Essilor MYOPIA EXPERT 700, Руководство пользователя

Страница: 54 / 132

52
12.6 T
OPOGRAPHY
+ B
IO
In the “TOPO+BIO”
acquisition mode is performed in combination with the following acquisitions:

Topography , same acquisition as described in the following paragraph

Axial Length , measured through repeated interferometry scans (express eye Axial Length as
ultrasound equivalent value
, assuming the eye is phakic). For each acquisition, six individual
interferometry scans are performed.
Fig.24
Note
: Ultrasound biometrical instruments measure the axial length as the distance between the cornea
and the inner limiting membrane because the sound waves are reflected at this membrane. To ensure
that the measured values obtained with the MYOPIA EXPERT 700 are compatible with those obtained
through acoustic axial length measurement, the system automatically adjusts for the distance difference
between the inner limiting membrane and the pigmented epithelium. The displayed axial length values are
thus directly comparable to those obtained by immersion ultrasound, and no re-calculation or correction
factors are necessary. Nevertheless, deviations may occur between the displayed axial lengths and
ultrasound readings (particularly in the applanation procedure).