Modeling the Interaction Between Blur and Automobile Tinting Films on Vision.

MARTIN, ANDRÉS; BARRIONUEVO, PABLO A.; SANTILLÁN, JAVIER; NANO, MARIA EUGENIA; LANSINGH, VAN; COLOMBO, ELISA

Fort Lauderdale

Congreso; ARVO 2010; 2010

The Association for Research in Vision and Ophtalmology

Purpose:In many countries it has became popular to darken the side and rear car windows by tinted films. It is done despite that, generally, countries laws ban drivers from getting dark the windows bellow a 70% transmittance. Possibly it is the lack of a precise knowledge linking the effect of window tinting to driver’s vision what enables its widespread use. In order to contribute with some evidence about this relevant link, we present here a series of measurements in which Contrast Sensitivity Function (CSF) was used to characterize the human visual system. Since it is known that many people have undetected refractive problems, we also measured the CSF for different blur degrees. Looking to make some predictions, we fitted to the data the Barten’s model (Barten, 2004) Methods:CSF was measured on 10 young observers with normal vision (VA 20/20 or above) under 3 window’s tint conditions and 4 different blur degrees. The tint conditions were: None (control), Middle and Dark (82%, 42% and 7% transmittance respectively) and the blur were equivalent to +0.5, +1, +1.5, and +2 diopters. The CSF was set at 1, 2, 4, 8 and 12 cycles per degree of visual angle. We also measured 5 young myopic observers Results: without blur, a car window with 7% transmittance significantly reduces the CSF at the spatial frequencies of 4, 8 and 12 c/deg while the Middle tinted window didn’t distinguish from control. For blur cases above +0.5 diopters, the results showed a significant CS reduction at higher spatial frequencies for all tinted conditions. The results also showed that the combined effect of tint and blur makes the CS to decay quickly. Conclusions: Model fits explains, on average, more than 90% of data. The myopic data also were well fitted by the model. A potential application of this research is to advice on futures regulations about tinting films for automobile windows.