OVERVIEW: In all sensory systems, stimuli originating in the “outside world” convey information about the environment to the organism. Common to the study of all sensory processes is the need to know (a) how information (e.g., pitch, color, odor, etc.) is coded in the physical properties of the stimulus, (b) how the organism captures the physical stimulus (e.g., via the eye, the ear, the nose), and (c) how the organism converts the physical information into electrical signals (sensory transduction) which lead to perception. The objectives of this lecture are to understand how the physical properties of light are related to the information used in vision, how the various structural parts of the eye convey this information to the retina, and how chemicals in the receptor cells convert light to electrical responses.

1. In the lectures on perception we will see how various aspects of sensory information are coded in the stimulus. For vision, know what aspects of light are responsible for coding the position (boundaries or form) of objects, the color of objects, and the motion of objects. Also know the limits of our perception for each of these attributes other aspects of visual processing that “lose” in formation (many examples will come from later lectures).

2. Understand the properties of light and how they are related to brightness and color perception.
   1. wavelength
   2. intensity
   3. luminance

3. Patterns of light coming from an object must be focused to form an image. Know the following terms related to image formation:
   1. refraction
   2. accommodation
   3. diopter
   4. pupillary reflex

4. Be able to identify and discuss the function of the various parts of the eye we will NOT go over each of these in lecture, you are responsible for obtaining the definitions, etc, from the movie shown in lecture and WWW sites (see The Eye, parts and Functions, above) :

   a. cornea	h. retina
   b. iris-pupil	i. choroid
   c. aqueous humor	j. sclera
   d. lens	k. fovea
   e. ciliary muscle	l. macula
   f. zonula (suspensory ligament)	m. blind spot
   g. vitreous humor	n. optic nerve

5. What are the following terms relating to visual disorders? we will NOT go over each of these in lecture, you are responsible for obtaining the definitions, etc, from WWW sites (see Disorders of the Eye above)

   a. emmetropia	f. strabismus	k. lasik surgery
   b. myopia	g. cataract	l. diabetic retinopathy
   c. hyperopia	h. glaucoma	m. AMD (age related macular degeneration)
   d. astigmatism	i. detached retina	n. conjunctivitis
   e. presbyopia	j. keratoconus

6. Describe the process of visual transduction, being sure to understand:
   1. 11-cis and all-trans retinal
   2. rhodopsin
   3. vitamin A and regeneration