China
Africa
Explore chapters and articles related to this topic
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 For some conditions this has largely been replaced by lamellar or partial-thickness graft surgery, in a technique termed DSEK or ‘Descamets stripping endothelial keratoplasty’.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.
Endophthalmitis in Eyes with Osteo-odonto Keratoprosthesis
Published in Ocular Immunology and Inflammation, 2022
Pukhraj Rishi, Ekta Rishi, Pradeep Manchegowda, Geetha Iyer, Bhaskar Srinivasan, Shweta Agarwal
Since the initial use of Osteo-odonto keratoprosthesis (OOKP) back in 1963,1 the surgical procedure has undergone several changes over the years.2 Devise improvisations leading to modified OOKP have drastically reduced the prosthesis extrusion rates, thereby reducing the complications and enhancing its long-term retention.3 Consequently, anatomical and functional outcomes have improved considerably and hence, it has become the treatment of choice for end-stage inflammatory corneal disease.4 Endophthalmitis is not an uncommon vitreoretinal complication associated with OOKP. Although there have been reports which have described complications of OOKP procedure,4–8 there is a need to analyze endophthalmitis in OOKP eyes with respect to incidence, microbiological profile, risk factors, treatment modalities, and outcomes. Pubmed search (November 27, 2019) with keywords <Osteo-odonto keratoprosthesis> and <Endophthalmitis> revealed six relevant reports. We have previously published our results of vitreoretinal complications in such eyes.9 However, in this report, we analyze OOKP eyes that developed endophthalmitis.
Oral mucosa grafting in periorbital reconstruction
Published in Orbit, 2018
OMGs have also been used for ocular resurfacing in preparation for implantation of osteo-odonto-keratoprosthesis.24,56 This technique is recommended to provide a stable epithelial cover for the keratoprosthesis, primarily in patients with a hostile ocular surface environment such as dry keratinized post-SJS eyes.24 However, complications may still occur including mucosal overgrowth over the optical cylinder obscuring vision or necrosis.24,57 Similarly, Hollick et al.58 reported using buccal mucosa as a preliminary protective cover overlying the Legeais BioKPro III keratoprosthesis after insertion of the device. In addition, sterile cornea stromal melts and extrusion of the keratoprosthesis implant may occur particularly in patients with chronic conjunctival inflammation in the setting of cicatricial ocular surface diseases. In such patients with conjunctival deficiency, buccal mucosa may be necessary to repair the overlying conjunctival defect. Ziai et al.23 successfully used a lamellar corneal graft covered by buccal OMG to repair cornea stromal melts in 3 patients following implantation of Boston type 1 keratoprosthesis. Traditionally, a Gundersen flap has been widely used to protect sensitive corneas in conjunction with cosmetic scleral shell wear.59 An alternative approach to permit cosmetic scleral shell fitting using an OMG was successfully adopted in 10 patients by Heher and Katowitz.60 Moreover, a small comparative case series conducted by Ma’luf and Awwad61 identified OMG to be superior to a Gundersen flap in eyes with conjunctival scarring or a large corneal diameter, with a lesser risk of graft versus flap retraction.
Biosynthetic alternatives for corneal transplant surgery
Published in Expert Review of Ophthalmology, 2020
May Griffith, Bijay Kumar Poudel, Kamal Malhotra, Naoufal Akla, Miguel González-Andrades, David Courtman, Victor Hu, Emilio I. Alarcon
Artificial corneas known as keratoprostheses were developed to manage high-risk patients by replacing the basic functions of light transmission into the eye for vision, and protection of the soft inner contents of the eyeball. Most prostheses have an optic for transmitting light and a shirt for the integration of the device into the patients’ corneas. The most successful models have been ‘biosynthetic’ ones, which combine a biological skirt with a synthetic plastic optic. These include the osteo-odonto-keratoprosthesis (OOKP) and the Boston Keratoprosthesis (KPro). Both of these use methacrylate plastic as the optic. The former uses a tooth or bone for the skirt while the latter uses a human donor cornea that is not suitable for regular corneal grafting. While retention rates are improving, it is agreed that these devices, which are invasive and non-reversible, are only used as last-resorts for vision restoration [61] as they have serious side effects. These side effects include lifelong use of antibiotics to guard against infection, formation of retroprosthetic membranes, melting, and glaucoma [61–65]. Even in the Boston KPro, the most successful prosthesis, lifelong antibiotics are necessary to prevent infection due to incomplete biointegration of the device [63] and the device exposes the patients to a high risk of glaucoma [62,65], in which optic nerve can be damaged, leading to non-reversible blindness. A Boston KPro implantation surgery package (KPro device, pre- and post-operative visits, clinical testing, surgery and hospital fees) in the USA costs as much as USD 55,000 [66]. KPro use is therefore limited to more affluent countries and patients who have had repeated surgeries where allografting has failed, or where donor allografting is contraindicated [64].