People always say they wouldn't cover a slave's eyes due to her expressiveness....normally, I agree, however consider that without her speech the only way she can influence her fate is with her looks so taking that last bit of 'control ' away from her will push her the last bit into a deeper subspace where you can meet the true girl under all the modern programming society has put into her.
That is a very, very pretty girl. I don't think I'd ever cover up those expressive eyes of hers. I wouldn't let her keep her clothes on, either. Now that she's been rendered helpless and is completely in his power, what next?