Ultrasound measurements were performed using paradigm ultrasound biomicroscope plus Model P45 (UBM plus), which is a
microprocessor-based digital instrument that uses very high frequency
ultrasound (50 MHz) to produce a two dimensional section
view of the examined tissue in B-scan (brightness) mode for diagnostic
evaluation, and A-scan mode that measures the axial length
with depth of penetration up to 5 mm. The ultrasound scan images
acquired by the UBM transducer are viewed on a high resolution
color monitor in real-time. The reflected ultrasound waves are controlled
and assembled by the computer and magnified to provide a
high resolution B-scan image. The cross-sectional picture can be
further enhanced by digital filters to improve image contrast or
brightness to identify interesting findings without altering the
original scanned file image. Skin thickness measurements were
made above the zygomatic bone. The following parameters were
measured: epidermis and dermis thickness and dermis density.
Ultrasonic images were taken three times at each time for each
subject.