The earlier and more accurate the diagnosis, the better, as it means more time for treatment and symptom management, and often a diagnosis gives people with a far better understanding of themselves.

Criteria to be diagnosed are required for many mental disorders. There are no tests that can identify what's happening. There is new research suggesting that an eye test could be a quicker and more reliable way to detect these conditions.

Scientists have been able to use a test called an ERG, which measures the electrical activity of the retina in response to light, to detect different patterns of activity in people with attention deficit disorder

The most common disorders diagnosed in children are ADD and ADHD. Making diagnoses for both conditions can be long and difficult.

We aim to improve this. We hope to develop more accurate and earlier diagnoses for different neurological conditions by exploring how signals in the retina respond to light.

A total of 226 kids were included in the research, with 55 of them having an eating disorder and 15 of them having an attention deficit disorder. Children with attention deficit disorder had higher overall ERG energy, while those with attention deficit disorder had lower ERG energy.

The researchers suggest that differences in the way the brains of people with attention deficit disorder and other disorders are wired can be seen in the eyes. Studies have shown how the eyes can tell what's going on in the brain.

This is the first study of its kind. The results show that patterns of eye behavior could be used to differentiate between the two disorders.

"Retinal signals have specific nerves that generate them, so if we can identify these differences and localize them to specific pathways that use different chemical signals that are also used in the brain, then we can show distinct differences for children with ADHD and possibly other neurological conditions."

The way that kids interact with the world and communicate with other people can be affected by the condition.

Between 5 and 8 children are thought to be affected by attention deficit disorder. It is characterized by being overly active, struggling to control impulsive actions, and having trouble concentrating.

There are effective treatments to manage the two disorders. It will be necessary to conduct further research to find out how the signals in the eye differ between people with and without these conditions.

Fernando Marmolejo-Ramos is a cognitive psychologist from the University of South Australia. As it happens, the eyes could reveal all, so it is truly a case of watching this space.

It has been published in a journal.