Eye Anatomy: Cornea and Sclera

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What is the function of the limbus in relation to the cornea?

To provide a pathway for aqueous humour outflow
To provide nourishment to the peripheral cornea (correct)
To regulate corneal stroma swelling pressure
To transmit circumferential or tangential collagen fibrils

What is the characteristic of terminal axons in the corneal nerves?

They are very sensitive to pain and temperature (correct)
They have a high myelin sheath content
They are relatively insensitive to pain and temperature
They are only present in the sclera

What creates a swelling pressure in the corneal stroma?

The relatively avascular nature of the sclera
The absence of elastic fibres
The Donnan effect (correct)
The presence of collagen fibrils

What is the characteristic of the corneal stroma?

It is a biological polyelectrolyte gel with a net electrical charge (C) Signup and view all the answers

What is the significance of the circumferential or tangential collagen fibrils in the limbus?

They provide structural support to the cornea (D) Signup and view all the answers

What is the relationship between the corneal touch threshold (CTT) and sensitivity (s)?

s = 1/CTT (C) Signup and view all the answers

What is the result of the transient binding of free chloride ions to the ligands?

Donnan-osmotic swelling (D) Signup and view all the answers

What is the refractive index of human corneal collagen?

1.411 (C) Signup and view all the answers

What is the name of the theory that suggests the cornea is transparent because the refractive index of the collagen fibrils matches the refractive index of the matrix?

Uniform Refractive Index (B) Signup and view all the answers

What is the main reason why the cornea is transparent, according to the Short Range Order theory?

The destructive interference of scattered light (D) Signup and view all the answers

What is the characteristic of the collagen fibrils that allows them to act as a diffraction grating?

Their uniform diameter (A) Signup and view all the answers

What happens to the straight through light when it passes through the cornea?

It undergoes constructive interference (B) Signup and view all the answers

What type of proteins are present in the cytoplasm of keratocytes?

Corneal crystallins (A) Signup and view all the answers

What type of order is absent in the arrangement of collagen fibrils in the cornea, according to X-ray diffraction studies?

Long-range order (D) Signup and view all the answers

Why are keratocytes transparent?

Due to their uniform refractive index and thinness in the direction of the light path (A) Signup and view all the answers

What is the characteristic of the hexagonal fibers in the lens?

They contain crystallins and have a liquid-like short range order (D) Signup and view all the answers

What is the function of alpha-crystallin in the lens?

It maintains the transparency of the lens (C) Signup and view all the answers

What is the prevalence of age-related cataracts in people over 85 years of age?

95% (C) Signup and view all the answers