observed on UDVA (Pearson correlation coefficient, r = 0.042). Conclusions: In enhanced monofocal IOLs, a higher level of spherical aberration is associated with better performance in UNVA and UIVA, whereas a larger angle α has a negative impact. A deeper ACD negatively affects the QoV. [ABSTRACT FROM AUTHOR]

The optical quality of an image depends on both the optical properties of the imaging system and the physical properties of the medium the light passes while travelling from the object to the image plane. The computation of the point spread function (PSF) associated to the optical system is often used to assess the image quality. In a non-ideal optical system, the PSF is affected by aberrations that distort the final image. Moreover, in the presence of turbid media, the scattering phenomena spread the light at wide angular distributions that contribute to reduce contrast and sharpness. If the mathematical degradation operator affecting the recorded image is known, the image can be restored through deconvolution methods. In some scenarios, no (or partial) information on the PSF is available. In those cases, blind deconvolution approaches arise as useful solutions for image restoration. In this work, a new blind deconvolution method is proposed to restore images using spherical aberration (SA) and scatter-based kernel filters. The procedure was evaluated in different microscopy images. The results show the capability of the algorithm to detect both degradation coefficients (i.e., SA and scattering) and to restore images without information on the real PSF. [ABSTRACT FROM AUTHOR]

As a highly prevalent global condition, myopia significantly impacts the ocular health of young individuals in China. Orthokeratology lens, as a rigid corneal contact lens, has demonstrated effective control over the progression of myopia; however, its mechanism of action remains incompletely elucidated. As one of the factors influencing visual acuity, higher-order aberrations will undergo marked changes after orthokeratology, with particular emphasis on the alterations in spherical aberrations and coma. The changes in corneal morphology induced by orthokeratology lead to significant positive increase in both spherical aberration and coma. Furthermore, the elevation of spherical aberration and coma demonstrates a negative correlation with the rate of axial length growth following orthokeratology. The interplay among spherical aberration, coma, defocus, accommodation, astigmatism, and pseudo-accommodation may constitute the underlying mechanism governing the control of myopia through orthokeratology.

Jun Zhang, Jie Shao, Xinfang Cao, Yonggang Zhang, Li Zheng Department of Ophthalmology, Hangzhou MSK Eye Hospital, Hangzhou, People’s Republic of ChinaCorrespondence: Jun Zhang, Hangzhou MSK Eye Hospital, No. 384, Fengqi Road, Gongshu District, Hangzhou, Zhejiang, People’s Republic of China, Tel +86 18667046602, Fax +86 85068587, Email zhangjun@mskyk.onaliyun.comPurpose: To investigate the visual acuity and satisfaction of patients after Zhang & Zheng’s corneal laser-enhanced accommodation refraction Q (ZZ-CLEAR-Q) surgery utilizing differential modulation of binocular longitudinal spherical aberration and determine its clinical significance.Patients and Methods: This prospective observational study enrolled a consecutive cohort of patients with presbyopia who underwent ZZ-CLEAR-Q surgery between December 2020 and January 2023. The study assessed visual acuity, distance-corrected defocus curve, satisfaction, Q factor, manifest spherical equivalent, and primary spherical aberration, among others, at 3 months postoperatively. Additionally, the study conducted a binocular comparison to analyze the clinical significance of setting the different longitudinal spherical aberrations.Results: A total of 232 eyes of 116 patients were included. The binocular uncorrected distance visual acuity was 20/20 for all patients. At 3 months postoperatively, the binocular uncorrected near visual acuity was Jaeger 1 for 96% of the patients and Jaeger 2 for 100% of the patients. Furthermore, 93.1% of the patients expressed satisfaction. The monocular distance-corrected defocus curve revealed that the dominant eyes had significantly better visual acuity at 0 D (P< 0.001), while the non-dominant eyes had significantly better visual acuity across various defocus levels except 0 and − 0.50 D (All P< 0.05). At 3 months, there were no significant differences between the expected and achieved manifest spherical equivalents, corneal Q factor values, and ocular primary spherical aberration values of both groups.Conclusion: Patients with presbyopia who underwent ZZ-CLEAR-Q surgery were likely to achieve normal uncorrected visual acuity and be satisfied. The increased depth of field has clinical significance for assisting near vision.Keywords: defocus curve, LASIK, presbyopia, Q factor, spherical aberration

Purpose: Previous transverse and a handful of longitudinal studies have shown that the slope of the static accommodation response/stimulus curve declines as complete presbyopia is approached. Changes in pupillary miosis and ocular spherical aberration (SA) are also evident. This study further investigated longitudinal changes in the relationships between the monocular static accommodative response, pupil diameter and SA of a single adult. Methods: A wavefront analysing system, the Complete Ophthalmic Analysis System, was used in conjunction with a Badal optometer to allow continuous recording of the aberration structure of the dominant eye in a low myope for a range of accommodative demands (−0.83 to 7.63 D) over a period of 17 years until the age of 50. Monocular accommodative response was calculated as the equivalent refraction minimising wavefront error. The associated longitudinal changes in pupil size and SA with accommodation were also recorded. Results: A decrease in accommodation response with age was found at almost all target vergences, with the changes being greatest for higher vergences. In addition, although absolute pupil diameter decreased with age, the rate of change in pupil diameter with accommodative stimulus remained approximately constant with age. Pupil constriction occurred for near stimuli even in full presbyopia. SA changed linearly with the accommodation response at all ages. Conclusions: The objective amplitude of accommodation declined linearly with age as complete presbyopia was approached, while the slope of the response/stimulus curve also fell. It was hypothesised that the retinal image blur associated with the larger lags of accommodation at higher accommodative stimuli was reduced by pupil constriction and the resulting lower levels of SA. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Jilin University (Science Edition) / Jilin Daxue Xuebao (Lixue Ban) is the property of Zhongguo Xue shu qi Kan (Guang Pan Ban) Dian zi Za zhi She 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.)

Head rotation in human spermatozoa is essential for different swimming modes and fertilisation, as it links the molecular workings of the flagellar beat with sperm motion in three-dimensional (3D) space over time. Determining the direction of head rotation has been hindered by the symmetry and translucent nature of the sperm head, and by the fast 3D motion driven by the helical flagellar beat. Analysis has been mostly restricted to two-dimensional (2D) single focal plane image analysis, which enables tracking of head centre position but not tracking of head rotation. Despite the conserved helical beating of the human sperm flagellum, human sperm head rotation has been reported to be uni- or bi-directional, and even to intermittently change direction in a given cell. Here, we directly measure the head rotation of freely swimming human sperm using multi-plane 4D (3D+t) microscopy and show that: (1) 2D microscopy is unable to distinguish head rotation direction in human spermatozoa; (2) head rotation direction in non-capacitating and capacitating solutions, for both aqueous and viscous media, is counterclockwise (CCW), as seen from head to tail, in all rotating spermatozoa, regardless of the experimental conditions; and (3) head rotation is suppressed in 36% of spermatozoa swimming in non-capacitating viscous medium, although CCW rotation is recovered after incubation in capacitating conditions within the same viscous medium, possibly unveiling an unexplored aspect of the essential need of capacitation for fertilisation. Our observations show that the CCW head rotation in human sperm is conserved. It constitutes a robust and persistent helical driving mechanism that influences sperm navigation in 3D space over time, and thus is of critical importance in cell motility, propulsion of flagellated microorganisms, sperm motility assessments, human reproduction research, and self-organisation of flagellar beating patterns and swimming in 3D space. [ABSTRACT FROM AUTHOR]

ObjectiveTo examine the causes and factors that lead to high order aberration (HOA) during the treatment of myopia using small incision lenticule extraction (SMILE), as well as the differences between SMILE and other corneal refractive surgeries through a systematic review and meta-analysis.MethodsA systematic search was conducted from January 2015 to February 2023 in Pubmed, Embase, Web of Science, and Google Scholar databases to gather relevant studies on SMILE and HOA. Studies meeting specific criteria were chosen, and clinical data was retrieved for analysis.ResultsThis meta-analysis resulted in the inclusion of 19 studies involving 1,503 eyes. Pooled results showed significant induction of total HOA (tHOA, d = −0.21, p -5D), lower preoperative astigmatism group (cylinder ≤ -1D), larger lenticule thickness group (lenticule thickness > 100 μm), shorter follow-up group (follow-up 1 month postoperatively) and the thicker CCT group (CCT > 550 μm) brought a significant induction of tHOA compared to the opposite comparison group (p

This study compares a standard monofocal intraocular lens (IOL) with two rotationally asymmetric refractive multifocal IOLs, analyzing power profiles and wavefront data across three nominal powers. Tested IOLs included monofocal Acunex AN6 and multifocal AN6V (addition +1.50 D) and AN6VM (addition +3.00 D) by Teleon Surgical, at powers +10.00 D, +20.00 D, and +30.00 D. Using NIMO TR1504, power profiles, spherical aberration, and coma were analyzed. Multifocal lenses displayed an asymmetrical design, with zones for far and near vision and a central notch for far power. The multifocal AN6V and AN6VM showed neutral spherical aberration in the center, increasing to positive values, and finally achieving negative values towards the periphery. The vertical coma coefficient [Z(3:−1)] remains almost stable for the monofocal IOLs. The lower-addition multifocal IOLs induce primary vertical coma of +0.11 microns at 3 mm away from the lens center compared to +0.21 microns obtained with the high-addition lens. We can conclude that the multifocal AN6V and AN6VM lenses display an asymmetrical design. The final addition provided by these lenses depends on its nominal power. The variation of SA with optic size is more pronounced for the monofocal model, and it is dependent on the nominal power.

Purpose: to compare anatomical and optical parameters and aberrations of both eyes in patients with acquired and congenital anisometropic myopia.Material and methods. 22 patients (44 eyes) aged 18–35 (averagely, 25.2) with acquired and congenital anisometropic myopia were examined using the Galilei G6 optical eye system analyzer (Ziemer, Switzerland). The analysis of total, corneal and internal aberrations of the eye was carried out on an OPD-Scan III (Nidek) aberrometer.Results. In both groups with acquired and congenital anisometropic myopia, the axial length of the higher myopic eye was greater than that of the fellow eye. A greater asphericity and higher astigmatism of the cornea were revealed in higher myopic eyes of patients with congenital myopia as compared to acquired myopia. The total RMS HOA in congenital myopia was significantly greater in the higher myopic eye compared to the fellow eye (1.07 D and 0.68 D, respectively) and greater than in cases of acquired myopia. All HOA were greater in higher myopic eyes as compared to the fellow ones in cases of congenital myopia. In case of acquired myopia only the total coma appeared to be greater in the higher myopic eye. Corneal aberrations in acquired anisometropic myopia did not differ in the paired eyes. In case of congenital myopia, the total tilt was significantly greater in the higher myopic eye, and total coma and spherical aberration have lower values, even with a transition to negative ones (p < 0.05).Conclusion. The revealed differences of the wavefront of the eyes with anisometropic congenital and acquired myopia are rather a consequence of anatomical and optical differences (the axial length of the eyes and the topography of the cornea), than the cause of anisometropia.

Abstract Purpose To observe the distribution characteristics of corneal higher-order aberrations (HOAs) in cataract patients, and analyze the relationship of HOAs with patients’ age and ocular biometric parameters. Methods This retrospective study reviews the patients with cataract in Wuhan Aier Eye Department from January to August 2022. Root mean square (RMS) of the total HOA (tHOA), spherical aberration (SA), coma and trefoil aberration of the anterior cornea at central 4 and 6 mm optic zone were measured by the Wavefront Aberrometer (OPD-Scan III; Nidek Inc, Tokyo, Japan). The biometric parameters including axial length (AL), keratometry (K), central corneal thickness (CCT) and lens thickness (LT) were measured by swept-source coherence laser interferometry (OA-2000; TOMEY Corp, Aichi, Japan). Subgroup analyses and multiple linear regression analyses were used to determine whether HOAs were associated with age and ocular biometric parameters. Results A total of 976 patients (976 eyes) were included, averagely aged 65 years. At central 4 and 6 mm optic zone, the mean RMS of tHOA were respectively 0.20 and 0.65 μm, the SA were 0.06 and 0.30 μm, the coma aberration were 0.11 and 0.35 μm, and the trefoil aberration were 0.12 and 0.30 μm. The tHOA decreased with age until 60 years and then started to increase afterwards. The tHOA, coma and trefoil aberration increased with corneal astigmatism. The tHOA, SA, and coma aberration differ among different AL groups, and emmetropes had the smallest tHOA, SA, and coma aberration. Conclusions With increasing age, the value of tHOA decrease first and started increasing at 60 years. The trends of corneal HOAs are consistent with corneal low-order aberrations. The values of tHOA, SA and coma aberration were the smallest in emmetropic eyes.

Pursuing higher topological charge—larger angular indices m of high‐order Laguerre–Gaussian (LG) beams—is not only important for frontier applications like optical/quantum communication, optical tweezers, and super‐resolution imaging, but also involves a novel laser cavity and beam dynamics. Active methods to directly generate high‐order‐mode vortex beams from a laser cavity have excellent power handling and conversion efficiency, but struggle to achieve hundred‐level ultra‐high‐order LG modes. Here, the generation of ultra‐high‐order LG beams with m beyond 300 is demonstrated, utilizing the spherical aberration of a lens in the cavity of a simple end‐pumped Nd:YVO4 laser at 1064 nm. LG0,±m modes with m up to 317, selectable across a large range, are generated. With a simple model, how the mode selection relates to the cavity parameters is explained, and it is predicted that even higher order mode output can be expected by appropriate management of the elements' aperture and laser gain. The approach provides a simple and flexible method to convert a wide range of lasers to generate ultra‐high‐order LG modes. [ABSTRACT FROM AUTHOR]

AIM: To investigate the size of functional optical zone (FOZ) after small incision lenticule extraction (SMILE) versus femtosecond laser assisted excimer laser keratomileusis (FS-LASIK) for myopia correction and potential associated factors for FOZ. METHODS: A total of 133 patients who received corneal refractive surgery in our hospital between November 2018 and July 2021 were retrospectively enrolled. There were 63 patients (123 eyes) in SMILE group and 70 patients (139 eyes) in FS-LASIK group. The size of FOZ was measured using Pentacam 3-dementional anterior segment analyzer before and 3mo after surgery, so as to analyze postoperative achieved functional optical zone (AFOZ) and its contributing parameters. RESULTS: When planned functional optical zone (PFOZ) was 6.5 mm for both groups, AFOZ was 1.45±0.27 and 1.67±0.25 mm smaller than preoperative FOZ in SMILE group and FS-LASIK group 3mo after surgery. AFOZ in SMILE group was significantly larger than that in FS-LASIK group (P

The optical quality of an image depends on both the optical properties of the imaging system and the physical properties of the medium the light passes while travelling from the object to the image plane. The computation of the point spread function (PSF) associated to the optical system is often used to assess the image quality. In a non-ideal optical system, the PSF is affected by aberrations that distort the final image. Moreover, in the presence of turbid media, the scattering phenomena spread the light at wide angular distributions that contribute to reduce contrast and sharpness. If the mathematical degradation operator affecting the recorded image is known, the image can be restored through deconvolution methods. In some scenarios, no (or partial) information on the PSF is available. In those cases, blind deconvolution approaches arise as useful solutions for image restoration. In this work, a new blind deconvolution method is proposed to restore images using spherical aberration (SA) and scatter-based kernel filters. The procedure was evaluated in different microscopy images. The results show the capability of the algorithm to detect both degradation coefficients (i.e., SA and scattering) and to restore images without information on the real PSF.

Background: Corneal refractive surgery induces high-order aberrations, specifically spherical aberration (SA). These aberrations can have implications when patients later develop cataracts and require the implantation of multifocal intraocular lenses (MIOLs). MIOLs with asymmetric designs pose challenges in predicting outcomes, particularly in these cases. The aim of this study was to evaluate how different values of SA, resulting from various types of refractive surgeries, affect the optical performance of the FEMTIS Comfort intraocular lens. Methods: The through-focus modulation transfer function (TF-MTF) curve and high-contrast images of tumbling E were used as parameters to assess the optical performance of the MIOL. These parameters were measured using an adaptive optics visual simulator. Results: Increasingly negative values of SA make the MIOL more bifocal, moderating its extended-depth-of-focus characteristic. Conversely, higher positive SA values cause the TF-MTF curve to shift towards positive vergences, leading to worsened distance vision in the +1.00 to +2.00 D range, but improved vision in the +0.50 D to +1.00 D range. Conclusions: Assessing SA in patients prior to implanting MIOLs with asymmetric designs is necessary for predicting outcomes and making informed decisions based on the visual requirements of patients. [ABSTRACT FROM AUTHOR]

Purpose: To observe the distribution characteristics of corneal higher-order aberrations (HOAs) in cataract patients, and analyze the relationship of HOAs with patients' age and ocular biometric parameters. Methods: This retrospective study reviews the patients with cataract in Wuhan Aier Eye Department from January to August 2022. Root mean square (RMS) of the total HOA (tHOA), spherical aberration (SA), coma and trefoil aberration of the anterior cornea at central 4 and 6 mm optic zone were measured by the Wavefront Aberrometer (OPD-Scan III; Nidek Inc, Tokyo, Japan). The biometric parameters including axial length (AL), keratometry (K), central corneal thickness (CCT) and lens thickness (LT) were measured by swept-source coherence laser interferometry (OA-2000; TOMEY Corp, Aichi, Japan). Subgroup analyses and multiple linear regression analyses were used to determine whether HOAs were associated with age and ocular biometric parameters. Results: A total of 976 patients (976 eyes) were included, averagely aged 65 years. At central 4 and 6 mm optic zone, the mean RMS of tHOA were respectively 0.20 and 0.65 μm, the SA were 0.06 and 0.30 μm, the coma aberration were 0.11 and 0.35 μm, and the trefoil aberration were 0.12 and 0.30 μm. The tHOA decreased with age until 60 years and then started to increase afterwards. The tHOA, coma and trefoil aberration increased with corneal astigmatism. The tHOA, SA, and coma aberration differ among different AL groups, and emmetropes had the smallest tHOA, SA, and coma aberration. Conclusions: With increasing age, the value of tHOA decrease first and started increasing at 60 years. The trends of corneal HOAs are consistent with corneal low-order aberrations. The values of tHOA, SA and coma aberration were the smallest in emmetropic eyes. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the prevalence and repeatability of high‐order aberrations (HOAs) from non‐cyclopleged eyes in 1515 children and adolescents 2.5–18 years of age. Methods: The Leipzig Research Centre for Civilization Diseases (LIFE)‐Child study is a population‐based, prospective, observational single‐centre study that investigates the development of children and adolescents in Germany. Wavefront measurements were repeated three times in each eye of 1515 healthy subjects. Results were described by 36 Zernike coefficients for a 5 mm reference pupil diameter. Short‐term repeatability is given for each coefficient. The impact on vision is described by the root mean squared (RMS) value of the HOA Zernike coefficients. Results: High‐order aberrations were dominated by five contributions. For 1004 right eyes: spherical aberration (c12 = 0.06 ± 0.07 μm), coma (c7 = 0.03 ± 0.09 μm, c8 = 0.03 ± 0.06 μm) and trefoil (c6 = −0.01 ± 0.07 μm, c9 = 0.008 ± 0.06 μm). The RMS value was 0.18 ± 0.06 μm. Modes higher than fourth order do not contribute clinically to the aberrations. HOAs show no clinically significant dependency with age. Instead, HOA values agree well with previous results on aberrations in adult eyes. Spherical aberration was highly correlated between the two eyes. Repeatability was worst for coma, 0.033 μm, due to variability in the alignment of the pupil centre. The left eye showed, on average, a 0.08 mm larger pupil diameter than the right eye (p < 0.02). Conclusions: Across the age span from 2.5 to 18 years, we see the same distribution of HOA as for adults. We established that only five Zernike coefficients, spherical aberration, coma and trefoil were of clinical significance in healthy eyes. A high correlation between the two eyes for spherical aberration suggests a common blueprint for each eye in any one subject. [ABSTRACT FROM AUTHOR]

We present a theoretical model of a cylindrical tunable liquid crystal lens based on the modulation of anchoring energy. The latter can be easily obtained using photoalignment techniques. The liquid crystal cell we propose exhibits strong anchoring at the top substrate and anchoring energy with a parabolic profile at the bottom substrate. The model describes the dependence of the focal length on the applied voltage and presents a theoretical study of the lens aberrations. The results obtained are of general relevance and can be used to optimize the performances of every type of liquid crystal lens with a parabolic profile. [ABSTRACT FROM AUTHOR]

To investigate visual outcomes early after implantable collamer lens (ICL) V4c implantation between patients with fully corrected and under-corrected spectacles preoperatively. Patients who implanted ICL V4c were divided into the full correction (46 eyes/23 patients) and under-correction groups (48 eyes/24 patients) based on preoperative differences between the spherical diopter of the spectacles and the actual spherical diopter. Refractive outcomes, scotopic pupil size, higher-order aberrations, and subjective visual outcomes as assessed using a validated questionnaire were compared between the two groups 3 months postoperatively. Moreover, the relationships between the severity of haloes and postoperative ocular or ICL parameters were analyzed. At the 3-month follow-up, the efficacy indices in the full correction and under-correction groups were 0.99 ± 0.12 and 1.00 ± 0.10, respectively; the safety indices were 1.15 ± 0.16 and 1.15 ± 0.15, respectively. Total-eye spherical aberration (p < 0.0001) and internal spherical aberration (p = 0.0005) were significantly different pre- and post-operatively in the under-correction group, while no differences were found in the full correction group. Total-eye spherical aberration (p = 0.002) and the severity of haloes (p = 0.03) were postoperatively different between the two groups. The severity of haloes was associated with postoperative spherical aberration (total-eye spherical aberration: r = −0.32, p = 0.002; internal spherical aberration: r = −0.24, p = 0.02). Good efficacy, safety, predictability, and stability were obtained early after surgery regardless of preoperative spectacle correction. Patients in the under-correction group possessed a shift to negative spherical aberration and reported greater severity of haloes at the 3-month follow-up. Haloes were the most common visual symptoms after ICL V4c implantation and the severity of them was correlated with postoperative spherical aberration. [ABSTRACT FROM AUTHOR]

Copyright of Baghdad Science Journal is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) 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.)

We live in a world of exponentially increasing technology advancements and improving patient care has become a priority for all health care providers. In the field of ophthalmology, quality of vision has taken an edge over the need for regular visual acuity. Aberrometry is a newer non-invasive technique to accurately measure the imperfections of the eye and largely aid in achieving the best post-operative visual outcome. This article aims in reviewing the basics of optical aberrations and how to make the best of this technique in our clinical practice.

Given the relationship between spherical aberrations and accommodation, the study of these aberrations can be helpful to understand accommodative response in subjects with accommodative dysfunctions. The purpose of this study was to evaluate on-axis and off-axis changes of primary and secondary spherical aberrations, Z(4,0) and Z(6,0), with accommodation in subjects with accommodative insufficiency (AI). Ten subjects with AI and eleven without any accommodative dysfunction (control) participated in this study. On-axis defocus Z(2,0), Z(4,0), and Z(6,0) were obtained in both groups with a Hartmann–Shack aberrometer for the unaccommodated state and with 1.00 D, 2.44 D, 3.83 D, and 4.73 D of accommodative stimuli. Z(4,0) and Z(6,0) were also measured on 11.5° and 23° temporal, nasal, superior, and inferior retinal areas for unaccommodated state and for 2.44 D of accommodative stimulus. In the control group, Z(4,0) became more negative with accommodation and Z(6,0) became more positive, as was expected according to previous studies. This tendency was not observed in the group of subjects with AI group for Z(4,0) or for Z(6,0). No differences on off-axis Z(4,0) and Z(6,0) were observed between the groups. The changes of spherical aberrations with accommodation seem different in subjects with AI compared to those without any accommodative dysfunction. Those with AI do not present a decrease in Z(4,0) and an increase in Z(6,0) with accommodation as occurs in eyes without this type of dysfunction. Understanding how the optics of the eye changes with accommodation can be helpful to understand the origin of accommodative dysfunctions. [ABSTRACT FROM AUTHOR]

Introduction: This study aimed to investigate the distribution of corneal spherical aberration (CSA) and the relationship between corneal curvature with CSA and anterior chamber parameters in age-related cataract patients with normal axial lengths and shallow anterior chambers. Methods: Preoperative data of age-related cataract patients were collected in this retrospective comparative study. According to the average corneal curvature, the eyes were divided into groups of Km < 42 diopters (D), 42 D ≤ Km < 45 D, and Km ≥ 45 D. The axial length (AL) and corneal curvature were obtained using IOLMaster. CSA, anterior chamber depth (ACD), anterior chamber volume (ACV), anterior chamber angle (ACA), and corneal diameter (CD) were acquired according to Pentacam. The above parameters were compared among the three groups. Correlation analysis was applied to these parameters. Results: The average CSA value of 753 eyes was 0.41 ± 0.27 μm, with no significant difference among the three groups. Overall, CSA was significantly correlated with corneal curvature and ACD. The comparison of ACD among the three groups showed significant differences between the Km ≥ 45 D group, Km < 42 D group, and 42 D ≤ Km < 45 D group. Corneal curvature was positively correlated with ACD, and further analysis confirmed that the relationship was significant only in the Km ≥ 45 D group. There were statistically significant differences in CD between the three groups. A significant correlation was found in corneal curvature and CD in all eyes, which was also found in the 42 D ≤ Km < 45 D group and the Km ≥ 45 D group. Concerning ACV and ACA, no correlation with corneal curvature was found. In addition, the mean ACV and ACA of the three groups did not show any significant difference. Conclusions: CSA was higher in this population and had individual variance. Compared with ACD, ACV and ACA were more stable in different corneal curvatures and more objective in representing the anterior chamber space. [ABSTRACT FROM AUTHOR]

This paper estimates a specific detailed diffractive aspheric bifocal intraocular lens (IOL) used to correct and reduce corneal aberration and a patient’s standard surgical implantation. Foldable acrylic hydrophobic materials have promising properties and are thus used in IOLs. Calculations and analyses were performed using the optical software design program Zemax, and important criteria, such as modulation transfer function and Seidel aberration, were tested over a range of fields of view (20°, 30° or 40°) and different values of entrance pupil diameter (1.5, 3 and 4 mm). Results showed that a significant amount of corneal spherical aberration can be compensated for. The diffractive hydrophobic IOL customizes and corrects the spherical aberration performance of the individual crystalline lens.

Background: Intraocular lenses with a negative aspherical design for correction of corneal spherical aberration (SA) have gained popularity in recent decades. In most cases, a 'one size fits all' concept is followed, where all eyes receive lenses with the same SA correction. The purpose of this study is to develop a strategy based on raytracing using anterior segment tomography data to extract corneal SA and to provide simple multivariable linear models for prediction of corneal SA. Methods: The analysis was based on a large dataset of 8737 measurements of 8737 eyes from 1 clinical centre, using the Casia2 anterior segment tomographer. An optical model based on: corneal front and back surface radius Ra and Rp, asphericities Qa and Qp, corneal thickness CCT, anterior chamber depth ACD, and pupil centre position (X‐Y position: PupX and PupY), was defined for each measurement. Corneal SA was derived using a 6‐mm aperture perpendicular to the incident ray and centred on the chief ray, and linear prediction models were derived for SA using biometric data. Cross‐validation was used for model performance evaluation. Results: Using raytracing, the wavefront error within an aperture (6‐mm diameter centred on the intersection of the chief ray with the cornea) was calculated and corneal SA was extracted. After identifying the relevant effect sizes (Ra, Qa, Rp Qp, ACD, PupX and PupY) using stepwise linear regression, linear mixed‐effects models (model 1: all effect sizes, model 2: Ra, Qa, Rp and Qp, model 3: Ra and Qa) were set up on the training data in terms of a Monte‐Carlo simulation. On the test data (training data), model 1 with a mean absolute/root‐mean‐squared prediction error of 0.0095/0.0130 (0.0095/0.0127) performed similarly to model 2 with 0.0097/0.0131 (0.0096/0.0127), and both outperformed model3 with 0.0152/0.0197 (0.0148/0.0190). Conclusion: Based on the Casia2 anterior segment tomographer, corneal SA could be derived using shape data (curvature and asphericities) of both corneal surfaces (model 2). This information could easily be used for selection of the appropriate negative aspherical lens design in cataract surgery. [ABSTRACT FROM AUTHOR]