If the eyes are not open (assuming they are older than 10-14 days) then please wet and open (not forced open though) them ASAP. In my last litter, two of my babies didn't open one eye each. I didn't notice until too late and now they have both lost the sight in that eye. I have spent about £150 in vets bills, all might have been avoided if I had noticed the eyes earlier and ensure they were open and infection free. One bun might still have to have an operation yet to correct the eye shape.
If you need any info/pictures (they are not nice), then feel free to contact me.
Please, please, please ensure the eyes are open x x
edit: the best way, I found was using a wet cotton bud, running it along where the opening should be. The first few days, I was doing this, pretty much on the hour, every hour, as they wouldn't stay open because of the amount of 'gunk' that was behind the eye.