First Author: L.Price UK
Co Author(s): R. Rosa G. Palexas
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To raise awareness of the rare condition known as AZOOR and to propose a link between autologous bone marrow transplant and AZOOR, suggesting an immune component to the pathogenesis.
Ophthalmology department at North Middlesex University (District General) Hospital in Central London, UK.
Case notes were retrospectively reviewed between June 2015 and August 2016 to obtain a full medical history and clinical examination findings including dilated fundoscopy and LogMAR visual acuity testing. Investigations included colour fundus photography, Humphrey 24-2 visual field testing, spectral domain optical coherence tomography (SD-OCT) and fundus autofluoresecence (FAF) imaging. Electrophysiologic testing was performed at Moorfields Eye Hospital. Written patient consent was obtained and records were fully anonymised.
A 33-year-old caucasian lady reported a general reduction of vision and nyctalopia over several months. Past history included acute myeloid leukaemia at age 13, successfully treated with total body irradiation and autologous bone marrow transplant (BMT). Initial examination revealed: best-corrected visual acuity (BCVA) of LogMAR 0.20 OU, no anterior chamber inflammation OU, IOP 12 mmHg OU, bilateral posterior subcapsular cataracts. Fundoscopy revealed bilateral peripheral inactive multifocal choroiditis with retinal arteriolar attenuation, bilateral peripapillary atrophy and no vitritis. Bilateral cataract extractions with intraocular lens implantation were performed with BCVA unchanged. Subsequent investigation showed reduced colour vision (2/17 Ishihara plates OU). Humphrey 24-2 visual field testing revealed generalized constriction with focal peripheral depression OS and peripheral inferotemporal depression with an enlarged blind spot OD. SD-OCT imaging showed generalised outer nuclear layer attenuation and focal RPE attenuation (ellipsoid and interdigitation layer disruption) with foveal sparing OU and epiretinal membranes OU. FAF imaging showed numerous focal areas of decreased FAF with surrounding increased FAF and relative sparing of both maculae. Electrophysiological testing revealed marked generalised retinal dysfunction affecting rods more than cones OS greater than OD. No evidence of optic nerve dysfunction was present.
The bilateral posterior subcapsular cataracts secondary to total body irradiation twenty years prior were presumed to be the cause of decreased vision. Further investigations were undertaken once cataract surgery failed to improve vision. The fundoscopic features in this case, including focal chorioretinal atrophy, peripapillary atrophy and retinal arterial attenuation were suggestive of AZOOR. Investigations consistent with AZOOR included SD-OCT showing ellipsoid and interdigitation layer atrophy and FAF showing hypoautofluorescent areas of RPE atrophy. Electrophysiologic testing disclosed asymmetrical generalised dysfunction at the level of the photoreceptors. Visual field testing demonstrated variable scotomata with blind spot enlargement, the most common defect. The aetiology of AZOOR remains unknown and it is classified as part of the 'white dot syndromes'. An autoimmune mechanism is proposed, particularly as young females are predominantly affected. This patient underwent previous immune modulation therapy. We postulate that this may have rendered her more susceptible to AZOOR, but the underlying mechanism remains unknown.