Right now there's not a medical test for autism. A diagnosis is based on observed behavior and psychological testing.

But a new piece of the autism diagnosis puzzle lies in the child's eyes.

"We found the pupil of a child with autism takes longer to react," Biological Engineer Xiaofei Fan said.

It's just a matter of about 30 milliseconds, much quicker than you'd ever notice, but still, pupillary light response, or PLR, is looking like a very reliable tool.

"By doing this test, predict by about 94 percent if the child is going to have autism or one of the typical developing children," Dr. Judith Miles Thompson from the Center for Autism said.

Besides sky rocketing autism rates in the U.S., family frustration is compounded by the limited and seemingly wishy washy ways a diagnosis comes about.

"There is no lab test you can do. There is no part in the brain that says this is how it's affected, this is exactly what it is," Miles explained.

Right now autism is often diagnosed through watching a child play. If this new research is put to good use, optical scans could offer doctors a new tool in diagnosing autism, much earlier, maybe before symptoms even begin. It's also less invasive and more objective.

The basics of the light response testing is a child with autism's eyes react more slowly and their pupils constrict less than other kids.

So far, that's just the facts, educated opinions aside.

And while it can't stand alone, figuring out a connection between the pupils, the brain and autism opens up all kinds of additional opportunities for treatment.

"We're able to put people into an MRI machine and track brain activity. We put them in an MRI machine and have them do different things. In this case, PLR and see which brain regions are reacting typically and a typically," Professor of Psychology Shawn Christ said.

The machinery that makes PLR tracking possible was developed by Gary Yao, not a medical doctor, but a biological engineer.

"This is a big problem ,so it would be better to get people from all different kinds of backgrounds together so we can find a better solution. That's my take on this," Professor of Biological Engineering Gary Yao said.

Each of the researchers interviewed were quick to mention this study group was pretty small, just 24 with autism were tested.

Also, they aren't looking to make this a one-step diagnosis for autism, but instead know it's going to be a really important additional tool in recognizing and treating autism.