binocular vision

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Post on 16-Jul-2015

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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