corneal neovascularization is defined as the occurrence of neovessels developed from preexisting vascular structures in the limbus , invading areas of the cornea initially not vascularized . the avascular character results from a balance between angiogenic and antiangiogenic factors . in pathological conditions such as inflammatory , infectious , degenerative , or traumatic ones , this homeostasis can be broken and can be responsible for the occurrence of corneal neovessels . several therapeutic modalities have been proposed : steroids , physical therapy by superficial keratectomy or argon laser , cauterization , and local   and subconjunctival application of anti - vegf ( bevacizumab , ranibizumab ) ; but there is so far no consensus in the therapeutic management of corneal neovessels . the aim of our study is to report the efficiency and safety of bevacizumab in intrastromal injection in the treatment of corneal neovascularization . this is a prospective , noncomparative study , conducted at the university hospital mohammed vi of marrakech , between september 2013 and december 2015 , and it included 25 eyes of 23 patients with deep predescemetic corneal neovessels who received intrastromal injections of bevacizumab . all patients underwent an eye examination with a measurement of best corrected visual acuity , examination at the slit lamp with photographs of the cornea , intraocular pressure measurement , and examination of the eye fundus with an ocular ultrasound in the absence of a refractive medium of the eye . the severity was assessed using a clinical grading scale ; this method aims to analyze directly photographs of the cornea ( table 1 ) . patients had to have a minimum setback of six months to be included in the study . all patients received initially a topical corticosteroid to reduce their diameter and act on their effects ( edema and inflammation ) . the bevacizumab at 25  mg / ml was prepared sterilely into a syringe with a needle of 30 gauge . an injection of about 0.01  ml was performed under topical anesthesia with instillation of oxybuprocaine hydrochloride 0.4% . the product was administered in the corneal stroma next to neovessels ; the exact location depends on the location of the neovessels compared to the limbus , their number , and their extension according to the quadrants . the intrastromal injections were spaced by a month and were continued until the stagnation of the regression of neovascularization . patients who received intrastromal injections of bevacizumab were monitored at day 7 , day 30 , and day 120 . patients received blood pressure test , visual acuity , intraocular pressure measurement , and the slit lamp exam with photographs . the photographs on photographic slit lamp were taken in the inclusion visit then monthly until the end of the treatment . the primary evaluation criterion was the corneal surface covered with neovessels before and after treatment . the analysis was performed by clinical grading scale and photoshop software ( adobe systems , inc . the second criterion for efficacy was the variation in visual acuity before and after treatment . twenty - five eyes of twenty - three patients ( 15 men and 8 women ) with nine months of setback after the beginning of bevacizumab therapy were included in the study . the average age of patients at the time of treatment with bevacizumab was 31 years ( between 16 and 44 years ) . the etiologies of corneal neovascularization were scars of herpetic keratitis in 10 patients ( 43.4% ) , ocular trauma in 6 patients ( 26.1% ) , postinfectious keratitis in 3 patients ( 13% ) , chemical burns in 2 patients ( 8.7% ) , and toxic epidermal necrolysis in 2 patients ( 8.7% ) . 10 patients received 3 intrastromal injections of bevacizumab , 9 received four injections , and 4 had 5 injections . the evolution was marked by the total regress in 15 patients ( figures 1 , 2 , and 3 ) , partial in 5 . overall , the percentage of corneal neovascularization is reduced by 43  19% ( between 14 and 70% ) at 18  16% ( between 0 and 39% ) in day 120 ( p < 0.001 ) . later on , intraoperatively , 6 patients received subconjunctival corticoids injections , and 2 were injected with subconjunctival bevacizumab . postoperatively , there was recurrence of neovessels at the collar of the receiver in 3 patients , which was well controlled under topical corticosteroids , and a backlash in 3 patients . there was also a recurrence of neovascularization in 2 patients after an average of five months . our study seems to suggest the efficacy of bevacizumab in the treatment of deep corneal neovascularization . the development of corneal neovessels occurs in several phases : a perivascular latency phase , a second active neovascularization , and finally a maturation phase of new vessels . the first two phases will be a potential target for angioregressive therapy by blocking angiogenic factors . classical treatment modalities include corticoids , nonsteroidal anti - inflammatory drugs , laser photocoagulation , and reconstruction of the ocular surface . however , these treatments have demonstrated limited therapeutic effect with considerable complications [ 710 ] . the development of inhibitors of vegf , a humanized monoclonal antibody bound to isoforms of vegf - a , introduced a new perspective in the treatment of various ophthalmic disorders , including damage to the ocular surface such as corneal neovascularization . the efficiency of bevacizumab in intrastromal injection has been reported ; the dose of 25  mg / ml appears to be effective and well tolerated in several studies [ 1215 ] ( table 2 ) . several hypotheses can be made to explain this variability in response to bevacizumab as the different etiologies of neovascularization are involved : the extension of the neovascularization , the state of limbo , and the delay between the appearance of neovessels and the beginning of treatment . indeed , in these patients , the decline was not only due to corneal neovascularization , but also due to corneal scars . compared to other forms of administration , the intrastromal injection allows greater exposure to bevacizumab and delivery of a known concentration of the drug . the penetration of the topical form of this drug may be limited by an intact epithelium because of the high molecular weight of bevacizumab . the intrastromal administration also ensures less risk of failure due to lack of patient compliance . patients may sometimes forget to install the medication at home , when using a topical preparation . the subconjunctival injection of bevacizumab allows better diffusion compared to topical instillation ; several studies have shown its effectiveness in the treatment of superficial and average depth neovessels [ 17 , 18 ] , and others have proved that subconjunctival injection of bevacizumab allows only partial reduction of deep neovessels [ 1921 ] . a recent study showed that the subconjunctival injection has no effect on mature neovessels ; it is quite effective in the active phase of the process of angiogenesis . used a ranibizumab having a lower molecular weight than subconjunctival topical instillation and found satisfactory results . the intrastromal injection of bevacizumab increases the concentration and duration of exposure ; in addition , it is also very effective in mature neovessels [ 13 , 14 ] . the intrastromal injection of bevacizumab might be a useful option in the management of corneal neovascularization . . however , further studies are needed to determine the optimum dosage and to define the indications , the frequency , and risk factors for developing possible side effects .