Advanced imaging technology for early detection of vision loss diseases.

 

Retina

Advanced imaging technology for early detection of vision loss diseases.

Scientists have developed a powerful new dual imaging tool that maps the retina's structure and oxygen consumption in unprecedented detail.
According to New Atlas, the new discovery could one day help doctors detect vision loss long before symptoms appear.
Oxygen for the retina
The retina converts light into electrical signals that are transmitted to the brain, where they are processed into images. This process requires a large amount of oxygen. If the oxygen supply is interrupted, for example, due to insufficient blood flow, it can lead to serious conditions that affect vision, such as glaucoma, age-related macular degeneration (AMD), and diabetic retinopathy.

Two advanced technologies

In a new study, researchers from Johns Hopkins University and the University of Pennsylvania developed and tested a new retinal imaging system that combines two advanced technologies to map retinal structure and oxygen levels to better study oxygen metabolism.

Ultra-detailed structural images

The researchers used a dual-channel system using visible light optical coherence tomography (VIS-OCT) to capture highly detailed structural images of the eye, and phosphorescence lifetime ophthalmoscopy (PLIM-SLO) to directly measure the partial pressure of oxygen (pO2) in an organ's microvasculature, or microvasculature. Simply put, pO2 is the amount of oxygen dissolved in the blood at a specific location. It is a key indicator of the amount of oxygen available to tissues.

Live rat eyes

These methods were used to image the eyes of living mice. VIS-OCT uses visible light to create high-resolution, three-dimensional images of the retinal layers and can also capture blood flow dynamics. PLIM-SLO involves injecting a safe, oxygen-sensitive dye called Oxyphor 2P, which emits light that changes depending on oxygen levels. By measuring the decay rate of this light (i.e., its phosphorescence lifetime), the researchers were able to calculate pO2 at the capillary level. Both systems share the same optical path, allowing them to capture structural and oxygen data simultaneously and in perfect alignment. The researchers also tested how pO2 readings changed with changes in the oxygen the mice inhaled to verify the accuracy of the new technique.

Different depths in the retina

PLIM-SLO accurately measured oxygen levels in arteries, veins, and capillaries. As the researchers expected, PLIM-SLO revealed that very small branches of arteries contained the highest percentage of oxygen, while the smallest veins, which return deoxygenated blood, contained the lowest, with capillaries in between. Adjusting the system's focus allowed the researchers to image oxygen at different depths in the retina, revealing the structure and oxygen levels in multiple vascular layers—something previous methods could not achieve.

Expected changes

Changes in inhaled oxygen led to predicted changes in retinal oxygen levels, confirming that the measurements reflect true physiological changes. Importantly, the system linked oxygen measurements to structural and flow data, paving the way for future studies on retinal oxygen metabolism and disease processes.

Major progress in diagnosis

This multimodal system could significantly advance eye disease research and diagnosis by providing a more complete picture of retinal health. It could also help scientists understand how oxygen supply changes in diseases such as diabetic retinopathy, glaucoma, and macular degeneration. Doctors may one day use similar technology to detect disease-related changes early before vision is affected.