Glasswing butterfly’s transparent wings inspire eye implants, can save glaucoma patients vision some day

Glaucoma is a group of eye diseases which can cause in damage to optic nerve and result in vision loss. Inspired by small structures on transparent butterfly wings, scientists have developed a manipulating surface which promises to ease the lives of glaucoma patients.

The research published in the journal Nature Nanotechnology stated that the wings of a glasswing butterfly (Greta Oro) were perfectly transparent as light could pass through them.

The sections of glasswing butterfly’s wings are coated in tiny pillars, which average only 100 nanometres in diameter and are spaced about 150 nanometres apart; as per the findings by the researchers at California Institute of Technology (Caltech).

Interestingly, the size of these pillars is 50 to 100 times smaller than the width of a human hair, which gives them unusual optical properties.

The pillars are able to redirect the light which strikes the wings so that rays pass through regardless of the direction. This means, there is almost no reflection of light from the surface of the wing.

This redirection property, which is known as angle-independent antireflection, caught the attention of Hyuck Choo.

Choo, who is an assistant professor at Caltech, has been trying to develop an eye implant which could improve the monitoring of intra-eye pressure in people suffering from glaucoma.

Though the exact mechanism by which glaucoma damages eyesight of a person is still under study, the leading theory has suggested that sudden spikes in the pressure inside the eye can cause damage to the optic nerve.

Medication is beneficial to reduce the sudden spike in eye pressure and can prevent damage, however, it must be taken during the first signs of increased eye pressure.

Hyuck has developed an eye implant which is shaped like a tiny drum and has the width of few stands of human hair.

When implant is inserted into a human eye, its surface moulds with the increasing eye pressure, thus narrowing the depth of the cavity inside the tiny drum.

As a matter of fact, one can measure the depth by a hand-held reader, which gives a direct measurement of the pressure the implant is under.

The implant, though is quite useful, but it has one weakness. The accurate measurement can be only taken when the angle between the optical reader and sensor is almost perfectly perpendicular, i.e. 90 degrees. In case of other angles, the risk of false reading increases.  

According to researchers, this is where the glasswing butterflies come into handy.

Choo stated that the angle- independent optical property of Greta Oro’s nanopillars could be used so that the light would pass perpendicularly through the implant. This would make the implant angle-sensitive and also provide an accurate reading regardless of how the reader is held.

(With agency inputs)