China
Africa
Explore chapters and articles related to this topic
Surgical Management of Mycotic Keratitis
Published in Mahendra Rai, Marcelo Luís Occhiutto, Mycotic Keratitis, 2019
Tadeu Cvintal, Diego Casagrande, Victor Cvintal
After adequate control of mycotic keratitis infectious process, individualized visual rehabilitation measures should be implemented to achieve optimal best-corrected visual acuity scores. Refractive errors must be corrected using either spectacles or contact lenses (Krachmer et al. 2011). If necessary, visual optimization is accomplished through optical surgical procedures. Commonly associated surgical follow-up techniques are optical penetrating keratoplasty, Descemet Stripping Automated Endothelial Keratoplasty (DSAEK), and lamellar keratoplasty. In cases of multiple penetrating keratoplasty failures, keratoprosthesis may be considered (Rogers et al. 2013).
Use of the temporary keratoprosthesis in ocular trauma repair
Published in A Peyman MD Gholam, A Meffert MD Stephen, D Conway MD FACS Mandi, Chiasson Trisha, Vitreoretinal Surgical Techniques, 2019
Maurice B Landers III, Steven M Williams
In the surgical procedure, the keratoprosthesis is positioned after removal of the central host cornea (Fig. 12.5). The clear wide-field temporary keratoprosthesis is placed in the corneal opening and sutured firmly in place. A pars plana vitrectomy and subsequent penetrating keratoplasty are carried out during one operative procedure. This technology allows surgical repair of eyes that otherwise might be irreparably damaged by combined anterior and posterior segment trauma.
The eye and orbit
Published in Professor Sir Norman Williams, Professor P. Ronan O’Connell, Professor Andrew W. McCaskie, Bailey & Love's Short Practice of Surgery, 2018
Professor Sir Norman Williams, Professor P. Ronan O’Connell, Professor Andrew W. McCaskie
In countries in the Far and Middle East, chronic infection with trachoma can cause corneal opacification and blindness, although the worldwide incidence of this condition is falling. Corneal grafting is the only cure for an opaque cornea. Until recently, full-thickness penetrating keratoplasty was the only corneal graft technique. For some conditions this has largely been replaced by lamellar or partial-thickness graft surgery, in a technique termed DSEK or ‘Descamets stripping endothelial keratoplasty’. However, penetrating keratoplasy remains the treatment of choice for severe corneal damage due to infection or injury. Rarely, osteo-odonto keratoprosthesis can be attempted in very severe cases of opaque corneas that are not suitable for grafting. Artifical corneal prostheses have also been developed. Acanthamoeba is a rare serious cause of corneal infection. This infection usually follows the use of contact lenses. Specialist management and treatment is recommended.
Characterization of an Electronic Corneal Prosthesis System
Published in Current Eye Research, 2020
Sarah Y. Shim, Songbin Gong, Victoria H. Fan, Mark I. Rosenblatt, Ahmed F. Al-Qahtani, Michael G. Sun, Qiang Zhou, Levi Kanu, Ibraim V. Vieira, Charles Q. Yu
The cornea is the transparent anterior part of the eye, focusing images from outside the eye onto the retina. Corneal disease causes loss of clarity, and is a leading cause of reversible blindness worldwide.1 Current treatments, which aim to restore clarity to the cornea, have well known limitations.2 Cornea transplantation replaces the diseased opaque host cornea with a clear cornea from a deceased donor and is highly successful.3 However, a shortage of donor corneas persists, with up to 50% of the world population having no access to corneal tissue, and in those countries with transplant capability a total 12.7 million people remain on waitlists.4 Furthermore, patients with diseases resulting in corneal vascularization, especially such as after severe chemical burns or Steven Johnson’s Syndrome, are poor candidates for transplantation due to high risk for rejection.5,6 Keratoprostheses, clear nonbiologic implants placed through the cornea, were developed for these situations.7 Keratoprostheses have been able to provide vision, often for years, to patients that would otherwise be blind. However, keratoprosthesis have an implant-cornea interface that is exposed to the unsterile outside environment, resulting in a chronic risk of infection.8 Also, the presence of a large trans-corneal implant leads to chronic inflammation, which may be the etiology of a high rate of complications, including prosthetic membranes (up to 65%) and glaucomatous optic neuropathy (up to 64%).9
Blood Levels of Tumor Necrosis Factor Alpha and Its Type 2 Receptor Are Elevated in Patients with Boston Type I Keratoprosthesis
Published in Current Eye Research, 2019
Eleftherios I. Paschalis, Elise V. Taniguchi, James Chodosh, Louis R. Pasquale, Kathryn Colby, Claes H. Dohlman, Lucy Q. Shen
The Boston keratoprosthesis (KPro) is presently considered the most successful artificial cornea for the treatment of corneal blindness in patients not amenable to standard penetrating keratoplasty.1,2 Over the past 15 years, more than 14,000 patients worldwide have received the device, many of whom regained functional vision.3–5 Accumulated clinical and laboratory data have helped to improve device retention and decrease post-operative complications.6 For example, the use of daily topical prophylactic antibiotic eye drops has reduced infection rates from over 10% to ~1% over the last decade.7,8 The addition of titanium back plate along with surgical and anti-inflammatory innovations have helped to decrease the incidence of retroprosthetic membrane formation from over 30% to about 13%.9 Also, careful glaucoma monitoring and earlier interventions for intraocular pressure (IOP) control in KPro eyes have substantially improved vision preservation.10 However, glaucoma remains one of the most prevalent and devastating post-operative complications in KPro eyes, often leading to permanent vision loss, despite rigorous efforts to prevent and treat the disease.11–13
Autologous ear cartilage as a carrier for the Boston Type Ⅰ Keratoprosthesis in a rabbit model
Published in Cogent Medicine, 2019
Yeqi Zhou, Yuying Zhang, Jiajie Zhai, Zhancong Ou, Jiaqi Chen, Jianjun Gu
The disease and lesion of the cornea is the fourth leading cause of blindness in the world. The success rate of keratoplasty for some corneal disease is greater than 90%. However, almost all authors believe that the success rate for vascularized cornea and recurrent rejected cornea is dismal. Keratoprosthesis is the last resort reserved for these patients in whom keratoplasty is not feasible. Boston keratoprosthesis is the most widely used keratoprosthesis. The device has a collar button configuration and is composed of a polymethylmethacrylate front plate and stem with a backplate. Although polymethylmethacrylate is well tolerated by the cornea, the incidence of corneal carrier melt around stem varies from 10% to 18%. This experimental study attempted to evaluate the use of auricular cartilage as the carrier to fix the Boston keratoprosthesis and prevent carrier melt, a devastating postoperative complication which leading to aqueous leaks or extrusion of the device.