Ultrasound Stimulates Retina; A New Non-Surgical Treatment to restore Vision Loss

 

According to a WHO (World Health Organization) report- Globally, it is estimated that approximately 1.3 billion people live with some form of distance or near vision impairment. With regards to distance vision, 188.5 million have mild vision impairment, 217 million have moderate to severe vision impairment, while 36 million people are blind. 

The leading causes of vision impairment and blindness are retinal degenerative diseases, the progressive degeneration of the light-sensitive photoreceptors in the retina, uncorrected refractive errors, diabetic retinopathy and cataracts. In such circumstances retinal surgery is suggested by ophthalmologists.

Scientists have been trying for decades to find perfect devices, tactics and procedures to restore vision to people living with blindness. But, there isn't a non-invasive treatment for the disorder yet, therefore, new technologies that can restore vision loss are still needed.

Now, a research team at the University of Southern California (USC) is developing a new treatment model that can stimulate retinal neurons with ultrasound waves.

With the increasing rate of elderly people around the world, age-related eye diseases and conditions are obvious, a “silver tsunami" is expected by experts, and in relation to this, it is not surprising that the number of people with visual impairment is also anticipated to surge.

From this new method of treatment of eye disease, the expectations of experts have increased positively.

"Right now, we are doing animal studies trying to use ultrasound stimulation to replace electric stimulation," said Qifa Zhou, a professor of biomedical engineering and ophthalmology at USC. Zhou also leads the study along with Mark S. Humayun, one of the inventors of Argus II, the world's first artificial retina.

The ultrasound stimulation system: Acoustic waves targeted at the retina excite the retinal neurons, which generate neural signals that are transmitted through the optic nerve to the brain. Brain activity is recorded using a multielectrode array inserted into the contralateral superior colliculus (SC) or visual cortex (VC). (Courtesy: CC BY 4.0/X Qian et al. BME Frontiers 10.34133/2022/9829316)

 

Stimulates the Retina,

In this treatment, a wearable ultrasound device will be provided, which will stimulate the retina by applying mechanical pressures on the eye, thereby activating the neurons and sending signals to the brain. Neurons in the retina of the eye have mechanically sensitive channels, which respond to mechanical stimulation. When ultrasound is used to generate mechanical pressure, these neurons are activated.

"The neurons present in the retina of the eye possess mechanically sensitive channels that respond to mechanical stimulation," said Gengxi Lu, who is a Ph.D. student in Zhou's lab. "These neurons are activated when we use ultrasound to generate mechanical pressure."

The study was published in the journal BME Frontiers.

Researchers used a blind rat for testing,

For this the researchers used a blind rat. High-frequency ultrasound waves were used to stimulate his eyes. They projected the pattern over a specific area of ​​the eye, but since the rat was unable to tell scientists what it was seeing, the team measured the activity of the rat's visual cortex using an electrode array. In the end, it turned out that the rats perceived the visualizations that were presented before the eyes.

The next step is testing the method on non-human primates and then adapting the ultrasound waves to a wearable contact lens. "Right now, we are using a transducer placed in front of the rat's eyeball to send the ultrasound signals to the retina, but our final goal is to create a wireless lens transducer," stated Dr. Zhou.

Vision loss can affect people of all ages. However, the majority of people with vision impairment and blindness are over the age of 50 years. While, many people are prone to retinal degenerative diseases. In this disease there is a progressive degeneration of the light-sensitive receptors in the retina. Retinal degeneration, which includes progressive deterioration and loss of photoreceptor function, is a leading cause of permanent vision loss worldwide. There is currently no non-invasive treatment available for this disorder, so new techniques that can prevent vision loss are still needed.

In such a situation, this ultrasound based noninvasive therapy can be a good solution in the easy treatment to restore vision. While the team is currently analyzing the capabilities of ultrasound technology for vision study, their future goal is to generate sharper images and install the ultrasound transducer on a wearable contact lens for next generation.

(Source: InterestingEngineering.Com)