In addition to explosions and other dangers, there were also a number of diseases that you could contract while working underground. One of them was ‘eye jitters’ (medical term: nystagmus), an eye disease associated with the use of safety lights. It is a condition where the eyeball moves back and forth at high speed. (p. 61)
It is believed that in the decades leading up to World War II, at least five percent of all Western European miners suffered from ‘eye jitters’. (p. 81)
There were several theories at the time about the cause of this eye disease. The most prevailing were: 'On the one hand it was caused by fatigue in the muscle that lifted the eyeball due to the constant gazing upwards when one is drilling coal’. ‘On the other hand it was due to the poor lighting in the mines combined with the weak light reflection from the layers of coal’. Ultimately, the second theory gained the most supporters at the time, making ‘the safety lamp’ the major culprit where the eye condition nystagmus was concerned. (p. 62)
Today scientists are still investigating ‘eye jitters’(nystagmus). It is without a doubt that the poor lighting conditions in the mines caused it. It could not be proven that the introduction of the safety lamp is to blame for the increase of ‘eye jitters’. (p. 81)
In addition to ‘eye jitters’, there were numerous other work-related illnesses. The best known is dust lung disease (Latin: silicosis). When drilling in the rock layers, fine particles of rock dust were released into the air. That dust was inhaled and lodged in the alveoli (tiny air sacs at the end of the bronchioles), causing inflammation and the formation of scar tissue. With the development of silicosis, the lung volume decreases. Breathing becomes difficult and therefore the oxygen intake becomes less.
In addition to silicosis, due to the physically demanding work in tight spaces, many miners had back problems, such as a hernia and bursitis of the knee, which is caused by crawling.
In the early mining period, there was also a parasite that could settle in the miner's intestines. This condition known as hookworm (medical term: Ancylostoma duodenale) was able to spread easily due to the warm and humid working conditions in the mines.
Peter Kerklaan: Blinded warriors on the coal front. Illness due to 'eye jitters’ was a pre-war stressor among miners, in: Journal of Social and Economic History, year 2005, volume 2, issue 1; Pages: 59 - 83