3.3- Hypermetropia Flashcards

1
Q

What does hypermetropia mean?

A
  • 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.
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2
Q

Where is the far point in hypermetropia?

A

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

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3
Q

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

A

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

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4
Q

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

A
  • 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
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5
Q

What is presbyopia?

A

reduction in accommodation with age- negligible after 60 years

  • Natural
  • defintion: condition where accommodation is insufficient for near work
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6
Q

How do hypermtropes accommodate?

A
  • 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
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