Lower Vertical Meridian Research Articles

Relative red-green sensitivity as a function of retinal position.

Hue cancellation was employed to obtain sensitivity curves for red and for green by the method of constant stimuli. Data were taken at the fovea, and at points every 2 deg along the lower vertical meridian of the visual field. The results show that sensitivity to red, relative to green, is highest at the fovea, and decreases as the peripheral angle is increased. The relative sensitivity to green is highest in the near periphery, from 2 to 10 deg from the fovea. Beyond this point it falls rapidly, and is no longer measurable at positions where red responses are still obtained.

Nature of the limit of the color zone in perimetry.

Blue and yellow outer color zones on the lower vertical meridian were measured in a Goldmann spherical projection perimeter using three different techniques and four observers.The limits of the color zones are not smooth but show irregular peaks and dips and do not have sharp cutoffs in sensitivity. The peaks and dips are reliable for any given observer, although they do not correspond between observers.The method of constant stimuli, the method of limits, and the clinical one-directional technique were compared. The method of constant stimuli is the most reliable method and it gives the most information about the shape and size of the color gradient.