False regarding retinitis pigmentosa is: (AIIMS Nov 2012)
|A||ERG is normal|
|B||Narrowing of vessel|
|C||Pale waxy disc|
1. Retinitis pigmentosa is also known as pigmentary retinal dystrophy.
2. It is a slow degenerative Qdisease of retina which begins in childhood and almost invariably affects both eyes. Q
3. It results in blindness in middle or advanced age.
4. The degeneration affects primarily the rods Q and invoves the as it progreses cones Starts near the equator of eye. Macular region is not affected until a very late stage.
5. Most important symptom is defective vision in night (nyctalopia).
6. The field of vision show concentric contraction leading to ring Q scotoma.
7. Central vision is retained for a long time but the patient experiences great difficulty due to their tube vision.
8. In the midperiphery of retina there are black pigmentation resembling bone corpuscles.
9. The retinal veins often have a sheath of Q pigment.
10. Retinal arteries never show such pigmentary changes.
11. The retinal blood vessels, both arteries and veins, are extremely Q attenuated Q and thread like.
12. As the disease progresses consecutive optic atrophy sets in.
13. The electroretinogram (ERG) is flat or extinguished early in the course of disease.
14. Usher syndrome is the most common systemic association of RP sensorineural hearing loss occuse.