Electrophysiology has been used as a tool for the examination of the basic mechanism of flicker and fusion. The classical studies based on the electroretinogram indicated that the important feature that determines fusion in the cone-dominated retina is the inhibition of the retina caused by each successive light flash, inhibition being indicated by the a-wave of the electroretinogram. In the rod-dominated retina—e.g., in man under scotopic conditions— the a-wave is not prominent, and fusion depends simply on the tendency for the excitatory response to a flash to persist, the inhibitory effects of a succeeding stimulus being small. More modern methods of analysis, in which the discharges in single ganglion cells in response to repeated flashes are measured, have defined fairly precisely the nature of fusion, which, so far as the retinal message is concerned, is a condition in which the record from the ganglion cell becomes identical with the record observed in the ganglion cell during spontaneous discharge during constant illumination.
A-horizontal-cross-section-of-the-human-eye-showing-theA horizontal cross section of the human eye, showing the major parts of the eye, including the …[Credits : Encyclopædia Britannica, Inc.]
Horizontal-section-of-the-eyeFigure 1: Horizontal section of the eye.[Credits : Encyclopædia Britannica, Inc.]
Structure-of-the-retinaStructure of the retina
Muscles-of-the-right-eyeMuscles of the right eye
Myopia-or-nearsightedness-can-be-corrected-with-glasses-that-haveMyopia, or nearsightedness, can be corrected with glasses that have concave lenses to allow near …[Credits : Encyclopædia Britannica, Inc.]
Hyperopia-or-farsightedness-can-be-corrected-with-glasses-that-containHyperopia, or farsightedness, can be corrected with glasses that contain convex lenses to reduce …[Credits : Encyclopædia Britannica, Inc.]
Visual-pathwaysVisual pathways
Perimeter-chart-showing-normal-visual-field-figures-on-the-perimeterFigure 2: Perimeter chart showing normal visual field; figures on the perimeter indicate degrees of …[Credits : Encyclopædia Britannica, Inc.]
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