Assessment of Multifocal Electroretinogram Abnormalities and Their Relation to Morphologic Characteristics in Patients With Large Drusen

Abstract

To determine the extent of functional changes in the first-order kernel multifocal electroretinogram (mfERG) responses in patients with large drusen by means of a localized analysis and to determine correlations between mfERG responses and morphologic changes. Methods: Thirty-one eyes from 20 patients ages 58 to 84 years with large drusen (Ն5 drusen Ն63 µm diameter) were studied. The mfERGs were recorded with a stimulus of 103 hexagons and a flash intensity of 2.67 candela (cd)•s −1 •m −2. Each of the 103 single first-order kernel mfERG responses was analyzed and compared with those of age-matched healthy control subjects. Imaging studies, including color stereo fundus photography, red-free fundus photography, and fluorescein angiography, were performed in all patients, and morphologic changes (drusen in red-free fundus photography, staining or window defect in fluorescein angiography) were determined with a digital measurement tool. The mfERG responses were correlated to areas with and without morphologic changes. Results: Reduced responses were found in 10.0% (scalar products) and 4.0% (response densities) and delayed implicit times in 13.8% (N1), 18.9% (P1), and 23.8% (N2) of all mfERGs. Abnormal mfERG responses extended up to 25°in radius. Significant morphologicfunctional relations were detected in only a few patients. Abnormal mfERG variables were present in areas without morphologic changes. Conclusions: Patients with large drusen exhibit functional changes in the cone-driven pathways evaluated by the mfERG, indexed particularly by implicit times. Morphologically visible changes do not predict retinal function. Large drusen are associated with a more general retinal dysfunction.

Retinal function and PKC alpha expression after focal laser photocoagulation

“…Accordingly, when we measured the local retinal function in the laser treated area, we found a pathological response in the mfERG in the form of an increased latency at all 3 time points after surgery. Clinically, increased mfERG latency has been reported to be a sensitive indicator of macular disease [8,39]. The rabbit retina, however, does not include a macula, but instead a horizontally oriented visual streak where the cone concentration peaks at a mere 18000 cells/mm 2 [7].…”

Monitoring retinal function in early age-related maculopathy: visual performance after 1 year

“…Delayed latencies in the conemediated mfERG have been shown to be early indicators in ARM 14 and in other diseases such as diabetes and hereditary retinal conditions. 29,30,39 Han et al 30 demonstrated that new diabetic retinopathy was predicted by delayed latencies in an area without diabetic retinopathy a year before diabetic retinopathy developed.…”

“…[1][2][3][4][5][6][7][8][9][10][11] There have been several studies showing impairment of the photopic and scotopic pathways in early ARM subjects. 8,10,[12][13][14][15][16] Phipps et al 12 demonstrated an alteration of cone adaptational kinetics by measuring the post-bleaching recovery time to various contrast multiples. Falsini et al 13 showed altered temporal cone flicker sensitivity using the focal ERG and could discriminate between different degrees of ARM based upon funduscopic changes.…”

“…Falsini et al 13 showed altered temporal cone flicker sensitivity using the focal ERG and could discriminate between different degrees of ARM based upon funduscopic changes. Gerth et al 14 and Li et al 15 tested cone-mediated function with the multifocal electroretinogram (mfERG) in early ARM and found the latencies to be very sensitive for objective detection of functional impairment. Scholl et al 16 showed that retinal areas of increased fundus autofluorescence corresponding to drusen had a greater loss of scotopic rather than photopic sensitivity.…”

The Clinical Applications of Multifocal Electroretinography: A Systematic Review

“…14,54,56,57,72,91,110,122,151,152,167,172,228,248,258 Patients with early AMD were found to have significant reduction in the foveal P1 amplitude and delay in N1 implicit time compared with normal age-matched controls. 167 The extent of mfERG changes is influenced by the severity of AMD as patients with neovascular AMD had more severe reductions in mfERG response amplitudes and delays in implicit times compared with patients with dry AMD.…”