Researchers in Japan discovered that blue light can be used to probe the depths of the eye and uncover areas afflicted by diabetic retinopathy (DR), a leading cause of blindness, in the same way that bright light can illuminate the depths of a darker room.
According a new study published in Asia-Pacific Journal of Ophthalmology, researchers from Tokyo Medical and Dental University (TMDU) have discovered that blue images obtained by multicolor widefield scanning laser ophthalmoscopy (SLO) can be used to identify areas of DR-induced damage in a larger portion of the eye than previous methods.
One of the most common types of eye imaging is fluorescein angiography, which includes injecting dye into the eye.
On the other hand, SLO is a non-invasive approach that does not require dye, and multicolor widefield SLO represents an advancement of this technique in which red, blue, and green lasers are used to simultaneously capture images of a wide portion of the eye.
According to previous studies, blue images recorded by traditional SLO can indicate hyporeflective patches in the eye, which are indicative of DR damage. Researchers at TMDU used widefield SLO to further investigate this finding.
In this retrospective study, the researchers compared blue widefield SLO pictures and fluorescein angiography images taken in patients with diabetes. The morphology of the retina was also evaluated in some individuals with DR.
“We found that the hyporeflective areas in the blue widefield SLO images appeared to correspond with areas of ischemia in the fluorescein angiogram images of patients with DR. We were pleased to find that the rate of concordance was high,” said Kyoko Ohno-Matsui, Senior Author.
Further examination of patient images showed that ischemic areas (i.e., areas of reduced blood flow) appeared to correspond with parts of the retina that were thin and partially disorganized.
"It's possible that the blue wavelength of light can pass more easily through these thinned areas of the retina, which presents as hyporeflective areas in the SLO images," said Horie.
The efficacy of blue widefield SLO as a simple and non-invasive method for detecting DR-related damage in the eye has been confirmed in this work. This approach could be useful for screening and tracking disease progression in people who have DR, researchers proved.