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Correlation between iris-registered static and dynamic cyclotorsions with?preoperative refractive astigmatism in PRK candidates
摘要： Purpose: To evaluate static and dynamic cyclotorsions during photorefractive keratotomy (PRK) surgery in refractive surgery candidates and their correlations with preoperative factors. Methods: This cross-sectional case series was performed in 138 eyes of 77 patients who underwent PRK surgery by Technolas 217z100. Iris registration was used to evaluate the degree of static and dynamic cyclotorsion. Wavefront measurements were performed in sitting position using Zywave (versions 3.1 and 3.2, Bausch & Lomb) Hartmann Shack aberrometer (Bausch & Lomb), and the cyclotorsion from upright to supine position was measured using iris image comparison. Dynamic cyclotorsions were measured by Advanced Cyclotorsional Eye Tracker (ACE) mounted on Excimer laser machine Technolas 217z100 during surgery. Results: The mean absolute static cyclotorsion that was captured in surgery time was 3.37 ± 2.38° (range, 0.00 to 11.30), and the mean absolute dynamic cyclotorsion was 2.54 ± 2.50° (range, 0.00 to 13.60). There was a significant correlation between dynamic cyclotorsions and static cyclotorsions (P < 0.001 and R = 0.704). There was a strong association between preoperative refractive astigmatism and range dynamic cyclotorsion. Total pulses (P = 0.009), ablation depth (P = 0.012), gender (P = 0.008), and laterality had significant correlations with cyclotorsional movements. Conclusion: The measurements of static and dynamic cyclotorsions are highly recommended for refractive surgery candidates with significant preoperative refractive astigmatism.
关键词： Astigmatism,Cyclotorsions,Refractive surgery
更新于2025-09-23 15:23:52
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Contact Lenses || Optics and Lens Design
摘要： Some aspects of contact lens design and optics are rarely applied nowadays, as they are less relevant to modern practice, but readers may still need to refer to them. They are available at: https://expertconsult.inkling.com/, whereas the more relevant topics are included here. The appendix, available at: https://expertconsult.inkling.com/, also describes various equations that are used in contact lens work, while the online resources include programs relating to both the optics and to lens design. There are two main aspects to be considered when dealing with the optics of contact lenses: the effects on the wearer of the optical differences from spectacles and the necessity for the practitioner to understand the components which affect the back vertex power (BVP) of the contact-lens/liquid*-lens system. There is some overlap of these two aspects, but for the sake of convenience they are discussed separately in the first two sections of the chapter. In the second section a set of approximate rules is included, the use of which should permit practitioners to make quick and reasonably accurate estimates of changes in power caused by altering certain lens parameters. The Cartesian sign convention2 is used throughout. For further understanding of the basic principles involved, readers are referred to the works of Bennett (1985), Tunnacliffe (1993), Freeman and Hull (2003), Douthwaite (2006) and Rabbetts (2007).
关键词： Lens Design,Astigmatism,Optics,Bifocal Contact Lenses,Power Variations,Contact Lenses,Ocular Refraction,Aberrations,Spectacles
更新于2025-09-23 15:23:52
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The Implantable Collamer Lens with a central port: review of the literature
摘要： The purpose of this review is to summarize preclinical and clinical data from publications appearing in the peer-reviewed scientific literature relevant to the safety and effectiveness of the EVO Implantable Collamer Lens (ICL) posterior chamber phakic refractive lens with a central port (V4c Visian ICL with KS Aquaport, STAAR Surgical, Inc.). A literature search was conducted using PubMed.gov to identify all articles relating to the EVO ICL. Articles were examined for their relevance, and the references cited in each article were also searched for additional relevant publications. On the basis of a total of 67 preclinical studies and clinical reports, including effectiveness data on 1,905 eyes with average weighted follow-up of 12.5 months and safety data on 4,196 eyes with weighted average follow up of 14.0 months, the EVO ICL is safe and effective for the correction of a broad range of refractive errors. High levels of postoperative uncorrected visual acuity, refractive predictability, and stability demonstrate the effectiveness of the EVO ICL. Safety data suggest reduced rates of anterior subcapsular cataract and pupillary block compared with earlier models. Improved safety and proven effectiveness make EVO an attractive option for surgeons and patients.
关键词： phakic refractive lens,myopia,hyperopia,astigmatism
更新于2025-09-23 15:22:29
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Comparison between Transepithelial Photorefractive Keratectomy versus Alcohol-Assisted Photorefractive Keratectomy in Correction of Myopia and Myopic Astigmatism
摘要： Purpose. The aim of the study was to compare visual acuity, refractive results, safety, and efficacy of TPRK with AAPRK as primary outcomes and surgical time, pain scores, haze levels, and healing time as secondary outcomes in TPRK and AAPRK groups. Setting. Security Forces Hospital, Ophthalmology Department, Riyadh, Kingdom of Saudi Arabia. Design. Prospective, non-randomized case-control comparative study. Methods. A total of 200 eyes of 100 consecutive patients were included. One hundred eyes underwent TPRK in the right eye (study group), and 100 eyes underwent AAPRK in the left eye (control group). Ablations were performed with the Schwind Amaris excimer LASER750S. Clinical outcomes during 6 months’ follow-up were compared. Results. The mean age of patients was 28.3 ± 6.3, 77 were females and 23 males. The mean surgical time was 162.17 ± 14.827 s and 243.24 ± 98.69 s, respectively. At day 1, the UDVA mean was 0.7 in 87% of eyes in the TPRK group while it was 0.5 in 45% of eyes in AAPRK; at week 1, it was 0.9 in 88% of eyes in the TPRK group and 0.6 in 60% of eyes in AAPRK. The mean pain scores were less and lower incidence of corneal haze in the TPRK. Complete epithelial healing time was shorter in TPRK, 3.20 ± 0.686 and 4.60 ± 1.969 days, respectively. Conclusions. TPRK and AAPRK produce similar results 6 months postoperatively. However, in the early postoperative period, there were significant differences in UDVA, pain score, level of haze, and complete epithelial healing time. The pain scores were lower, level of haze was less, and healing time was shorter in the TPRK group which provided patient better felling and comfort in this period. Both of procedures are effective and safe for correction of myopia and compound myopic astigmatism. This trial is registered with NCT03569423.
关键词： TPRK,myopia,photorefractive keratectomy,AAPRK,myopic astigmatism
更新于2025-09-23 15:21:21
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Rotational Stability and Patient Satisfaction after Implantation of a New Toric IOL
摘要： Purpose: To evaluate rotational stability, astigmatism correction, visual outcomes, and patient satisfaction after implantation of the toric intraocular lens (IOL) Torica-aA following cataract extraction over a 6-month follow-up period. Methods: This prospective observational study enrolled 40 eyes of 26 patients presenting with preexisting corneal astigmatism of 1.00 to 2.60 D. The rotational stability of the IOL was evaluated using retroillumination photographs taken within 24 hours after surgery and 1 week and 6 months postoperatively. Other main study outcomes were assessed 6 months postoperatively and included uncorrected and distance-corrected visual acuities, astigmatism correction, and patient satisfaction. Results: Six months postoperatively, mean absolute IOL rotation was 1.99 ± 1.88° (range 0.10-7.40°) and secondary repositioning was not required. The IOL rotation was <3° in 85% of eyes, ≤5° in 94% of eyes, and <8° in 100% of eyes. Mean residual refractive cylinder was -0.57 ± 0.34 D. The magnitude of the J0 vector was significantly decreased postoperatively (p<0.0001). The mean J45 vector was close to zero preoperatively and postoperatively (p = 0.27). Mean monocular uncorrected distance visual acuity (UDVA) was 0.09 ± 0.12 logMAR and 97% of eyes achieved UDVA of 20/40 or better including 66% of eyes having 20/25 or better. The good UDVA resulted in high levels of spectacle independence and patient satisfaction. conclusions: Implantation of the Torica-aA IOL was safe and effective in reducing low to moderate preexisting corneal astigmatism and provided good rotational stability and refractive outcomes, which led to a high degree of patient satisfaction.
关键词： Hydrophilic acrylic,Astigmatism,Intraocular lens,Toric IOL,Cataract,Rotational stability
更新于2025-09-23 15:21:21
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Transepitheliale photorefraktive Keratektomie; Transepithelial photorefractive keratectomy;
摘要： Objective. To analyze and assess the refractive outcome after transepithelial photorefractive keratectomy (TransPRK). Material and methods. The treatment was performed with the AMARIS 1050RS laser (SCHWIND eye-tech-solutions GmbH, Kleinostheim, Germany). The method used an aspheric, aberration-neutral ablation profile and a standardized epithelial tissue removal of 55 μm in the center and 65 μm at a radius of 4 mm as well as SmartPulse technology. Only spherical and/or cylindrical refraction values were treated. Only untreated eyes with preoperative best corrected visual acuity equal to or better than 0.8 were included in the cohort. Follow-up examinations were performed after 1 and 4 days, after 1 and 3 months and after 1 year Results. A total of 939 consecutive TransPRK laser treatments performed in the period from December 2014 to December 2016 were retrospectively analyzed. The mean age of the patients was 34 years. The preoperative sphere had a range of –7.75 D up to +3.00 D and cylinders up to 5.00 D. The 3-month follow-up control was performed in 728 eyes (77.5%). The predictability showed 89% of eyes within the target correction of less than 0.50 D and 99% of eyes less than 1.00 D. The astigmatic correction showed 91% of eyes with less than 0.50 D. In the safety 1% of eyes showed a visual loss of 2 Snellen lines because of haze. In 26 eyes (2.7%) follow-up treatment was performed with renewed TransPRK laser treatment, in the myopic cohort in 1.8% and in the hyperopic cohort in 13.0%. A residual refraction occurred in 20 eyes without haze and 6 eyes showed a residual refraction with signs of haze. Conclusion. The TransPRK led to similar results to intrastromal refractive surgery techniques but with fewer clinical complications.
关键词： Myopia,SmartSurface,Astigmatism,Haze,Refractive surgery,Hyperopia
更新于2025-09-23 15:21:21
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Systematic review and meta-analysis of femtosecond lasera??enabled keratoplasty versus conventional penetrating keratoplasty
摘要： Purpose: The aim of this meta-analysis is to compare femtosecond laser–enabled keratoplasty with conventional penetrating keratoplasty regarding postoperative astigmatism, visual functions, graft rejection, graft failure, and complications. Methods: Eligible studies were retrieved from five mainstream electronic databases, including PubMed, Embase, Ovid MEDLINE, Cochrane Library, and ClinicalTrial.gov. Postoperative topographic astigmatism was set as the primary outcome, and best-corrected visual acuity, spherical equivalent, endothelial cell density, graft rejection, graft failure, and complications were chosen as the secondary outcomes. Standard mean difference and risk ratio were the size effects for continuous data and binomial data, respectively. The data were pooled through either the random-effects model or the fixed-effects model based on data heterogeneity. Moreover, subgroup analyses were conducted when the heterogeneity occurred distinctly (I2 > 50%). Results: A total of seven comparative studies were included. The pooled standard mean difference (?0.32, 95% confidence interval: ?0.74 to 0.10) showed that femtosecond laser–enabled keratoplasty was not superior over conventional penetrating keratoplasty to decrease postoperative topographic astigmatism (p = 0.14). However, best-corrected visual acuity after femtosecond laser–enabled keratoplasty was significantly better than that after conventional penetrating keratoplasty (p = 0.00, standard mean difference: ?0.23, 95% confidence interval: ?0.37 to ?0.10). Furthermore, endothelial cell density after femtosecond laser–enabled keratoplasty was preserved significantly better (p = 0.03, standard mean difference: 0.63, 95% confidence interval: 0.07–1.20). Moreover, spherical equivalent, graft rejection, graft failure, and complications represented no distinct differences between femtosecond laser–enabled keratoplasty and conventional penetrating keratoplasty (p > 0.05). Conclusion: Femtosecond laser–enabled keratoplasty may not be superior over conventional penetrating keratoplasty in decreasing postoperative topographic astigmatism, but might have advantages to achieve best-corrected visual acuity and endothelial cell density preservation. In addition, the two techniques seem to be comparable regarding spherical equivalent, graft rejection/failure, and complications.
关键词： Astigmatism,meta-analysis,femtosecond laser–enabled keratoplasty,conventional penetrating keratoplasty,cornea
更新于2025-09-23 15:21:01
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Laser-assisted in-situ keratomileusis (LASIK) with a mechanical microkeratome compared to LASIK with a femtosecond laser for LASIK in adults with myopia or myopic astigmatism
摘要： Laser-assisted in-situ keratomileusis (LASIK) is a surgical procedure that corrects refractive errors. This technique creates a flap of the outermost parts of the cornea (epithelium, bowman layer, and anterior stroma) to expose the middle part of the cornea (stromal bed) and reshape it with excimer laser using photoablation. The flaps can be created by a mechanical microkeratome or a femtosecond laser.
关键词： mechanical microkeratome,femtosecond laser,myopic astigmatism,LASIK,myopia
更新于2025-09-23 15:21:01
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Irregular Astigmatism and Higher-Order Aberrations in Eyes With Dry Eye Disease
摘要： Visual disturbances were included in the de?nition of dry eye disease in the 2007 Dry Eye Workshop report. As a result, quality of vision (QoV) in dry eye patients has received increased attention. Corneal topography and wavefront sensors have been used to objectively and quantitatively evaluate optical quality, with data showing increases in irregular astigmatism and higher-order aberrations (HOAs) in dry eye patients. Furthermore, ocular optical characteristics are in?uenced by the tear ?lm, which constantly ?uctuates over time. Therefore, dynamic quantitative assessments of optical quality with continuous measurements are essential to understanding QoV in dry eye patients. This review summarizes what is known and what advances have been made in evaluating and understanding QoV in dry eye patients. In particular, corneal topographic and wavefront analyses, conducted both overseas and in Japan, are described.
关键词： wavefront sensor,dry eye,higher-order aberrations,corneal topography,irregular astigmatism
更新于2025-09-23 15:21:01
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Study on the adaptability of augmented reality smartglasses for astigmatism based on holographic waveguide grating
摘要： Background Augmented reality (AR) smartglasses are considered as the next generation of smart devices to replace mobile phones, and are widely concerned. But at present, AR smartglasses are usually designed according to the human normal eyes. In order to experience AR smartglasses perfectly, abnormal eye users must first wear diopters. Methods For people with astigmatism to use AR smartglasses without wearing a diopter lens, a cylindrical lens waveguide grating is designed in this study based on the principle of holographic waveguide grating. First, a cylindrical lens waveguide substrate is constructed for external light deflection to satisfy the users' normal viewing of the real world. Further, a variable period grating structure is established based on the cylindrical lens waveguide substrate to normally emit the light from the virtual world in the optical machine to the human eyes. Finally, the structural parameters of grating are optimized to improve the diffraction efficiency. Results The results show that the structure of cylindrical lens waveguide grating allows people with astigmatism to wear AR smartglasses directly. The total light utilization rate reaches 90% with excellent imaging uniformity. The brightness difference is less than 0.92% and the vertical field of view is 10°. Conclusions This research serves as a guide for AR product designs for people with long/short sightedness and promotes the development of such products.
关键词： Astigmatism,Augmented reality smartglasses,Holographic waveguide grating,Cylindrical lens
更新于2025-09-23 15:19:57