surgery is required to reattach the retina in most eyes with rhegmatogenous retinal detachment ( rrd ) . if the interval from onset to surgery is too long or if reattachment can not be achieved , serious visual impairment can result , with blindness occurring in the worst cases . vitrectomy is sometimes required , especially for rrd involving the macular region ( macula - off rrd ) . however , even when reattachment of the retina is achieved , postoperative visual impairment is generally unavoidable , and the visual outcome varies from case to case .   in recent years , the structure of the retina has been clarified owing to advances in optical coherence tomography ( oct ) , and various reports have been published concerning factors that determine the visual outcome after retinopexy in patients with rrd [ 16 ] . in this study , determinants of the visual outcome were investigated retrospectively by spectral domain oct in eyes with macula - off rrd that underwent surgical reattachment of the retinal . the subjects were 26 patients ( 26 eyes ) who underwent surgery after the diagnosis of macula - off rrd at the department of ophthalmology of juntendo university , shizuoka hospital between april 2010 and november 2011 . in these patients , reattachment of the retina was achieved by initial surgery , and postoperative followup was continued for at least 6 months . patients with other macular diseases or with the complication of proliferative vitreoretinopathy were excluded from this study . vitrectomy was performed in 19 patients ( 19 eyes ) , while scleral buckling was done in 7 patients ( 7 eyes ) . the day of onset was defined as the day when the patient became aware of a visual field defect or visual impairment . visual acuity data was done after transformation ; the data were converted to logarithm of the minimum angle of resolution ( logmar ) values . preoperative hrd was measured by hd - oct ( cirrus : manufactured by zeiss ) , preoperative retinal architecture , and postoperative elm and is / os junction continuity.based on the data obtained by these examinations , the following 6 parameters were investigated : relationship between the duration of retinal detachment and postoperative visual acuity , relationship between the preoperative hrd and preoperative / postoperative visual acuity , relationship between the time until the resolution of retinal detachment at the fovea ( hrd = 0 ) and postoperative visual acuity , investigation of the preoperative structure of the retina and comparison between eyes with a normal retinal architecture and eyes with edema of the outer nuclear layer , relationship of postoperative visual acuity to postoperative is / os junction continuity , relationship of postoperative visual acuity to postoperative is / os junction and elm continuity . relationship between the duration of retinal detachment and postoperative visual acuity , relationship between the preoperative hrd and preoperative / postoperative visual acuity , relationship between the time until the resolution of retinal detachment at the fovea ( hrd = 0 ) and postoperative visual acuity , investigation of the preoperative structure of the retina and comparison between eyes with a normal retinal architecture and eyes with edema of the outer nuclear layer , relationship of postoperative visual acuity to postoperative is / os junction continuity , relationship of postoperative visual acuity to postoperative is / os junction and elm continuity . statistical analysis was performed by the mann - whitney u test , and differences of p < 0.05 were considered significant . the subjects were 19 men ( 19 eyes ) and 7 women ( 7 eyes ) with a mean age of 50.7  15.6 years ( range : 28 to 72 years ) . the mean follow - up period was 11 months ( range : 6 to 28 months ) . the mean logmar visual acuity was 0.66  0.67 before surgery and 0.32  0.42 6 months after surgery . the mean interval from onset to surgery was 23.2 days ( range : 3 to 120 days ) . the logmar visual acuity 6 months after surgery was 0.27    0.38 for 12 patients in whom this interval was 10 days and 0.45  0.49 for 14 patients in whom this interval was 11 days . the visual outcome showed no significant difference in relation to the interval from onset to surgery . the mean preoperative hrd of all cases was 561  521  m ( range : 76 to 1,704  m ) . table 1 shows the relationship between preoperative hrd and visual acuity . in 7 eyes with a preoperative hrd 1,000  m , the mean logmar visual acuity was 1.54  0.50 before surgery and 0.70  0.36 after surgery . in 19 eyes with an hrd < 1,000  m , the mean logmar visual acuity was 0.65  0.67 before surgery and 0.25  0.38 after surgery . the mean preoperative visual acuity and the visual acuity 6 months after surgery showed a significant difference between the hrd  1,000  m and hrd < 1,000  m groups ( p < 0.05 , mann - whitney u - test ) . there were no significant differences in the mean age between hrd  1,000  m and hrd < 1,000  m groups .   figure 1 shows the typical oct findings . the mean logmar visual acuity 6 months postoperatively was 0.12  0.23 for 16 eyes ( vitreous surgery : 14 eyes , scleral buckling : 2 eyes ) in which foveal detachment was resolved within 3 months after surgery , while it was 0.51  0.48 for 10 eyes ( vitreous surgery : 4 eyes , scleral buckling : 6 eye ) in which detachment persisted for 3 months and more . the visual acuity 6 months postoperatively was significantly better when foveal detachment resolved within 3 months after surgery than when it persisted for 3 months or more after surgery ( p < 0.01 ) . foveal detachment persisted for 3 months or more in 4 eyes ( 25% ) after vitrectomy and in 6 eyes ( 75% ) after scleral buckling . the subjects were divided into 2 groups based on the preoperative retinal architecture , that is , group 1 with a normal retinal architecture and group 2 with edema affecting the outer nuclear layer of the retina . the mean age of the subjects was 35  12.7 years in group 1 and 56  12.1 years in group 2 . the mean preoperative logmar visual acuity was 0.17  0.17 in group 1 and 1.08  0.71 in group 2 , while the mean logmar visual acuity 6 months after surgery was 0.06  0.20 for group 1 and 0.44  0.45 for group 2 . the mean age , preoperative visual acuity , and visual acuity 6 months after surgery showed significant differences between group 1 and group 2 ( p < 0.01 ) . table 3 shows the relationship between the presence of is / os junction continuity 3 and 6 months after surgery and the visual acuity 6 months after surgery , while figure 3 displays typical examples . the visual acuity 6 months postoperatively was 0.07  0.14 for 11 eyes that showed is / os junction continuity both 3 and 6 months after surgery , while it was 0.12    0.11 for 5 eyes in which is / os junction continuity was not noted 3 months after surgery but was observed at 6 months . the visual acuity 6 months postoperatively was 0.77  0.42 for 9 eyes without is / os junction continuity both 3 and 6 months after surgery ; that is , postoperative visual acuity was significantly worse than that of eyes with is / os junction continuity both 3 and 6 months after surgery ( p < 0.01 ) . 
 table 4 shows the is / os junction and elm continuity 3 and 6 months postoperatively , as well as the mean logmar visual acuity 6 months after surgery . eyes without is / os junction continuity 3 months after surgery were classified into 2 groups based on the presence of elm continuity . the first group consisted of with elm continuity and the second group without elm continuity . is / os junction continuity was noted 6 months after surgery in 4 of 6 eyes with elm continuity ( 67% ) , and the logmar visual acuity was 0.22  0.25 6 months postoperatively . in contrast , is / os junction continuity was noted 6 months after surgery in only 1 of 9 eyes without elm continuity ( 12% ) , and the logmar visual acuity was 0.88  0.36 6 months postoperatively . the visual outcome 6 months postoperatively was more favorable for the eyes with elm continuity 3 months after surgery than for the eyes without it ( p < 0.01 ) . oct has made it possible to estimate the visual outcome of retinal detachment surgery by analyzing postoperative morphologic changes of the photoreceptor cell layer of the retina . the preoperative visual acuity , duration of detachment , height of macular detachment [ 4 , 5 ] , and presence / absence of vitreous traction   have been reported as preoperative factors related to restoration of macular function after surgery for retinal detachment , while cystoid macular edema [ 3 , 7 ] , epimacular membrane , retinal wrinkles [ 5 , 8 ] , shifting of the retinal pigment epithelium , and subretinal fluid   have been reported as postoperative factors . it has been reported that recovery of visual function is possible when surgery is done within 1 week after the onset of retinal detachment . however , the logmar visual acuity 6 months after surgery showed no significant difference between our groups with an interval from onset to surgery before 10 days and 10 days and more . the incidence of postoperative residual retinal detachment affecting the macular region varies among surgical techniques . according to kambara et al . , it is 63% after transscleral surgery and only 13% after vitrectomy . in our series , postoperative subretinal fluid was noted in 86% after scleral buckling versus 33% after vitrectomy , so the incidence of postoperative residual subretinal fluid was higher after scleral buckling . chihara and nao - i   investigated subretinal fluid in 10 patients with fresh retinal detachment and reported that the fluid was absorbed within 23 hours if the lacuna was closed . postoperative subretinal fluid may be ascribable to disturbance of the choroidal circulation , but its cause is unknown . it has been reported by many researchers that prolonged retention of subretinal fluid is one of the causes of delayed restoration of visual acuity [ 5 , 12 ] . in this study , the visual acuity 6 months after surgery was also worse in the patients who had residual subretinal fluid for 3 months or more after surgery . according to hagimura et al . , the visual outcome becomes worse as the height of retinal detachment increases . we obtained similar results ; that is , the preoperative and postoperative visual acuity of eyes with a preoperative hrd  1,000  m was worse than the preoperative and 6-month postoperative visual acuity of eyes with a preoperative hrd < 1,000  m . it has been reported that structural abnormalities caused by retinal detachment are related to the visual outcome , and if there is retinal separation or a wavy external layer before surgery , the final visual acuity is unfavorable . in our series , the visual acuity 6 months after surgery was worse for the eyes with preoperative edema of the outer nuclear layer of the retina than for the eyes with a normal retinal architecture before surgery . reported that is / os junction disruption was noted in the reattached retina , while wakabayashi et al .   stated that the postoperative visual acuity of eyes with macular detachment was significantly correlated with is / os junction and elm defects . because the elm is the boundary between the external nuclear layer , which contains the nuclei of the photoreceptor cells , and the inner segment of the photoreceptor cell layer , it is suggested that elm and is / os junction defects may also influence the nuclei of the photoreceptor cells . this is supported by the report that apoptosis of photoreceptor cells and separation of the outer segment occur after experimental retinal detachment , while the outer segment regenerates after retinal reattachment . kawashima et al .   suggested that the improvement of vision after reattachment of the retina was correlated with a decrease of is / os junction disruption and that resolution of elm disruption was a prerequisite for restoration of the is / os junction . in our series , the visual acuity at 6 months postoperatively was better if there was is / os junction continuity at both 3 and 6 months after surgery than if this was not the case . in addition , the rate of achieving is / os junction continuity was higher , and the visual acuity 6 months postoperatively was better for the eyes with elm continuity 3 months after surgery .    in patients with macula - off retinal detachment , oct makes it possible to evaluate the preoperative retinal architecture and hrd , as well as the postoperative is / os junction and elm . thus , oct may be useful for estimating the visual outcome after surgery in such patients .
purpose . to evaluate morphologic changes of the macula , we observed eyes with rhegmatogenous retinal detachment ( rrd ) involving the macular region by optical coherence tomography ( oct ) . 
 subjects and methods . 
 we studied 26 eyes with rrd before and after surgery , assessing visual acuity , the height of retinal detachment at the fovea ( hrd ) , and morphologic changes of the macular region . 
 the interval between the onset and surgery was also determined . 
 we examined the external limiting membrane ( elm ) after surgery and the continuity of the inner segment - outer segment junction ( is / os junction ) of the photoreceptor layer . 
 results . 
 impairment of visual acuity was observed when hrd was over 1,000  m , when there was outer nuclear layer edema before surgery , and when there was is / os junction disruption 3 months after surgery . however , 67% of eyes with a continuous elm and is / os junction disruption 3 months after surgery eventually showed restoration of the continuity of is / os junction at 6 months . 
 conclusions . 
 impairment of visual acuity was observed in eyes with hrd > 1,000  m , preoperative outer nuclear layer edema , and is / os junction disruption 3 months postoperatively . 
 it is suggested that continuity of elm might affect restoration of is / os junction after surgery for retinal detachment .