3.3- Hypermetropia

Question 1

What does hypermetropia mean?

Answer 1

• Means beyond (measure of) the eye
• Second focal point Fe’ falls behind the retina for an unaccounted eye
• Retinal image is blurred but not always.

Question 2

Where is the far point in hypermetropia?

Answer 2

Far point mR is behind the eye- virtual point- have converging light into eye and towards far point and then forms a sharp point onto retina
-virtual point that is conjugate with a real image on the retina

Question 3

What are the effects of different levels of hypermetropia on vision?

Answer 3

-Test chart can look the same if increase hypermetropia - no change in vision compared to myopia having loss of vision

Question 4

Why doesn’t vision change for increasing levels of hypermetropia?

Answer 4

• due to accommodation
• lens shape from being accommodated on one side and unaccomodated on the other side which increases the dioptric power of the eye
• Hence have good ability to focus on near objects
• Unaccomodated - eye has its weakest optical power
• Accomodated - the ability of eye to increase its optical power with an effort to focus at near objects

Question 5

What is presbyopia?

Answer 5

reduction in accommodation with age- negligible after 60 years

• Natural
• defintion: condition where accommodation is insufficient for near work

Question 6

How do hypermtropes accommodate?

Answer 6

• Increase in dioptric power of the eye place the optical image/focus image on the retina from behind retina.
• In young subjects, accommodation can compensate for hypermetropia but there are consequences e.g squint
• Accommodation can explain results when refracting a hypermetrope