Changes in Optical Coherence Tomography Findings in Acute Zonal Occult Outer Retinopathy

Abstract

Purpose: To report a case of acute zonal occult outer retinopathy (AZOOR) in a 39-year-old woman. Methods: Images were obtained with fundus photography and optical coherence tomography (OCT). A multifocal electroretinogram (mfERG) was also obtained to evaluate retinal function. Results: The patient's right visual acuity was 0.8. Fundus photographs showed no specific abnormal findings. OCT showed attenuation of the photoreceptor inner segment/outer segment (IS/OS) line and the cone outer segment tip (COST) line in the right eye. The mfERG showed corresponding amplitude reductions. One month after the initial visit, her right visual acuity improved to 1.2. There was partial recovery of the IS/OS line; however, the COST line was still absent, and there was no apparent improvement in the mfERG responses. Conclusions: Our findings showed a discrepancy between the microstructural findings and visual function during recovery of AZOOR.

From A… to… Z(OOR): The Clinical Spectrum of Acute Zonal Occult Outer Retinopathy

“…12 Abnormalities of the cone outer segment tip (COST) line have been reported in AZOOR. 13 COST line has been recognised in SD-OCT images as a thin, highly reflective line between the IS/OS junction and the RPE. 14 The characteristic features described in the recent original investigation by Mrejen et al included a demarcating line of the progression at the level of the outer retina and a trizonal pattern of sequential involvement of the outer retina, RPE and choroid, as well as frequent zonal progression.…”

Acute zonal occult outer retinopathy complex disease: Lessons learned about choroid, photoreceptors, and retinal function

“…A discrepancy between microstructural findings and retinal function recovery has been reported but in that case, there was a partial restoration of the EZ but no improvement of the visual function. 11 It has been also reported that damaged human photoreceptor outer segments are capable, under certain circumstances, of spontaneous regeneration. 17 The cellular events underlying this gradual regeneration are still poorly understood.…”

“…Characteristic SD-OCT findings in AZOOR include disruption or loss of the EZ, attenuation or loss of the outer nuclear layer (ONL) and/or the external limiting membrane, irregularity of the RPE such as the abnormalities or absence of the interdigitation zone (IDZ) or the cone outer segment tip (COST) line, and decreased retinal thickness. 9–11 All these abnormalities are probably due to the impairment of photoreceptors, although the mechanism of vision loss in AZOOR patients remain unclear. Mrejen et al proposed a classification of AZOOR complex disease based on clinical fundus and modern multimodal imaging, including SD-OCT, FAF, FA and ICG.…”

“…14 Also, the IDZ can be still absent even when the EZ is recovered during the follow up in AZOOR patients. 11,15 If the IDZ can be used to detect and follow the abnormalities of the outer retina in AZOOR, the ONL is thought to be useful in predicting the recovery of the scotoma in the eyes of AZOOR patients. In fact, the recovery of visual field loss and the restoration of the EZ are possible only if the ONL is intact.…”

Three “Red Lines” for Pattern Recognition-Based Differential Diagnosis Using Optical Coherence Tomography in Clinical Practice

“…The large blind spot syndromes include the Acute Zonal Occult Outer Retinopathy (AZOOR) (39). The OCT features in AZOOR are well-recognized and consist of disruption of the inner outer segment and changes on autofluorescence (40,41). For OCT research, AZOOR provides a model for the study of acquired anterior axonal degeneration in the retina that starts distal to the INL.…”