Results of Keratoprosthesis
References (5)
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Prostokeratoplasty
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Keratoprosthesis
Editorials on recent advances. Invest. Ophthalmol
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Cited by (28)
Infectious endophthalmitis in adult eyes receiving Boston type i keratoprosthesis
2012, OphthalmologyCitation Excerpt :In addition, all presentations of vitreitis in a K-Pro eye may not be infections, and all vitreous samples may not yield organisms when cultured. Noninfectious, sterile, and culture-negative endophthalmitis have been reported in eyes with K-Pro.12–16 In a case series reviewing a similar number of eyes as this report, Zerbe et al15 reported 7 cases of unspecified vitreitis with negative vitreous culture results.
To report the clinical characteristics of infectious endophthalmitis after Boston type I keratoprosthesis (K-Pro) implantation.
Retrospective study.
One hundred forty-one adult eyes receiving a K-Pro at a single institution from May 2004 through July 2008.
A retrospective chart review was performed of all adult eyes receiving a K-Pro at the University of Rochester from May 2004 through July 2008. Those patients identified as having been treated for exogenous bacterial endophthalmitis were reviewed for demographic data, indication for K-Pro, bandage contact lens use, prophylactic antibiotic use, timing and clinical presentation of endophthalmitis, gram stain and culture results of intraocular fluid, timing and presentation of any subsequent episodes of endophthalmitis (recurrent endophthalmitis), and preoperative and postoperative visual acuity through August 2010.
Incidence of endophthalmitis, time to occurrence, recurrence rates, visual outcomes, and risk factors associated with K-Pro endophthalmitis.
Ten (7.1%) of 141 eyes of 130 adult patients were diagnosed and treated for bacterial endophthalmitis. Average time to endophthalmitis developing after K-Pro was 9.8 months (standard deviation [SD], 6.2 months; range, 2–25 months). Coagulase-negative staphylococci were identified in 7 eyes. In 7 of the 10 eyes, recurrent endophthalmitis developed that occurred at a mean of 4 months (SD, 3.9 months; range, 1–13 months) after resolution of the initial episode. At each episode of endophthalmitis, no eye was receiving vancomycin ophthalmic drops and most eyes were receiving only fluoroquinolone ophthalmic drops for prophylaxis.
Infectious endophthalmitis after K-Pro implantation has a higher incidence, delayed onset, and high risk for recurrence compared with postoperative endophthalmitis associated with more common intraocular procedures such as cataract surgery. The concurrent use of topical vancomycin is recommended because it seems to be important in reducing the incidence and recurrence of endophthalmitis and because fluoroquinolone ophthalmic drops do not seem to be sufficient prophylaxis in these eyes.
The author(s) have no proprietary or commercial interest in any materials discussed in this article.
Keratoprosthesis: The dohlman-doane device
2005, American Journal of OphthalmologyTo determine the usefulness of the Dohlman-Doane type I keratoprosthesis for visual rehabilitation in cases of poor prognosis for traditional penetrating keratoplasty.
A retrospective, noncomparative interventional series of 25 patients who had sustained multiple graft failure or who were otherwise deemed poor candidates for conventional keratoplasty.
Candidates were evaluated for potential acuity, intraocular pressure, inflammation, the quality of the ocular surface, and overall prognosis for penetrating keratoplasty. The keratoprosthesis was assembled and mounted on an 8.5- or 9.0-mm diameter donor corneal button and sutured into an 8.0- or 8.5-mm diameter recipient bed with 12 to 16 9–0 nylon sutures. Patients were examined on the first day and subsequently in 1 week and 1 month and then at 3-month intervals.
All devices were retained without dislocation or extrusion. There were no instances of endophthalmitis or surface infection. Fundus details were visible on the first postoperative day. Patients achieved their best acuity in an average of 2 months (range, 1 to 180 days). Improvement in acuity was observed in an average of 13 days (range, 1 to 60 days). Retroprosthetic membranes occurred in three cases, with multiple recurrences in one instance. Visual acuity ranged from no light perception to 20/25.
We conclude that this prosthesis can be implanted routinely and maintained with minimal complications in poor prognosis keratoplasty, which presents the potential for visual rehabilitation.
A second generation of artificial cornea (Biokpro II)
1998, BiomaterialsThe properties of a new second-generation colonizable artificial cornea were evaluated in humans. The prosthesis consisted of a peripheral rim of a translucent microporous fluorocarbon polymer (expanded polytetrafluoroethylene) fused with the polymer of the central optic. The optic was made of medical-grade polydimethylsiloxane coated with polyvinylpyrrolidone. Its refractive power was 42.2 diopters and it measured 7.0 mm in diameter and 0.55 mm in thickness. The geometry of the optic was tested by high-frequency ultrasound and intraocular pressure and distensibility were measured in an artificial chamber. Prostheses were implanted in one eye of 13 humans. The average follow-up was 6 months (range 3–9 months). Most of the eyes (11/13) were clinically stable after a 7 months follow up. Seven patients had visual acuity improvements. Mean corrected final visual acuity was 20/200 (range, 20/30 to light perception). Five anatomical failures occured (two extrusions, two retroprosthetic membranes, one endophthalmitis). The new optical core, junction, and surface properties of the polymers offer many advantages, quicker colonization of the supporting skirt, and an optical core with a geometry similar to that of a normal human cornea. Epithelial cells did not migrate over the interface and optical core. It seems that formation of an epithelium over the artificial device is essential for the long-term stability of the implant.
Keratoprostheses: Advancing toward a true artificial cornea
1997, Survey of OphthalmologyKeratoprosthesis surgery is carried out in very few centers. Elaborate surgical techniques and high complication rates limit the application of currently available keratoprostheses (KPros). However, the clinical need for an alternative to donor tissue has sparked considerable research interest in the development of new KPros. This paper charts the evolution of KPros from the earliest devices to those currently used, describes their drawbacks and discusses the specifications of an ideal device. Recent research focuses upon the use of porous polymers as the skirt component of core-and-skirt KPros in order to obtain improved biological integration of the prosthetic material. Developments in biomaterials technology make a KPro analogous to a donor corneal button an increasingly realistic goal. However, two particular problems still need to be addressed. First, it must be demonstrated that secure long-term fixation that is able to withstand trauma is achievable in a full-thickness artificial cornea. Second, an ideal artificial cornea for a wet eye requires an epithelialized surface, and this has yet to be achieved.
Chemical injuries of the eye: Current concepts in pathophysiology and therapy
1997, Survey of OphthalmologyChemical injuries of the eye may produce extensive damage to the ocular surface epithelium, cornea, and anterior segment, resulting in permanent unilateral or bilateral visual impairment. Patholphysiological events which may influence the final visual prognosis and which are amenable to therapeutic modulation include 1) ocular surface injury, repair, and differentiation, 2) corneal stromal matrix injury, repair and/or ulceration, and 3) corneal and stromal inflammation. Immediately following chemical injury, it is important to estimate and clinically grade the severity of limbal stem cell injury (by assessing the degree of limbal, conjunctival, and scleral ischemia and necrosis) and intraocular penetration of the noxious agent (by assessing clarity of the corneal stroma and anterior segment abnormalities). Immediate therapy is directed toward prompt irrigation and removal of any remaining reservoir of chemical contact with the eye. Initial medical therapy is directed toward promoting re-epithelialization and transdifferentiation of the ocular surface, augmenting corneal repair by supporting keratocyte collagen production and minimizing ulceration related to collagenase activity, and controlling inflammation. Early surgical therapy, if indicated, is directed toward removal of necrotic corneal epithelium and conjunctiva, prompt re-establishment of an adequate limbal vascularity, and re-establishment of limbal stem cell populations early in the clinical course, if sufficient evidence exists of complete limbal stem cell loss. Re-establishment of limbal stem cells by limbal autograft or allograft transplantation, or by transfer in conjunction with large diameter penetrating keratoplasty, may facilitate development of an intact, phenotypically correct corneal epithelium. Limbal stem cell transplantation may prevent the development of fibrovascular pannus or sterile corneal corneal ulceration, simplify visual rehabilitation, and improve the visual prognosis. Advances in ocular surface transplantation techniques which allow late attempts at visual rehabilitation of a scarred and vascularized cornea include limbal stem cell transplantation for incomplete transdifferentiation and persistent corneal epithelial dysfunction, and conjunctival and/or mucosal membrane transplantation for ocular surface mechanical dysfunction. Rehabilitation of the ocular surface may be followed, if necessary, by standard penetrating keratoplasty if all aspects of ocular surface rehabilitation are complete, or by large diameter penetrating keratoplasty if successful limbal stem cell transplantation cannot be achieved but other ocular surface rehabilitation is complete.
Titanium and bioactive glass-ceramic coated titanium as materials for keratoprosthesis
1996, Experimental Eye ResearchThe current problem with keratoprosthesis is the ingrowth of corneal or conjunctival epithelium into the anterior chamber. This may lead to infections and extrusion of the prosthesis as well as to the development of retroprosthetic membrane and secondary glaucoma. Glass-ceramic coated and uncoated titanium has been tested as material for the keratoprosthesis to prevent epithelial ingrowth. Twenty-two Supra-Descemet's membrane keratoprostheses were inserted in the eyes of 22 rabbits for 1, 2, 4, 8, or 12 months. The prosthesis had an optic part made of polymethylmetacrylate (PMMA). The support for the optic part and the flange of the prosthesis were made of titanium. Eleven of the prostheses were coated with glass-ceramic. The histological sections of the enucleated eyes were prepared through the central part of the cornea and the prosthesis using a cutting-grinding method. The histological analysis was made on both halves of the implants separately giving two analysis areas in each eye. All 11 titanium prostheses were retained for the time period planned. Two glass-ceramic coated prostheses were lost at 2 and 4 weeks, respectively. This was caused by difficulties at surgery due to a thick coating. These eyes were excluded from the histological analysis. No significant ingrowth of epithelium was seen in 15/18 (83%) and in 16/22 (73%) of the analysed areas of the glass-ceramic coated and titanium prostheses, respectively. Titanium appears to be a suitable material for the keratoprosthesis. The ingrowth of the epithelium may be hindered further by coating the titanium with bioactive glass-ceramic.
Reprint requests to Gullapalli N. Rao, M.D., 1160 Chili Ave., Rochester, NY 14624.
This study was presented in part before the Annual Scientific Session of the Castroviajo Society, Kansas City, Missouri, Oct. 21, 1978.