OL 6 Flashcards
what is the refracting power of the anterior and posterior cornea?
what is the equivalent power?
Anterior cornea= +48.205D
Posterior cornea= -5.970D
equivalent power= +42D
what happens to the lens as we age and the effects it has o the radius of curvature?
lens grows throughout life becoming axially thicker with age.
As a result, the radius of curvature alters with age. Radius of curvature also alters with accommodation.
What is the Radius of curvature of the average unaccommodated anterior and posterior lens surface?
anterior surface = 10.000 mm posterior surface = -6.000 mm
what is the Radius of curvature of the average unaccommodated anterior and posterior nucleus?
anterior surface = 7.911 mm posterior surface = -5.760 mm
what is the refractive index of the cornea?
1.376
what is the refractive index of the aqueous humour?
1.336
what is the refractive index of the vitreous humour?
1.336
what is the refractive index of the crystalline lens including both the cortex and the nucleus?
cortex= 1.386 nucleus= 1.406
describe gull strands simplified schematic eye?
It has a single surface cornea
The cystalline lens is considered as a single homogenous entity with two refracting surfaces.
what is the power of the reduced eye?
+60D
what is the reduced eye?
eye can be further simplified by ignoring the lens altogether and considering the cornea as the only refracting surface (for calculation purposes)
The eye in its weakest dioptric state is said to be ———
unaccommodated
define far point?
The far point is that point which is conjugate (interchangeable) with the centre of the macula by refraction at the unaccommodated eye
where is the far point in emmetropia?
at infinity
where is the far point in myopia?
a finite distance from the front of the eye
