The Relationship Between Ultrasound Characteristics of Human Cataract and in vitro Measurement of Mechanical Characteristics of the Lens after Extracapsular Cataract Surgery

摘要

In this paper, the relationship between ultrasound and physical characteristics of the extracted lens has been investigated. A pre-operative examination and assessment of cataract biometry and LOCSIII grade have been applied to 16 patients who had a planned standard extracapsular cataract extraction. Post-operative in vitro measurement of the ultrasonic characteristics of the extracted lenses has also been carried out to calculate the ultrasound attenuation and speed of sound through these lenses. Promptly after finishing the ultrasound measurements, an in vitro evaluation of nucleus with measurement of linear compressibility and the force required to compress a lens to 75% of its original thickness was carried out using a newly purpose-designed device. Attenuation of ultrasound signal across the lens correlates with both measures of lens 'hardness', linear compressibility (R=−0·673, R2=0·453, P=0·011) and the force required to compress the lens to 75% of its original depth (R=0·722, R2=0·521, P=0·008). The speed of sound in the lens correlates negatively with lens linear compressibility (R=−0·383, R2=0·147, P=0·197), but did not reach statistical significance for this sample size. These results provide a sound basis for further research and may have implications for future pre-operative assessment of cataract 'hardness' using ultrasound techniques.