Vision deficiency

Color-order systems, such as the many MunseU collections available from Macbeth, have been described previously. Essential for visual color matching is a color-matching booth. A typical one, such as the Macbeth Spectrahte, may have available a filtered 7500 K incandescent source equivalent to north-sky daylight, 2300 K incandescent illumination as horizon sunlight, a cool-white fluorescent lamp at 4150 K, and an ultraviolet lamp. By using the various illuminants, singly or in combination, the effects of metamerism and fluorescence can readily be demonstrated and measured. Every user should be checked for color vision deficiencies. 

N-acetyl-camosine over trial periods of 2 and 6 months were reported to alleviate vision deficiency (lens opacity, visual acuity) associated with cataractogenesis, compared to placebo group. The improvements were sustained for 24 months (Barbizhayev, 2004, 2005). 

M. D Zmura, K. Knoblauch, M.-A. Henaff, and F. Michel, Dependence of Color on Context in Case of Critical Vision Deficiency. Vision Res., 38, 3455-3459 (1998). 

Figure 35-12 Farnsworth-Munsell 100-hue test results in three patients with differing digoxin serum levels (0, 0.74, and 3.97 ng/ml, respectively). Total error scores were 20,132, and 364, respectively. (Modified from Rietbrock N,Aiken RG. Color vision deficiencies a common sign of intoxication in chronically digoxin-treated patients. J Cardiovasc Pharmacol 1980 2 93-99.)...

Color vision deficiencies are probably the most sensitive indicator of early ethambutol optic neuropathy and can occur even before visual acuity and visual fields are affected. Sometimes, contrast sensitivity can be affected before either visual acuity or color vision becomes impaired. 

Lawrenson JG, Kelly C, Lawrenson AL, Birch J. Acquired colour vision deficiency in patients receiving digoxin maintenance therapy. Br J Ophthalmol 2002 86(11) 1259-61. 

Selection and training of appropriately qualified and motivated persons for participation in analytical panels is essential to effective performance. Individuals participating in panels in which colour judgements are involved should have been screened for colour vision deficiencies using Ishihara charts. However, other tests may be necessary for the optimal performance of certain... 

Vitamin A is probably best known for its role in maintaining normal vision. Deficiencies of the compound are likely to manifest themselves earliest in a variety of eye problems, most commonly night blindness. Night blindness is a condition in which one loses the ability to distinguish objects in reduced light. If left untreated, vitamin A deficiencies may lead to decreased ability to see in normal light and, eventually, to complete blindness. 

Approximately 8% of men and 0.4% of women perceive colors in significantly different ways from the remainder of the population. Most of this color-deficient vision is inherited, but some can be acquired as a result of pathology, illness, or old age. The most common inherited causes relate to deficiencies or absence of the p- or y-cones. The Ishihara charts may be used to detect the presence of such conditions. These charts consist of a number of plates made up of differently colored spots, which form numbers that may wrongly be described or not detected at all. This is a first screening for detection of a color vision deficiency. 

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