Hyperobia

• What is hyperopia also known as?

  Hypermetropia
• In a hyperopic eye, where does the far point lie?

  Behind the eye
• What happens to the retinal image in a hyperopic eye?

  The retinal image is defocused
• How can a hyperopic eye bring an image into sharp focus?

  By having sufficient amplitude of accommodation
• What causes hyperopia in the eye?

  • Mismatch between the length of the eye and its power
  • Eye being too short for its length
  • Eye being too weak for its power
• How can a hyperopic eye focus clearly on distant objects?

  By viewing through a positive powered lens of appropriate power
• What is the prevalence of hyperopia in children aged 2–6 years?

  1. 8%
• What is the prevalence of hyperopia in adults aged 18–35 years?

  1. 9%
• What difficulty do many young hyperopes face?

  Relaxing their accommodation completely
• What produces a degree of latent hyperopia in young hyperopes?

  A residual tonus in the ciliary muscle
• What are the components of total hyperopia?

  • Manifest hyperopia
  • Latent hyperopia
  • Facultative hyperopia (overcome by accommodation)
  • Absolute hyperopia (remaining deficit)
• How does the manifest component of total hyperopia change with age?

  It increases at the expense of the latent component
• What symptoms do uncorrected hyperopes commonly experience?

  Sore eyes and headaches with close visual tasks
• What term is used to describe the visual discomfort experienced by hyperopes?

  Asthenopia
• Why do hyperopes experience more accommodative effort than emmetropes and myopes?

  Because they must exert more effort to view close objects
• How does the degree of convergence used by hyperopes compare to the level of accommodation demanded?

  It is inappropriate for the level of accommodation
• What happens to the clarity of vision for hyperopes at near versus distance?

  Blurring is greater at near than at distance
• Why should the term "long sight" be discouraged when describing hyperopia?

  Because hyperopes may not see distant objects clearly
• In hyperopia, where is the far point located?

  Behind the eye
• What does a hyperopic eye struggle to focus on?

  Distant objects
• What does it mean when the far point is described as "beyond infinity"?

  It means the far point is located beyond the retina
• What is the relationship between the far point and clear vision in a hyperopic eye?

  Clear vision is possible if accommodation is engaged
• How does the distance of the far point relate to the severity of hyperopia?

  The closer the far point is to the eye, the larger the hyperopia
• What is a significant risk associated with high hyperopia in infants?

  Increased likelihood of developing strabismus
• What is the association of high hyperopia with amblyopia and strabismus?

  It is a major justification for universal vision screening
• What developmental disorders are associated with high hyperopia?

  Microphthalmos and nanophthalmos
• What is antimetropia?

  A condition where one eye is myopic and the other is hyperopic
• What characterizes axial hyperopia?

  The eye's second focal length is longer than its axial length
• If the axial length is $k' =$$+$$21.75 \text{ mm}$, what is the power of the eye?


  $Fo =$$+$$60D$
• What is the ocular refraction if $K =$$K' - F$ and $K' =$$+$$61.29D$?


  $K =$$1.29D$
• If an object is situated $77.52 \text{ cm}$ behind the reduced surface, what is the far point distance?


  $k =$$1 \text{ m} \cdot K =$$1 \cdot 100 \cdot 1.29 =$$+$$77.52 \text{ cm}$
• What is the magnification of the system if $h =$$5 \text{ mm}$ and $m =$$\frac{K}{K'} =$$\frac{1.29}{61.29}$?


  $h' =$$0.021 \cdot 5 =$$0.105 \text{ mm}$
• How is refractive hyperopia characterized?

  Power of the eye is non-standard, but axial length is standard
• If ocular refraction $K =$$+$$1.25D$, what is the power of the ametropic eye?


  $F' =$$K' - K =$$60 - 1.25 =$$+$$58.75D$
• What is the second focal length if $f' =$$\frac{n'}{F'} =$$\frac{1.333 \times 1000}{58.75}$?


  $f' =$$+$$22.69 \text{ cm}$
• What is the far point distance if $k =$$\frac{n}{K} =$$\frac{1 \times 100}{1.25}$?


  $k =$$80 \text{ cm}$
• What is the magnification of the system if $m =$$\frac{K}{K'} =$$\frac{1.25}{60}$?


  $m =$$+$$0.0208$
• How is hyperopia corrected?

  By imaging a distant object in the far point plane of the eye
• What type of lens is used to correct hyperopia?

  A positive spectacle lens
• What is the relationship between the second principal focus of the spectacle lens and the far point of the eye?

  They are coincident