physiology of eye and vision

2. .
PHYSIOLOGY AND
NEUROLOGY OF
VISION

3. Physiology of eye
Physiology of eye:
• 0,2ul/mint 10%
• Aqueous secration and execration
Active 75%
• Light wave
• Red,Orange, yellow , green,blue ,
indigo, violet (7colors rays)
Primary color is red, green, blue.

5. Physiology of vision
The spectrum of light:
From397mu to723mu
Mechanism of colour vision
e.g: white all rays reflect
black all rays absorb

8. Physiology of vision
• Refraction of the light rays:
• Refreactive media
• Cornea, Aqueous humor, lens,
vitreous
• ACCOMMODATION FOR THE EYE
• LENS
• PUPIL
• MOVEMENT OF THE EYE BALL

9. Function of the retina
• Sensitive cells RODS and CONS
• Rods is more sensitive then cons
• (Scotopic) vision sensitive to dim
light (periphery of retina)
• Rhodopsin (carotene)
• (phot optic vision) Cons sensitive
to bright and color (macula )
• Phot opsin

10. Visual perceptions
1.Light sense
• Light minimum
• Dark adaptation
dark adaptation time
2. Form sense (Visual aquity)
3. Sense of contrast
4. Color vision
Color vision test (ishchara chart)
Trichromatic (red , green ,blue)
Color blindness (achromatopsia)
a. Congenital b. acquired
Male 1% female 0,4 %
Most case blindness GREEN

11. Color vision test (ishchara
chart)

12. Binocular vision
• Binocular (stereoscopic vision)
• Optic media
cornea, Aqueous humor, lens, vitreous

13. Visual pathway
• First : order neuron (cons and rod)
• Second : order neuron(Ganglion
cells L.G.B)
• Third : order neuron (occipital
cortex visual center)

14. Lesions of the visual
pathway
1.Hemianopia: :‫نیمای‬ ‫سترګی‬ ‫یو‬
‫تللی‬ ‫مینځه‬ ‫له‬ ‫دید‬ ‫مخیطی‬.
Trauma.
Inflammation
Tumor
vascular lesion
Degeneration
2. Amblyopia
3. Amaurosis

15. Hemianopia
Homonymous hemianopia ‫ښي‬ ‫سترګو‬ ‫دواړو‬ ‫د‬
‫تګ‬ ‫لمنځه‬ ‫له‬ ‫ددید‬ ‫طرف‬ ‫نیمایي‬ ‫چپ‬ ‫یا‬ ‫او‬ ‫نیماي‬
(optic tract, optic radiation occipital
cortex)
Bitemporal hemianopia
(central part of optic chiasma)
Binasal hemianopia
(either side optic chiasma)

17. +

18. 2. Amblopia (blunt)
‫دی‬ ‫د‬ ‫سترګو‬ ‫دواړو‬ ‫د‬ ‫یا‬ ‫او‬ ‫یوي‬ ‫د‬ ‫ډول‬ ‫موضوعي‬ ‫په‬‫د‬‫د‬‫اندازي‬
‫کمبود‬،‫اپتلموسکوپ‬ ‫د‬ ‫چي‬ ‫کي‬ ‫حال‬ ‫داسي‬ ‫په‬‫په‬ ‫واسطه‬ ‫په‬
‫سترګو‬‫د‬ ‫کی‬‫شي‬ ‫لیدل‬ ‫نه‬ ‫و‬ ‫عالیم‬ ‫پتالوژي‬
Etiology :
1. Unilateral amblyopia :
visual pathway problem
high refractive error
retro bulbar neuritis
1. Bilateral amblyopia
• Toxic amblyopia
• Hysteria

21. Amaurosis (dark)
•‫په‬‫مکمل‬‫لن‬ ‫د‬ ‫سترګو‬ ‫دواړو‬ ‫د‬ ‫یا‬ ‫او‬ ‫سترکی‬ ‫یوی‬ ‫د‬ ‫ډول‬‫ډ‬
‫کیږی‬ ‫ویل‬ ‫ته‬ ‫تللو‬ ‫منځه‬ ‫له‬ ‫دید‬ ‫د‬ ‫لپاره‬ ‫وخت‬
Complete loss of sight one or both eye
Etiology:
Unilateral anaurosis
Bilateral amaurosis
• Uremia
• Meningitis
• Hysteria
• Retinal aplasia

22. ‫پوښتنی؟‬