Safety and Effectiveness of Subconjunctival Injection of Bevacizumab in the Treatment of Corneal Neovasculization

Inclusion Criteria: * Significant unilateral or bilateral corneal neovascularization that extending over the limbus at least 2mm * The underlying etiologies that caused corneal neovascularization included post penetrating keratoplasty (PKP), trauma, infectious or non-infectious corneal ulcer, post-keratoplasty, etc. * Corneal neovascularization induced lipid keratopathy, corneal edema, or irregular corneal surface. The best-corrected visual acuity was less than 20/25 * Post-PKP corneal neovascularization that had no associated lipid keratopathy, no corneal edema, or corneal irregularity. But the neovascularization was highly possible to cause graft rejection. * The corneal neovascularization was refractory to other medical treatment * The patient had received PKP or other corneal surgeries more than half a year ago and was not in the acute post-operation phase * The patient had no active endopthalmitis, glaucoma with uncontrolled intraocular pressure, or vitreoretinal diseases * The patient signed inform consent to have regular follow up and treatment Exclusion Criteria: * The neovascularization had clinical improvement three months before the first injection * The lipid keratopathy had clinical improvement three months before the first injection * The patient that suspected to have poor visual outcome or had already been light sense negative * Glaucoma patient that had uncontrolled intraocular pressure * Poor corneal epithelialization * Post-PKP patient that had graft failure or rejection * Patient that had systemic disease which was not suitable for bevacizumab use * Pregnant patient