Application of technology developed for one purpose to achieve something that borders on the miraculous in an unrelated field happens every now and then. This time, a compact fibre-optic probe that was originally developed for the space programme has become the first non-invasive early detection device for cataract, which is the leading cause of vision loss worldwide.

Researchers at the US National Eye Institute (NEI) and the National Aeronautics and Space Administration (NASA) have collaborated to develop a simple, safe eye test for measuring a protein related to cataract formation. They say that if subtle protein changes are detected prior to the development of a cataract, chances are good that the risk can be averted by taking evasive action such as avoiding exposure to sunlight, quitting smoking, stopping certain medications or controlling diabetes, all leading causes of vision loss.

Manuel B Datiles III, the NEI medical officer who is also the co-author of the clinical study was quoted in the media as saying that by the time the cataract is diagnosed, which is usually when the eye's lens appears cloudy, it is typically too late to reverse or medically treat this process. He says the technology can detect some of the earliest damage to lens proteins, "triggering an early warning for cataract formation and blindness."

Based on a laser light technique called dynamic light scattering (DLS), the device was was initially developed to analyse the growth of protein crystals in a zero-gravity space environment. However, back on Earth, the DLS technique will aid vision scientists to evaluate long-term lens changes due to ageing, smoking, diabetes, LASIK surgery, eye drops for treating glaucoma, and the surgical removal of the vitreous gel within the eye, a procedure that is known to be a cause of cataracts that develop within six months to one year.

Reports said that the technology might just advance the early diagnosis of Alzheimer's disease, wherein an abnormal protein may be discovered in the lens. Additionally, NASA researchers will use the device to study the impact of long-term space travel on the visual system.

At NASA's end, senior scientist at the John H Glenn Research Centre Rafat R. Ansari brought the technology's possible clinical applications to the attention of NEI vision researchers, after finding out that his father's cataracts were caused by changes in lens proteins.

The NEI-NASA clinical trial looked at 380 eyes of people aged between seven and 86, who had lenses ranging from clear to severe cloudiness from cataract. According to a NEI-NASA release, the researches then used the DLS device to shine a low-power laser light through the lenses, having previously determined the alpha-crystallin's light-scattering ability that was used to detect and measure the amount of alpha-crystallin in the lenses.

They found that as cloudiness increased, alpha-crystallin in the lenses decreased. The quantum of alpha-crystallin also decreased with the increase in age, even when the lenses were still transparent. These age-related, pre-cataract changes are virtually undetected by presently available imaging tools. The research findings were first reported in the December Archives of Ophthalmology.

Reports quoted Ansari as saying, "We have shown that this non-invasive technology that was developed for the space program can now be used to look at the early signs of protein damage due to oxidative stress, a key process involved in many medical conditions, including age-related cataract and diabetes, as well as neurodegenerative diseases such as Alzheimer's and Parkinson's. By understanding the role of protein changes in cataract formation, we can use the lens not just to look at eye disease, but also as a window into the whole body."