1) Materials and methods In order to investigate the human eye affected by photochemical
smog, epidemiological examinations were carried out 7 times during two summer
seasons. The subjects studied were students who belonged to a senior high school in the
southwestern area of Tokyo. The numbers of subjects were from 43 to 28 as shown in
Table 4 and all subjects were 16 or 17 years old. On a typical summer afternoon between
1 and 4 o'clock prone to photochemical smog, each of examined items were performed,
which consisted of the concentration of oxidant at the testing place, eye irritation, the tear
lysozyme value, the tear pH and the slit-lamp examination (only in 1976).