Indian scientists have developed a new approach to identifying retinal disease, with potential for diagnosing the condition earlier and preventing blindness. The study took place entirely in India in three institutes: the Indian Institute of Science Education and Research , Kolkata, L.V. Prasad Eye Institute, Hyderabad, and the Bhabha Atomic Research Centre, Visakhapatnam.
The peer reviewed study, published in the Journal of Biomedical Optics uses optical coherence tomography (OCT) to study the thickness of the retinal layer during disease progression of diabetic macular edema (DME) compared to a control group tested and deemed to have good retinal health. Left untreated, DME causes progressive blindness.
The OCT technique is useful as it is a non-invasive way of assessing eye health with no need for surgery. The concept of the process involves shining a light beam into the patient’s eye and recording the levels of refraction. The thickness of the retina will determine the levels of refraction as the more tissue is present the more the light will be deflected. The technique can be used for much more than just analysis of retinal thickness. It has a high degree of sensitivity with a spatial resolution of just a few micrometres, as well as being able to detect signals as small as ~10−10 of the original optical power.
The study found that early disease symptoms are often minute enough to be undetectable. This led to the development of software utilising OCT but applying algorithms to the data produced. The retina consists of a number of layers, any changes related to disease will rarely cause a uniform decrease in thickness, though the algorithms allow for partial changes in thickness to be detected.
The technique was tested in DME as its effects are well characterised, with effects occurring in the macula, resulting from damaged blood vessels in the eye causing fluid leakage. The resultant density changes resulting from the fluid leakage caused differing levels of diffraction compared to healthy eyes and were picked up by the algorithm, allowing for detection of the symptoms of DME at earlier stages.
The technique along with the associated algorithms have broader applications to the study of, and upon further testing with diseases that are well characterised it is possible to utilise the process to diagnose many other eye conditions.
The process could also be used to study less-understood diseases to assess where and how the eye has been affected, opening up the potential to further investigate the onset of disease pathology for a number of conditions.
The research will be important: India has a problem with diabetes due to genetic predispositions to the disease. This new technique already has a potentially vital usage in diagnosing, and so, treating DME.