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123 active trials for Cataract

Impact of a Novel Extended Depth of Focus Intraocular Lens on Visual and Lifestyle Enhancement

The introduction of presbyopia-correcting intraocular lenses (PC-IOLs) has provided cataract and refractive surgeons the ability to provide patients with a wider range of visual success and spectacle independence post-cataract surgery.Multifocal (MFIOL) IOLs have the ability to provide near and distance vision, and in the case of trifocal IOLs, near, intermediate and distance. Despite the significant technological evolution of MFIOL's, the potential for visual disturbances, such as glare, halos and starbursts still exists-and in much greater frequency compared to their monofocal counterparts. Extended depth of focus (EDOF) IOLs aim to provide patients with a functional range of vision, with a similar visual disturbance profile to a monofocal lens. In this way, this subset of PC-IOL's can offer patients some degree of spectacle independence, with a significantly lower incidence of visual disturbances. The Vivity Extended Vision IOL is the first of its kind to offer Wavefront Stretching technology, providing patients with an excellent extended range of vision from intermediate to distance, as well as some functional near vision. Prior studies have demonstrated very good vision in both bright and dim lighting conditions, as well as a high degree of spectacle independence with the Vivity IOL, as compared to a monofocal IOL. Studies evaluating the ability of the Vivity IOL to provide a significant impact on patient lifestyle (e.g. patient independence from spectacles for most activities with a low rate of visual disturbances) in the United States in a 'real-world' setting have yet to be performed. In addition, influence of pre-and-perioperative variables such as sex, age, prior refractive surgery, IOL formula used, axial length, astigmatism, use of intraoperative aberrometry, femtosecond laser and pupillary expansion devices has yet to be evaluated on the postoperative success of this IOL. This study will be comprised of patients with visually significant cataracts who will undergo cataract extraction with implantation of the spherical and/or toric models of the Vivity Extended Vision (Alcon, Fort Worth TX) intraocular lens. Upon decision of the patient and surgeon to undergo surgery, patients will be offered the option to enroll in this observational study.

Start: October 2020
Objective Measurements of the Opacification of the Lens After Vitrectomy

Cataract is the opacification of the lens. Usually cataract occurs slowly, causing progressive vision loss over several months or years. In ophthalmic clinical practice, repeated objective quantitative measurements of lens opacity may be necessary to document its progression and support a surgical indication. The subjective methods of evaluating the opacification of the lens have limitations, in particular due to the lack of reproducibility between observers. Thus, innovative objective techniques with precise and reproducible cataract classification results have been developed, such as the Objective Scatter Index (OSI) on the Optical Quality Analysis System (OQAS), Visiometrics SL in 2010 and, more recently, Average Lens Density (ALD) on the IOLMaster® 700 device. Cataract is diagnosed as mature when the OSI is ? 2 and / or when the ALD is ? 74 pixel units. Vitrectomy is a surgery of the posterior segment of the eye indicated for retinal detachment, epimacular membranes, macular holes, vitreous hemorrhage. The incidence of post-vitrectomy cataract varies among studies, and the methodology is often retrospective. Age has already been identified as a risk factor for progression since in a study of 28 eyes of patients under 50 years old, only 7% developed cataracts secondarily, compared to 79% in the 'over 50' group. To date, there is no prospective study describing the progression kinetics of lens opacification according to precise and reproducible quantitative objective criteria in patients treated by vitrectomy. It also involves confirming the age and preoperative lens status as a risk factor for postoperative cataract progression.

Start: September 2020
Molecular Background of Endothelial Cell Loss in Patients With Phakic Intraocular Lenses: a Tear and Aqueous Humour Analysis Study

Rationale: The number of highly myopic patients is increasing. Especially in East and Southeast Asia, up to 90% of adolescents are currently myopic. Long-term treatment of high myopia can be obtained by three types of surgery: laser refractive surgery, phakic intraocular lens (pIOL) implantation, and refractive lens exchange Implantation with a pIOL is the preferred treatment for high myopes, resulting in increasing patient numbers implanted due to the increasing numbers of patients with high myopia. Long-term results show that implantation of a pIOL induces an accelerated decrease in corneal endothelial cells (EC). Although some risk factors for increase EC loss have been identified, the underlying mechanism is currently unknown. It is hypothesized that the aqueous flow in the anterior segment of the eye (i.e. anterior chamber) is disturbed, causing an altered nutritional flow in the anterior chamber. Another hypothesis is that the pIOL causes chronic subclinical inflammation in the anterior chamber resulting in increased EC loss. Currently there is insufficient proof to confirm or reject either hypothesis. If one of these hypotheses can be confirmed, it is likely to induces significant changes in clinical practice. Objective: The primary objective of the study is to explore the role of inflammation in the anterior chamber on endothelial cell loss in patients implanted with iris-fixated pIOLs. The secondary objective is to identify whether there is a correlation between biomarkers in aqueous humour and biomarkers in tears, both related to the accelerated progression of EC loss. Study design: Two strategies are incorporated in the design of this study. The first part will retrospectively evaluate EC loss in patients with iris-fixated (IF) phakic intraocular lenses (pIOLs). The second part is prospective and will compare EC measurements, cytokines in aqueous humour and in tears from patients scheduled for IF-pIOLs explantation and compare them to patients with routine cataract surgery. Study population: Patients over 18 years of age, undergoing regular cataract surgery, and patients undergoing pIOL explantation in combination with cataract surgery. A total number of 126 patients is needed, equally divided over two groups.

Start: July 2020
Evaluating Safety and Efficacy of a Modified Technique of Scleral Fixation Intraocular Lens Implantation

Cataract is the leading cause of blindness globally and cataract surgery with the implantation of intraocular lens (IOL) is the most commonly performed operation worldwide. After removal of the cataract, an IOL is usually implanted within the capsular bag. However, endocapsular implantation of IOL is not always feasible due to inadequate zonular or capsular support, intraoperative posterior capsule rupture, or in primary intracapsular cataract extraction. Predisposing factors including prior ocular trauma, intravitreal injection or intraocular surgery, co-existing ocular comorbidities like chronic uveitis, pseudoexfoliation syndrome, may increase the risk of failure of in-the-bag implantation. In such situation, the surgeons may consider implanting the IOL in the anterior chamber, ciliary sulcus, or using fixation techniques. In Asian eyes, the anterior chambers are often shallow and placement in anterior chamber may accelerate corneal endothelial cell loss leading to corneal decompensation, or worsen pre-existing glaucoma. Placement in the ciliary sulcus depends on the amount and integrity of the capsular remnant, and inadequate support may result in dislocation of the IOL. In recent years, newer forms of scleral fixation of IOL using glue or glue-less approach, although these procedure appeared to be simpler, the long-term stability of these IOL have not been evaluated against conventional approach with suture fixation. The main limitations of suture fixation technique are related to the sutures either intraoperatively (e.g. entanglement, failure to rotate and bury the suture knot) or postoperatively (breakage, dissolution of suture with time), and the learning curve required for surgeons in training. Our study aims to study the efficacy and safety of a modified technique of scleral fixation of an intraocular lens in the posterior chamber.

Start: October 2020
The Oscillation of Crystalline and Intraocular Lenses

The crystalline lens of the human eye helps to sharpen vision. There can be issues with the support/stability of the lens. This could be seen with the naked eye of an external observer or with the use of a slit lamp. Certain eye conditions can predispose to issues with lens stability. If patients have stability issues with their natural lens- this would be termed as "phakodonesis". However, in patients who have had prior cataract surgery with implantation of an artificial lens (IOL)- this would be termed as "pseudophakodonesis". Eye conditions such as pseudoexfoliation or Marfan-syndrome can lead to unstable lens support- this can be detected if there are advanced stability issues. However, small instability in the eye's would not be detected with present descriptive methods. The authors have designed a high-speed camera which is able to detect stability of the lens, especially during eye movements. The high-speed camera can detect variation in the change of light reflex from the lens and calculate the amount of lens instability/oscillation. The results (in normal eyes) of this high-speed camera has already been published in a peer-review journal. It is non-contact and measures lens movement. The test lasts less than 5 minutes. Further research is required to assess the amount of lens oscillation (wobbling) in different eye populations - patients with previous cataract surgery (an artificial implant is used to replace the lens) or eye conditions (such as pseudoexfoliation, Marfan syndrome). The amount of lens stability has a role in the planning of further intraocular surgery - especially cataract extraction - however, at present, there is no approved quantitative measurement for this. Participants will be recruited through Anglia Ruskin University (educational establishment), local community groups, and through Southend University Hospital eye clinics (NHS organisation). Participants' data will remain anonymous.

Start: October 2020