Chapter 3- Refractive error (2) Flashcards
What lenses do we use to treat myopia?
Negative lenses
What is the far point?
The farthest point from the eye where objects can still be seen clearly.
What does the negative lens do to light?
It diverges the light
By diverging the light, how are objects perceived?
It makes objects appear to come from the far point of the eye.
For myopia correction, what is the connection between the objects at the far point and the retina?
Objects at the far point are focused clearly on the retina
What lenses are used to treat hypermetropia?
Positive lenses
What do the positive lenses do?
They make objects appear bigger.
What do positive lenses do to light?
It converges light
By converging light, how are objects perceived?
It makes object appear to come from the far point of the eye.
For hypermetropia correction, what is the connection between the objects at the far point and the retina?
Objects at the far point are focused clearly on the retina
What are positive lenses also used for?
Reading
What is accommodation?
The adjustment of the optics of the eye to keep an object in focus on the retina.
What does accommodation allow?
Accommodation allows the eye to automatically adjust focus from seeing things at a distance to seeing nearer objects.
What is presbyopia?
A reduction in focus/ accommodation over time. Comes with age.
For a sphere, +VE is for what?
Hypermetropia
