retinal vein occlusion ( rvo ) is the most common primary retinal vascular disorder which can involve the central retinal or branch retinal veins [ 13 ] . macular edema ( me ) is the main cause of visual impairment in both branch retinal vein occlusion ( brvo ) and central retinal vein occlusion ( crvo ) . several therapies including laser photocoagulation , antivascular endothelial growth factor ( anti - vegf ) agents , and triamcinolone have been suggested for the treatment of me associated with rvo . recently , ozurdex ( allergan inc . , irvine , ca , usa ) , a new sustained - release intravitreal dexamethasone implant , has been demonstrated to be effective in the treatment of patients with rvo related me . ozurdex implant lowers the levels of many mediators that cause deterioration of blood - retina barrier , especially vegf , and decreases the vascular permeability . however , it has been shown to be associated with intraocular pressure ( iop ) elevation [ 811 ] . measurement of peripapillary retinal nerve fiber layer ( rnfl ) is used as a sensitive method for detecting early glaucomatous damage [ 12 , 13 ] . in glaucoma , peripapillary rnfl is affected before the other glaucoma signs such as optic disc excavation and visual field defects occur . although ozurdex implant has been found to cause iop elevation [ 811 ] , to the best of our knowledge , there is no study investigating the effect of this iop elevation on peripapillary rnfl thickness . therefore , in the present study , we aimed to evaluate the peripapillary rnfl thicknesses of patients treated with intravitreal ozurdex implant due to rvo related me . thirty - three eyes of 33 patients who were treated with ozurdex implant due to me associated with brvo , in kartal education and research hospital ophthalmology department , between november 2013 and june 2014 , were included in the study . patients with ocular hypertension , glaucoma , neovascularization in angle , peripheral or macular ischemia on fundus fluorescein angiography ( ffa ) , optic disc or peripapillary rnfl edema on optical coherence tomography ( oct ) , and a history of antiglaucomatous drug use , intravitreal or subtenon corticosteroid injection , vitreoretinal surgery , or trauma were excluded . the study was in accordance with the rules of the declaration of helsinki and the approval of the local ethics committee was obtained . all patients were informed about the study procedure and risks of the treatments and informed consents were obtained . each subject underwent a comprehensive ophthalmologic examination including determination of best corrected visual acuity ( bcva ) , measurement of iop by applanation tonometry ( same examiner ) , biomicroscopic evaluation , fundoscopy , gonioscopy , central macular thickness ( cmt ) and peripapillary rnfl assessment with oct , and ffa before the injection of ozurdex implant . bcva was measured in snellen decimals and converted to logarithm of the minimal angle of resolution ( log  mar ) for statistical analyses . ozurdex implant was injected to each eye intravitreally with its special applicator , from the pars plana region , in the operation room , under steril conditions . after the injection , topical antibiotics were given five times a day for one week . follow - up visits were performed on day 1 and months 1 , 2 , 3 , and 6 . iop was measured at day 1 , week 1 , and months 1 , 3 , and 6 visits . the average and the superior , inferior , nasal , and temporal quadrant peripapillary rnfl thicknesses were measured by using spectral domain oct . topical antiglaucomatous agents were started in patients who had iop  22  mmhg at any control visit . the mean age of the study population was 55.2  7.4 ( range : 4068 ) years . the bcvas were significantly increased and cmts were significantly decreased at month 3 and month 6 visits compared to baseline values . the mean iop was significantly increased from baseline at day 1 , week 1 , and month 1 visits ( p = 0.008 , p = 0.018 , and p = 0.022 , resp . ) . on the other hand , month the average and inferior quadrant peripapillary rnfl thicknesses were significantly reduced at month 6 control visit compared to baseline values ( both p < 0.001 ) . there was no significant differences between month 6 and baseline superior , nasal , and temporal quadrant rnfl thicknesses . we did not observe any other side effect that could be related to the injections such as endophthalmitis , cataract development , or increase of previously available cataract . our results displayed that although the bcva significantly increased and the cmt significantly decreased in eyes with me associated with brvo during the 6-month follow - up period after intravitreal injection of ozurdex implant , iop elevations occurred within the first month after the injection and the average and inferior quadrant rnfl thicknesses were reduced at month 6 control visit . ozurdex implant is a biodegradable polymer including 700  g of dexamethasone and polylactic acid - polygcolic acid . high concentrations occur within the first two months after the injection and then lower concentrations are seen after the third month . in the current study , the iop values were not higher than at baseline and at month 3 and month 6 control visits . however , it was significantly increased from baseline at day 1 , week 1 , and month 1 visits . previous studies have shown the steroid - induced iop increases after the intravitreal injection of ozurdex implant in the treatment of rvo related me [ 8 , 9 , 11 ] . in addition , some studies have found an association between the secondary glaucoma and ozurdex implant [ 10 , 17 ] . however , in none of those previous studies [ 811 , 17 ] peripapillary rnfl thicknesses of the patients have been evaluated . to our best notice , it is the first time in the literature we found the average and inferior quadrant rnfl thinning , despite use of topical antiglaucomatous agents in eyes with iop  22 , after the intravitreal injection of ozurdex implant in eyes with brvo related me . the pattern of rnfl thinning in glaucoma has the superior and inferior quadrant preference . in our study , inferior quadrant rnfl was significantly thinner at month 6 visit than at baseline ( p < 0.001 ) . in addition , superior quadrant rnfl had also thinning ; nevertheless , the difference could not reach the statistical significance ( p = 0.059 ) . accordingly , it can be said that the month 6 peripapillary rnfl profile of the eyes was consistent with glaucomatous injury . the rnfl thinning that was found in our patients could be due to the resolution of a brvo related peripapillary rnfl edema , after the injection of ozurdex implant . since rvo causes blood flow blockage , a diffuse type of retinal edema may affect all retinal layers . accordingly , swelling of the optic nerve head and the adjacent retinal tissue may affect oct analyses . all peripapillary rnfl values were inside normal limits according to the device 's data base before the injections . lu and zang   investigated the rnfl thicknesses of ischemic and nonischemic eyes with rvo and the fellow eyes . they found that retinal ischemia could cause rnfl defects , and the severity of those defects was correlated with the severity of ischemia . in our study , although we excluded the eyes with ischemia , we had not a control group to understand whether the rnfl thinning of our patients was due to the ozurdex related iop elevations or due to rvo related retinal ischemia . however , a control group including rvo patients treated with anti - vegf agents may be used in the future studies . in conclusion , our results demonstrated that ozurdex implant improved the bcva and reduced the cmt in the eyes with me associated with brvo . however , iop elevations occurred within the first month after the injection and the average and inferior quadrant rnfl thinning were found six months after the injection . on the other hand , it is not clear whether this rnfl thinning was caused by the ozurdex related iop elevations or brvo related retinal ischemia itself .
purpose . to evaluate the peripapillary retinal nerve fiber layer ( rnfl ) thicknesses of patients treated with intravitreal ozurdex implant due to branch retinal vein occlusion ( brvo ) related macular edema ( me ) . 
 methods . 
 thirty - three eyes of 33 patients treated with ozurdex implant due to me associated with brvo were included in the study . 
 ophthalmic examinations including determination of best corrected visual acuity ( bcva ) , measurement of intraocular pressure ( iop ) , and central macular thickness ( cmt ) and peripapillary rnfl assessment with optical coherence tomography ( oct ) were performed before the injection of ozurdex implant and during the 6-month follow - up period after the injection . 
 results . 
 the mean age was 55.2  7.4 ( range : 4068 ) years . 
 the bcvas were significantly increased and cmts were significantly decreased at month 3 and month 6 visits compared to baseline values . 
 the mean iop was significantly increased from baseline at day 1 , week 1 , and month 1 visits ( p1 = 0.008 , p2 = 0.018 , and p3 = 0.022 , resp . ) . 
 the average and inferior quadrant peripapillary rnfl thicknesses were significantly reduced at month 6 control visit compared to baseline values 
 ( both p < 0.001 ) . conclusions . 
 ozurdex implant improved the bcva and reduced the cmt in the eyes with rvo related me . 
 however , iop elevations occurred within the first month after the injection and the average and inferior quadrant rnfl thinning was found six months after the injection . 
 further controlled studies are warranted .