binocular vision
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Binocular Vision
Horopter
Empirical Horopter
Panums Area
Panums Area
Physiological Basis
Requirements for StereopsisBinocular Overlap
Partial Decussation
Coordinated Eye Movements
Overlapping Fields: Panoramic
Overlapping Fields: Binocular
Overlapping Fields: Binocular
Partial Decussation
Coordinated Eye MovementsGaze Holding
Gaze Shifting
Retinal Function
Visual Function
SummaryObject on horopter will stimulate corresponding pointsObjects within Panums region create retinal disparity and signal depthObjects beyond Panums region produce diplopia
ReflexesUnconditioned or innate
Conditioned
Oculomotor ReflexesPostural
Psycho-optical
Postural reflexesOldest reflexes found in vertebrates
Stabilise eyes with respect to gravity
Stabilise eyes with respect to head and body movement
Vestibular System
Vestibular SystemStatic reflexMaintains orientation relative to gravity
Kinetic reflexStabilise with respect to head movement
VOR
Gaze-Holding
Gaze-Holding: Visual Perception
Gaze-Holding
Gaze-Holding: Visual Perception
Gaze-Holding: Visual Perception
Gaze-Shifting
Psycho-Optical ReflexesFixation reflexRefixationPursuitSteady fixation
Fusion reflex
Development of Visual Function
Fixation Eye Movements
Refixation Movements
Development of Saccades
Pursuits: Infant
Pursuit: Nave Adult
Optokinetic Nystagmus (OKN)
OKN
OKNCan be used to estimate acuityUsed to evaluate binocular developmentNormal OKN at 4 monthsSlow phase velocity 25 degree/sec in newbornsSlow phase velocity 40 degrees/sec in adults
OKN with BV anomaliesOKN is asymmetricSlow phase has higher velocity to nasalward motion than temporal motionResponse seen in affected eye and normal eyeOKN remains asymmetrical in adults who have had congenital cataract or strabismus in early life
Development of Accommodation
Development of Accommodation
Development of Vergence
Accommodation and VergenceAC/A
CA/C
SummaryStereopsis requires binocular overlap, partial decussation and coordinated eye movementsEye movements have various componentsDevelopment of eye movements rapidVergence high order control