Regional cone-mediated dysfunction in age-related maculopathy evaluated by focal electroretinograms: relationship with retinal morphology and perimetric sensitivity.

Purpose: To assess regional cone-mediated function in agerelated\r\nmaculopathy (ARM) by focal electroretinograms\r\n(FERGs), and to compare FERGs with morphologic changes\r\nand perimetric sensitivity at corresponding locations. Methods:\r\nTwenty-six ARM patients and 12 age-matched controls\r\nwere evaluated. FERGs were elicited by either a central (0–\r\n2.25°, C) or a paracentral annular (2.25–9°, PC) flickering (41\r\nHz) field, presented on a light-adapting background. Morphological\r\nchanges (soft drusen and/or retinal pigment epithelium\r\ndefects) at matched locations were assessed by fundus\r\nphotography and fluorescein angiography. Perimetric\r\nsensitivity was measured by Octopus 10° program (tM2). Results:\r\nWhen compared to controls, mean C and PC FERG amplitudes\r\nof patients were reduced (p ! 0.01), and the mean\r\nPC FERG phase was delayed (p ! 0.01). Both FERG delays and\r\nmorphologic lesions tended to involve to a greater extent\r\nthe PC compared to the C region. In the C region, perimetric\r\nlosses were correlated with the extent of morphologic lesions\r\n(p ! 0.05). In the PC region, perimetric losses were correlated\r\nwith FERG amplitudes (p ! 0.05). Conclusions: In ARM, FERG losses are eccentricity-dependent, not quantitatively\r\nlinked to retinal morphology, and correlated with perimetric\r\nlosses, suggesting a heterogeneous dysfunction with\r\nloss of both C and PC perimetric sensitivities