Архитектура Аудит Военная наука Иностранные языки Медицина Металлургия Метрология
Образование Политология Производство Психология Стандартизация Технологии


Intravitreal Injection of bevacizumab



 

Bevacizumab (Avastin, Genentech, Inc.) is a recombinant, humanized monoclonal antibody that binds all isoforms of VEGF-A. Intravitreal injection of bevacizumab (0.05 mL/1.25 mg) has been shown to be effective not only in resolving the edema but also in corresponding improvement in vision. In a prospective, randomized, double-masked clinical study by Epstein et al, intravitreal injections of bevacizumab given every 6 weeks for 12 months improve visual acuity and significantly reduce edema compared with sham. Early treatment is important in these patients to optimize visual outcome, as patients in whom treatment is delayed have limited visual improvement. In addition, none of the patients developed neovascular glaucoma when treated with bevacizumab.

 

Bevacizumab is approved for treatment of various metastatic cancers, including metastatic colorectal cancer, non-small cell lung cancer, and glioblastoma multiforme. Intravitreal injection of bevacizumab is considered off-label use. Bevacizumab is not commercially available as an intravitreal injection. Reports of small series of eye infections due to contamination from repackaging into preservative-free single use vials have been reported.

 

Significant complications were reported with high doses of bevacizumab given intravenously for the treatment of cancer. There have been no significant reports of these complications when used in low dosage in eye.[13, 33, 34, 19, 35]

Surgical Care

Laser photocoagulation

Laser photocoagulation is the known treatment of choice in the treatment of various complications associated with retinal vascular diseases (eg, diabetic retinopathy, branch retinal vein occlusion). Panretinal photocoagulation (PRP) has been used in the treatment of neovascular complications of central retinal vein occlusion (CRVO) for a long time. However, no definite guidelines exist regarding exact indication and timing of PRP. A National Eye Institute (NEI) sponsored multicenter prospective study, the Central Vein Occlusion Study (CVOS), provided guidelines for the treatment and follow-up care of patients with CRVO. [1, 10, 36, 37, 38]

 

CVOS evaluated the efficacy of prophylactic PRP in eyes with 10 or more disc areas of retinal capillary nonperfusion, confirmed by fluorescein angiography, in preventing development of 2 clock hours of iris neovascularization or any angle neovascularization or whether it is more appropriate to apply PRP only when iris neovascularization or any angle neovascularization occurs. CVOS concluded that prophylactic PRP did not prevent the development of iris neovascularization and recommended to wait for the development of early iris neovascularization and then apply PRP.

 

Argon green laser usually is used. Laser parameters should be about 500-µm size, 0.1-0.2 second duration, and power should be sufficient to give medium white burns. Laser spots are applied around the posterior pole, extending anterior to equator. They should be about 1 burn apart and total 1200-2500 spots.

 

If ocular media is hazy for laser to be applied, cryoablation of the peripheral fundus is performed. About 16-32 transscleral cryo spots are applied from ora serrata posteriorly.

 

CVOS evaluated the efficacy of macular grid photocoagulation in preserving or improving central visual acuity in eyes with macular edema due to central vein occlusion (CVO) and best-corrected visual acuity of 20/50 or poorer. Macular grid photocoagulation was effective in reducing angiographic evidence of macular edema, but it did not improve visual acuity in eyes with reduced vision due to macular edema from CVO. At present, the results of this study do not support a recommendation for macular grid photocoagulation for macular edema.


Поделиться:



Последнее изменение этой страницы: 2019-06-07; Просмотров: 173; Нарушение авторского права страницы


lektsia.com 2007 - 2024 год. Все материалы представленные на сайте исключительно с целью ознакомления читателями и не преследуют коммерческих целей или нарушение авторских прав! (0.012 с.)
Главная | Случайная страница | Обратная связь