Vision Experiment

8/18/2019 Vision Experiment

1/38


2/38

VISIONSosa, Diane

Visual Field

Visual Acuity Train Nystagmus


3/38

PERIMETRY

a visual feldtest o eacheye

To diagnoseblindness in

specifc portiono the retina


4/38

P!"#T!$ %&A!T

'FT $ !"(&T $


5/38

VISUALFIELD

Visual area seen bythe eye at a giveninstant)

NASA' F"'D *FV"S"*N

Area seen on thenasal side

'AT!A' F"'D *FV"S"*N

Area seen on thelateral side


6/38

The normalextent of eld ofv!on

+-nasally)

.-superiorly

/-ineriorly )

0-

temporally

/


7/38

FA%T*!S T&AT '"#"TS V"S1A' F"'D

• Superiorly2 – !oo o the *rbit,

Forehead, and

(labella)• #edially2

– Nose

• "neriorly2 – %hee3 bones


8/38


9/38

V"S1A' F"'D DF%TS


10/38

%auses2

optic atrophy

indirect opticneuropathy

acute optic neuritistraumatic avulsiono optic nerve)

%haracterised by2complete blindness in

a4ected eye 5ith losso both direct onipsilateral 6concensual lightre7e8 on

contralateral side)Near re7e8 ispreserved)

g) !ight opticnerve

involvement


11/38

Le!on! thro'(h)roxmal )art ofo)t* nerve %

ipsilateral

blindness) contralateralhemianopia

abolition o directlight re7e8 on

a4ected side 6concensual lightre7e8 oncontralateral side)

near re7e8 intact)

g) !t optic nerve

"nvolvement in

Pro8imal part


12/38

causes2 suprasellar aneurysm

tumors o pituitarygland

craniopharyngioma

suprasellarmeningioma 6 glioma o9rd ventricle)

third ventriculardilatation due to

obstructivehydrocephalus)

chronic chiasmalarachnoiditis)

$hara*ter!ed -.%

:itemporalhemianopia

:itemporalhemianopic

paralysis o pupillary

re7e8) ;usually lead topartial descending optic


13/38

/#Lateral *ha!malle!on! %

causes2

•

Distension o 9rd

ventricle causingpressure on each sideo optic chiasma

•Atheroma o carotids6 posterior

communicating artery)

%haracterised by

•:inasal hemianopia

•:inasal hemianopic

parallysis opupillary re7e8;usually lead to partialdescending opticatrophy<


14/38

tra*t %

%auses2

Syphilitic meningitis=gumma)

Tuberculosis

Tumors o opticthalamus

Aneurysm o superiorcerebellar or posteriorcerebral arteries)

%haracterised by 2•"ncongruoushomonymoushemianopia 5ith %='hemianopic pupillaryreaction; 5ernic3e>s

reaction<

• These lesions usuallylead to partialdescending opticatrophy 6 may be

associated 5ith %=' 9rd

nerve paralysis 6


15/38

1#Le!on! oflateral

(en*'late-od. %

leads tohomonymoushemianopia 5ithsparing opupillary re7e8es6 may end inpartial opticatrophy)


16/38

2#Le!on! of o)t*radaton! %

%auses2

Vascular occlusionPrimary 6 secondarytumors

Trauma

%haracterised by 2

%*#P'T&*#*N$#*1S&#"AN*P"A; sometimes sparing macula<

T*TA' *PT"%!AD"AT"*N

"NV*'V#NT


17/38

'S"*NS *FPA!"TA' '*:

;involvingsuperior fbres

o opticradiations<

"NF!"*!?1AD!ANT"%&#"AN*P"A;

P" *N T&F'**!<

'S"*NS *F T#P*!A'

'*: ;involving

inerior fbres ooptic radiations<

S1P!"*!?1AD!ANT"%

&#"AN*P"A; P"

*N T&!**F<


18/38

3#Le!on! of

v!'al*ortex %

pupillary lightre7e8 is normal

6 optic atrophydoes not occurollo5ing visualcorte8 lesions)

%ongruoushomonymous

hemianopia;sparing macula<

*cclusion oposterior cerebral

artery supplyinanterior part ooccipiatl corte8

%ongruoushomonymous

macular deect

&ead in@ury=gunshot in@ury

leading to lesionso tip o occipital

corte8


19/38

P&$S"*'*("%A' :'"ND SP*T

%orresponding to optic nerve head

B. deg temporal to point o f8ation

Span C . deg horiontal

EE / deg vertical

T5o thirds belo5 the horiontalmeridian

B


20/38

V"S1A' A%1"T$

A measure o spatial resolution o theeye

An estimation o its ability todiscriminate bet5een t5o points


21/38

!S1'TS

R(htE.e

LeftE.e

Githout'ens

9=B =B

Gith'ens

=9 =.


22/38

F*VA %NT!A'"S


23/38

V"S1A' PAT&GA$


24/38

V"S1A' PAT&GA$


25/38

SN''N>S %&A!T

• Principle2 D"STANTV"S1A' A%1"T$

• the ratio o one>svisual acuity tothat o a person5ith normal visualacuity

"V V"S1A' A%1"T$


26/38

"V) V"S1A' A%1"T$

EEEEH

the distancethat thepatient 5asmade to standrom the chart

the distanceassigned to thelast ro5 they5ere able toread


27/38

RETINAL OR TRAIN

NYSTA4MUSJ*PT*K"NT"% N$STA(#1SLEhappens 5hen repetitive stimuli traverse the feld ovision

Eallo5s the eye to ollo5 ob@ects in motion 5hen headremains stationary


28/38


29/38


30/38


31/38


32/38

!etinal ;train nystagmus<

E JDancing eyesL

E *scillatory or rhythmic movementso the eye in 5hich there is a ast anda slo5 phase)

E "t is named according to the directiono the ast phase, because it is moreeasil observed)


33/38


O)to5net* Re6ex ,O7R#

- "s a second mechanism by 5hich thenervous system stabilie the visualscene on the retina

E Activated by movement o the visualscene)


34/38


Sa**ade!

- To be able to move the eye 5ith respect to

the 5orld

- So that ob@ects o importance can be ocusedonto the ovea

E Scrutinied 5ith this highEresolution part othe retina)


35/38


Smooth P'r!'t

E This system allo5s us to 3eep itstable on the ovea despite itscontinued motion)


36/38


N.!ta(m'!

E these re7e8es 5ill initially counterErotate the eyes in an attempt tomaintain a stable image on the retina)


37/38


Ver(en*e

E these re7e8es 5ill initiallycounterrotate the eyes in an attempt tomaintain a stable image on the retina)

E allo5s a target to be maintained onboth ovea during eye movement


38/38

T&ANK $*1

Documents

Vision Experiment