Ocular toxicity, humans

Offord EA, Sharif NA, Mace K, Tromvoukis Y, Spillare EA, Avanti O, Howe WE, Pfeifer AM. Immortalized human corneal epithelial cells for ocular toxicity and inflammation studies. Invest Ophthalmol Vis Sci 40 1091-1101 (1999). 

Ocular damaging and irritant agents can be identified and evaluated by the Draize rabbit test [114]. However, more recently this test has been criticized on the basis of ethical considerations and unreliable prognosis of human response. Alternative methods such as the evaluation of toxicity on ocular cell cultures have been recommended and are being indicated as promising prognostic tools [115-120]. Direct confocal microscopic analysis [121], hydration level of isolated corneas [122], and various other tests on isolated corneas or animal eyes have also been proposed for evaluation of ocular toxic effects. 

The eye irritation test is probably the most criticized by advocates of animal rights and animal welfare, primarily because it is inhumane. It has also been criticized on narrower scientific grounds in that both concentration and volumes used are unrealistically high, and that the results, because of high variability and the greater sensitivity of the rabbit eye, may not be applicable to humans. It is clear, however, that because of great significance of visual impairment, tests for ocular toxicity will continue. 

Although dermal exposure is potentially important as a route of exposure around hazardous waste sites, the limited data on dermal/ocular toxicity do not permit a complete evaluation of the toxic potential of the tin compounds by this route. Skin and eye irritation and dermatitis have been observed in both humans and animals after acute and intermediate exposure to inorganic tin or organotin compounds. None of the compounds appear to cause dermal sensitization in humans or animals. 

White Phosphorus. There is limited information on the ocular toxicity of white phosphoms. Ocular effects were not reported in humans or animals following inhalation exposure. Very few human studies reported ocular effects following acute ingestion of white phosphoms. 

Carcinogenicity 2-year rat inhalation study Other intravenous and intratracheal studies in rats and monkeys blood and serum compatability (human and monkey), ocular toxicity... 

This test uses the eyes of a live animal, preferentially rabbits, to obtain information of the possible ocular toxicity of various chemicals. This test is most closely related to the human situation where these chemicals will later be used as ocular drugs or cosmetics or where the human eye might be exposed accidentally to these substances. This is a classical test developed about 60 years ago (Draize et al. 1944). 

The eyes of the rabbit differ in certain aspects from the eyes of humans. They are more sensitive, have a lower tear production and blink frequency and posses a nictitating membrane. Nevertheless, the Draize test predicts human ocular toxicity correctly in 85 % cases but overestimates in 10% and underestimates in 5 % (Gad and Chengelis 1991). In addition, ethical concerns have been raised in the use of animals and benefit vs risk of these tests for the protection of the human eye must be carefully evaluated. 

SAFETY PROFILE Poison by ingestion, inhalation, skin contact, intraperitoneal, intravenous, subcutaneous, and ocular routes. Human systemic effects by ingestion a cholinesterase inhibitor. Has been found to inhibit peripheral cholinesterase without pronounced effects on the central nervous system. An insecticide. When heated to decomposition it emits toxic fumes of NO and POx. See also PARATHION and ANHYDRIDES. 

The toxic properties of methanol are the result of accumulation of the formate intermediate in the blood and tissues of exposed individuals. Formate accumulation produces metabolic acidosis leading to the characteristic ocular toxicity (blindness) observed in human methanol poisonings. 

Iodate is generally considered to be an important component of the human diet, as it is rapidly reduced to iodide in the body and iodide is essential for thyroid function (Burgi et ai, 2001). However, high levels of iodate (>600 mg/day) have been shown to cause damage to the retina, resulting in ocular toxicity (Burgi et ai, 2001). 

Considerable inference has been made from melanin binding to ocular toxicity. Analysis of the data by Leblanc et al. (1998) indicates that in aU cases, there are no direct consequences of drug-melanin binding. Any drug-related toxicity of the retina in humans and animals was described... 

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