focal choroidal excavation ( fce ) was first described by jampol et al1 as an anomalous excavation of the choroid ; it is typically observed by optical coherence tomography ( oct).1,2 this condition has been associated with several chorioretinal conditions and asymptomatic status , including central serous chorioretinopathy , choroidal neovascularization , and best vitelliform macular dystrophy.112 however , the mechanisms underlying the formation of fce remain uncertain .
wakabayashi et al2 described two patterns of fce : 1 ) conforming pattern  excavations that involved the outer retinal layers up to and including the external limiting membrane ; and 2 ) nonconforming pattern  excavations that involved only the retinal pigment epithelium ( rpe ) .
here we describe a clinical course of fce associated with vkh before and after treatment and compare the morphological findings of fce in four subjects with different chorioretinal conditions .
a 55-year - old man ( subject 1 ) presented with bilateral metamorphopsia , with decimal visual acuity being 0.8 in the right eye and 1.2 in the left .
the clinical diagnosis of vkh was made based on bilateral panuveitis and multifocal exudative retinal detachments at the posterior poles ( figure 1 ) .
the serous detachments entirely resolved within 9 weeks and visual acuity in the right eye improved to 1.2 .
serial spectral - domain oct ( sd - oct ) images obtained at the preuveitic , uveitic , and posttreatment phase are shown in figure 2 .
sd - oct obtained 1 year before the onset of vkh due to symptoms of a floater and visual disturbance demonstrated a dome - shaped posterior protrusion of the rpe and outer retinal layers into the choroidal cavity ( ie , conforming fce ) at the fovea in the right eye .
sd - oct at the uveitic phase identified multiple bilateral sensory retinal detachments , with the fce now involving only the rpe ( ie , nonconforming fce ) .
the fce pattern and its alteration during treatment of the case with vkh were compared to those of four subjects with fce associated with other chorioretinal conditions ( figure 3 ) .
this comparison group consisted of two patients with age - related macular degeneration ( amd ; subjects 2 and 3 ) , one subject with a macular hole ( mh ; subject 4 ) , and one asymptomatic individual ( subject 5 ) .
treatment with intravitreal ranibizumab injections and vitrectomy had been performed in the patients with amd and mh , respectively .
a conforming fce was observed in three patients ( subjects 2 , 3 , and 5 ) and pattern alteration from nonconforming to conforming fce was found after treatment in one subject ( subject 4 ) . in the two subjects with amd ,
a hyperreflective material around the fce was absorbed , resulting in a well - demarcated conforming fce after treatment .
a detailed clinical course of fce at the fovea was documented in a case with vkh disease .
sd - oct images obtained at the preuveitic , uveitic , and posttreatment phase suggested the preexistence of fce before the onset of vkh , and the fce pattern change ( from conforming to nonconforming pattern during the period of choroidal inflammation ) was observed during the follow - up .
the fce identified at the preuveitic phase in our case supported the congenital / acquired posterior pole malformation , as previously suggested.1,4,9,11,12 on the other hand , hashida et al13 speculated that a direct pressure effect on the choroidal layer by subretinal fibrin disrupted the choroidal integrity and focal choroidal atrophy / thinning following inflammation and resulted in a formation of fce in a case with vkh.4,7,13 although such a remarkable subretinal fibrin was not detected , the association between the fce formation and choroidal inflammation could not be excluded entirely in our case , considering other possible subclinical inflammatory events prior to this disease history .
an alteration of the fce pattern observed in vkh was also found in the comparison group with other chorioretinal conditions . in subject 4 with an mh ,
the nonconforming fce at presentation associated with vitreomacular traction changed to conforming fce after treatment . in two subjects with amd , a hyperreflective material around the fce
was observed to be absorbed , resulting in a well - demarcated conforming fce via treatment ( subjects 2 and 3 ) .
these findings suggest that the cavity within fce can be filled with subretinal fluid associated with inflammation and exudative material generated by choroidal neovascularization .
given the proximity between the fce and the active lesions , the involved retina around the active lesion may well show disorganization of retinal layers in the pathological process ; then the conforming pattern is hard to maintain , unsurprisingly .
in addition , it is possible that the cavity within fce may potentially accelerate the pathophysiological changes of chorioretinal disorders .
 we describe focal choroidal excavation ( fce ) in a case of vogt  koyanagi  harada ( vkh ) disease and compare the findings with different chorioretinal conditions . 
 a 55-year - old man was diagnosed with vkh based on panuveitis and exudative retinal detachments . 
 spectral - domain optical coherence tomography demonstrated a dome - shaped protrusion with a nonconforming pattern at the fovea , which had been detected as a conforming pattern 1 year before the onset . 
 the fce pattern returned into a conforming pattern following corticosteroid therapy . 
 these findings suggest that the natively existent fce could be affected by pathophysiological changes of vkh as well as other chorioretinal conditions . 
Introduction
Case report
Discussion