vision

Question 1

what are the two classes of ganglion cells

Answer 1

magnocellular and parvocellular

Question 2

what are the eye changes in albinism

Answer 2

nystagmus, astigmatism, hypoplasia of optic nerve

Question 3

what are the differences between magnocellular and parvocellular pathways

Answer 3

M: motion sensitive pathway and luminance control; L: fine detail and colour vision

Question 4

what is the split of pathways in reticular radiation

Answer 4

inferior fibres => through Meyers loop of temporal lobe ; superior fibres => through parietal lobe

Question 5

what are the orientation columns

Answer 5

arrangement of neurons of similar receptive fields in orientation columns=> horizontal, vertical R and L oblique

Question 6

What is a blob

Answer 6

interaction of orientation column relate to colour vision

Question 7

what are the hyper-columns

Answer 7

columns that lines between orientations in a region

Question 8

what is Amblyopia

Answer 8

lazy eye : Abnormalities within the eyes that lead to the brain ignoring one of the eyes to prevent double vision

Question 9

what is starbism

Answer 9

misalignment of the eyes

Question 10

what is anisometropia

Answer 10

refractive differences between two eyes

Question 11

name eye turned out/in eye higher/lower

Answer 11

EN/ESO TROPIA; hyper/hypo TROPIA

Question 12

define conjugate movement

Answer 12

parallel movements of the eyes in order to maintain focus on a moving object

Question 13

define saccades

Answer 13

: rapid eye movements allowing rapid re-fixation of gaze from one object to another

Question 14

define nystagmus

Answer 14

repetitive to-and-from movement of the eye

Question 15

what are pendular nystagmus

Answer 15

when the two phases are of equal lengths

Question 16

what are phasic/jerky nystagmus

Answer 16

slow movement to a limit of one direction by jerky movement in the opposite direction (described in relation of the first phase, can be horizontal or vertical)

Question 17

what are causes of nystagmus

Answer 17

visual, vestibular, cerebellar and brain stem pathways

Question 18

what are the P and M pathways in the cortex

Answer 18

P (ventral)= V2 (counter) V4 (colour and form) M(dorsal) = V3(global motion) V5 (motion)

Question 19

define visual field

Answer 19

part of physical world from which source of light impinges on defined part of retina

Question 20

define retinal field

Answer 20

piece of retina upon which light from external objects falls upon

Question 21

What is the pathway of ocular reflex

Answer 21

CNII=> lateral geniculate nucleus=> pretectal nucleus=> (No Suggestions) nucleus=> CNIII=> pupil constriction

Question 22

What is the pathway of corneal reflex

Answer 22

CNV1 => temporal and zygomatic of facial => orbicularis oculi

Question 23

What is the pathway of vestibulo-ocular reflex

Answer 23

eye movement opposite to the head movement. Vestibular apparatus (movement detection)=>CNVIII=>CN of extraocular muscles

Question 24

what is the problem with Mayer’s loop lesion how is it different to optic tract lesion

Answer 24

Homonymous Upper Quadrantanopia splitting of fibres in the optic tract it is homonymous hemianopia

Question 25

What would be presentation and cause of right nasal hemianopia

Answer 25

diplopia, headache and nausea due to loss of vision in temporal retina e.g. due to cortex tumour

Question 26

what is exophthalmos

Answer 26

Protrusion of the eye, causing the eyelids to part more than normal so that the whites of the sclera are visible all around the cornea and iris

Question 27

what are the causes of exophthalmos

Answer 27

bilateral Graves; unilateral aneurism or haematoma

Question 28

what signs of RICP can be seen in the eye

Answer 28

papilloedema