Progressive cone dystrophy (CD) is usually marked in the initial stages by reduced visual acuity, color vision deficiency and alterations in the photopic electroretinogram, while morphological alterations can be very mild; in some forms rods are affected in a later stage as well. We examined 40 patients with progressive cone dystrophy to determine the extent of functional losses in the cone sys...

PURPOSE Normal color vision depends on normal long wavelength (L), middle wavelength (M), and short wavelength sensitive (S) cones. Hereditary "red-green" color vision deficiency (CVD) is due to a shift in peak sensitivity or lack of L or M cones. Hereditary S cone CVD is rare but can be acquired as an early sign of disease. Current tests detect CVD but few diagnose type or severity, critical f...

It is evident that color vision evolved to inform organisms about their environment and thus must be shaped by the environment the organism is in. The color properties of the world are a potent factor affecting not only the basic mechanisms of color vision within a species but also how they are calibrated and fine-tuned within the individual. As a result, many aspects of the physiology of color...

The HRR pseudoisochromatic plate (pip) test was originally designed as a screening and diagnostic test for color vision deficiencies. The original HRR test is now long out of print. We evaluate here the new 4th edition of the HRR test, produced in 2002 by Richmond Products. The 2002 edition was compared to the original 1955 edition for a group of subjects with normal color vision and a group wh...

purpose: to evaluate the effect of levodopa-carbidopa on improvement of visual acuity, color vision, and visual field in patients with nonarteritic anterior ischemic optic neuropathy (naion) with onset less than 6 wks. methods: in this double-blind randomized controlled trial, 13 patients were treated with levodopa-carbidopa and 12 patients were treated with placebo for 3 weeks. after 6 months,...