ISSN:1040-8738    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Over the years, most researchers have approached corneal epithelial and stromal wound healing as separate events. However, it is becoming increasingly clear that even the simplest epithelial debridement wound results in keratocyte death and a subsequent stromal response to regenerate the affected area. Thus, the interaction between stromal and epithelial healing must be considered to fully understand corneal wound healing. Although wound healing has been an active area of research for many years, the advent of refractive surgery has stimulated research into the regulation of wound repair and provided important insights into the molecular components involved in repair. Epithelial and stromal wound healing are influenced by extracellular matrix components. The purpose of the current article is to review progress in the year 2000 toward understanding mechanisms involved in corneal wound healing and how extracellular matrix affects the healing processes.

ISSN:1040-8738    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Corneal neovascularization (NV) is a sight-threatening condition usually associated with inflammatory or infectious disorders of the ocular surface. It has been shown in the field of cancer angiogenesis research that a balance exists between angiogenic factors (such as fibroblast growth factor and vascular endothelial growth factor) and anti-angiogenic molecules (such as angiostatin, endostatin, or pigment epithelium derived factor) in the cornea. Several inflammatory, infectious, degenerative, and traumatic disorders are associated with corneal NV, in which the balance is tilted towards angiogenesis. The pathogenesis of corneal NV may be influenced by matrix metalloproteinases and other proteolytic enzymes. New medical and surgical treatments, including angiostatic steroids, nonsteroidal inflammatory agents, argon laser photocoagulation, and photodynamic therapy have been effective in animal models to inhibit corneal NV and transiently restore corneal “angiogenic privilege.”

ISSN:1040-8738    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Conjunctival fibrosis may result from chronic inflammation and may lead to alterations of conjunctival architecture. This results in ocular dryness, entropion and trichiasis, and corneal complications. Causes of conjunctival cicatrization are not limited to autoimmune diseases, such as ocular cicatricial pemphigoid, a severe disease associated with poor ocular prognosis. Other well-known causes include thermal and chemical burns, postinfectious conjunctivitis, and Stevens-Johnson syndrome. Ocular rosacea and atopic keratoconjunctivitis often are underdiagnosed causes of conjunctival fibrosis. Medical history, physical exam, and laboratory tests often allow for diagnosis of the underlying disease. Medical management varies according to specific causes, and many surgical strategies are available to restore corneal transparency and normal palpebral architecture.

ISSN:1040-8738    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Penetrating keratoplasty in infants and young children is performed on an infrequent basis. The most common indication is visually significant congenital corneal opacity. Surgery must be performed early to avoid amblyopia. Surgical techniques differ from those used in adult penetrating keratoplasty because of the reduced ocular rigidity encountered in infants and young children. Use of a multispecialty team approach is important to improve visual outcome. Poor prognostic indicators include bilateral disease, concomitant infantile glaucoma, lensectomy and vitrectomy at the time of surgery, previous graft failure, extensive goniosynechiae, and extensive corneal vascularization. Prompt postoperative optical rehabilitation, combined with occlusion therapy when appropriate, is an important determinant of success.

ISSN:1040-8738    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Posterior keratoplasty is a new surgical technique that may be valuable in treating patients with corneal decompensation secondary to endothelial dysfunction. There are currently two approaches to posterior keratoplasty. In the first approach, a corneal flap is created using a microkeratome (similar to laser in situ keratomileusis flap), and posterior stromal tissue is excised (by trephination or excimer laser keratectomy). In the second approach, a deep stromal pocket is created across the cornea through a superior scleral incision. A custom-made flat trephine is inserted into the pocket to excise a posterior lamellar disc. Preliminary studies have shown the feasibility of performing these techniques in sighted human eyes. Despite potential advantages, further clinical studies are needed to determine whether these techniques reduce interface scarring, astigmatism and graft rejection, improve visual outcomes, or are potentially an alternative for penetrating keratoplasty.

ISSN:1040-8738    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Human amniotic membrane (AM) is composed of three layers: a single epithelial layer, a thick basement membrane, and an avascular stroma. Amniotic membrane has anti-adhesive properties and is felt to promote epithelialization and decrease inflammation, neovascularization, and fibrosis. Amniotic membrane transplantation (AMT) is currently being used for a continuously widening spectrum of ophthalmic indications. Amniotic membrane transplantation has been shown to be effective in the reconstruction of the corneal surface in the setting of persistent epithelial defects, sterile corneal ulcerations, and partial limbal stem cell (LSC) deficiency states, including those secondary to chemical or thermal burns. Amniotic membrane transplantation also has been used in conjunction with limbal stem cell transplantation (LSCT) both in a concurrent fashion as well as in preparation for LSCT. Amniotic membrane transplantation also has been used in place of conjunctival autografting after pterygium excision and to reconstruct the conjunctival surface after removal of conjunctival lesions. Most recently, ex vivo cultivation and expansion of limbal epithelial cells has been performed utilizing AM as a matrix. However, the superiority of AMT over other treatment modalities in many of these settings needs to be substantiated by controlled clinical trials.

ISSN:1040-8738    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Porous polytetrafluoroethylene and polyurethane skirt materials, as well as copolymers of poly (2-hydroxyethyl methacrylate), have shown promise in approaching the goal of a “biointegratable” keratoprosthesis. A novel fixation method that uses scleral haptics also has been introduced to increase stability. An all silicone device that can be sewn into position has been used successfully, temporarily, during vitreoretinal procedures. The prognosis of keratoprosthesis (KPro) procedures depends on the preoperative diagnosis: graft failure-noncicatrizing disease>ocular cicatricial pemphigoid>chemical burns>Stevens-Johnson syndrome. The likelihood of endophthalmitis after KPro surgery follows this scheme. Causative organisms tend to be gram-positive. Modified vitreoretinal techniques also have been developed, allowing successful treatment of posterior segment complications. The science of keratoprosthesis is advancing more rapidly than in previous years. However, use of KPro to address complicated corneal blindness worldwide remains limited. The authors conducted an English language literature review from January 1, 2000 to April 1, 2001 and describe advances of note in the field of keratoprosthesis design, materials, and medical and surgical management.

ISSN:1040-8738    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Excimer laser phototherapeutic keratectomy (PTK) is an important tool in the management of superficial corneal pathology. It works well in the treatment of anterior corneal dystrophies and degenerations, but we are learning that it may have a role in the treatment of certain patients with deeper corneal pathology. Indications also are being expanded to treat much less common conditions and also to treat children. Irregular astigmatism, which is not treated very well with current PTK techniques, may be addressed better with newer approaches, such as selective zonal ablation and the use of BioMask. As current PTK techniques are improved and newer methods are developed, this procedure will continue to be an excellent option for certain patients with superficial corneal problems.

ISSN:1040-8738    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Wavefront sensing is an emerging technology that can measure irregular astigmatism as a higher-order wavefront aberration. The application of wavefront sensing in ophthalmology might enable the non-invasive observation of living retinal cone cells; the measurement of detailed visual function of the central nervous system by eliminating higher-order aberrations during examinations by adaptive optics; the correction of irregular astigmatism; and the prevention of iatrogenic irregular astigmatism induced by conventional refractive surgical procedures. In addition, it will be theoretically possible to obtain supernormal vision by wavefront-guided refractive surgery.

ISSN:1040-8738    

出版商:OVID    

年代:2001

数据来源: OVID