Definition

1. Noun:
   • A diagnostic technique in ophthalmology: "A-scan ultrasonography" refers specifically to a medical procedure that uses ultrasound technology to obtain precise measurements of the eye's axial length (the distance from the cornea to the retina). This is a one-dimensional amplitude scan, where the 'A' stands for 'amplitude'.

Usage

• This term is used exclusively in medical contexts, particularly in ophthalmology and optometry, to describe a specific diagnostic test.
• It is typically used by healthcare professionals when discussing preoperative planning (e.g., for cataract surgery) or diagnosing certain eye conditions.

Examples

• Noun:
  • The ophthalmologist ordered an A-scan ultrasonography to calculate the correct power for the intraocular lens implant.
  • Accurate measurement of the eyeball via A-scan ultrasonography is crucial for successful cataract surgery.

Advanced Usage

• "to perform an A-scan": a common shorthand in clinical settings for conducting this procedure.
  • The technician will perform an A-scan before your consultation with the surgeon.

Variants and Related Words

• A-scan (n): The common abbreviated form of "A-scan ultrasonography."
• Biometry (n): The broader process of measuring the eye, which often includes A-scan ultrasonography as a key component.
• B-scan ultrasonography (n): A related diagnostic technique that produces a two-dimensional, cross-sectional image of the eye and orbit.

Synonyms

• Ocular biometry: A more general term for the measurement of the eye's dimensions, which this procedure facilitates.
• Axial length measurement: Describes the primary objective of the procedure.

Related Phrases

• IOL calculation: (Intraocular Lens calculation) This is the primary purpose for performing an A-scan ultrasonography.
  • The data from the A-scan ultrasonography is used for IOL calculation.

Noun

1. the use of ultrasonography to measure the length of the eyeball