Optics & Vision

Question 0

What happens when light is refracted?

Answer 0

Light enters the cornea; then the lens; exiting the lens.

The lens curvature & shape allow for fine focusing of an image

Question 1

What is the pathway of light entering the eye?

Answer 1

1. Cornea
2. Aqueous humor
3. Lens
4. Vitreous humor & neural layer of the retina to the photoreceptors

Question 2

Where do the suspensory ligaments attach?

Answer 2

To the ciliary body & the lens

Question 3

How does one focus for distance?

Answer 3

-Light from a distance needs very little refractory for proper focusing.

Question 4

What is the Far Point of Vision?

Answer 4

The distance beyond which the lens does not need to change shape to focus.

Question 5

What are the ciliary muscles & suspensory ligaments like during the Emmetropic eye?

Answer 5

Ciliary muscles = relaxed

Suspensory ligaments = Taut

Lens = Flat

Question 6

When the lens is flattened, is that sympathetic or parasympathetic?

Answer 6

Sympathetic

Question 7

How does one focus for Close Vision?

Answer 7

Light from a close object diverges as it approaches the eye & requires active adjustments to place image at the fovea focal point.

Question 8

What is the near point of vision?

Answer 8

The closest point at which we can focus clearly.

Representing maximum lens bulge achievable (4 inches in Emmetropic eye)

Question 9

What are the 3 simultaneous responses required for Close Vision?

Answer 9

1. Accommodation: changing the lens shape by ciliary muscles.
2. Constriction: the pupillary reflex constricts the pupils to prevent the most divergent light rays from entering the eye.
3. Convergence: medial movement of the eyeballs toward the object being viewed.

Question 10

What happens to the ciliary muscles and suspensory ligaments during Close Vision?

Answer 10

Ciliary muscles = contracted

Suspensory ligaments = Relaxed

Lens = Bulges

Question 11

When the lens is bulged, is that sympathetic or parasympathetic?

Answer 11

Parasympathetic