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Night Blindness Diagnosis and RP Signs
1. Case
20 year old boy presented with complaint
• Gradual decrease in night vision - 6 months
2. History
• Presented with a slow and gradual decrease in vision
after dark
• Problem increased for past 1 months
• No associated headache ,ocular pain, fever or
vomiting
3. Past History
• No history of trauma
• No history of any prolong illness
• No history of diabetes, hypertension or any other
systemic disease.
• No drug history or any known drug allergies
4. Family History
• Lives with parents and two younger brothers, all
healthy
• Positive family history of night blindness in maternal
grandfather
12. Retinitis pigmentosa (RP) defines a group of
hereditary retinal dystrophies initially and
predominantly affecting the rod photoreceptor cells
with subsequent degeneration of cones
Most common hereditary fundus dystrophy
Retinitis Pigmentosa
13. Inheritance pattern
Autosomal recessive - most common type of RP.
The chance of having this condition is higher if
the parents are related (for example, cousins).
14. Inheritance pattern
• Autosomal dominant - in this form of RP, only one parent
has the gene, and is usually affected by the disease as well.
Each child has a 50 per cent chance of inheriting this gene
and developing RP.
15. Inheritance pattern
X Linked. If the father is affected, all sons will be
unaffected and all daughters will be carriers. If the
mother is the carrier, 1 in 2 sons will be affected and 1
in 2 daughters will be carriers.
16. Diagnostic Criteria
SYMPTOMS
• Bilateral Involvement
• Loss of peripheral vision (Tunnel vision)
• Loss of night vision (nyctalopia)
SIGNS
Classical Triad
Retinal bone-spicule pigment
Arteriolar attenuation
Waxy disc pallor
18. Why Nyctalopia and tunnel vision?
• Rods detect low light levels.
• Rods, found in greater numbers than cones, are located
across the entire retinal surface. There is a higher
concentration of rods around the periphery (edges) of the
retina, which allows you to see what is above, below and to
the sides of the object you are directly viewing.
19. Signs of RP usually appear during childhood or adolescence. The first sign
is often night blindness followed by a gradual loss of peripheral vision. As
the disease develops, people with RP may often bump into chairs and
other objects as peripheral vision worsens and only central vision persist.
They see as if they are in a tunnel (thus the term tunnel vision).
26. Prognosis
• AR has favorable prognosis, retention of central
vision until 5th
-6th
decade.
• AD best prognosis, retention of central vision
beyond 6th
decade
• XL worst prognosis with severe visual loss by
the 4th
decade.
29. There is no cure for RP.
Low vision aids, including telescopic and magnifying
lenses, night vision scopes as well as other adaptive
devices.
Vitamin A and lutein may slow the rate at which the disease
progresses.
Treatment and Research
30. Treatment and Research
• Gene therapy research introducing a healthy
gene into retina.
• Transplant Research transplanting healthy retinal
cells
• Retinal Prosthesis implantable light-sensitive
electrode (retinal prosthesis). This prosthesis
would be introduced into the eye and function as a
“bionic retina”
31. Improving Quality of Life
• Find best vision field.
• Use low vision devices if necessary.
• Rearrange the furniture to reduce the risk of
stumbling or bumping into things.
• Have a support system
• Tell your family about ways in which they can help you
• GENETIC COUNSELING