It's so small it can’t be seen with the naked eye, but research is showing that CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) is bringing sight to the blind.

UC San Diego researchers are using CRISPR, a technology that allows scientists to edit genomes, to cure disease.

For the last two years, Ophthalmologist Dr. Kang Zhang and UC San Diego researchers have been working with CRISPR, injecting CRISPR into the eyes of mice to cure retinitis pigmentosa – a genetic form of blindness. “What we've seen in mice is that we can bring back actually 30 percent of vision sometimes even 50 percent of vision,” Dr. Zhang told NBC 7.

Retinitis pigmentosa is a genetic mutation in the DNA, and if a scientist can identify the mutation they can use CRISPR to fix it. It's worked in his tests with monkeys too, so the lab just got the green light for human trials as early as the fall.

Dr. Zhang describes CRISPR as a guided missile. Scientists use Guide RNA to send CRISPR to the part of the mutated DNA code, and it releases an enzyme which is like the bomb that wipes out and replaces the mutation.

“Obviously we want to be cautious,” he advised. “Safety is our primary concern.”

If the trial goes well, the ceiling for CRISPR is sky high. “In principle, CRISPR can be applied to all human genetic diseases. We have over 6,000 genetic diseases,” he explained.

However, there are concerns over the role CRISPR could play in the ethical debate around genetic engineering. With genetic diseases, Dr. Zhang says he sees no problem.

“I think it's going to be much more of an ethical debate if we start thinking about editing the embryo,” he said, “where we completely change the genetic makeup of genetic material that can be transferred to the next generation.