Shutter eyeglasses to replace eyepatch in amblyopia

U.K: The Fraunhofer researchers have found a major breakthrough alternative which may replace the standard treatment for a so-called lazy eye (amblyopia) in children by developing electronic shutter eyeglasses that automatically darken the lens in front of the nonimpaired eye when the context is appropriate. These eyeglasses also have integrated sensors that provide young wearers with feedback on whether they are being worn in the correct position.

Amblyopia, also known as lazy eye, is a vision development disorder in which an eye fails to achieve normal visual acuity, even with prescription eyeglasses or contact lenses.

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The standard treatment for the so-called lazy eye (amblyopia) in children is to cover the nonimpaired eye with a patch. This trains the impaired eye to work harder. Such therapy is successful only when the patient wears the eyepatch for the prescribed period of time. But often this may not be the case as children feel uncomfortable about wearing the patch and reject this form of treatment.

The sooner treatment begins, the greater the chances of recovery. However, there are two main drawbacks to this form of occlusion therapy: vision is spatially restricted, and children often experience the eyepatch as unsightly and therefore refuse to wear it. Moreover, such treatment is successful only when the eyepatch is worn for the prescribed period of time.

The researchers hope that the new interactive, context-dependent shutter eyeglasses with sensor-based feedback will increase treatment compliance for this complaint. This new technology covers up the patient's good eye only when the situation is appropriate. During sport, for example, or other activities that demand good spatial vision, this function is deactivated so as to avoid any risk of an accident.

Researchers at Fraunhofer Institute for Biomedical Engineering IBMT have developed this new technology along with a smartphone app to enable parents to monitor the treatment. All the data generated by this technology is compiled in a digital patient file system, which was also developed by the IBMT team. This web-based application is compliant with data-protection laws and can be accessed by the ophthalmologist in order to monitor, adjust and enhance treatment.

Data for real-time processing is generated by various sensors. These include temperature and skin-contact sensors to monitor the length of time and the position in which the eyeglasses have been worn. They also measure the occlusion phases, during which the LCD lenses are darkened.

The eyeglass lenses are darkened by means of an electronically controlled shuttering system based on integrated liquid crystals. The frequency and duration of the occlusion therapy can be individually adjusted to each specific case. It is, therefore, more versatile than conventional eyepatch treatment.

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This will motivate young patients to wear the eyeglasses for the prescribed duration. The skin-contact sensors monitor whether the eyeglasses are being worn in the correct position and even provide the young wearer with child-friendly feedback. This can help increase acceptance for this form of therapy, too.

An acceleration sensor recognizes specific patterns of movement and can distinguish between different activities such as standing up, lying down, sitting down, walking, running, jumping, cycling and climbing stairs.

Fraunhofer researchers will be exhibiting a functional model of the electronic shutter eyeglasses at the MEDICA trade fair in Düsseldorf from November 12 to 15Initial tests with amblyopic children are scheduled for the second quarter of 2019. In addition, it is hoped that a validation study to be conducted toward the end of the project will confirm the medical benefits of the therapy.