Visual fatigue in reading microfilms.
D000328:Adult; D005128:Eye Diseases / Q000209:etiology; D005221:Fatigue / Q000209:etiology; D005260:Female; D006261:Headache / Q000209:etiology; D006801:Humans; D008029:Lighting; D008843:Microfilming; D008875:Middle Aged; D011932:Reading; D013997:Time Factors