Binocular Vision

Question 1

Sudden symptoms of CI

Answer 1

Consider patient having MS or Myasthenia gravis.

Question 2

CE may accompanied by

Answer 2

Accommodative excess or latent hyperopia

Question 3

CE must be differentiated from

Answer 3

Pathological causes of accommodative/convergence spasm .

• uveitis, Scleritis
• tertiary syphilis, sympathetic paralysis
• pharmacological

Question 4

DE

Answer 4

Main symptoms is Diplopia
May lead to intermittent exotropia
PFV ranges are Normal at distance and near.
Patient may have a V pattern Exo deviation

Question 5

Basic exophoria

Answer 5

Normal AC/A
Reduced PFV at D and N
Reduced NRA
Low lag or lead 
Inability to fuse BO in VF testing

Question 6

Fusional vergence dysfunction

Answer 6

Reduced PFV and NFV

-abnormal results with binocular AF testing and normal results with monocular testing

Question 7

Low lag or lead of accommodation

Answer 7

CI, basic exophoria ,

AE

Question 8

High lag

Answer 8

CE, Basic esophoria

AI

Question 9

Accommodative infacility

Answer 9

Reduced NRA and PRA

Difficulty clearing plus and minus lenses.

Question 10

Critical period to develop Amblyopia is

Answer 10

Critical period of development of the visual cortex from birth to 7-9 yrs of age. First 2-3 yrs of life are most sensitive.

Question 11

Degree of amblyopia

Answer 11

Moderate = 20/40-20/80
Severe= 20/100-20/400

Question 12

Plastic period

Answer 12

Time frame when amblyopia can be treated.

Question 13

Amblyogenic Refractive errors-Anisometripia

Answer 13

Myopia: >3.00D
Hyperopia: > 1.00D
Astigmatism : > 1.50D

Question 14

Amblyogenic Refractive errors-Isometripia

Answer 14

Myopia: >8.00D
Hyperopia: > 5.00D
Astigmatism : > 2.50D

Question 15

Anomalous retinal correspondence happens

Answer 15

If the foveal misalignment develops before age of 5

• only happens under binocular condition
• objective angle - subjective angle

Question 16

In normal correspondence

Answer 16

Subjective angle and objective angle are equal

Question 17

Harmonious ARC

Answer 17

Sensory adaptation completely corresponds for angle of strabismus
Angle H=Angle A

Question 18

Paradoxical ARC

Answer 18

Objective and subjective angle are in opposite directions.
A= H +S
Even though the person has ET , he visualizes objects as if he were XT.
Type I= surgical under correction of an ET
Type II= surgical over correction of an XT

Question 19

Test for eccentric fixation

Answer 19

Visuoscopy
Haidinger’s brush
Maxwell’s spot
Monocular Hirschberg test

Question 20

Test for ARC

Answer 20

After image test

Bagolini lenses

Question 21

4 BO test

Answer 21

BO on OD

• If OS makes outward movement and refixates= no suppression of OD and OS
• if OS makes outward movement but doesn’t refuxates= suppression of OS
• if OS doesn’t do both= suppression of OD

Question 22

After image test

Answer 22

NRC ( ET, XT) = perfect cross image
ARC ET = vertical line to ward the left of the center
ARC XT= vertical line to ward the right of the center
ARC ET and nasal EF = perfect cross
HARC and ET =vertical line to ward the left of the center
HARC and ET and Nasal EF=vertical line to ward the left of the center

Question 23

Contour stereopsis

Answer 23

Uses laterally displaced targets with Monocular cues.
Better at detecting peripheral stereopsis (> 60seconds of arc)
-wirt circles
-Titmus fly
-animals
Normal result is 20seconds of arc

Question 24

Midline shift

Answer 24

• Stroke affecting the left side of the brain, pt will have right sided hemiparesis, visual midline will shifted away from effected side, toward left
• Treatment with yoked prism

Question 25

Aphasia

Answer 25

Difficulty expressing language or difficulty understanding the speech of others.

Question 26

Apraxia

Answer 26

Motor planning deficit

Question 27

Binasal occlusion

Answer 27

2BI

Helps to reduce patient symptoms by decreasing the degree of binocular processing .

Question 28

Sheard ‘s criteria

Answer 28

Most effective for exophorias

S=2/3(D)-1/3(R)

Question 29

Percival’s criteria

Answer 29

For esophoria

P= 1/3(G)-2/3(L)