to describe a case of choroidal neovascularization ( cnv ) following photorefractive keratectomy ( prk ) to correct myopia .
we performed prk in both eyes of a 20-year - old girl to correct myopia .
refractive error was 4.75 2.25    5 in the right eye and 5.00 1.25    180 in the left eye .
metamorphopsia was noticed by the patient in the right eye one month after the surgical procedure .
fluorescein angiography and optical coherence tomography ( oct ) were performed which were compatible with cnv .
after three monthly intravitreal bevacizumab injections , sub - retinal hemorrhage and intraretinal fluid resolved , but subretinal scar remained without any visual acuity improvement .
also , refractive surgeons should consider cnv development in cases with visual compliant or metamorphopsia following prk .
there are some reports of cnv after laser in situ keratomileusis ( lasik ) surgery , but to our knowledge , only one case of cnv following prk has been reported . here
prk was performed in both eyes of a 20-year - old girl to correct myopia .
the procedure was performed at refractive surgery center of baqiyatallah hospital , tehran , iran . a preoperative examination including refraction and best corrected visual acuity ( bcva ) measurements , slit - lamp examination , intraocular pressure ( iop ) measurement , and fundoscopy with dilated pupil was performed by the surgeon and reported as normal .
preoperative refractive error was 4.75 2.25    5 and 5.00 1.25    180 in the right and left eye , respectively .
alcohol - assisted corneal epithelium debridement was done , and mitomycin c was used at the end of the procedure .
one month after surgical procedure , metamorphopsia developed in the right eye , and visual acuity reduction happened 3 months later .
the patient was referred to retina clinic of the baqiyatallah hospital , tehran , iran 4 months after prk .
on fundus examination there was an area of subretinal hemorrhage in the para foveal area associated with macular edema of the right eye .
fluorescein angiography showed para foveal leakage ( fig .  1 ) , and optical coherence tomography ( oct ) revealed a hyper - reflective sub - retinal material associated with intraretinal fluid and pigment epithelial detachment ( fig . 
although the effect of intravitreal anti vascular endothelial growth factor ( anti - vegfs ) in the cases of cnv following excimer laser refractive surgery has not been completely understood , we used 1.25  mg intravitreal bevacizumab ( avastin ; genetech inc , south san francisco , california , usa ) for treatment .
after 3 monthly intravitreal injections , sub - retinal hemorrhage resolved and intraretinal fluid improved , but sub - retinal scar developed ( fig .  3a and b ) .
one month after the 3rd intravitreal injection , the bcva was 20/400 , and no visual acuity improvement was observed .
high myopia has been reported as a major cause of cnv formation ( 62% ) in young patients . in the present report
neo et  al reported 3 cases of unilateral cnv after lasik for high myopia . among their patients , the mean spherical equivalent was 11.42  d ( range from 6.75 to 20.00  d ) .
they used a combination of intravitreal ranibizumab and photodynamic therapy ( pdt ) with verteporfin for the treatment .
the mean bcva was 0.44 logmar and 0.17 logmar at presentation and after treatment , respectively .
saeed et  al described a case of cnv after lasik for correction of low myopia .
the refractive error in their patient was 2.75  d in both eyes , and cnv developed in one eye 3 months after surgery .
although loewenstein et  al described macular hemorrhage in three patients with high myopia ( 13.00 to 20  d ) after prk , to date , there has only been one report of cnv after prk .
ruiz - mareno and colleagues evaluated the incidence of cnv in 5963 eyes undergoing prk for the correction of myopia .
cnv developed in one eye after correction of 12.00  d of myopia 26 months after prk .
the same researchers reported one case of cnv after the same number of prk surgeries .
progressive elongation of the axial length and degenerative changes of the choroid in highly myopic eyes may cause the linear breaks in bruch 's membrane which are called lacquer cracks .
lacquer cracks may be related to development of cnv.9 , 10 myopic changes and lacquer cracks were not observed in the fundus examination of our case .
iop elevation induced during lasik surgery may result in posterior segment pathologies and may be a factor for cnv formation .
iop elevation does not happen during prk , and this may be the cause of lower reports of cnv formation following prk compared with lasik .
acoustic shock waves produced by the excimer laser are another factor proposed to play a role in the cnv formation after both prk and lasik .
cnv is not common in a 20-year - old patient without obvious myopic chorioretinal changes and lacquer cracks . also , our patients visual symptoms developed only 1 month after prk surgery .
therefore , prk may play a role in the development of cnv in our case .
since idiopathic and myopic cnv can not be ruled out in our case , the cause - and - effect relationship between the surgical procedure and cnv formation is not established . in conclusion
also , refractive surgeons should consider cnv development in cases with visual compliant or metamorphopsia following prk .
 purposeto describe a case of choroidal neovascularization ( cnv ) following photorefractive keratectomy ( prk ) to correct myopia.methodswe performed prk in both eyes of a 20-year - old girl to correct myopia . 
 refractive error was 4.75 2.25    5 in the right eye and 5.00 1.25    180 in the left eye.metamorphopsia was noticed by the patient in the right eye one month after the surgical procedure . 
 the patient was referred 3 months later when visual loss happened.resultsfluorescein angiography and optical coherence tomography ( oct ) were performed which were compatible with cnv.after three monthly intravitreal bevacizumab injections , sub - retinal hemorrhage and intraretinal fluid resolved , but subretinal scar remained without any visual acuity improvement.conclusionsit seems that cnv may occur after prk in myopic eyes . 
 also , refractive surgeons should consider cnv development in cases with visual compliant or metamorphopsia following prk . 
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