Advances In Refractive Surgery Research Articles

Cyclodextrin Enhances Corneal Tolerability and Reduces Ocular Toxicity Caused by Diclofenac

With advances in refractive surgery and demand for cataract removal and lens replacement, the ocular use of nonsteroidal anti-inflammatory drugs (NSAIDs) has increased. One of the most commonly used NSAIDs is diclofenac (Diclo). In this study, cyclodextrins (CDs), α-, β-, γ-, and HP-β-CDs, were investigated with in vitro irritation and in vivo ulceration models in rabbits to reduce Diclo toxicity. Diclo-, α-, β-, γ-, and HP-β-CD inclusion complexes were prepared and characterized and Diclo-CD complexes were evaluated for corneal permeation, red blood cell (RBCs) haemolysis, corneal opacity/permeability, and toxicity. Guest- (Diclo-) host (CD) solid inclusion complexes were formed only with β-, γ-, and HP-β-CDs. Amphipathic properties for Diclo were recorded and this surfactant-like functionality might contribute to the unwanted effects of Diclo on the surface of the eye. Contact angle and spreading coefficients were used to assess Diclo-CDs in solution. Reduction of ocular toxicity 3-fold to16-fold and comparable corneal permeability to free Diclo were recorded only with Diclo-γ-CD and Diclo-HP-β-CD complexes. These two complexes showed faster healing rates without scar formation compared with exposure to the Diclo solution and to untreated groups. This study also highlighted that Diclo-γ-CD and Diclo-HP-β-CD demonstrated fast healing without scar formation.

Repeatability of whole-cornea measurements using an anterior segment imaging device based on OCT and Placido-disk

ABSTRACTBackground: Current advances in refractive surgery require high accuracy of corneal measurements. We aim to evaluate the repeatability of topographic measurements using an integrated Placido disk - OCT device.Methods: Thirty right eyes of thirty healthy and young subjects were included. The topographic parameters of simulated keratometry, asphericity, minimum pachymetry, white-to-white distance, spherical aberration and corneal elevation were studied. Three measurements were taken by the same observer using the Visante omni device. The coefficient of repeatability (CoR), coefficient of variation (CoV) and intraclass correlation coefficient (ICC) were calculated to assess the repeatability. The Bland-Altman graphical method was also applied.Results: No significant differences between repeated measurements were found. The mean difference for simulated keratometry was between 0.01 and 0.02 D. For asphericity was −0.01 ± 0.02, and for minimum pachymetry, spherical aberration and WTW was equal or less than 0.02 mm. The mean differences for corneal elevation, in millimeters and diopters, were between 0.00 and 0.01. Overall, most topographic parameters had a CoV less than 0.4%, a CoR less than 0.3 and an ICC higher than 0.98.Conclusions: The Visante omni device provides good repeatability for topographical measurements of simulated keratometry, asphericity, pachymetry, spherical aberration and corneal elevation.

Advances in Refractive Surgery: June 2014 to July 2015.

The objective of this study was to review the advances in the field of refractive surgery as reported in the peer-reviewed literature during the previous year. A literature review. In this review, we highlight the most pertinent articles in the field from June 2014 to the end of July 2015. This past year has seen a growing body of research on small-incision lenticule extraction, presbyopic inlays, and phakic intraocular lenses, as more clinicians are adopting these techniques into their armamentarium. Laser-assisted in situ keratomileusis and photorefractive keratectomy continue to dominate the keratorefractive literature, as they remain the most frequently performed refractive surgeries.

Dry Eye and Refractive Surgery Outcomes

The purpose of this study is to review effective diagnostic and management strategies for dry eye disease (DED) and technological advances in refractive surgery for improving patient satisfaction and surgical outcomes. In addition to clinical examination and previously used diagnostic tools for DED, newer devices can now allow for earlier detection by measuring surrogate markers for DED and meibomian gland dysfunction. These markers include lipid layer thickness, tear film breakup time, tear osmolarity, and matrix metalloproteinase-9 levels. There continues to also be evolution of newer corneal refractive procedures such as corneal inlays and small-incision lenticular extraction. DED affects millions worldwide and negatively affects vision quality and refractive surgery outcomes. It is critical to effectively diagnose and manage patients with DED, prior to undergoing refractive surgery. Advances in both DED management and surgical technology are making it easier to offer patients the refractive outcomes they desire.

Refractive surgery following corneal graft.

To review the different surgical procedures for management of postkeratoplasty refractive errors after total suture removal. There are different surgical options to address residual refractive errors that frequently occur after corneal transplantation. The correction can be done on the corneal surface or intraocular with intraocular lens (IOL) implantation which requires complete tectonic and refractive stability after suture removal. The most commonly used procedures are photorefractive keratectomy, laser in-situ keratomileusis and Phakic IOLs. Keratoplasty has been profited by recent advances in refractive surgery. Custom excimer laser ablation is an alternative way to treat irregular errors. New IOL modalities are good practical options for a wide range of errors. Femtosecond laser, as a new option in the toolbox, can modify corneal grafting refractive results and assist corrective refractive procedures. Although being the most successful organ transplantation, keratoplasty is usually followed by significant ametropia. Different corrective modalities exist and the choice should fit ocular conditions, patient requirements, surgeon skills and the available technologies. Recent advances in ophthalmic surgery have improved the outcomes.

Advances in Refractive Surgery: May 2013 to June 2014.

The field of refractive surgery is changing quickly in the areas of screening, treatment, and postoperative management. The objective of this study was to review advances in the field of refractive surgery as reported in the peer-reviewed literature during the previous year. This was a literature review. In this article, we highlight the progression in the field from May 2013 to the end of June 2014. This article is organized as preoperative, intraoperative, and postoperative considerations. The growing use of newer modalities of treatment, such as small-incision lenticule extraction (SmILE) and phakic intraocular lenses, and their safety and efficacy add to the armamentarium in treating refractive error. This past year has seen many studies, which show these procedures to be safe and effective. Also, structurally, SmILE may result in a more biomechanically stable cornea, so that we may be able to safely treat higher refractive errors. While laser-assisted in situ keratomileusis is the predominant surgical procedure, photorefractive keratectomy is still an appropriate choice in certain scenarios (higher risk for ectasia postrefractive surgery and patient choice) with safe, predictable results, and patient satisfaction. Many of the new developments in laser-assisted in situ keratomileusis have focused on flap creation with femtosecond lasers. Histopathology and in vivo optical coherence tomography studies have shown that the stromal bed is smoother, the side cuts are vertical, and the flap has predictable thickness. New surgical modalities, such as femtosecond lenticule extraction and SmILE, are increasingly being used.

Advances in Refractive Surgery.

The objective of this study was to review advances in the field of refractive surgery as reported in the peer-reviewed literature over the previous year. This was a literature review. We conducted a PubMed search for terms related to refractive surgery and reviewed prominent international ophthalmic journals published from May 2012 through April 2013. All pertinent articles were reviewed, and selected articles with the greatest relevance were included. Many studies over the previous year have highlighted progress in the field of refractive surgery; topics included keratoconus screening, photorefractive keratectomy and laser in situ keratomileusis, corneal cross-linking, small-incision lenticule extraction, phakic intraocular lenses, corneal inlays, presbyopic corneal treatments, and femtosecond laser-assisted astigmatic keratotomy. The field of refractive surgery continues to provide exciting developments. Improvements in established procedures and promising new surgical options make the current climate an appealing one for refractive surgeons and patients.

Wavefront aberrometry advances in refractive surgery

AbstractWavefront aberrometry has been adapted from optical astronomy in order to analyze complex image distortions caused by the human optical system, called higher order aberrations. The aberrations increase with larger pupil size or during nocturnal vision when the pupil dilates. They may have a significant impact on vision, even in a patient with 20/20 visual acuity. Most Shack Hartman aberrometers can be used as a super auto refracto‐keratometer during refractive surgery pre‐operative evaluations. They can capture the full amount of astigmatism and so will minimize the need for retreatment due to undercorrection. Modern Shack Hartman aberrometers give also the refractive surgeons the possibility to measure aberrations induced by flap creations. In addition they will be useful for performing customized excimer laser ablation (data coming from the aberrometer mapping out a path for the laser in reshaping the cornea). This technique has been shown to improve the correction of lower order aberrations (90% of the aberrations of the human eye), but is there a real benefit for treating higher order aberrations? Is a Shack Hartman aberrometer needed for every day refractive surgery practice? Thru an evidence based review of the literature confronted to personal experience we will try to answer these questions.

Refractive surgery in the United States Air Force

Laser refractive surgery in the United States Air Force has developed into a robust program since its inception in 2001. The goal of this study is to summarize recent developments in the program. Presentations at national meetings, recently published articles, and unpublished data from ongoing studies in the area of photorefractive keratectomy and laser-assisted in-situ keratomileusis are discussed. Photorefractive keratectomy continues to be the most commonly performed corneal refractive surgery procedure in the United States Air Force. However, as the overall superiority of femtosecond laser-assisted in-situ keratomileusis flaps compared with microkeratome-assisted flaps continues to be established, there is an increasing trend towards this procedure. With a recent change in Air Force policy, photorefractive keratectomy and laser-assisted in-situ keratomileusis are now both approved for nonaviators and aviators, with the aviators undergoing contrast sensitivity and other additional testing to ensure readiness. As members of the United States Air Force have stringent visual demands in carrying out their duties, the quality and safety of any refractive procedure are of the utmost importance. Thorough evaluation of ongoing advances in refractive surgery will help ensure that our airmen continue to meet the visual demands placed on them.

Anisometropic Amblyopia: The Potential Role of Keratorefractive Surgery

IntroductionTraditional therapy for anisometropic amblyopia often fails when severe anisometropia is present. Recent advances in refractive surgery for anisometropic amblyopia suggest that surgical treatment may be a viable alternative in certain situations.MethodsThe potential indications for refractive surgery for anisometropia, the different refractive procedures available, and the risks and benefits of each procedure are discussed.ResultsThe most reasonable indication at present is severe anisometropia that is nonresponsive to conventional therapy. The risks, though rare, of PRK and LASEK are corneal haze and regression of refractive correction, and risks of LASIK are keratectasia, flap loss, flap tear, or buttonhole, and regression of refractive correction.ConclusionsSurgical interventions now exist that have value in the treatment of anisometropic amblyopia. Randomized clinical trails are needed in order to optimally evaluate the long-term safety and efficacy of these treatments.

Advances in refractive surgery: microkeratome and femtosecond laser flap creation in relation to safety, efficacy, predictability, and biomechanical stability

Methods of flap creation have changed over the years from the evolution of the mechanical microkeratome to the introduction of the IntraLase femtosecond laser keratome, both of which have different mechanisms of action to create corneal resections. Previous studies report the advantages and disadvantages of the mechanical microkeratome and the IntraLase femtosecond laser. The critical components in laser in-situ keratomileusis surgery remain the same, however: safety, efficiency, predictability, and biomechanical stability. Keratoectasia and flap efficiency remain a constant safety concern in laser in-situ keratomileusis surgery. Unexpectedly thick flaps as well as variable thickness continue to be a concern with safety in relation to microkeratome technology. Epithelial preservation, flap complications, and newer issues such as Transient Light Sensitivity Syndrome are safety concerns of flap creation. Improved outcomes with regards to vision, induced astigmatism, induced higher-order aberrations, and enhancement rates are seen to favor predictability of femtosecond technologies over the microkeratome. Recent biomechanical studies show improved healing with femtosecond laser flap creation compared with blade-assisted flap creation. The aim of this review is to summarize the key components for both the microkeratome and the femtosecond laser and to update on the recent advances reported on these topics.

Depth-of-Focus of the Human Eye: Theory and Clinical Implications

The depth-of-focus, or the perceptual tolerance of the human eye to retinal defocus, is important to and imbedded in many aspects of clinical refraction and physiological optics. Although the depth-of-focus is a common concept in classical optics, there is relatively little detailed discussion of its implications as related to normal vision function and to vision anomalies. With current advances in refractive surgery and ophthalmic lens design, the demand for knowledge in this topic is both timely and important. This review of our current understanding of the depth-of-focus should prove to be useful to clinicians, researchers, and students as an introduction to the subject. Two areas will be considered: 1) basic definitions of and factors affecting the depth-of-focus, and 2) its contemporary clinical implications.

Refractive surgery after corneal transplantation

Many patients who have undergone corneal transplantation are unable to achieve satisfactory visual acuity with spectacle and contact lens correction alone. For these patients, refractive surgery becomes a viable option to reduce the post-keratoplasty ametropia. With the many recent advances in refractive surgery for naturally occurring refractive error, new possibilities arise for application to this complicated set of patients. This review discusses key recent developments in refractive surgery after corneal transplantation. The biomechanical effects of incisional keratotomy on post-keratoplasty corneas continue to be studied, and these techniques remain a common and simple method of reducing astigmatism. Photorefractive keratectomy, previously problematic for regression and haze formation, is gaining new prominence as early experience with the adjunctive use of mitomycin C has demonstrated good results. Long-term studies with laser in-situ keratomileusis (LASIK) have continued to show good safety and efficacy. Modern developments in cataract surgery appear to have lower incidences of graft rejection and failure. Developments in lens implantation technology continue to offer expanding options for intraocular refractive surgery. Although visual rehabilitation after corneal transplantation remains a formidable challenge, developments in refractive surgery for naturally occurring ametropias directly translate into an improved ability to help these most challenging refractive cases. Continued research will bring about improved efficacy while maintaining a high level of safety.

Latest Advances in Refractive Surgery

Latest Advances in Refractive Surgery

Advances in refractive surgery: 1975 to the present.

To review the major advances in the field of refractive surgery occurring over the past 25 years. Literature review. The major developments in refractive surgery over the past 25 years are reviewed. The past 25 years have witnessed great changes in refractive surgery. As a result of advancements in technology, instrumentation, and technique, we have seen improvements in the treatment of all types of ametropias. In this article, we review some of the successes and failures of the past quarter-century.

Advances in refractive surgery

PREVIEWThe Food and Drug Administration's approval of the excimer laser in 1995 heralded the age of laser refractive surgery in the United States. Since then, other advances in refractive surgery have spurred great public interest in and enthusiasm for these procedures. In this article, the authors review the major types of refractive surgery and discuss their indications, results, and complications.