Stiffness of the Natural Lens

(Funded by Leverhulme Trust and Wellcome Trust)

Dr Harvey Burd, Mr Geoffrey Wilde, Dr Stuart Judge

It is generally thought that the mechanical behaviour of the lens changes with age and that age-related changes in lens stiffness are an important factor in the development of presbyopia. However, until relatively recently, remarkably few data on lens stiffness are reported in the published literature.

The data on lens stiffness that are currently available in the research literature suggest that the lens stiffness increases substantially with age. However, there remains considerable inconsistency between stiffness data obtained by different researchers using different techniques. In particular, the classic data given by Fisher (1971) seems out-of-line with more recent measurements.  Following an earlier pilot study (Burd, Wilde & Judge, 2006) we are collecting some new data on lens stiffness using the spinning lens technique. This study is described in an abstract to ARVO 2008. Our recent results, obtained on human lenses using a spinning lens test, show very large increases in lens stiffness with age. An abstract describing these data has been submitted to ARV0 2009

Below is an image of a porcine lens in the spinning lens rig.

We are also exploring the use of other, novel, methods of measuring lens stiffness.

References

• Wilde, G. S., S. J. Judge and Wilde, G.S. (2008). Measurement of lens stiffness using a spinning lens test. ARVO. Fort Lauderdale, Abstract 3785.
• Burd, H.J., Wilde, G.S. and Judge, S.J. (2006) Can reliable values of Young's modulus be deduced from Fisher's (1971) spinning lens measurements? Vision Research, 46(8-9), 1346-1360.
• Burd, H.J., Wilde, G.S. and Judge, S.J. (2005) A reassessment of Fisher's spinning lens test. EVER abstract No. 4322