Abstract
Purpose: :
To evaluate the relationship between central retinal function evaluated with multifocal electroretinography (mfERG), visual field test and fundus autoflurescence displayed in rod-cone dystrophy (RCD) patients with good visual acuity (minimum 20/40).
Methods: :
Twenty-two patients with a clinical diagnosis of RCD and a perifoveal ring of autofluorescence were selected. Local macular function was assessed with mfERG, performed according to the ISCEV (International Society for Clinical Electrophysiology of Vision) standards, and visual field using Goldmann kinetic perimetry. Fundus autofluorescence (FAF) imaging was achieved using a Heildelberg Retina Angiograph 2 (HRA2). To analyze the size inside the ring of abnormal FAF, we chose either the average of the horizontal and vertical diameters of the autofluorescence ring by measuring the distance from the four medial points (superior, inferior, nasal and temporal) of the ring, or calculated the ring surface.
Results: :
Central macular function is preserved as documented by MfERG and visual field in correlation with the size of increased autofluorescence ring. The diameter of the high density ring, as well as its surface, correlates highly with mfERG P1 amplitude (diameter, r=0.74; surface, r=0.76). The size of the isopter III1 is also correlated with the ring surface (r=0.73). Interestingly, there is a higher correlation between the diameter of the ring and the isopter III1 (r=0.82).
Conclusions: :
The size of the perifoveal ring of high density autofluorescence in RCD patients with good visual acuity is correlated with preserved macular central function. This suggests preservation of the Retinal Pigment Epithelium/Photoreceptor complex and its metabolism. It confirms the value of FAF, an objective, non-invasive and fast technique, to monitor the course of the disease in patients with RCD and good visual acuity in particular to assess efficiency of future therapies.
Keywords: retinal degenerations: hereditary • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • clinical research methodology