3.3 - Hypermetropia

Question 1

What is hypermetropia

Answer 1

• Second focal point Fe’ falls behind the retina for an unaccommodated eye
• Retinal image is blurred but not always!

Question 2

Where is sharp image produced in hypermetropia

Answer 2

Behind retina

Question 3

Ray diagram for hypermetropia

Answer 3

• Parallel converting rays of light coming into reduced eye and converge towards far point
• Sharp image behind retina
• Infinitely distant object forming image at 2nd focal point behind retina
• Virtual point is conjugate with real image - object point conjugate with retina

Question 4

Where is far point in hypermetropia

Answer 4

Behind eye - virtual point

Question 5

What happens to axial length in hypermetropia

Answer 5

Too short

Question 6

What is effect of hypermetropi on vision

Answer 6

Can sometimes look the same, no change in vision with increasing levels of hypermetropia

Question 7

How does sharp image form at retina in hypermetropia

Answer 7

• Converging light coming into eye converging towards the far point
• The light then converges and forms a sharp image at the retina

Question 8

What is acommodation

Answer 8

• Ability of eye to increase its optical power with an effort to focus at near objects
• Good ability to focus on objects closer to eye

Question 9

What happens as you get older

Answer 9

You lose ability to accommodate

Question 10

Why does lens change in acommodation

Answer 10

Lens changes to increase its dioptric power allowing to focus on near objects

Question 11

What happens in unacommodated eye

Answer 11

Eye has its weakest/least optical power

Question 12

What is presbyopia

Answer 12

• As you get older, ability to accommodate decreases

- Its a condition where accomodation is insufficient for near work

Question 13

At what age does accommodation become negligible

Answer 13

Accommodation declines with age – negligible after 60 years

Question 14

True or false - myopes can focus on near objects without acommondation

Answer 14

True

Question 15

What happens if you increase the dioptic power of the eye

Answer 15

It can place the optical image on the retina

It can compensate for the hypermetropia

Question 16

What happens in process of accommodation

Answer 16

Acommodation is ability of eye to increase its positive power – converge light more rapidly so it can move that image from behind retina to on retina = sharp clear image = no decrease in vision as hypermetropia increases