Mechanical characteristics of the porcine retina in low temperatures

We previously observed that the stiffness of the porcine retina was significantly higher when deforming at room temperature than at body temperature. The present study further investigates this phenomenon by examining the mechanical properties of the retina in saline at temperature lower than room temperature.

Tensile testing was performed on a total of 15 retinal strips dissected from pig eyes. Equal amount of strips from the dissection were tested at 37.0 ± 0.3°C, 26.1 ± 0.1°C, and 7.8 ± 1.2°C. Their transition modulus, stress, and strain were measured for statistical analysis.

The transition modulus, the transition stress, and the transition strain of the retinal strips were found to be 11.12 ± 6.10 kPa, 0.12 ± 0.07 kPa, and 0.016 ± 0.001, respectively, at 37.0°C. These values were 111.25 ± 88.16 kPa, 1.11 ± 0.85 kPa, and 0.016 ± 0.001 at 26.1°C, and 125.13 ± 63.61 kPa, 1.30 ± 0.50 kPa, and 0.017 ± 0.003 at 7.8°C, respectively. The differences of the transition modulus and the transition stress at between 37.0°C and 26.1°C and at between 37.0°C and 7.8°C were statistically significant (P < 0.05). There were no significant differences in these values at between 26.1°C and 7.8°C.

These findings suggest that lowering the temperature of the retina from body temperature is potentially useful to decrease retinal damage in posterior eye surgeries by increasing the resistance of the retina to mechanical deformation.