Yes, a person with undiagnosed/untreated sleep apnea might sleep for what seems like a long time because their sleep isn't restful. No matter how much sleep they get, it isn't enough because they aren't getting enough (or any) quality sleep.

I don't understand your second question. I have sleep apnea and I'm not aware that my eyes look any different than anyone else's nor has it ever been discussed in my 20+ years of CPAP treatment.