Evaluation of the Relationship between Color Vision and Blood Lead Concentration at Koushk Lead and Zinc Mine Employees in Bafgh City

This study was performed to determine the color vision and blood lead concentration in Koushk lead and zinc mine employees.
This cross-sectional study was carried out at Koushk lead and zinc mine in Bafgh city. All participants were male. They were divided into two groups: The exposed groups (114 patients) and the non-exposed groups (76 patients). According to the exclusion criteria, 190 subjects recruited for the study with complete satisfaction. A preliminary optometric examination and evolution of color vision were performed for all subjects. Color vision was determined using the D15-Fransworth test. The concentration of blood lead was recorded based on the blood test sheet.
Percentage frequency of the color vision defect was 2.72% in the control group and 11.55% in the case group. The difference between the average of color confusion index between the two groups both in the right eye (case: 1.169 ± 0.283, control: 1.07 ± 0.17) and the left eye (case: 1.168 ± 0.282, control: 1.06±0.14) was statistically significant (right eye p=0.011, left eye p=0.002). Mean blood lead in case and control groups were 10.07 ± 15.81 and 6.46 ± 9.03, respectively. This difference was statistically significant between two groups (P = 0.047).
The difference between groups in the color vision defect indicates that long-term exposure to minerals in the lead and zinc mine may cause color vision defect and could be a potential cause of this disorder.