Anna University, with Sankara Nethralaya, has developed a device that can check vision without any assistance from the patient.
This, researchers say, will particularly benefit preverbal children and people with cognitive disabilities who cannot participate in conventional vision tests that require them to say if they can see the image or read letters / numbers on the chart.
Now, all a child needs to do is to look at the stimulus monitor with different patterns and the system picks up brain-generated visual evoked potential (VEP) through electrodes attached to his / her head.
“The monitor shows visual patterns that are large in the beginning. The patterns get smaller and smaller during the procedure. For each pattern, the brain generates a signal and size of the pattern is correlated with the vision.
Based on the VEP’s magnitude for mentioned patterns, problems in vision are detected,” said S Shenbaga Devi, professor in the department of electronics and communication at Anna University and lead researcher of the project.
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“The main challenges are developing patterns to evoke VEP, the signal acquisition and extraction. Because of these technical difficulties, no electrophysiological system is currently from India,” she said.
Dr Parveen Sen, a retina specialist from Sankara Nethralaya and clinical investigator for the project, said the technology was not new. “Large electro physiological machines currently in use are expensive and have other functions. This is a standalone machine which does only one function. It is smaller and easy to use, portable and cheap,” she said.
Some children are born with genetic diseases, while others have some other problems. “Since they cannot communicate during a conventional vision test, procedures like physiotherapy and vision enhancement can be initiated if the problem in vision is diagnosed,” she added.
“If young children have a problem with the vision and it is not corrected at that stage, the vision can be permanently impaired,” said Dr Ronnie George, research director, Sankara Nethralaya.
The project is funded by technology development and transfer division of department of science and technology (DST) and Appasamy Associates is involved in bringing the final industry prototype. “After further validation tests, the device will be out soon,” Prof Shenbaga Devi said.
