Effects on Vision

Ocular Effects. Vision was blurred in 15 of the 23 workers examined as a result of intermediate-or chronic-duration inhalation exposures to high blood concentrations (in excess of 2 pg/L) of chlordecone during its production. The effects on vision were characterized by a disruption of ocular motility following a horizontal saccade by rapid random multidirectional eye movements. Visual acuity and smooth eye movements were unaffected (Taylor 1982, 1985). The rapid eye movements were probably due to disturbance of the brain stem. 

Like many volatile halocarbons and other hydrocarbons, inhalation exposure to carbon tetrachloride leads to rapid depression of the central nervous system. Because of its narcotic properties, carbon tetrachloride was used briefly as an anesthetic in humans, but its use was discontinued because it was less efficacious and more toxic than other anesthetics available (Hardin 1954 Stevens and Forster 1953). Depending on exposure levels, common signs of central nervous system effects include headache, giddiness, weakness, lethargy, and stupor (Cohen 1957 Stevens and Forster 1953 Stewart and Witts 1944). Effects on vision (restricted peripheral vision, amblyopia) have been observed in some cases (e.g., Johnstone 1948 Smyth et al. 1936 Wrtschafter 1933), but not in others (e.g., Stewart and Wtts 1944). In several fatal cases, microscopic examination of brain tissue taken at autopsy revealed focal areas of fatty degeneration and necrosis, usually associated with congestion of cerebral blood vessels (Ashe and Sailer 1942 Cohen 1957 Stevens and Forster 1953). 

Apart from the effects on vision, most of the effects of vitamin A deficiency (Section 2.4) involve derangements of cell proliferation and differentiation (squamous metaplasia and keratinization of epithelia), dedifferentiation, and loss of ciliated epithelia. Retinoic acid has both a general role in growth and a specific morphogenic role in development and tissue differentiation. These functions are the result of genomic actions, modulating gene expression by activation of nuclear receptors. Both deficiency and excess of retinoic acid cause severe developmental abnormalities. 

Arndt CF, Salle M, Derambure PH, Defoort-Dhellemmes S, Hache JC. The effect on vision of associated treatments in patients taking vigabatrin carbamazepine versus valproate. Epilepsia 2002 43(8) 812-17. 

Overall, PDT with verteporfin had no short-term effect on vision, with a mean change at week 1 of +0.7 line. Substantial vision improvement of three or more lines was noted in a small number of patients (14%) at week 1. The mean change in visual acuity at week 4 was +0.2 line and -0.5 line at week 12. There was a small but statistically significant difference in the mean visual acuity change at week 4 between... 

Santonin (137), a potent anthelmintic, has been used to treat ascaridiasis and oxyuriasis, but several cases of fatal poisoning by santonin have been reported. Small doses may produce effects on vision, cause headache, nausea and vomiting, and higher doses, epileptiform convul-... 

CHRONIC HEALTH RISKS may have effects on vision, nervous system, skin (hair), heart, and gastrointestinal tract possibly causes toxic effects upon human reproduction. 

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