Binocular Vision Advantages and Disadvantages PDF

OPTBINOV, OPTBINOL Binocular Vision and Perception Dr. Hannah Alessandra D. Jong Course Facilitator Binocular Vision: Advantages and Disadvantages Pre-requisites  INTRODUCTION Binocular vision defined as the state simultaneous vision with two seeing eyes that occur...

OPTBINOV, OPTBINOL Binocular Vision and Perception Dr. Hannah Alessandra D. Jong Course Facilitator Binocular Vision: Advantages and Disadvantages Pre-requisites  INTRODUCTION Binocular vision defined as the state simultaneous vision with two seeing eyes that occurs when an individual fixes his visual attention on an object of regard The coordinated use of the two eyes to produce a single mental impression. 1. Single Binocular Vision - unification of Retinal Image into one ADVANTAGES Result: Fusion/ Diplopia 2. Field of vision is larger Your field of vision can be measured in terms of degrees from the center. With a healthy and normal eye, you should be able to see approximately The temporal crescent is a 30- 95 degrees temporally (towards your ear) and degree segment of temporal field approximately that begins 60 degrees from 60 degrees nasally (towards your nose) from the fixation. It is entirely unshared and monocular (i.e., seen by one eye center. only). These nasal retinal axons horizontal field range of 155 degrees decussate in the optic chiasm and You should also be able to see 60 degrees above terminate at the most anterior and 75 degrees below from the center. occipital cortex. Focal damage here vertical field range of 135 degrees at a given time.could theoretically produce a Monocular 130 V & 150 H monocular visual field defect that Binocular 180 degrees only involves the temporal crescent of the contralateral eye. Monocular Crescent 30 degrees  ADVANTAGES 3. Presence of Stereopsis - the perception of depth stimulated by objects that possess horizontal disparity, with one object usually located in front of or behind the fixation point. 4. Visual Acuity is better with both eyes / Improved vision 5. Spare tire effect – one eye damage still have another eye 6. Any deficiency is compensated by one eye - Should be detected early if not Amblyopia 1. Diplopia DISADVANTAGES 2. Ocular Dominance 3. Amblyopia PRE-REQUISITES FOR DEVELOPMENT OF BINOCULAR VISION Anatomical factors: The eyes are spruced up in the orbit in such a way that the visual axis of both eyes is aligned. This occurs as a result of multiple anatomical factors. Architecture of the orbit Ligaments, muscles and connective tissues, i.e., adjacent ocular structures. The extra-ocular muscles play an important role as they provide motor correspondence because of the reciprocal innervation of the extra- ocular muscles. Following are the aims of motor correspondence: To convert field of vision into field of fixation thereby widening the view. To ensure that the object of attention is sustained and maintained on fovea. To ensure that both the eyes are aligned at all times. Physiological factors: Normal physiological binocular reflexes determine the development of binocular vision. These physiologic reflexes can be either innate or acquired as a result of appropriate environmental stimulation. Different physiological binocular reflexes are described as below: Fixation reflexes Gravitational reflex, i.e., compensatory fixation reflex: Whenever there is a movement of body, limbs, etc., this reflex helps maintaining the position of eyes in such a way that the eyes look in the compensating direction to the movement. This reflex occurs as a result of frontal position of eyes as well as utricle and saccule presiding over the tone of vertical rectii and obliques respectively. Orientation fixation reflex: A slow continuous movement of eyes can be demonstrated while observing a moving object or a panorama maintaining continuous fixation as opposed to a jerky movement. Accommodation convergence reflex The refixation reflex: The aim of this reflex is to bring the eye back to the original orientation point or to the new orientation point. The pupillary reflex  PRE-REQUISITES FOR DEVELOPMENT OF BINOCULAR VISION Sensory Mechanism: Motor Integrative/ approximately equal Mechanism: Mental Process: image clarity and size in correct ability of visual the two eyes neuromuscular cortex to corresponding retinal development so promote mental areas so that the eyes that the visual images are cyclopean axes are Results in normal visual pathways directed at the fusion/ single object overlap mental of visual fields perception DEPTH PERCEPTION: BINOCULAR DISPARITY DEPTH PERCEPTION: BINOCULAR DISPARITY Horopter