Naphthalene cataract

Skin or eye surface contact may result in naphthalene cataracts, ocular irritation, skin irritation, and in the case of a sensitized person, severe dermatitis. Topical lesions will clear spontaneously, as soon as the exposure is terminated. 

M. Kojima, Enzyme distribution pattern of rats lenses and changes during naphthalene cataract development. Ophthalmic Res 24 73 (1987). 

Kojima, M., 1992, Enzymatic distribution patterns of rat lenses and the changes that occur during naphthalene cataract development, Ophthalmic Res. 24, 73 - 82. 

To demonstrate the effect of Phakan treatment on the development of naphthalene cataracts in rats, the cortical peak heights from all Scheimpflug images was evaluated, because the cortex is the site of zonular cataract formation in this model. Immediately after enucleation, the wet weights of the lenses were determined. Thereafter, the lenses were frozen-sectioned and the crystallin patterns analyzed by lEF (Bours and Ahrend, 1992). 

The densitometric data from Scheimpflug photography did not demonstrate any positive effect of the compound on the development of the naphthalene cataract, neither with pretreatment nore with the double dosage of Phakan. ... 

The lens wet weights (LWW) of the naphthalene-cataractous lenses were 27.23 0.71mg (in groups 2 - 4) and those of the normal lenses 27.30 0.65mg (Group 1). 

A--------A the naphthalene-cataractous lens, treated twice a day with Phakan, ... 

The Brown-Norway rat is the animal of choice to induce naphthalene cataracts in rats. The association of eye pigmentation and the presence of phenol oxidase in pigmented animals, contrary to its absence in albino rats, is the reason that naphthalene cataracts develop fast and regular in BN rats, as compared to albino rats (Murano et al., 1993). 

Our results concerning the effects of Phakan in the posterior cortex of the lens are in agreement with the data of Kojima (1994, this volume). He could demonstrate that drug penetration is highest in the posterior cortex of the lens, if the administration is per oral route. A beneficial effect of Phakan on the anterior cortex of the lens might have been found during earlier stages of naphthalene cataract development. 

Bours, J., Ahrend, M.H.J.iThe effect of Phakan treatment on the crystallin composition of the naphthalene-cataractous rat lens. Abstract, 32th AER Congress, Arhus (DK). 

Murano, H., Kojima, M., Sasaki, K. Differences in naphthalene cataract formation between albino and pigmented rat eyes. Ophthalmic Res. 25 16 (1993). 

Selzer, M., Wegener, A., Hockwin, O., 1991, Regional enzyme profiles in rabbit lenses with early stages of naphthalene cataract. Lens and Eye Toxicity Research 8(4), 415 - 430. 

Rainbow trout exposed to naphthalene in surrounding water accumulate this hydrocarbon in eyes (14). The retention (including bioconversion products) may be related to observed morphological changes, such as cataract formation, which occurs in marine fish exposed to individual hydrocarbons ()8) and petroleum (19). Roubal et al. (20) have demonstrated that gills of salmonids are major sites forHischarging naphthalene, which implies that the more water-soluble hydrocarbons in general are cleared via this route. 

Toxicology. Naphthalene is a hemolytic agent and an irritant of the eyes it may cause cataracts. 

Naphthalene may adversely affect the eye, causing cortical cataracts and retinal degeneration.11 These affects are attributed to the naphthalene dihydrodiol metabolite (see the product of reaction 13.6.3). 

Acute ingestion of naphthalene by rabbits produced effects similar to those observed in humans. Rabbits fed acute doses of naphthalene presented browning of the lenses and eye humors and developed cataracts. In contrast to humans, where the major target organ of toxicity is the blood and eyes, for rats and mice the major target organ of toxicity is the lung. 

Oral administration of 1 g kg day in rabbits leads to lenticular changes, initially observed as swelling in the peripheral portion of the lens. Within 2 weeks, the whole lens is affected with mature cataract. The biochemical basis for cataract has been shown to be related to a liver metabolite of naphthalene, l,2-dihydro-l,2-dihydoxynaphthalene. 

Reports of adverse effects following chronic naphthalene exposure include the development of cataracts and retinal hemorrhage in a 44-year-old man occupationally exposed to powdered naphthalene. Unilateral chorioretinitis was reported for a coworker and cataracts developed in 8 of 21 workers exposed to naphthalene fumes or dust for 5 years in an industrial setting. Chronic exposure to powdered naphthalene in the workplace has been associated with an increased incidence of cataracts. However, few of these effects have been confirmed in animal studies. 

Naphthalene (CAS 91-20-3) Highly Irn tating to eyes upon direct contact. Vapors are Irritating to eyes and may cause cataracts upon chronic exposure. Dermally well absorbed. May induce methemoglobinemia (see p 261). Symptoms of overexposure include headache and nausea. See also p 275. 

Tao, R.V., Holleschau, A.N., Rathbun, W.B. Naphthalene-induced cataract in the rat. II. Contrasting effects of two aldose reductase inhibitors on glutathione and glutathione redox enzymes. Ophthalmic Res 23 272 (1991). 

The observation that naphthalene feeding produced cataracts in rabbits suggested a relationship between mercapturic acid formation and sulfur amino acid metabolism in mammals, In the period between World Wars I and II, most advances in the biochemistrj of mei capturic acids were made through study of tlie nutritional effects produced by mercapturic acid precursors. During this period, the concept of mercapturic acids as... 

---