Refraction (Lab)

3 instruments for subjective refraction

Most commonly used test chart

Gold standard for VA testing

3 types of optotypes

Three types of EOR

Cause of EOR: Greater curvature cornea

Cause of EOR: Irregularities on the curvature of the cornea

Cause of EOR: Flatter cornea

What type of lens is used to correct Astigmatism?

What type of lens is used to correct Hyperopia?

What type of lens is used to correct Myopia?

Type of EOR where the eye has stimulated accommodation (pwersado)

Type of EOR where px will see shadows

3 types of Astigmatism

Astigmatism where there is more curve vertical and less curve horizontal

Astigmatism where there is more power vertical and less power horizontal

Astigmatism that measures axis 59

Astigmatism where there is less curve vertical and more power horizontal

Astigmatism that measures principal meridian 120

Astigmatism that measures axis 140

Astigmatism that measures principal meridian 2

Astigmatism that measures principal meridian 31

In refraction, we assume that all patients are

Goal in Refraction

Technique where we decrease 0.25D steps until BCVA is reached

Technique where there is increased +0.25D steps until 20/200 cannot be read anymore

Meaning of BCVA

Should we refract both eyes simultaneously?

Test distance of Subjective Refraction (in ft)

The endpoint of Fogging Technique is known as

Endpoint of Unfogging Technique is known as

Starting point of Fogging Technique

Perform the Unfogging Technique with the patient's correction

Endpoint criterion for Unfogging Technique

Starting Point of Unfogging Technique is known as

If the patient has 20/20 vision on both +2.00D and +1.75D, what correction would you give the px?

If the patient has 20/20 vision on both +2.25D and +2.50D, what correction would you give the px?

Fog: 8 clicks ; Unfog: 2 clicks. The power of the fogging lens is

Fog: 8 clicks ; Unfog: 13 clicks. The power of the tentative sphere is

Fog: 10 clicks ; Unfog: 10 clicks. The power of the fogging lens is

Fog: 7 clicks ; Unfog: 9 clicks. The power of the fogging lens is

Fog: 4 clicks ; Unfog: 9 clicks. The power of the tentative sphere is

Fog: 2 clicks ; Unfog: 7 clicks. The power of the tentative sphere is