<em><strong>Objective:</strong></em> To determine the behavior in corneal thickness during 30 days using high and low lens transmissibility (Dk/t). <em><strong>Materials and methods:</strong></em> 26 eyes of 13 non contact lens wearers were studied. On the right eye, a high Dk lens was adapted, lotrafilcon A and in the left eye a low Dk lens, vasurfilcon A, for 30 days in daily use. Before adaptation, the corneal thickness was measured with the Oculus Pentacam, the test was repeated on the first day within 4 and 8 hours and then within 3, 8, 15, 20, 25 and 30 days. In each control, the corneal thickness was measured after 6 hours of use. The Anova test was used, as well as the Student’s t test and the Pearson correlation coefficient. <em><strong>Results:</strong></em> During daily use for 30 days with lotrafilcon A, significant differences (p<0.05) in edema (0.76 ± 2.05 %) were found within 8 days of use. With vasurfilcon A, increment occurred after 4 hours of use, being statistically significant (p<0.05), edema (1.27 ± 1.64) within 3 days of use. anova showed significant differences (p<0.05) in the percentage of edema during the month ofuse of each type of lens, but not in the intergroup variance (p>0.05). <em><strong>Conclusion:</strong></em> The lotrafilcon A and vasurfilcon A lenses in daily use did not induce significant changes in corneal thickness, with edemas lower than 2 %.

Dry eye may be caused by working environment due to exposition to temperatures and flying particles, such as wood. A Schirmer test 1 wsa done before and after the working day to a sample of 40 male patients between 20 and 50 years old at the company Maderas Pinares divided in two groups of 20 workers each. The first group who was in direct contact with the predisposition factor, and the second group who was not to be considered as control group. It was found that environment pollution in the workplace has an accumulative influence on the quantity of lachrymal film in exposed workers and it also has a strong repercussion at the end of the working week in both groups with a value t =1.01 of signification. Based on the Murube questionnaire it was founf that an 80% of workers exposed to the risk factor present symptoms of dry eye and the non exposed group was a 55%.