Clinical Skills Certificate Course:

Refractometry (Refraction)


Course level:

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

Course structure:

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:

Two hours.

Short Course Description:

This course refractometry (refraction) discusses basic refraction techniques, binocular balancing, high power refractometry, cylinder power optimization, controlling accommodation, near add determination, intermediate vision lenses, characteristics of astigmatism, unusual add powers, using keratometry, the astigmatic dial, and the red-green test. A discussion of how to handle glasses complaints is included.

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, $10 for 2 months of 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

Refraction: The basic techniques

The beginning correction
   The auto-refractor
   Current or old glasses
The Setup
Testing Procedures
   Lights on or lights off
   The visual target
   Communicating with the patient
   Order of testing
   The initial sphere check
   Cross-cylinder axis refinement
   Cross-cylinder power refinement
   Refine the sphere power

Binocular balancing

What is balancing?
Why use balancing?
Should I balance everyone?
How do you balance?

High Power Refractometry

Phoropter vertex device
Over-refraction method
Trial frame method
High astigmatism

Cylinder Power Optimization

The power ratio and spherical equivalency
What is the spherical equivalent?
How is the spherical equivalent used in refractometry?
Using minus cylinder
Using plus cylinder
Slide sequence

Controlling Accommodation When Refracting

Methods of control
Cycloplegic drops
Factors affecting cycloplegia
Retinoscopy and refractometry
How fogging works
Fogging procedure

Near Add Determination When Refracting

Factors affecting reading ability
The Rotochart
Add power and lens types
The add and the pseudophake
The near point of accommodation and the amplitude of accommodation

Refracting for Intermediate Vision

Measuring the add power
A shortcut
Music glasses
Half glasses
Computer glasses
Other factors

More on Refractometry

More on the add power
Unequal add powers
Add powers less than 1.00
Add powers greater than 2.50
Characteristics of astigmatism
The near advantage of against-the-rule astigmatism
The distance advantage of with-the-rule astigmatism
Keratometry and refractometry: 
The Javal rule
Astigmatic dials
The red-green test 

Handling Glasses Complaints

The Systematic Evaluation

Confirm the prescription with the lensometer.
Mark the optical centers with the lensometer.
Measure the base curves with a lens clock.
Measure the patient's PD with a PD ruler.
Check the patient's distance and near vision with the glasses on.
Look at how the patient's glasses fit on his/her face.

Handling Specific Complaints

Distance vision is blurry
Progressive lenses, any complaint
Can't read small print
Has to hold reading too close
Cannot see the computer screen well
Can only read with one eye, or closes one eye to read
The eyes don't focus at the same distance at near
Glasses seem too strong
Distortion, including slanting lines
Headache, eye soreness, eyestrain
Double vision when looking straight ahead
Double vision when looking through a lens edge
Double vision or discomfort only when looking through a bifocal

An Ounce of Prevention

Tips about keeping out of trouble when refracting and prescribing