Astigmatism

This study evaluates corneal epithelial thickness using anterior segment optical coherence tomography (AS-OCT) in patients with refractive errors. It aims to assess the relationship between epithelial thickness patterns and different types of refractive errors.

The purpose of this research study is to generate safety and performance data for Clareon TruPlus Monofocal Intraocular Lenses (IOLs). IOLs are medical devices that are implanted in the eye during cataract surgery to restore clear vision after the cloudy natural lens has been removed. IOLs are intended to remain in the eyes for the duration of the patient's lifetime.

The goal of this clinical trial is to learn if nomogram could promote treatment outcomes in astigmatism correction. The main question it aims to answer is: does the nomogram could promote treatment outcomes in astigmatism correction? If there is a comparison group: Researchers will compare non-nomogram adopted to see if the outcome acceptable. Participants will ask to complete 3-month follow-up of manifest refraction and visual acuity test.

The aim of this study is to evaluate the agreement between subjective and objective toric lens prescriptions.

The purpose of this study to assess the wear experience of people who have astigmatism when wearing a daily disposable contact lens for astigmatism over long days of wear.

This study is a single-arm, prospective, observational study conducted at one site to evaluate the comfort and vision of the TOTAL30 Multifocal (T30MF) contact lenses over the course of long wear days. The study will assess the proportion of positive subjective Visual Analog Scale (VAS) assessments of comfort and vision at 10, 12, 14, and 16 hours of wear on Days 1, 7, 14, and 30. Additionally, the study will explore subjective assessments of lens comfort using the CLDEQ-8 survey and measure logMAR visual acuity at both distance and near at Visit 1, Visit 2, and after 1 month of lens wear. Participants will undergo three site visits, with at-home surveys conducted at specified intervals to gather real-time data on comfort and vision.

Cataract surgery in patients with irregular corneas presents unique challenges, primarily due to the high variability in keratometry and corneal tomography measurements, which complicates accurate intraocular lens (IOL) calculations. In these patients, therapeutic options are currently limited to either non-toric IOLs and rigid contact lenses postoperatively or conventional toric IOLs for the reduction of total astigmatism within cataract surgery. While conventional toric IOLs may be beneficial in selected cases with a stable astigmatic pattern and clear axis, their effectiveness is largely limited, as significant irregularity and higher order aberrations reduce predictability, accuracy of formulae, and refractive outcomes. Therefore, the development of a reliable method to reduce total astigmatism - including irregular components - would represent a major advancement, potentially improving both visual function and patient quality of life. The aim of this exploratory study is to evaluate the effectiveness of customized toric intraocular lenses (AMILens Individual, AMIPLANT GmbH, Germany) in reducing total corneal astigmatism in patients with a significant irregular astigmatic component. These lenses are designed to address corneal aberrations up to the 6th Zernike order, thereby extending correction beyond the capabilities of conventional toric IOLs. To our knowledge, no clinical study has yet investigated this novel approach.

We are enrolling participants aged 22 and older to have LASIK surgery in both eyes. We will perform wavefront-guided LASIK in one eye and ray tracing-guided LASIK in the fellow eye of each participant. We are trying to see if there are any differences in the efficacy between the two types of LASIK procedures.

This study aims to evaluate the safety and effectiveness of femtosecond laser arcuate corneal relaxing incisions (AK) combined with Light Adjustable Lens (LAL) implantation for correcting pre-existing corneal astigmatism in patients undergoing cataract or refractive lens exchange surgery. Postoperative assessments will focus on residual refractive astigmatism, visual outcomes, patient satisfaction, and the incidence of adverse events. Arcuate keratotomy and toric IOLs are well-established methods for astigmatism correction, and this study will compare their combined effectiveness using advanced femtosecond laser technology.

The goal of this observational methodological study is to validate the Turkish version of the DDIVAT visual acuity measuring device in a Turkish-speaking adult population. The main questions it aims to answer are: Does the Turkish version of the DDIVAT provide reliable and valid visual acuity measurements in Turkish speakers? Are the results of the DDIVAT comparable to those obtained with the standard Snellen chart used in clinical practice? Researchers will compare DDIVAT visual acuity test results with Snellen chart results to see if both methods produce consistent measurements. Participants will: Be adults aged 18 years or older, including both patients and healthy volunteers. Undergo visual acuity testing using the DDIVAT system displayed on a smart TV connected to the university server. Have their visual acuity re-measured using the standard Snellen optotype under the same conditions. No medication or invasive procedure will be used. The study carries no risk to participants.

This is a post-market observational clinical investigation. The objective of this observational study is to evaluate the visual performance and HCP satisfaction of REVIVE samfilcon B custom toric contact lenses.

To evaluate the clinical outcomes and patient satisfaction of two commercially available trifocal toric intraocular lenses Primary Objective: To compare the distance-corrected intermediate visual acuity between the two trifocal toric intraocular lenses. Secondary Objectives: To assess and compare the safety of two trifocal toric intraocular lenses.

This study is a single-site, single-arm, prospective, observational study of subject satisfaction, quality of vision, and quality of life after bilateral LASIK surgery. Subjects will be assessed up to 3 months post-operatively. Clinical evaluations will include refractive outcomes, visual acuity, and administration of the adapted PROWL and Low Luminance Questionnaire (LLQ-32) Questionnaire.

This purpose of this study is to compare a new form of LASIK called Ray Tracing Guided LASIK to 3 other forms of corneal refractive surgery: 1. KLEx (KeratoLenticule Extraction) using the Zeiss Visumax 800 Laser, 2. WFO LASIK (Wavefront Optimized LASIK) using the Alcon EX500 Laser, and 3. Topography Guided LASIK (Contoura LASIK) also using the Alcon EX500 Laser.

This study is a single-site, single-arm, prospective, observational study of subject satisfaction, quality of vision, and quality of life after bilateral LASIK surgery. Subjects will be assessed up to 3 months post-operatively. Clinical evaluations will include refractive outcomes, visual acuity, and administration of the adapted PROWL and the Quality-of-Life Impact of Refractive Correction (QIRC) Questionnaire.

The main objective of this study is to demonstrate acceptable safety and effectiveness (performance) of comfilcon A Sphere, Toric, Multifocal, Toric Multifocal and Energys lenses, when used in the general population.

Current refraction assessment in children is dependent on the Eye Care Specialist and lacks standardization. Essilor has developed new algorithm assisted subjective refraction software dedicated to children of 6-12 years old and suitable for use with Vision-S™ and Vision-R™ phoropters, in addition to existing software. Two different versions of the software have been developed: the first incorporating only the steps needed to perform an entire subjective refraction process (vA), and the second, identical to the first but incorporating additional steps useful for managing the child's attention and cooperation (vB). The software performance in terms of subjective refraction results will be compared to a conventional subjective refraction method performed with the Vision-R™700 phoropter in manual mode.

The investigational devices are approved intraocular lenses (IOL) intended to be implanted after phacoemulsification in individuals suffering from age-related cataract with the need of cataract surgery. Within the study, three different IOLs will be investigated and separately evaluated. Cataract surgery with IOL implantation will be performed in subjects who have signed an informed consent form. Postoperative examinations will be postoperative refraction, visual acuity, slitlamp examination, and rotation of the IOL within 1 hour, 1 week, 1 month and 4-7 months. In the Alcon Clareon toric, RayOne EMV toric and PODEYE Toric group, patients receive a toric IOL according to their preoperative astigmatism

To compare the effect of Limbal relaxing incisions (LRIs) plus spectacle correction versus spectacle correction alone on subjective and objective improvement in visual function for correcting post phacoemulsification high astigmatism .

Corneal refractive surgery is an effective way to correct refractive error. Modern corneal refractive surgery for the correction of myopia or hyperopia can achieve or close to the expected goal, but to eliminate astigmatism is always one of the major problems of corneal refractive surgery. The key point in the correction of astigmatism is that as a vector parameter, astigmatism has both magnitude and direction. The angle error may be caused by the rotation of the patient's head position and the involuntary rotation of eyes. Phototherapeutic keratectomy can precisely cut the corneal tissue, and is often used in clinic to remove corneal scars or repair corneal surface morphology. In this study, the excimer laser therapeutic keratectomy mode was used to achieve accurate marking of the axis of astigmatism by setting the treatment laser parameters. With the help of the static cyclotorsion of the eye, the precise treatment of astigmatism could realize.

The principle investigator is evaluating self-reported quality of vision and quality of life in physicians undergoing LASIK, SMILE and PRK surgery.

To analyze the difference between measured total corneal astigmatism and actual corneal astigmatism under different region modes and optimize the region setting.

Software refraction in the mobilerone for myopia and astigmatism is a novel medical device for myopia adults and elder children with or without astigmatism. And the investigators would like to test its accuracy and efficacy as well as safety.

Comparing post-operative visual acuity and patient reported satisfaction between Contoura with Phorcides and WaveLight Wavefront Optimized.