Opt - Lec1a - Anatomy

Question 1

Name the 4 anatomical structures involved in tear drainage

Answer 1

Lacrimal puncta
Lacrimal canaliculi
Lacrimal sac
Nasolacrimal duct

Question 2

Name the gland involved in tear production and how many portions does it consist of

Answer 2

Lacrimal gland

2

Question 3

How many bones form the adnexa orbit

Answer 3

7 (B1-7)

Question 4

How many canals and fissures are there in the adnexa orbit and which canal does the optic nerve and blood vessels pass?

Answer 4

C1-3

Through C1

Question 5

What is Orbital Cellulitis

Answer 5

An infection that spreads to the eye from neighbouring sinuses

Question 6

What are the extraocular muscles?

Answer 6

Four pairs of recti (R1-4)

Two pairs of obliques (O1-2)

Levator papebrae superioris

Question 7

What are the common disorders optometrists screen for concerning the extraocular muscles?

Answer 7

Strabismus - refers to ‘squint’

Amblyopia - ‘lazy eye’

Question 8

What part of the eyelid closes eyes and how does it assist in tear drainage?

Answer 8

Orbicularis oculi

Pumping action on lacrimal canaliculi and sac

Question 9

Which muscle opens eyes; normally

Wide with fright

Answer 9

Levator palpebrae superioris

Tarsal Muscles

Question 10

What is the meibomian gland?

Answer 10

Gland in the eyelid that secretes a portion a tears that prevents dry eye

Question 11

What disorders of the eyelid do optometrists screen for?

Answer 11

Blepharitis - common and sometimes called ‘dandruff’ of the eyelid

Chalazion - common eyelid lump caused by infected eyelashes or glands

Ectropion - eyelid is turned out and can occur with age and lead to damage of the eye surface

Question 12

What is the conjunctiva and why is it important?

Answer 12

Mucosal Epithelium that forms continuous sac over the sclera (White of the eye) and the inner surface of the eyelids

Why it is not possible to lose a contact lens around the back of the eye

Secretes mucus that lubricates the eyes surface

Question 13

Name 2 conjunctival disorders optometrists screen for

Answer 13

Conjunctivitis - commonly occurs due to dry eye, allergy and viral or bacterial infection

Pinguecula - common age related and harmless degeneration of the conjunctiva (seen as areas of yellowing on older eyes)

Question 14

Which part of the eye has the most refractive power?

Answer 14

Cornea - why laser refractive surgery is so effective - reshape so the cornea to correct refractive errors

Question 15

Describe 3 of the anatomical layers of the cornea

Answer 15

Epithelium - has rapid healing properties ( :) contact users)

Stroma - thickest layer - regular collagen fibres which ensure transparency

Endothelium - thinnest layer - regulates water content maintaining transparency

Question 16

How do optometrists measure corneal shape?

Answer 16

Keratoscopy/Keratometry

Question 17

What is Keratitis?

Answer 17

Inflammation of the cornea

Question 18

What is the Sclera?

And why can it appear - a. Bluish and b. yellowish

Answer 18

White part of fibrous layer of the eye consisting of 3 layers including the episclera (containing lots of blood vessels) and stroma (thickest layer, irregular collagen fibres therefore opaque) and the lamina fusca (innermost zone made up of elastic fibres)

Bluish in young children because sclera is thin or possibility of collagen disease

Yellowish in elderly (lipid deposits) or possibility of jaundice

Question 19

What sclera disorders do optometrists screen for?

Answer 19

Episcleritis - harmless form of red-eye

Scleritis - painful and more serious form of red-eye that can threaten sight

Question 20

What is the transition zone between the cornea and sclera called and what is its role?

Answer 20

Limbus or Trabecular meshwork

Involved in aqueous humour drainage. Aqueous humour is like transparent blood that feeds cornea and crystalline lens

Question 21

What Limbal disorders do optometrists screen for?

Answer 21

Tonometry - method of checking intra-ocular pressure that rises if the trabecular meshwork is blocked

Glaucoma - results from blockage of the trabecular meshwork

Question 22

Which layer of the eye is the Iris a part of?

Answer 22

Vascular layer

Question 23

Name the muscle involved in MIOSIS (constriction of the pupil)

Answer 23

Sphincter Pupillae

Question 24

Name the muscle involved in MYDRIASIS (dilation of the pupil)

Answer 24

Dilator Pupillae

Question 25

What is the role of the ciliary muscle?

Answer 25

Smooth muscle that brings about accommodation (allows eye to focus) via attachments to the crystalline lens

Question 26

What is the role of the ciliary processes?

Answer 26

Secrete aqueous humour Some anti-glaucoma drugs reduce aqueous humour production from the ciliary body

Question 27

What is Anterior Uvetitis

Answer 27

Very serious form of painful 'red-eye' that may involve the ciliary body Occurs with iritis

Question 28

What are the 3 layers of the Choroid? | The posterior part of the vascular layer of the eye

Answer 28

Bruch's membrane - passes material to and from retina Vascular layer = contains numerous blood vessels that bring nourishment to the retina Suprachoroid - contains melanin to absorb stray light

Question 29

Disorders that may affect the choroid include

Answer 29

Choroiditis - occurs with posterior uveitis and is a threat to sight Macular degeneration - may arise from disfunction of Bruch's membrane

Question 30

Name 3 key components of the crystalline lens

Answer 30

Lens capsule - governs shape changes that occur during accommodation Cortex - youngest lens fibres Nucleus - oldest lens fibres

Question 31

How is the transparency of the crystalline lens maintained?

Answer 31

Crystallins - soluble proteins Regular arrangement of lens fibres Lack of cellular organelles Antioxidants

Question 32

Name 2 common disorders of the crystalline lens

Answer 32

Cataract - occurs when mechanisms that maintain transparency fail Presbyopia - Occurs when the lens can no longer bring about accommodation therefore reading glasses required

Question 33

What is the role of the Vitreous body

Answer 33

It is a transparent gel that mechanically supports crystalline lens and retina Has a refractive component

Question 34

What are the 2 disorders of the Vitreous body that are associated with "floaters"

Answer 34

VITREOUS SYNERESIS - commonly occurs when the vitreous starts breaking down with age POSTERIOR VITREOUS DETACHMENT - occurs when the vitreous body comes away from the back of the eye leading to a large floater reports of flashes of light could indicate possible retinal tear or detachment

Question 35

Name and give the role of the 4 types of cells present in the retina

Answer 35

Rods - predominate in periphery Cones - predominate in fovea Bipolar and ganglion cells integrate and process photoreceptors signals

Question 36

The optic nerve head is the route by which

Answer 36

Ganglion cell nerve fibres take visual signals from eye to brain Central retinal arteries enter eye Central retinal veins leave eye

Question 37

Why is the optic nerve head a physiological blind spot? And how is it typically shaped?

Answer 37

Because photoreceptors are absent Cupped

Question 38

Name 2 common disorders that might cause optic nerve damage

Answer 38

Glaucoma - may cause exaggerated cupping of the optic nerve head Brain disease - may cause optic. Nerve swelling or pallor

Question 39

``` The ocular adnexa include all EXCEPT: A. Extraocular muscles B. Conjunctiva C. Lacrimal gland D. Cornea E. Eye-lids ```

Answer 39

Cornea (? Check paper copy of lecture)

Question 40

Is this statement true or false? Contraction of the sphincter Pupillae brings about MYDRIASIS

Answer 40

False - Contraction of the sphincter Pupillae brings about MIOSIS - constricts the pupil MYDRIASIS = dilation of the pupil is caused by the Diltor Pupillae

Question 41

Is this statement true or false? Ciliary processes are connections between the ciliary body and the crystalline lens

Answer 41

False - Ciliary processes secrete aqueous humour It is the ciliary muscle that attaches the ciliary body and crystalline lens to bring about accommodation

Question 42

Is this statement true or false? The Uveal tract is made up of the iris, ciliary body and the choroid

Answer 42

True

Question 43

Is this statement true or false? Macular degeneration may occur due to dysfunction of the supra choroid

Answer 43

False - Macular degeneration may arise from dysfunction of Bruch's membrane

Question 44

Is this statement true or false? The nucleus of the crystalline lens governs lens shape during accommodation

Answer 44

False - the LENS CAPSULE governs shape changes that occur during accommodation The Nucleus is the oldest lens fibres

Question 45

What is the ocular adnexa

Answer 45

Lacrimal apparatus, orbit, extra ocular muscles, eyelids, conjunctiva