Clinical Skills Certificate Course:

A-scan Ultrasonography (Biometry)


Course level:

This course is intended for ophthalmic assistants, technicians and technologists.

Course structure (no CE credit):

This course consists of short, illustrated reading segments. There is a quiz at the end of the course. Upon passing the quiz, the user will receive a certificate of completion.

Estimated time to complete:

One hour.

Short Course Description:

This course on A-scan ultrasonography (Biometry) includes discussion of basic concepts, scanning procedures, instrumentation, pseudophakic A-scan instruction, immersion A-scan instruction, intraocular lens power calculations, and A-scan biometry vs. optical biometry.

For the Detailed Course Description, see below

The course can be purchased via Paypal (you don't need a Paypal account) by using the button below ($7 for 2 months access). More than one course can be purchased at the same time by going to the course catalog. Courses can also be purchased via from the course catalog.

After purchase, the course can be accessed immediately by using the "courses" tab on the top menu bar to link to your "my courses" page.


Detailed Course Description

Basic concepts of A-scan biometry, including:

Gain level
Optical axis
Spike height
Corneal compression
Velocity of sound

A-scan Scanning procedures, including:

Hand-held method
Tonometer mount method
Immersion method
Probe positioning
Scan evaluation
Aphakic scan
Measuring gates
Extra lens spikes
Corneal compression

A-scan Instrumentation, including:

Gate Protocol
Automatic acquisition
Gain control
Audible signal
Corneal compression recognition
Foot switch operation
Probe tip
Menu operation
Adjustable settings
IOL formulas

Pseudophakic A-scan instruction, including:

Factors to consider
IOL Material
Measuring Protocol
Evaluating the scan

Immersion A-scan instruction, including:

The problem
The solution
Equipment needed
Hansen shells
The Prager shell
The procedure
Potential problems

Intraocular Lens Power (IOL) Calculations:

Types of formulas
Theoretical, including: Holladay, Hoffer Q, Haigis
Regression formula calculations
Regression formula compensation
Regression formula table
Emmetropia and ammetropia
Post refractive surgery IOL power calculations, including the History method, and the Contact lens method

A-scan Biometry versus Optical Biometry

Includes discussion of the IOLMaster 500, Haag Streit Lenstar LS900, and IOLMaster 700