[Foveal cone dystrophy: diagnostic ranking of the multifocal electroretinogram].
BACKGROUND
In case of visual loss without morphologic pathology differentiation between a functional visual loss and a retinal disorder may be difficult.


METHODS
We report on two women, aged 33 and 44, who were complaining of a progressive visual loss occurring over the past several weeks to months. They were referred to our department with the presumed diagnosis of functional visual loss. Biomicroscopy of the anterior and posterior segments, perimetry (Goldmann), colour (FM-100-Hue-Test) and stereopsis testing (Lang-Stereotest), fluorescein angiography (FLAG) and electrophysiological testing (P-ERG, VECP, EOG, multifocal electroretinography [mfERG]) were performed.


RESULTS
Visual acuity was 0.16 OU and 0.25 OU respectively. A small relative central scotoma (I/1) was detected by dynamic perimetry. Colour vision, random-dot stereopsis and the results of electrophysiological testing except multifocal electroretinography (mfERG) were normal. The mfERG was able to detect a cone dysfunction which was related to the fovea.


CONCLUSIONS
In case of visual loss of unknown etiology electrophysiological testing is indicated. The mfERG as an objective diagnostic method is able to detect a foveal cone dystrophy.
Hübsch
Simone
S
Augenklinik für Schielbehandlung und Neuroophthalmologie der Universitäts-Augenklinik, Giessen.
Gräf
Michael
M
D000328:Adult; D003937:Diagnosis, Differential; D018450:Disease Progression; D004596:Electroretinography; D005260:Female; D006801:Humans; D008268:Macular Degeneration / Q000175:diagnosis* / Q000503:physiopathology; D011237:Predictive Value of Tests; D017949:Retinal Cone Photoreceptor Cells / Q000503:physiopathology*; D014786:Vision Disorders / Q000175:diagnosis / Q000209:etiology*; D014787:Vision Tests; D014792:Visual Acuity / Q000502:physiology