Expanding retinal elasticity measurements into multiple directions

Retinas are made up of layers of different types of cells. The condition, arrangement, and connectivity of these cells can affect elasticity, allowing elasticity measurements to be used to assess functionality, reveal damage, and diagnose disease in retinas.

Optical coherence elastography (OCE) is a high-resolution imaging technique that quantifies the elasticity of tissues by measuring how they deform in response to mechanical loads. However, previous OCE measurements of retinas only evaluated their elasticity in one direction.

Ma et al. proposed an OCE method that can map retinal elasticity in multiple directions. This method excites retinal tissue with acoustic radiation force. Detecting the vibration frequency allowed the authors to measure the axial elasticity; detecting the elastic wave velocity allowed them to measure the lateral elasticity.

The authors used this method to map the elasticity of ex vivo pig retinas. They found that the elasticity varies among the layers of cells in the retina in both the axial and lateral directions. The axial elasticity of the retina is much smaller than the lateral elasticity, confirming that the retina’s elasticity is anisotropic.

“Mechanical elasticity of the retina can provide valuable information on retinal disease diagnosis and function assessment,” said author Jiang Zhu. “This method can also be used for elasticity measurements of other multilayered tissues, such as the skin.”

Next, the authors will use this method to study retina elasticity in living organisms.

“We plan to extend this method to in vivo retina measurements and study the elasticity differences between healthy and diseased retinas,” Zhu said.

Source: “Anisotropic elasticity measurements of the retina using optical coherence elastography,” by Jiawei Ma, Fan Fan, Chongyang Wang, Zongqing Ma, Xiaochen Meng, Xinxiao Gao, and Jiang Zhu, Applied Physics Letters (2024). The article can be accessed at https://doi.org/10.1063/5.0228306 .