Retinal Dystrophies ✅ Flashcards
What is phototransduction?
The process by which light is converted into electrical signals
How can the electrical transmission of light be assessed?
Using an electrodiagnostic test called electroretinogram
What does the electroretinogram test?
The rod pathway after dark adaptation, and the cone pathway after light adaptation
How is the rod pathway tested with an electroretinogram?
Using a dim light (to which cones are insensitive)
How is the cone pathway tested?
Using a bright flash and flicker light stimulus (to which rods are unable to respond)
What does the phototransduction pathway rely on?
Many proteins
What is the result of the phototransduction pathway relying on many proteins?
Retinal dysfunction due to mutation or deletion of genes encoding these proteins is common
What % of males are colour blind?
8%
What causes colour blindness?
Mutations of the cone pigments, which alters spectral sensitivity, causing colour blindness
What is implicated in retinal and macular dystrophy?
Hundreds of different gene mutations
What does retinal and macular dystrophy account for?
A quarter of all childhood blindness in the UK
When during childhood can retinal dystrophies develop?
At any stage
Are retinal dystrophies progressive or non-progressive?
Can be either
Give an example of a cause of progressive retinal dystrophy?
RDS gene mutation in autosomal dominant retinal dystrophy
What causes the progressive retinal dystrophy in RDS gene mutation?
Ongoing cell death from accumulated toxic metabolic products
