This is to do with the development of gene therapy to treat blindness. If the blindness is caused by a defective gene, it may be possible to replace the gene with new DNA. But it’s hard to insert DNA into cells in the body so people are studying new ways to do that.
An easy way to test if your method for getting DNA into cells (and particularly into the cell types that need to be repaired) is to test it using the DNA for a gene that codes for a fluorescent protein. People have cloned the gene for Green Fluorescent Protein (GFP) from jellyfish! If you can insert the GFP gene into a cell, the cell makes the protein and, under UV light, it will glow green: so it is easy to see if your experiment has worked.
So the rabbits you saw were probably part of a test like that. It looks a bit weird but it doesn’t hurt the rabbits.
Once you have your method working, you can use it for any DNA.
I’ve had a good look for this one, but I haven’t been able to track down the science you are talking about. It could be true – glowing “bioluminescent” protein (called GFP) is quite often engineered into laboratory animals to keep track of other genetic changes, so it is likely that this is an experiment aimed at addressing the genetic causes or treatments for blindness, but using GFP as a marker. I found a number of stories about an artist who has tried to attach himself to this or other serious science project and make a name for himself as “creator of glow in the dark bunnies”. Takes all sorts, I suppose.