Clinical analysis of spectral-domain optical coherence tomography imaging in the diagnosis and follow-up of acute zonal occult outer retinopathy

Abstract

Objective To investigate the clinical manifestations and spectral-domain optical coherence tomography (SD-OCT) imaging features of acute zonal occult outer retinopahy (AZOOR) and to explore the role of SD-OCT in the diagnosis and follow-up of AZOOR.Methods Retrospective analysis of clinical data of 52 cases (66 eyes) who were diagnosed through comprehensive eye examinations including best corrected visual acuity,fundus exam,OCT,electroretinogram (ERG),fluorescein angiography (FFA) and indocyanine green angiography (ICGA).Results A total of 52 cases of AZOOR (66 eyes) were collected.The majority of patients complained of blurred vision,photopsia and acute onset of a scotoma.In this group,24 cases (28 eyes) with normal fundus were defined as AZOOR type Ⅰ,while the other 28 cases (38 eyes) with fundus changes were AZOOR type Ⅱ,including 9 eyes of multiple evanescent white dot syndrome (MEWDS),25 eyes of punctate inner choroidopathy (PIC),4 eyes of multifocal choroiditis (MC).All type Ⅰ cases went through visual field,ERG and OCT tests.The most common visual field defect was central and paracentral scotoma,which was seen in 15 eyes (53.6％).Nine eyes (32.1％) presented with blind spot enlargement or even associated with other visual field defects.Four eyes (14.3 ％) showed scattered scotoma.In the series of 24 type Ⅰ cases (28 eyes),12 eyes (42.9％) demonstrated depressed scotopic and photopic amplitudes,and nine eyes only yielded reduced scotopic amplitudes,while seven eyes showed normal.All OCT showed an absence of both the inner and outer segment (IS/OS) line,and (or) the cone outer segment tip (COST) line between the IS/OS line and RPE.Many grey-white or yellowish white punctuate lesion of different sizes were found in posterior pole of the fundus in all of type] AZOOR which were more obvious in FFA.The manifestations of OCT showed IS/OS irregularity or absence in the area corresponding to the lesions.At final follow up from 15 days to two years,the IS/OS line became discernible in 13 of 24 type Ⅰ cases got discernible IS/OS line,while it was still absent in the other 11 case.During one to two month follow up period,nine eyes of MEWDS and four eyes of MC showed the presence of the a continuous IS/OS line in their OCT images after treatment,but there is no significant change for 25 eyes of PIC.Conclusions OCT showed abnormalities in the microstructures of the outer retina,e.g.,IS/OS line.The high resolution of OCT images has allowed better evaluations of the intraretinal IS/OS line in AZOOR,which presented a significant correlation with different stage in the course of AZOOR.In conclusions,OCT plays an important role in the diagnosis and follow up in AZOOR. Key words: Retinal diseases/diagnosis; Disease attributes; Tomography, optical coherence