Acute Zonal Occult Outer Retinopathy (AZOOR) and Acute Idiopathic Blind Spot Enlargement Syndrome (AIBSE):

34-year-old female awoke with painless loss of vision OS 3 weeks prior to presentation

Acute Zonal Occult Outer Retinopathy (AZOOR) and Acute Idiopathic Blind Spot Enlargement Syndrome (AIBSE):

34-year-old female awoke with painless loss of vision OS 3 weeks prior to presentation

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Chief Complaint: 34-year-old female awoke with painless loss of vision OS 3 weeks prior to presentation.

History of Present Illness: She saw her local ophthalmologist immediately after the onset of vision loss. Her ophthalmologist noted 1+ vitreous cells, VF defect OS, and a head MRI was reported normal.  A diagnosis of retrobulbar optic neuritis was made. Her vision continued to decline. One week prior to our evaluation, she complained of photopsias x 1 week and a diffuse, frontal headache x 3 days.

PMH/FH/POH: Previously healthy without prior ocular surgeries or trauma. She is 5'7" and weighs 250 lbs.

EXAM

• Best corrected visual acuities: 20/15 OD and 20/60 OS.
• Pupils: 5 mm in dark, 3 mm in light, 1.5 LU RAPD OS
• IOP: 18 mmHg OD and 17 mmHg OS
• EOM: Full OU
• VF: See below.
• Anterior segment normal.
• DFE: melanocytoma OS; otherwise, normal macula, periphery, and vessels OU.

Figure 1: HVF

OS	OD
Enlarge blind spot with superior and inferior visual field (VF) loss. The VF loss does not respect the vertical midline; thus, this lesion is unlikely to be cortical.	Full VF OD.

Figure 2: GVF

OS	OD
Extensive superior & inferior VF loss around where the blind spot should be located. The VF loss does not respect the vertical midline. Constriction of I2e (red), I4e (blue), I3e (grey), and V4e (purple) isopters.	Full VF.

Figure 3: DFE

OD	OS
Normal optic nerve and macula.	Incidental melanocytoma and peripapillary choroidal nevus. No optic nerve edema. Macula normal.

Figure 4: Multifocal Electroretinogram (MERG)

OD	OS
OD Waveform	OS Waveform
Normal MERG OD.	Marked depression of retinal function OS.

Discussion

Our patient presented with: a normal optic nerve (except for the incidental finding of melanocytoma OS), normal dilated fundus exam, mild vitreous cells, decreased vision OS associated with RAPD, photopsias, headache, VF loss, and depression of retinal function OS illustrated by the MERG. Considering a normal MRI, age of the patient, and heavy stature of the patient, we felt that the patient may have presented as an atypical pseudotumor cerebri. Without disc swelling, the diagnosis of pseudotumor cerebri is not typical. The patient had a spinal tap which demonstrated a normal opening pressure.

The other symptoms and clinical presentation in this patient is more typical for acute idiopathic blind spot enlargement (AIBSE) syndrome or acute zonal occult outer retinopathy (AZOOR). This led us to perform a MERG which demonstrated depression of retinal function OS and confirmed the diagnosis of AIBSE/AZOOR. Some will call this disease AIBSE but others will call it AZOOR when there are large areas of retina involved. Several clinicians believe that AIBSE and AZOOR fall in the spectrum of the white dot syndromes, which are idiopathic chorioretinal inflammatory diseases. Some have suggested that AIBSE and AZOOR are multiple evanescent white dot syndrome (MEWDS) without the dots. AIBSE and AZOOR are less aggressive than the other white dot syndromes, and many patients with AIBSE/AZOOR will recover vision.

Diagnosis: Acute Zonal Occult Outer Retinopathy (AZOOR) and Acute Idiopathic Blind Spot Enlargement Syndrome (AIBSE)

EPIDEMIOLOGY young women (30s) incidence unknown etiology: unknown	SIGNS Normal Exam (33%) RPE changes (26%) Optic disc edema (20%) Grayish peripapillary retina (15%) White/gray dots-MEWDS (15%) Chorioretinal scars (7%)
SYMPTOMS Photopsias (74%) RAPD (41%) Decreased vision (22%) Recurrent (20%) Bilateral presentation ( 15%) Headache (9%) Eye Pain (6%)	TREATMENT Follow the patient: 86% will improve 36% with residual photopsias 65% with residual large blind spot

Differential Diagnoses: White Dot Syndromes

• acute idiopathic blind spot enlargement (AIBSE) syndrome
• acute zonal occult outer retinopathy (AZOOR)
• multiple evanescent white dot syndrome (MEWDS)
• mutifocal choroiditis
• punctate inner choroidopathy
• acute posterior mutifocal placoid pigment epitheliopathy (APMPPE)
• serpiginous choroiditis
• Birdshot retinochoroidopathy (HLA-A29 associated in 95% of cases)
• Presumed ocular histoplasmosis syndrome (POHS)