Color discrimination

As above, except dose is 50 pg Pb/kg BW Rhesus monkey, Macaca mulatta Blood lead 154 pg/L (vs. 35 pg/L in controls), declining to 109 pg/L at day 150 postadministration. At age 3 years, group showed impaired color discrimination. No overt signs of toxicity, normal blood chemistry (except lead), normal growth and development skills 21... 

Laties, A.M., Ellis, P, and Mollon, J.D., The effects of sildenafil citrate (Viagra ) on color discrimination in volunteers and patients with erectile dysfunction, Inv. Ophthalmol. Vis. Sci., 40, S693, 1999. 

Visuai disturbances Single oral doses of phosphodiesterase inhibitors have demonstrated transient, dose-related impairment of color discrimination (blue/green), with peak effects near the time of peak plasma levels. The findings were most evident 1 hour after administration, diminishing but still present 6 hours after administration. 

The major toxicity associated with ethambutol use is retrobulbar neuritis impairing visual acuity and red-green color discrimination this side effect is dose related and reverses slowly once the drug is discontinued. Mild GI intolerance, allergic reaction, fever, dizziness, and mental confusion are also possible. Hyperuricemia is associated with ethambutol use due to a decreased renal excretion of urates gouty arthritis may result. 

Hypersensitivity to ethambutol is rare. The most common serious adverse event is retrobulbar neuritis, resulting in loss of visual acuity and red-green color blindness. This dose-related adverse effect is more likely to occur at dosages of 25 mg/kg/d continued for several months. At 15 mg/kg/d or less, visual disturbances are very rare. Periodic visual acuity testing is desirable if the 25 mg/kg/d dosage is used. Ethambutol is relatively contraindicated in children too young to permit assessment of visual acuity and red-green color discrimination. 

In the same manner, repeat the transfer and comparison procedure at accurately timed intervals until the a-amylase color is reached, at which time record the elapsed time. In cases where two comparisons 30 s apart show that one is darker and the other lighter than the Reference Color Standard, record the endpoint to the nearest quarter min. Shake out the 13-mm Comparator Tube between successive readings. Minimize slight differences in color discrimination between operators by using a prism attachment and by maintaining a 6- to 10-in. distance between the Comparator and the operator s eye. 

Color blind is a loose term because it implies a complete lack of ability to see color, and total color blindness is rare. Because color deficiencies do occur within the population, it is important to know this for individuals who are matching or evaluating color. The Farnsworth-Munsell 100-hue test is an excellent tool for both color discrimination and analysis of color vision defects. Because the observer is a significant variable in the color equation, it is important to understand their color vision capabilities. 

D. Farnsworth, The Farnsworth-Munsell 100-Hue Test for the Examination of Color Discrimination, Munsell Color, Macbeth, Division of Kollmorgen Instruments Corporation, New Windsor, NY, 1957. 

The effects of occupational exposure to organic solvents on color discrimination have been reviewed (22). Workers who have been exposed to styrene have subtle impairment of color discrimination compared with age-matched controls. The impairment generally tends to be of the tritan (blue-yellow) type, although some cases of... 

Baelumelal, 198S hu 1 100 390 100 1 sensory irritation, sleepiness, inwxication, decrcitsrrd manual dexterity and color discrimination... 

Dimenhydrinate altered color discrimination, night vision, reaction time, and stereopsis in healthy volunteers (1). 

Styrene exposures between 50 and 100 ppm have been associated with neurological effects including decrements in color discrimination, nerve conduction, and neurobehavioral performance. These changes appear to be transient, with improvement... 

Adverse Effects. Sildenafil is well tolerated in patients with normal cardiovascular function. Most of the side effects reported in the clinical trials at a higher rate than placebo are mild and are related to the drug s vasodi-latory effect. They include headache, flushing, and nasal congestion. Other frequent side effects include abnormal vision (impairment of color discrimination) and dyspepsia. The... 

Adams AJ, Brown B, Haegerstrom-Portnoy G, Horn MC (1976) Evidence for acute effects of alcohol and marijuana on color discrimination. Percept Psychophys 20 119-124... 

Sildenafil causes increased sensitivity to light, blurred vision, or loss of blue-green color discrimination in 3% to 10% of patients. This results from the agent s inhibition of phosphodiesterase type 6 in the photoreceptor cells in the retina, particularly at doses larger than... 

Ethambutol should not be given with antacids. The ethambutol dose should be reduced to three times per week in patients with renal failure. Retrobulbar neuritis is the major adverse effect. Patients may complain of a change in visual acuity, the inability to see the color green, or both. They should be monitored monthly while on the drug using Snellen wall charts for visual acuity and Ishihara red-green color discrimination cards. ... 

Raitta C, Teir H, Tolonen M, et al. 1981. Impaired color discrimination among viscose rayon workers exposed to carbon disulfide. JOM J Occup Med 23 189-192. 

Ocular toxicity due to ethambutol is dose-dependent and is usually reversible when the drug is discontinued. Thiamine is not protective. Periodic testing of visual acuity is advisable during treatment. Ethambutol is relatively contraindicated in children too young for assessment of their visual acuity and red-green color discrimination. The answer is (C). 

S.L. Merbs. J. Nathans. Molecular determinants of human red/green color discrimination. Neuron, 1992. 

In addition to so-called good concentrate samples exhibiting on-spec color, several formulations were also supplied in an off-spec form. These materials consisted of nominally identical formulations that had suffered minor weigh-up errors, contamination or insufficient pigment development during manufacture. They were thought to represent a realistic test for color discrimination trials. 

The fourth woman had a skin rash and red welts that had kept her away from direct contact with epoxy and styrene. She had abnormal color discrimination, decreased vibration sensation, a blind spot in the retina of the left eye and decreased recall of stories. She was the least impaired although her POMS score and symptom frequencies were increased. 

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