The Developing Eye 7 Flashcards
What are some structural facts about the eye
It has 2 refractive surfaces
The cornea contributes 2/3rds and bends the light so rays come into focus near the eye
What is Emmetrophia
Eyes under active neural control, once this happens the eye stops growing
What is hypermetropic
In some children the eye does not start to grow due to genetic factors
What is myopia
In some children the eye continues to grow and does not stop, so the rays of light fall short of the retina
When does the eye sight usually go wrong
Teenage years, sometimes eye is stimulated to grow again- late onset myopia
Often occurs around GCSEs, a level, university so could be related to close work and stress
Teenagers need glasses
When does the retina start to fully develop
Once you are born
Due to changes in the neurons
The retina becomes in tuned to incoming info and then later on the other parts of the eye change too
The NGI is passed to the V1 and this is where most important change happens
What techniques are there to measure the visual status of a baby
Preferential looking techniques- babies tend to look at what they’re interested in, then change another screen to see if baby just looks continually at one or changes
EEG- when baby look at something interesting there should be electrical activity in the V1
Histological examinations- look how the brain alters with age, post mod term studies shows how brain develops
What is plasticity and its difference
How much we can change a system
Motor system contains huge plasticity
But perceptual system is much less- we can tune it in terms of ability however the plasticity is short lived
What happens if plasticity runs out before the system is developed
Amblyopia- child cannot see clearly
The cells do not develop properly and plasticity disappears
Occurs a lot in individuals with caterax
What is caterax
Often associated with old age, but can occur in babies
In UK they cannot out a lens in babies because the eye is still developing and growing
So they use contact lenses, or glasses until they can have a cataract operation
In terms of education why is it important to understand why children may suffer
If you spend most time thinking about what you’re doing with your hands then you cannot think as fast creatively
If you can’t make saccadic movements accurately you cannot read- so higher cognition abilities are underpinned by movement
What are motor milestones
Progress through certain ones following a pattern
Complex skills are built upon the fundamental skills you have developed
Orderly, in a time frame
What are some basic skills in the first 12 months
7-25 days (visually reaching)
3-4 months (visually controlled reaching)
5-6 months (closed loop visual control)
12 months (mature grasping behaviours)
How to assess movement in children
Movement ABC: three sections 1. Manual dexterity task 2. Ballskills 3. Static balance task Assess poor motor skills Expensive, purchasing, time consuming
How does prehension develop
Elements are mastered then brought together
At 11 yrs old it takes 400 Ms to complete an action, the time increases as age decreases
