I've been getting the same blurry purple lines on my iphone 5.
The first time I sent it to the service provider, they kept my phone for 10 days and dismissed the issue saying it is non-existent, and that I would have to show them 'proof' of the blurry lines issue. After a couple of days of receiving it back from the service provider, I got the blurry lines again, and this time I managed to capture a photo of it.
I sent the phone back to the service provider with the photo, but now they've dismissed this issue saying it is caused due to 'environmental' conditions, and therefore they cannot do anything about it or issue me a replacement phone.
I'm extremely frustrated and don't know what to do about this.
Very disappointing and shameful service from Apple!