Nyctalopia eye disease Night blindness

2. DEFINITION
Also termed as Night blindness
Defined as diminution of vision in
dim light
Observe as a symptoms of different
eye disease

3. ETIOLOGY
• Causes:
• Vitamin A deficiency
• Retinitis pigmentosa
• Congenital night
blindness
• Pathological myopia
• Advance primary open
angle glaucoma
Night
blindness
may exist
from birth or
be caused by
injury or
malnutrition
(for example
Vitamin A
deficiency)

4. VITAMIN A DEFICIENCY
 Inhibits the production of rhodopsin(the
eye pigment responsible for sensing low
light situations) found in the retina
composed of retinal(active form of retina)
 The decreased amount of rhodopsin in the
eye implies that there is inadequate retinal
to bind opsin. Therefore night blindness
result.

5. RETINITIS PIGMENTOSA
A disorder in which the
rod cell in the retina
gradually lose their to
response to the light.
Patients suffering from
this genetic condition
have progressive
nyctalopia and eventually
their day time vision may
also affected(Hamarlopia)

6. TREATMENT
 Treat the underlying cause:
The treatment method depends on the cause
of the night blindness:
I. Vitamin A deficiency- treated by giving
Vitamin A supplement
II.Retinitis pigmentosa-not completely
curable but the rate of progression of
this disease may reduced by intake of
vitamin A supplement and surgeries
(retinal transplant)

7. TREATMENT CONT.
Myopia: use of
corrective glasses
or lenses or
refractive surgery
Glaucoma:
Switching of
glaucoma medicine
medicine may help
Peripheral cataract:
cataract surgeries
Oguchi’s disease:
incurable

8. THANK YOU