2. Optokinetic Response - Eye Movements & Binocular Vision Summer 2026

Gaze holding eye movement

What is the Optokinetic response (OKR)?

psychooptical reflex

Optokinetic response (OKR) is a ______ reflex

reflexive eye movement that requires visual input

What is a psychooptical reflex?

No

Is VOR response a psychooptical reflex?

Because it does not require visual input. VOR can occur with eyes closed.

Why is VOR NOT a psychooptical reflex?

movement of all or a large part of the visual field

What is the Optokinetic Response (OKR) elicited by?

optokinetic nystagmus (OKN)

Under certain conditions, OKR can cause _________

An involuntary jerk nystagmus

What is optokinetic nystagmus (OKN)?

constant

Optokinetic nystagmus has a ________ velocity slow phase that gives it the jerk nystagmus look

By presenting a moving square wave pattern, alternating black and white strips (OKN Drum or Video display) moving at a constant velocity

How is OKN elicited?

left beat nystagmus

What direction is this nystagmus?

-Slow: OKR (direction of the drum moving)

-Fast: Direction of the corrective saccade towards primary gaze

What is generating the two phases of this nystagmus?

stripes

The slow phase of OKN is in the direction of the ______

Direction of the corrective saccade towards primary gaze

The fast phase of the OKN is in the direction of what?

140msec

What is the latency period of the OKR?

slow

Latency of the OKR is (slow/fast) comapred to RVOR and TVOR

Very little effect

Does blur have any effect on the OKN response?

stripes are big and easy to see

Why does blur not have a lot of effect on the OKN response?

Yes -- if you do not get a OKN response, something is seriously wrong

Should you get OKN response if vision is very poor?

Yes

Can OKN response help you detect malingering?

gain

1 parameter of OKN that has been studied a lot is ______

response velocity / stimulus velocity

Optokinetic Gain Equation

1.00

Perfect Optokinetic Gain = ?

0.80

What is avg gain for "Stare OKN" where the subject just stares ahead passively?

1.00

What is avg gain for "Look OKN" where the subject is told to fixate a feature of the stimulus?

-Observe OKN while using smaller and smaller stripes

-No OKN observed when the stripes cannot be resolved

-VA will equal the smallest angular size of the stripes that can generate a response

How can OKN be used to estimate VA?

-infants

-IDD patients

-malingerers

OKN used for VA measurements can be used for what patients?

asymmetry

In newborns, ______ exists in the OKR

temporal to nasal

_____ to ____ OKN develops first in infants and therefore is a stronger monocular response

nasally

Stronger monocular response when the stripes of the OKR is moved (nasally/temporally)

2-6

Asymmetry in the OKR response will disappear by ______ months in infants

strabismus/amblyopia present that prevents normal development of binocular vision

OKR Asymmetry may remain if what is present in an infant?

-Accessory optic system (AOS) and nucleus of the optic tract in the midbrain

-Will receive input from the retina and the cortex (direct visual input)

What are the neurological pathways that are present for OKN?

monocularly

OKR should be run (Monocularly/binocularly) in infacts

true

True or False:

The OKR can work in tandem with the VOR during sustained rotations and translations

VOR

______ is initially a very strong response and then diminishes when rotation in constant

OKR

______ can take over once the VOR response diminishes to help stabilize the visual scene

positive

A (positive/negative) after-effect of the OKR may also help stabilize the world during post-rotary nystagmus

true

True or False:

OKR can help cancel out the post-rotary nystagmus

-Can be used to estimate visual acuity by gradually reducing strip size until OKN stops

-Can be used to check for cortical blindness

-Can be used to screen for amblyopia and strabismus

SUMMARY: What is OKN used for?

temporal to nasal

SUMMARY: OKN response will be better when the stripes go ______ to _____