Fig. 1 — 1,532 m/sec. Immersion
A-scan using the
Note that all gates (above) are set to 1,532 m/sec. and that the
technique is by immersion. As is typical, the consistency between
individual scans is excellent. This technique is not for use by the
The true axial length is obtained by adding +0.32 mm to the displayed
axial length. In this case, it would be: 21.74 mm +0.32 mm = 22.06 mm.
This new number is then used for intraocular lens power calculations.
By adopting the above changes in the approach to A-scan
ultrasonography, you and your staff can significantly tighten the
accuracy of these measurements and increase the satisfaction of your
cataract surgery patients.
Read more about this technique: Immersion
For further reading, we highly recommend the
book A-scan Axial Length Measurements by Sandra Frazier Byrne.
It is an excellent resource that you wouldn't want to miss.
Also, there is an excellent, national certification
program in Ophthalmic Biometry available for your technicians:
American Registry of Diagnostic Medical