THE EYEBALL AND FIBROUS LAYER

Question 1

length of an eyeball

Answer 1

25 mm in diameter

Question 2

eyeball is suspended

Answer 2

Suspended by 6
extrinsic muscles and a
connective tissue layer

Question 3

the connective tissue of the eyeball

Answer 3

Posteriorly bulbar
fascia*

Anteriorly bulbar
conjunctiva

Question 4

episcleral space

Answer 4

above sclera facilitates

movement of the eye

Question 5

the fibrous layer of an eyeball

Answer 5

1. sclera
2. cornea
3. corneal limbus

Question 6

1. sclera

Answer 6

opaque white of eye
covering 5/6 posteriorly.
Provides attachment for
extrinsic and intrinsic
muscles. Largely avascular

Question 7

2. cornea

Answer 7

transparent 1/6
anteriorly. Greater convexity
than sclera. Totally avascular,
highly sensitive (ophthalmic
nerve CN V1).

Question 8

3. corneal limbus

Answer 8

is the angle
formed by the intersecting
curvatures of the cornea and
sclera at the corneoscleral
junction*

Question 9

the vascular layer of an eyeball

Answer 9

1. choroid
2. ciliary body
3. iris

Question 10

1. choroid

Answer 10

The choroid is dark red and
forms most of the
vascular layer between
the sclera and the retina.

Dense vascular bed*
with larger vessels
externally and finer ones
(capillary lamina) close
to retina.

Adheres to
retina, but can detach
from sclera easily.

Question 11

2. ciliary body

Answer 11

Ciliary body continuous
with choroid anteriorly
and connects the choroid to
the circumference of
the iris.

Muscular* and
vascular ring‐like
thickening behind
corneoscleral junction.

Provides attachment for
the lens*.

 Internal folds
known as ciliary
processes secrete
aqueous humor* into
anterior chamber of
eye

Question 12

3. iris

Answer 12

Iris lies on the anterior surface
of lens.

Thin contractile
diaphragm with an opening
to allow in light know as
the pupil.

 Sphincter
pupillage (circular)
decreases diameter and is
an instant
parasympathetic response.

Dilator pupillae (radial)
increases the diameter and is a
much slower sympathetic
response*

Question 13

the inner layer of an eyeball

Answer 13

the retina

Question 14

the retina

Answer 14

The retina is the sensory
neural layer and consists
of:
 The visual/optic part is
photosensitive and has a
neural light receptive layer
and a pigmented layer*
with rods and cones

 The non-visual part is the
anterior continuation of
the pigmented layer and
covers the ciliary body and
iris to the pupillary margin.
It is a layer of supporting
cells

Question 15

Fundus of the eyeball where
light enters and is
concentrated on the

Answer 15

e posterior

part of eyeball

Question 16

The optic disc has no
photoreceptors (blind spot) in
the fundus where the

Answer 16

neurovascular bundle of the
optic nerve (CN II) enters the
eye

Question 17

Macula lutea is

Answer 17

oval area with
photoreceptive cones* just
lateral to the optic disc

Question 18

Fovea
the central area of most acute
vision. Foveola is

Answer 18

central part

approx. 1,5 mm in diameter

Question 19

movements of the eye

Answer 19

• Three axes:
 Vertical:
abduction/adduction

 Transverse:
elevation/depression

 Anterior‐posterior: medial
rotation or intorsion/lateral
rotation or extortion

• Note! Orbital axis is not
the same as the optical
axis