sclera

Question 1

overview of sclera

Answer 1

• Tough white outer protective collagenous coat of the eye
• Sclera is continuous with the cornea, the line of union is called the limbus
• Contains collagen, proteins & mucopolysaccharide

Question 2

function of sclera

Answer 2

• Protects the eye from injury
• Supports the eye (with help of IOP & allow vessels, nerves to pass through)
• Anchorage for structures both within the globe and outside (uvea & extraocular muscles )

Question 3

sclera openings

Answer 3

has 2 large openings and few other smaller openings:
- Large openings
> Anterior scleral foramen (adjacent to cornea)
> Posterior scleral foramen (in optic nerve head)
- small openings
> the rest of openings are passages for nerve and blood vessels

Question 4

sclera layers (further to closest to choroid)

Answer 4

1. episclera
2. sclera stroma
3. lamina fusca

Question 5

episclera

Answer 5

• vascular tissue layer lying between scleral stroma and bulbar conjunctiva. has collagen
• fine blood vessels can be seen through conjunctiva

Question 6

scleral stroma

Answer 6

• composed of collagen fibres, fibroblast and mucopolysaccharide
• collagen fibrils are of various thickness & irregularly arranged
• relatively avascular

Question 7

lamina fusca

Answer 7

• Inner most layer of the sclera between scleral stroma and choroid
• Consist of collagen fibres, fibroblasts and melanocytes
• Has blood vessels and nerve endings that enroute to other parts of the eyeball

Question 8

sclera blood supply

Answer 8

• Few blood vessels
• Anteriorly supplied by:
  > anterior ciliary arteries and veins
• Posteriorly supplied by:
• circle of Haller-Zinn (around optic nerve)

Question 9

sclera nerve supply

Answer 9

• Few sensory nerve fibres (not as sensitive as cornea)

- Nerves in the sclera join the long or short posterior ciliary nerves