Mouse lens stiffness measurements.

Area of Science:

• Ophthalmology
• Biomechanical Engineering
• Gerontology

Background:

• Presbyopia, or age-related loss of accommodation, is a significant visual impairment.
• Increased eye lens stiffness is a proposed contributing factor to presbyopia.
• Previous methods for measuring lens stiffness include lens spinning and conical probe penetration.

Purpose of the Study:

• To evaluate the stiffness of isolated mouse lenses using two novel techniques.
• To compare the mechanical properties of lenses from young and older mice.
• To investigate the relationship between age and lens stiffness in mice.

Main Methods:

• Two compression-based methods were employed: microscope cover-slips and an automated squeezer system.
• Incremental compressive forces were applied to isolated mouse lenses.
• Lens diameter changes under force were captured via microscopy and analyzed.

Main Results:

• Older male mice (7-9 months) exhibited stiffer lenses compared to younger male mice (4 weeks).
• Both compression methods provided reliable measurements of lens stiffness.
• A quantifiable difference in lens diameter change was observed between age groups at various force levels.

Conclusions:

• Lens stiffness increases with age in mice.
• The developed compression techniques are effective for assessing mouse lens mechanical properties.
• These findings support the hypothesis that age-related changes in lens stiffness contribute to presbyopia.