Structural and Functional Imaging of the Eye in Disruptive Inner and Outer Segment Disease

Abstract

Purpose: : To describe novel findings in 3 patients with retinal disease using multifocal electroretinogram (mfERG) for functional assessment and the scanning laser ophthalmoscope/optical coherence tomography (SLO/OCT) for retinal micro-structure. In 2 patients these techniques were combined (multimodal imaging).

Methods: : Three patients with presumptive diagnoses of multiple evanescent white dot syndrome (MEWDS), acute macular neuropathy and acute zonal occult outer retinopathy (AZOOR) have had multiple, serial investigations over two years. These have included amsler grid assessment, goldmann visual fields, mfERG, SLO/OCT (and combined with mfERG using an organic light emitting diode, OLED) and fundus photography.

Results: : There was clinical, functional and structural correspondence at multiple stages of each syndrome unlike other retinal diseases. In the patient with MEWDS there was initially sub-retinal fluid at the optic disc on SLO/OCT that corresponded to an enlarged blind spot and delayed implicit time on mfERG. This fluid then tracked to the macula on SLO/OCT, white dots were visualised and there was reduced amplitude and delays in macular function on mfERG. The area of white dots expanded with a larger sector of reduced function on mfERG. There was eventual resolution of fundus, OCT/SLO and mfERG changes indicating the transient nature of MEWDS. In the patient with acute macular neuropathy there was disruption of outer nuclear layer and junction between inner and outer segments on SLO/OCT corresponding to abnormal amsler readings. In the patient with AZOOR there was loss of photoreceptor signal on SLO/OCT corresponding to visual field defects and delayed implicit time on mfERG.

Conclusions: : New techniques are available that can allow greater understanding of structural and functional changes in retinal disease.

Keywords: retina: distal (photoreceptors, horizontal cells, bipolar cells) • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • electrophysiology: clinical