Active clinical trials for "Astigmatism"

The purpose of this study is to measure visual acuity and Intraocular Lens (IOL) rotational stability after implantation of TORIC IOL and to assess the post operative complications after implantation of TORIC IOL.

This clinical study has been planned to evaluate the safety and effectiveness of the SUPRACR presbyopic excimer laser treatment algorithm for myopic eyes developed for applying to the cornea of the human eye in a single center. The developed software algorithm uses the subjective refraction of the eye to create a treatment for the distance vision correction. This part of the treatment does not show any difference to a regular aspheric LASIK treatment for myopic cases. In addition to the treatment for the distance vision an additional central ablation component will be added to address the near vision. The study design is applied as a single center unilateral eye safety and effectiveness study of the SUPRACOR presbyopic algorithm for myopia with a 3 months postoperative follow up.

This study evaluates the intrastromal correction of ametropia with a femtosecond laser made by 20/10 PERFECT VISION. This laser generates a beam of ultrashort, infrared pulses which enables very precise cuts in the cornea. By these cuts lamellae of the cornea are separated locally, and in the consequence the curvature of the cornea is changed, and the correction of the diagnosed ametropia can be achieved. On the contrary to cuts which are generated with a sharp knife, the cuts generated when using a laser can be generated just inside the cornea without opening the surface of the cornea. This means the procedure is minimal-invasive. The study hypothesis is: Different types of ametropia can be corrected safely and on long-term by intrastromal cuts.

This is a multicenter study to evaluate the clinical performance of the SynergEyes A2 lens in patients with refractive errors with or without astigmatism.

Aim of the work is to compare the results of femtosecond assisted LASIK and small incision lenticule extraction (SMILE) as regards safety, efficacy and predictability. As a secondary outcomes , the investigators will compare the results of both techniques on corneal biomechanics, dry eye measures, corneal asphericity and higher order aberration.

This study investigates the effects of trabeculectomy and combined phacoemulsification plus trabeculectomy on corneal astigmatism.

The purpose of the study is to compare the astigmatism reducing effect of a toric intraocular lens (IOL) (model MX60T - Bausch & Lomb) with that of limbal relaxing incisional surgery combined with a non toric IOL (model MX60 - Bausch & Lomb) in patients with corneal astigmatism between 1.0 and 1.5 diopters and also the effect of cylinder reduction on patient's quality of vision.

The AQUARIUZ ablation laser is a solid-state laser and has been CE approved for corneal surgery since March 2020 for the treatment of short- and longsightedness with and without astigmatism. The aim of this study is to collect the first clinical data. Safety and performance are examined here. The treatment with AQUARIUZ is comparable to treatments with an excimer laser, with the difference that these are operated with gas. Solid-state lasers and excimer lasers use the same process for tissue ablation, with a small difference in wavelength. This difference manifests itself in the lower involvement of water in the ablation process with the result of a gentler and safer treatment. Similar to excimer lasers for corneal surgery, the AQAURIUZ system (Ziemer Ophthalmic Systems AG) is equipped with a fast eye tracker (eye tracking system) to correct eye movements during the treatment. The shape of the removed portion of the cornea has an aspherical profile corresponding to the state of the art. The primary objective is to assess the safety of use of the AQUARIUZ corneal ablation laser for LASIK procedures in myopia and myopia with astigmatism. The secondary objective is to compare the predicted visual and refractive outcomes of LASIK procedures using the AQUARIUZ Ablation with clinical data. The study is planned in 3 phases to mitigate the inherent risk of a first in man study and to allow for verification and confirmation of the system correction factor at an early stage.

Background: Small Incision Lenticule Extraction or SMILE is a novel form of 'flapless' corneal refractive surgery that was adapted from Refractive Lenticule Extraction (ReLEx). SMILE uses only one femtosecond laser to complete the refractive surgery, potentially reducing surgical time, side effects and cost. If successful, SMILE could potentially replace the current, widely practiced Laser In-situ Keratomileusis or LASIK. The aim of this study is to evaluate whether SMILE is non-inferior to LASIK in terms of refractive outcomes at 3-months post-operatively. Methods/ Design: Single tertiary center, parallel group, single-blinded, paired-eye design, non-inferiority, randomized controlled trial. Participants who are eligible for LASIK will be enrolled for study after informed consent. Each participant will be randomized to receive SMILE and LASIK in each eye. Our primary hypothesis (stated as null) in this non-inferiority trial would be that SMILE differs from LASIK in adults (>21 years old) with myopia (> -3.00D) at a tertiary eye center in terms of refractive predictability at 3 months post-operatively. Our secondary hypothesis (stated as null) in this non-inferiority trial would be that SMILE differs from LASIK in adults (>21 years old) with myopia (> -3.00D) at a tertiary eye center in terms of other refractive outcomes (efficacy, safety, higher-order aberrations) at 3 months post-operatively. Our primary outcome is refractive predictability, which is one of several standard refractive outcomes, defined as the proportion of eyes achieving a postoperative spherical equivalent (SE) within ±0.50 diopter (D) of the intended target. Randomization will be performed using random allocation sequence generated by a computer with no blocks or restrictions, and implemented by concealing the number-coded surgery within sealed envelopes until just before the procedure. In this single-blinded trial, subjects and their caregivers will be blinded to the assigned treatment in each eye. Discussion: This novel trial will provide information on whether SMILE has comparable, if not superior, refractive outcomes compared to the established LASIK for myopia, thus providing evidence for translation into clinical practice.

Pterygium is known to induce with-the-rule astigmatism. Excision of pterygium will steepen the cornea and reduce corneal astigmatism. We postulate that the alteration of keratometry reading will indirectly affect the IOL power calculation in cases with concurrent pterygium and cataract. Concurrent pterygium and cataract is common in Hong Kong and other tropical regions. The effect of pterygium excision on intraocular lens power calculation is investigated.