Abstract

Although it is known that the onset of miners' nystagmus is related to the age of the worker, the nature of the relationship is difficult to determine from clinical data. An attempt has been made to clarify this relationship by the use of animal subjects. Thirty-five cats of ages ranging from 1 to 41 weeks were kept in darkness and examined regularly for oscillation of the eyeballs. The rate at which the amplitude of oscillations increased appeared to be a logarithmic function of the age at which the animal was placed in darkness. This result is discussed in relation to the mechanisms involved in the disease. A second important finding is that every animal tested developed detectable oscillations. It is suggested that the same would be true of man, given sufficient exposure to conditions of low illumination. This raises more acutely the question why incapacity resulting from the disease is found in only a minority of miners, and is not clearly related to the severity of the visual disorder.