New test to detect glaucoma can help prevent blindness

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Test to prevent glaucoma

A phenomenon that won C. V. Raman his physics Nobel Prize could revolutionise the diagnosis of glaucoma - by detecting it well in time for treatment.

Glaucoma is the second leading cause of vision loss and blindness worldwide.

A common chemistry lab technique called Raman spectroscopy could lead to a breakthrough in glaucoma detection, said Chenxu Yu of Iowa State University while speaking at the annual meeting of the American Chemical Society ( ACS) on Wednesday.

The new technique is based on a phenomenon called Raman Scattering or Raman Effect that explains the scattering of a photon ( a basic unit of light) and the gaining or losing of energy.

Raman won the 1930 Nobel Prize in physics for this finding.

Glaucoma is a group of eye disorders that can damage the optic nerve, which carries visual information from the eye to the brain. It usually occurs when fluid pressure inside the eye slowly increases over time. The fluid presses on the optic nerve and damages it.

The condition affects about 70 million people worldwide.

Glaucoma damages vision by stealth, with no obvious warning symptoms. And once it develops, it causes loss of vision.

Doctors currently use two main techniques to detect the disease. One is tonometry, which measures eye pressure by gently touching a special instrument to the outer surface of the eye.

The other is ophthalmoscopy, in which an eye specialist uses an instrument called ophthalmoscope to look directly through the pupil at the optic nerve. The nerve's colour and appearance can indicate damage from glaucoma.

'All too often, these tests detect glaucoma after the disease has been silently causing damage to the optic nerve,' Yu said. 'Years may pass between the first biological change associated with glaucoma inside the eye and the diagnosis.' Yu's method uses Raman Spectroscopy to shine laser light through the pupil of the eye. Optic nerve cells ( called retinal ganglion cells) inside the eye scatter the light, producing a rainbow- like 'spectrum' or pattern, revealing the chemical composition of the cells.

Scientists can use this snapshot to identify biochemical changes in retinal cells that announce the presence of glaucoma. Source: