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What retinal layer are the rods and cones found in?
Outer nuclear layer
What retinal layer are the horizontal cells, bipolar cells, and amacrine cells found?
Inner nuclear layer
What layer of the retina are the ganglia found?
inner plexiform layer
What are the three symptoms of vitamin A deficency in the eye?
- Nycatopia (night blindness)
- Xerosis (Drying of eye, Cornea)
- Xerophthalmia (faliure to produce tears)
What is the medical term for night blindness?
what is the medical term for drying of the eye or cornea?
What is the medical term for the failure to produce tears?
What is the main blood supply of the retina?
Central retinal artery
What is the main purpose of vitamin A in vision?
Converts 11-trans retinal back to 11-cis retinal
What is protanope ?
Loss of red cones
What is deuteranope?
loss of green cones
What are the most common types of color blindness?
Protanope (loss of red cones)
Deuteranope (Loss of green cones)
What causes the Na+ channels to close during visual stimulation?
Decrese in cGMP as it is converted to 5GMP by phosphodiesterase?
During phototropic conditions what are most photochemicals reduced to?
Retinal and opsins
During scotopic conditions what does retinal convert back to?
What is the visual pathway?
- 1. optic nerve
- 2. optic chiasm
- 3. optic tract
- 4. dorsal lateral geniculate body
- 5. optic radiation
- 6. Visual cortex
What are the four parts of the old visual system?
- 1.Suprochiasmatic nucleus of hypothalamus
- 2. Pretectal nuclei
- 3. Superior Colliculus
- 4. Ventral lateral genicuate body
What is the main function of the suprachiasmatic nucleus of the hypothalamus?
Regulate circadian rhythms
What is the function of the pretectal nuclie?
- Pupillary light reflex
- Accommodation of lens
How many layers are in the dorsal lateral geniculate body?
What is the function of layers II, III, and V of the LGB?
Receive info from lateral half of ipsilateral eye
What is the function of layers I, IV, VI of the LGB?
Receive info from medial half of contralateral eye
What are the magnocellular layers of the LGB?
Layers I, II
What are the main features of the magnocellular layers (I, II) of the LGB?
- Rapid conduction to V1
- Comprised of large Y ganglion cells
- Black and white only
- Poor, point-to-point
What LGB layers contain small to medium X retinal cells, have a moderate conduction, and Good color / point-to-point.
In what layer of the visual cortex do geniculocalcarine signals enter first?
What is a blind spot in the field of vision called?
What is Retinitis pigmentosa?
Melanin deposits of retina
What is strabismic Amblyopia?
What disease has lens accommodation, no pupil reaction, associated with neurosyphilis?
What are the three parts of the uveal tract?
What eye muscle is responsible for miosis?
Sphincter pupalae m.
What nerve is responsible for miosis and what type of innervation does it have?
CN 3 (Parasympathetic)
What tract in the eye has the following order Retina-->optic nerve--> pretectal neurons--> edinger-westphal neuron--> Ciliary ganglia-->sphincter pupalae muscles (Via Acetylcholine)?
What function of the eye is the following derived? Superior thoracic spinal chord--> preganglionic neurons--> superior cervical ganglion--> Dilator pupalae muscles?
what reflex utilizes increased optic power, pupillary constriction, activation of medial rectus muscles ?
How much of the refractory power is derived from the cornea?
What is the total refractory power of the eye?
what cranial nerve controlls accommodation? and is it sympathetic or parasympathetic?
What ligament and muscle are used to adjust the length of the lens?
- Suspensory ligament
- Ciliary musccle
What is the inability to accommodate which may be caused by denaturing of proteins of the lens?
What is the normal papillary diameter?
1.5 to 8mm
What type of correction is needed for astigmatism?
What is caused by short eye or weak lens which causes the focal point to be behind the retina?
Hyperopia (far sighted)
What type of lens is used to correct hyperopia?
What is myopia and what type of lens is used to fix it?
- Near sighted
- focal point anterior to retina
What is caused by O2 toxicity in premature babies?
What is the normal ocular pressure?
12-20 mm hg
What is a malignant retinal tumor in children?
What retinopathy is seen as microaneurysm, exudate, and hemorrage?
What retinopathy is seen as flame hemorrhage, papilloedema, cotton wool spots, and hard exudate?