Fine-needle diathermy for corneal vascularisation

Background: Corneal angiogenesis occurs as a sequel to an insult and it brings with it cells that mediate immunity as well as repair and aids in flushing toxins out. These vessels are formed in haste and leak lipid and cells, ultimately resulting in loss of transparency, lipid keratopathy and immunogenicity. So, they may need treatment prior to an optical keratoplasty. Purpose: To demonstrate the procedure of Fine Needle Diathermy (FND) to treat corneal neovascularization, its indications and contraindications. Synopsis: FND uses coagulating current from a monopolar cautery unit to occlude the afferent and efferent blood vessels. FND works best at the stage of mature vessel formation. The needle is placed across a tuft of vessels or parallel to a single large vessel, being mindful of the depth and direction. FND is avoided in necrotic tissue where the blood vessel is needed for healing process. Occlusion of the vessel in these situations may result in tissue melt. Highlights: Corneal neovascularization follows the stages of latent phase, active neovascularization, mature vessel formation and then regression. The treatment modality depends on the stage of angiogenesis. FND works best for neovascularization due to infectious keratitis. Keratoplasty is best performed 3 to 4 months later when regression of corneal vascularization occurs.

Bevacizumab for ocular neovascular diseases: a systematic review / Bevacizumabe para doenças oculares neovasculares: revisão sistemática

CONTEXT AND OBJECTIVE: Many eye diseases involve increased local levels of vascular endothelial growth factor (VEGF), and there are several therapeutic strategies for them. Thus, the aim of this study was to evaluate the effectiveness and safety of bevacizumab for treating eye diseases involving increased local levels of VEGF, as the assumed pathophysiological mechanism. DATA SOURCES: The following databases were systematically searched for evidence: PubMed, CENTRAL (Cochrane Library), Literatura Latino-Americana e do Caribe em Ciências da Saúde (Lilacs) and reference lists, without language restrictions. Only randomized controlled trials were included. The primary outcome of interest was visual acuity, irrespective of the evaluation method. DATA SYNTHESIS: A total of 667 eyes in nine randomized trials were included. Meta-analysis showed that the proportion of patients with age-related macular degeneration who presented improvements from baseline regarding best-corrected visual acuity was higher among those treated with bevacizumab than among those in the photodynamic therapy group (risk ratio, RR, 0.49; 95 percent confidence interval, CI, 0.31 to 0.78; P = 0.01). CONCLUSIONS: The evidence available demonstrates that bevacizumab alone or combined with other treatments is more effective than other options, including photodynamic therapy, focal photocoagulation and triamcinolone. The use of bevacizumab instead of photodynamic therapy could reduce treatment costs by more than 99 percent and could significantly increase access to treatment. However, long-term studies are still needed in order to reduce uncertainty concerning the safety of this medication for all ocular neovascular diseases in which bevacizumab has the potential to improve visual acuity.

CONTEXTO E OBJETIVOS: Muitas doenças oculares envolvem o aumento dos níveis locais de fator de crescimento do endotélio vascular (FCEV), uma diversidade de estratégias terapêuticas para tais condições. Assim, o objetivo do presente estudo é avaliar a efetividade e a segurança de bevacizumabe para o tratamento de pacientes com doença ocular que envolva o aumento dos níveis locais de FCEV, como mecanismo patofisiológico assumido. FONTE DAS INFORMAÇÕES: Foi realizada busca sistemática pelas evidências disponíveis nas seguintes bases de dados da eletrônicas: PubMed, CENTRAL (The Cochrane Library), Literatura Latino-Americana e do Caribe em Ciências da Saúde (Lilacs), além de referências bibliográficas de estudos relevantes, sem restrições de língua. Foram incluídos apenas ensaios controlados e aleatórios. Acuidade visual, independentemente do método de avaliação, foi considerada o desfecho primário de interesse. SÍNTESE DOS DADOS: Foi incluído um total de 667 olhos testados em nove ensaios clínicos aleatórios. A metanálise demonstrou que a proporção de pacientes com degeneração macular relacionada à idade que melhoraram a acuidade visual foi maior entre os tratados com bevacizumabe do que entre os pacientes em terapia fotodinâmica (risco relativo [RR] 0.49, 95 por cento intervalo de confiança [IC] 0,31 a 0,78, P = 0,01). CONCLUSÕES: A evidência disponível demonstra que bevacizumabe isolado ou combinado com outras terapias é mais eficaz que terapia fotodinâmica, fotocoagulação focal e triancinolona. O uso de bevacizumabe em vez da terapia fotodinâmica poderia reduzir os custos do tratamento em mais de 99 por cento e aumentar significativamente o acesso ao tratamento. Entretanto, o aspecto de segurança do fármaco ainda necessita ser avaliado por estudos em longo prazo com todas as doenças neovasculares em que bevacizumabe tenha o potencial de melhorar acuidade visual.

Inhibition of Corneal Angiogenesis by a Farnesyl Transferase Inhibitor

Farnesyl transferase inhibitor(FTI) disrupt farnesylation of ras protein and thus, suppress tumor growth in vivo. The ras oncogene is thought to contribute to tumor development directly by promoting tumor cell proliferation and indirectly by stimulating vascular endothelial growth from Cinnamomum Cassia Blume(CB2`-ph) interferes with angiogenesis, we studied the effect of CB2`-ph on rabbit corneal angiogenesis induced by VEGF. A hygrogel disk containing 250ng of VEGF was implated intrastromally in the superior cornea of 16 NZW rabbit eyes. All eyes received a second intrastromal disk, randomized to contain either 40 micro gram of CB2`-ph(n=8) or phosphate-buffered saline(PBS)(n=8). Both disks were positioned side-by-side, 1.2mm from the superior limbus. Each eye was examined daily by two masked observers and assigned an angiogenesis score based on number and length of new blood vessels. At 3, 5 and 7 days postimplantation of VEGF disks, eyes treated with CB2`=ph showed mean angiogenesis score of 2.0 +/- 1.7, 13.4 +/- 6.6 and 23.8 +/- 11.3, respectively, while PBS=treated controls scored 8.6 +/- 4.4, 30.3 +/- 20.8 and 52.2 +/- 26.9, respectively(p<0.05, Wilcoxon signed rank test). In a rabbit corneal pocket assay, CB2`-ph appears to be effective on VEGF-induced corneal angiogenesusis in the model.

Rat Cornea Model for Inhibition of Angiogenesis Induced by Suture

The purpose of this study was to establish a model system of induced neovascularization(NV) and the inhibitory chemicals tested on the avascular tissue, namely cornea. We induced corneal NV condition by suturing the cornea of Sparague-Dawley rat with one stitch of 10-0 nylon in immitation of corneal transplantation and terramycin was applied on the cornea for 1 week to prevent corneal inflammation. The progression of suture-induced corneal NV was investigated at various time pints(1, 7 days, 2, 3, 4 and 8wks) after the suture. The formation of new capillary tubs was observed at 5-7 days after suture. The arc of NV was increased gradually and peaked in 3 weeks and decreased hereafter while the length of vessels did not change during he course of NV once it reached the maximum. We also developed a corneal model for NV inhibition in which CB 2`-ph(1)(2`-O-Benzonylcinnamaldehyde), the NV inhibitor, contained in the form of Hydron Pellet was inserted into the stroma of the cornea followed by suturing the cornea. In this model for inhibition of NV, Hydron Pellet was inserted in the cornea successfully without causing the corneal inflammation. In this study, we developed a suture-induced corneal NV model system which enables us to perform various experiments reproducibly and investigate the effect of NV inhibitor.