What should you recap by the end of this lecture?
Refraction, convex/concave lenses, reflection, magnification, and their relation to optical instruments and the eye.
What should you understand about the eye?
Emmetropia and different ametropias.
What should you be aware of regarding optical instruments?
Non-visual and visual instruments and the optics involved.
How do lenses form images?
By refraction.
What has been covered about lenses?
Image formation and ray diagrams with convex and concave lenses.
What has been covered about mirrors?
Law of reflection and total internal reflection (T.I.R).
What mirror concepts were covered?
Image formation with convex and concave mirrors.
What additional concept was covered in recap?
Magnification.
What can be done with knowledge of optics principles?
Describe how most optical instruments work in real life.
What is emmetropia?
Light from optical infinity is focused precisely on the retina.
What structures provide refractive power in emmetropia?
Cornea and lens.
Where is the far point in emmetropia?
At infinity.
What balance exists in emmetropia?
Between axial length and optical power.
What does accommodation do in emmetropia?
Allows focus on near objects.
Can emmetropes see near and distance simultaneously?
no
What is myopia?
Short/near sightedness.
What is the far point in myopia?
Finite distance in front of the eye.
Where is the image formed in myopia?
Before the retina.
Causes of myopia?
Increased axial length, increased lens thickness, or increased corneal curvature.
What vision is affected in myopia?
Far objects cannot be seen clearly.
How is myopia corrected?
With −ve (concave) lenses.
What is hypermetropia?
Long/far sightedness.
Where is the image formed in hypermetropia?
Behind the retina.
Can accommodation improve vision beyond the far point in myopia?
no
