Abstract
Purpose :
To test the hypothesis that the sclera is an electroactive hydrogel and determine its electromechanical properties.
Methods :
Scleral strips were dissected from the area close to the optic nerve head in the superior-inferior direction from porcine eyeballs. After measuring the thickness of the strips using a pachymeter, they were mounted at the center of a custom-designed container between two carbon electrodes. The scleral samples were fixed from one side and their other end was free to move. After filling chamber with NaCl solution, the two carbon electrodes were connected to a DC current power supply and the strips were subjected to 5, 10, and 15 volts for 60 seconds. The deformation of strips was recorded by a digital microscope camera as a function of time during the experiments.
Results :
The average thickness of porcine posterior sclera samples was found to be 1.3 mm at the beginning of the experiments. No difference in the thickness of the samples was observed after they were removed from the custom-made container. Upon applying the electric voltage, the strips started to bend towards the cathode, Figure 1. The amount of bending of the scleral strips gradually increased with time and its magnitude was a function of the applied voltage. The maximum bending angle of scleral strips was 2.6±0.5, 11.4±1.0, and 22.4±1.6 at 5, 10, and 15 V, respectively.
Conclusions :
It was found that the sclera is an electroactive tissue that mechanically deforms when subjected to DC electric voltage. The amount of deformation depends on the strength of the electric field and the duration of the application of the electric voltage. These findings are important for both biomechanical and biochemical characterizations of the sclera and have important implications for the future efforts to characterize the electromechanical properties of ocular tissues.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.