A-scan ultrasound biometry
 | This article needs more primary sources. (August 2018) |  |
| A-scan ultrasound biometry | |
|---|---|
| Purpose | diagnostic test used in optometry |
A-scan ultrasound biometry, commonly referred to as an A-scan (short for Amplitude scan), is a routine type of diagnostic test used in
keratometry), a simple formula can be used to calculate the power of the intraocular lens needed. There are several different formulas that can be used depending on the actual characteristics of the eye.[citation needed
]
The other major use of the A-scan is to determine the size and ultrasound characteristics of masses in the eye, in order to determine the type of mass. This is often termed quantitative A-scan.[citation needed]
Instruments used in this type of test require direct contact with the cornea, however a non-contact instrument has been reported. Disposable covers, which come in actual contact with the eye, have also been evaluated.[citation needed]
See also
- B-scan ultrasonography
- Ultrasonography
References
- Santodomingo-Rubido, J.; Mallen, E.A.H.; Gilmartin, B.; and Wolffsohn, J.S. (2002). A new non-contact optical device for ocular biometry. British Journal of Ophthalmology. 86, 458–462.
- Cass, K.; Thompson, C.M.; Tromans, C.; and Wood, I.C.J. (2002). BALA Evaluation of the validity and reliability of A-scan ultrasound biometry with a single use disposable cover. British Journal of Ophthalmology. 86, 344–349.