Night blindness, also known as nyctalopia, is caused by three main factors: 1) rod dysfunction due to vitamin A deficiency, tapetoretinal degeneration, congenital high myopia, or genetic conditions; 2) conditions affecting the transparency of the visual media like lenticular opacities or peripheral corneal issues; 3) conditions causing delayed dark adaptation such as primary open angle glaucoma.

1. CAUSES OF NIGHT
BLINDNESS
ANNA JOY
ROLL NO. 11

3. NIGHT BLINDNESS
* Impaired vision in dim light
and dark(scotopic).
* Medical term is
NYCTALOPIA

4. CAUSES
1. ROD DYSFUNCTION
2. CONDITIONS AFFECTING VISUAL
MEDIA
TRANSPARENCY
3. CONDITIONS CAUSING DELAYED
DARK

5. 1. ROD DYSFUNCTION
* Night vision is function of rods.
* seen in :
Vitamin A deficiency
Tapetoretinal Degeneration eg. Retinitis
Pigmentosa
Congenital High Myopia
Familial congenital Night Blindness
Oguchi’s disease (CSNB)

7. 2.CONDITIONS AFFECTING VISUAL
MEDIA TRANSPARENCY
In dim light , pupils dilate to allow more light
to reach retina.
Causes are
Paracentral lenticular
opacities
Peripheral Corneal

8. 3. CONDITIONS CAUSING DELAYED
DARK ADAPTATION
-PRIMARY OPEN ANGLE GLAUCOMA

10. THANK
THANK YOU