View clinical trials related to Lenses, Intraocular.
Filter by:The goal of this observational study is to assess the effect of intraocular lens (IOL) movement in patients who have undergone Clareon® Vivity® IOL implantation. The main question it aims to answer is: Does an association exist between IOL movement and patient quality of vision? Participants implanted with Clareon® Vivity® and Vivity® Toric IOLs will be asked to do the following: - consent to participate in the study - allow researchers to access their personal medical records - undergo a series of tests to assess the position of their IOLs and quality of vision Researchers will compare the patients' preoperative and postoperative test results to determine whether an association exists between IOL movement and patient quality of vision.
Multiple intraocular lens are nowadays available for implantation after cataract surgery. They use different technology to try to improve patient spectacle independence. It is necessary to better characterise the performence of each type of lens, as well as to define how they are affected by residual refractive errors. The purpose of this study is to evaluate visual function in patients implanted with different lenses (advanced monofocals, trifocals) in order to be able to recommend the best type of lens for each patient.
Pterygium is known to induce with-the-rule astigmatism. The corneal curvature along the long axis of the pterygium body is flattened. The excision of pterygium will result in steepening of the cornea and reduction of astigmatism. Therefore, the effect of pterygium excision on intraocular lens (IOL) power calculation has been examined in our previous study. The study confirmed that pterygium can cause alteration of IOL power. The determination of IOL power for cataract surgery is usually calculated from IOL formula called SRK II formula. IOL power = A - (2.5 x AL)-(0.9 x K). Variable A denotes the A-constant of the intraocular lens which is dependent on the IOL material and refractive index. Other variables for input include axial length (AL) and keratometry (K). A larger K reading will result in a lower estimated IOL power and vice versa. Previous studies have documented simultaneous cataract and pterygium operation resulted in reasonable visual outcome without adjustment of IOL power. With the presence of a pterygium, the cornea is flattened and lead to a reduction of K value and over-estimation of calculated IOL power. This randomized controlled trial is designed to compare the refractive outcomes of sequential and simultaneous pterygium and cataract operation. Pterygium excision should be done with various adjuvant therapies to minimize recurrence. Our previous studies reliably demonstrated limbal conjunctival graft and mitomycin C were effective methods to achieve low pterygium recurrence. We use limbal conjunctival autograft as the adjuvant therapy in the current study because this method is safer to be performed either alone or in combination with phacoemulsification. We avoid using mitomycin C as the adjuvant therapy in order to minimize the possibility of intraocular toxicity due to seepage.