Do you have google analytics installed so that you can determine how long people are staying on your site and from what page they are leaving? If you don't have that installed you should do so. Having 600+ visitors a day that don't convert or even add to cart definitely signals some type of issue. From just looking at the site quickly I didn't notice any major errors, but that doesn't mean there might not be one that something like analytics picks up. I do see a couple of smaller things.
After staring for a few minutes, I did notice the slideshow banner photo is odd. It looks like it says designer made eye wear, but if you look closely there is a black logo hidden in there that says "retro eyewear?" It's really hard to see. The shipping policy is very broad. It says:
"Please allow between 7-45 days for your order to arrive. If more than 45 days have passed please email us to review the status of your order. Refunds will be handled through email if necessary."
So that means I might get my item anywhere from 1 to almost 7 weeks or maybe not at all and you will have to refund. Even when I add to cart and try to go through the checkout process, it doesn't give me any shipping estimated time whatsoever. It doesn't even tell me which carrier you are using so I would get an idea that way. That would turn me off completely as customer.
If you are drop shipping from China, for example, you could still give a better idea. Like e-packet from China to US typically takes 10-20 days. In some cases can take up to 45 days. So I would say something on the site like this for example, "Shipping to united states typically takes 10-20 days. Occasionally postal hold ups outside of our control can occur. Therefore, if you for some reason haven't received your package within 45 days you should contact us right away."