Procedures I - Subjective Refraction

Fogging

adding excessive plus lenses to artificially make a patient myopic

relax

Fogging a patient makes their accommodation do what?

- determine refractive state of the eye

- provide best VA with relaxed accommodation

What are two purposes of subjective refraction?

myopic

Fogging the eye makes the patient artificially _______________

behind

If the eye is not fogged before beginning subjective refraction the image could form where in regards to the retina?

blur

_____________ is a stimulus for accommodation

asthenopia

condition in which a patient experiences eye strain with extended near vision work

Maximum Plus Power for Maximum Acuity (MPMA)

What is the endpoint criterion for subjective refraction?

horizontal

On a patient that has WTR astigmatism, rays of light traveling in the vertical meridian will form which focal line?

vertical

On a patient that has WTR astigmatism, rays of light traveling in the horizontal meridian will form which focal line?

horizontal line

On a patient that has WTR astigmatism, which focal line will be closer to the optical system?

vertical line

On a patient that has ATR astigmatism, which focal line will be closer to the optical system?

vertical line

On a patient that has WTR astigmatism, which focal line will be further from the optical system?

horizontal line

On a patient that has ATR astigmatism, which focal line will be further from the optical system?

vertical

On a patient that has WTR astigmatism that is fully fogged, which focal line will be clearer?

horizontal

On a patient that has ATR astigmatism that is fully fogged, which focal line will be clearer?

- clock dial chart

- sunburst chart

What are two fixed types of astigmatic charts?

- rotating T chart

- paraboline chart

What are two rotating types of astigmatic charts?

Conoid of Sturm

When you are finding the power for the correcting cylinder in a subjective refraction, it is referred to as "collapsing the __________________"

Jackson Cross Cylinder Test

The terms JCC, Flip Cylinder, and Cross Cylinder all refer to what test?

- refine the axis

- refine the power

What are two purposes of performing JCC?

parallel to principle meridians of correcting lens

When refining the power with a JCC lens, the principle meridians are oriented how?

45 degrees from the principle meridians of the correcting lens

When refining the axis with a JCC lens, the principle meridians are oriented how?

- analysis

- diagnosis

- prognosis

- treatment

The function of subjective refraction is to provide further information for what four things?

- determine best monocular sphere power

- refine astigmatic axis and power

What are two purposes of the monocular phase of subjective refraction?

1. Determine the initial tentative monocular best sphere power (initial MPMA)

2. Refine the axis and the power of the cylindrical component

3. Determine a second monocular best sphere (second MPMA) if indicated

What are the three steps of monocular subjective refraction?

0.25DS

If -0.50DC is added or reduced while determining the cylinder power in a subjective refraction, the sphere must be decreased or increased by how much?

accurate

In general the greater the correcting cylinder, the greater the need for __________ axis determination

- plus cylinder axis

- minus cylinder power

What two things does the white dot on a JCC lens represent?

- minus cylinder axis

- plus cylinder power

What two things does the red dot on a JCC lens represent?

1. Balance the accommodative stimulus

2. finalize the sphere power binocularly

What are the two steps of binocular subjective refraction?

Prism Dissociated Blur Balance Test

What is the test that is usually used to balance the accommodative stimulus during the binocular portion of the subjective refraction?

presbyopes

The prism dissociated blur balance test is usually omitted with what types of patients?

equal acuities

The prism dissociated blur balance test is only used if the patient has what following the monocular subjective refraction?

blurring the eye with a better VA to equal the eye with the worse VA

If you were to perform the prism dissociated blur balance test in a patient with unequal acuities, what would the result be?

asthenopia

The prism dissociated blur balance test intends to prevent unequal or excessive accommodative status between the patient's eyes which will help prevent what?

green (shorter)

During bichrome testing, which wavelengths are refracted the most?

red (longer)

During bichrome testing, which wavelengths are refracted the least?

chromatic interval

Bichrome testing creates a _____________ similar to a conoid of sturm

yellow (555nm)

The retina is the most sensitive to _____________ light