The visual axis is one of the axes through the eye that has been defined and used by optical equipment designers and people who work with the physics, specifically the optics, of the eye - rather than by people concerned with the biology and physiology of human vision.
The visual axis is not a physical feature of the eye and so cannot be identified by dissection or by any physical imaging techniques.
A simple definition of the visual axis is:
" A straight line that passes through both the centre of the pupil and the centre of the fovea".
There is also a stricter definition (in terms of nodal points) which is important for specialists in optics and related subjects.
Other axes through the eye include the geometrical axis.
Where are the concepts of visual axes used?
The subject of visual (also known as "physiological") optics is part of many courses in the fields of both biology and physics. It is also important for the design of displays and control units used in many applications from mobile telephones to advanced aircraft. In the context of engineering 'visual optics' is one of several medical and psychological aspects of 'Human Factors'.
More about Ophthalmology:
This section includes short definitions and descriptions of the parts of the eye.
For other descriptions in this category, choose from the list to the left (but note that this is not a complete / exhaustive list).
Other related sections include:
- A labelled diagram of the eye
- A concise description of the human retina with brief descriptions of the parts of the retina
- Diseases and disorders of the human eye and the human visual system
- Clinical and surgical procedures re. eyes and human visual system
For further information see also our pages of books about ophthalmology.