Binocular Subjective Refraction

Question 1

Binocular refraction techniques are performed with

Answer 1

• both eyes open and unoccluded

- both eyes viewing a common distance target

Question 2

Advantages of a binocular refraction

Answer 2

• testing conditions are more realistic; closer to the habitual state
• accommodation, convergence and light adaption are held more constant
• greater control of accommodation

Question 3

Which is better, monocular or binocular refraction?

Answer 3

-monocular subjective refraction is much more commonly performed in routine optometric practice, although expert opinion suggests that binocular refraction is superior

Question 4

Difference in findings between monocular and binocular refraction

Answer 4

May be subtle or profound, depending upon the individual patient

Question 5

Refractive conditions for which bino subjective refraction may be especially advantageous

Answer 5

• hyperopic anisometropia
• antimetropia
• intermittent latent hyperopia
• pseudomyopia

Question 6

Unequal maximal acuity conditions for which bino refraction may be advantageous

Answer 6

• amblyopia

- disease condition

Question 7

Ocular motility conditions for which bino refraction may be advantageous

Answer 7

• large heterophoria
• cyclo phoria
• latent nystagmus

Question 8

What are techniques of achieving binocularity during refraction

Answer 8

• partial occlusion
• blur
• vectographic techniques

Question 9

Partial occlusion as a bino refraction technique

Answer 9

The target is partially occluded such that only part of its visible to the right eye and only part is visible to the left eye

Question 10

Disadvantage of partial occlusion in bino refration

Answer 10

May suffer from inadequate fusion lock

Question 11

Blur as a bino refraction techniques

Answer 11

Use of plus lenses over eye not being examined

Question 12

Disadvantage for using blur as bino refraction technique

Answer 12

May suffer from inadequate suppression control

Question 13

Vectographic technique as a bino refraction

Answer 13

Polarized targets or filters are used such that only part of the target visible to the right eye and only part is visible to the left eye

Question 14

Disadvantage of vectographic techniques as bino refraction

Answer 14

Suffers from decreased contrast of targets

Question 15

Fusion locks

Answer 15

• when viewing an acuity chart under partial occlusion or vectographic conditions, portions of the chart can be seen by both eyes, while other parts are seen by only the left of right eye
• the potions seen by both eyes ensures the binocular fusion necessary for associate of the target

Necessary for good refraction

Question 16

Expected findings in binocular refraction

Answer 16

• similar to those obtained using a monocular subjective

- additional plus acceptance and/or a small change in the cyl axis

Question 17

What kind of bino refraction uses a septum as a fusion lock

Answer 17

Turville

Question 18

What is the most common blur technique to use during bino refraction

Answer 18

Humphriss immediate contrast test

Question 19

What kind of binocular blur refraction do you add +0.75 to fog the other eye, and reach an endpoint that is a reversal from -0.25D being preferred to a +0.25D being preferred

Answer 19

Humphriss immediate contrast

Question 20

What kind of bino refraction uses polarized light

Answer 20

Vectographic technique

Question 21

Why is it good to have convergence of both eyes during a bino refraction

Answer 21

It will help stabilize accommodative system

Question 22

Why do fusion lock?

Answer 22

Ensures binocularity

Question 23

What do we use to check for suppression

Answer 23

Vectographic acuity chart

Question 24

What do we use to find associated phoria with no fusion lock

Answer 24

Vectographic acuity chart

Question 25

What do we use to find associated phoria with fusion lock

Answer 25

Vectographic acuity chart

Question 26

What can we use to test for steropsis at distance with stereoacuities ranging from 4 min to 1 min of arc

Answer 26

Vectographic acuity chart

Question 27

Disadvantages for a vectographic acuity chart

Answer 27

• decreased contrast!!!
• unpolarized light projected acuity chart (97%)
• vectographic projected acuity chart (75-80)
• dim illumination
• if light from the acuity chart is not reflected directly toward the patient, the chart may appear dim