Ophthalmology

Question 1

Emmetropia

Answer 1

Eye with no visual defects

Question 2

Ametropia

Answer 2

Refractive error present/light rays not directly focused on retina

Question 3

Myopia

Answer 3

Short sighted

• light rays brought to focus in front of retina
• eye is too long = axial myopia
• lens is too strong = index myopia

Question 4

Hypermetropia

Answer 4

Long sighted
- light rays brought to focus behind retina –> eye is too short
OR converging power of cornea or lens is too weak

Question 5

Astigmatism

Answer 5

Cornea is not spherical

Rugby ball NOT football

Question 6

What is accommodation?

Answer 6

Physiological mechanism that allows close objects to be focused on the retina

• In non accommodative state - ciliary muscle relaxed allowing suspensory ligaments of lens to remain taut
• During accommodation - ciliary muscle contracts + suspensory ligaments become lax allowing lens to assume a convex shape

Question 7

Entropion

Answer 7

In-turning of the lid, usually lower

• Causes = ageing, bacterial
• Tx = topical abx to prevent infection, tape down lower lid (temp), surgery

Question 8

Ectropion

Answer 8

Eversion of lower lid
Causes = ageing, VII CN palsy
Tx = lubrication + surgery

Question 9

Ptosis

Answer 9

Drooping of the eyelid

Question 10

Blepharitis

Answer 10

Chronic inflammation of eyelid margins

Question 11

Characteristics of Glaucoma

Answer 11

Optic disc cupping
Visual field loss
IOP is increased to impair normal optic nerve function

Question 12

Types of Glaucoma

Answer 12

Primary open angle (POAG)
Primary acute angle closure
Secondary
Congenital

Question 13

POAG syndrome

Answer 13

• Raised IOP >21
• Open aqueous draining angle e.g. no macroscopic blockage of aqueous outflow
• Pathologically cupped optic disc
• Glaucomatous visual field loss

Question 14

Normal IOP

Answer 14

10-21mmHg

Question 15

What is ocular HTN

Answer 15

Raised IOP >21 but normal optic disc + field

Question 16

Causes of POAG

Answer 16

Ageing
Steroids (topical + systemic)
Inherited

Question 17

Associations of POAG

Answer 17

Fam hx
Ocular (high myopia, retinal vein occlusion)
Systemic e.g. DM

Question 18

Sx of POAG

Answer 18

Usually none but visual loss is noticed when condition advanced

Question 19

Diagnosis of POAG

Answer 19

Reduced visual acuity (advanced)
Pathologically cupped optic discs 
- C:D ratio >0.5, pallor
- Nasal shift of vessels
- Haemorrhages 
- Asymmetry of C:D 
Glaucomatous visual field loss
Raised IOP >21
Open drainage angle on gonioscopy

Question 20

What is glaucomatous visual field loss?

Answer 20

Initially nasal step progressing to arcuate Scotoma then later tunnel vision

Question 21

Rx of POAG

Answer 21

Topical ocular hypotensive
- 1st line = latanoprost 
- 2nd line = timolol 
Systemic hypotensives e.g. acetazolamide 
Drainage surgery

Question 22

Cataracts

Answer 22

Any opacity in the normally transparent lens of the eye

Question 23

Causes of cataracts

Answer 23

Ageing = commonest 
2nd to ocular disease 
2nd to systemic disease
2nd to drugs e.g. steroids
Congenital

Question 24

Sx of cataracts

Answer 24

Gradual blurred/cloudy/misty vision, glare

Question 25

Tx of cataracts

Answer 25

Surgery - phakoemulsification + posterior chamber intraocular lens (IOL) implant

Question 26

Central retinal artery occlusion

Answer 26

- Sudden profound loss of vision - Caused by emboli obstructing the retinal artery e.g. stroke - Occasionally caused by vasculitis e.g. GCA - Cherry red spot --> due to intact reflex of fovea standing out against ischaemic retina

Question 27

Cherry red spot

Answer 27

Central retinal artery occlusion - intact reflex of the fovea stands out against ischaemic retina

Question 28

Central retinal vein occlusion

Answer 28

- Secondary to atherosclerotic thickening of central retinal artery compressing the central retinal vein at a common crossing point - Occlusion of vein results in retinal hypoxia + resultant endothelial cell damage leads to extravasation of blood Fundoscopy = severe tortuosity, engorgement of retinal veins, deep haemorrhages, cotton wool spots + optic disc swelling

Question 29

Optic atrophy

Answer 29

Death of nerve fibres in optic nerve - Pale optic disc - Primary caused by inflammation (optic neuritis), glaucoma or general retinal ischaemic - Secondary caused by longstanding papilloedema

Question 30

Papilloedema

Answer 30

Optic disc swelling secondary to raised ICP "optic disc swelling" is term used for any cause e.g. space occupying lesion, optic neuritis, malignant HTN, uveitis (TB, sarcoidosis) - Optic disc appears blurred + small haemorrhages

Question 31

Hypertensive retinopathy - grade 1

Answer 31

Arteriolar narrowing

Question 32

Hypertensive retinopathy - grade 2

Answer 32

Areas of focal narrowing + compression of venules at sites of arteriovenous crossing (AV nipping)

Question 33

Hypertensive retinopathy - grade 3

Answer 33

Features similar to those of DM retinopathy e.g. retinal haemorrhages, hard exudates + cotton wool spots

Question 34

Hypertensive retinopathy - grade 4

Answer 34

Optic disc swelling

Question 35

What are the stages of diabetic retinopathy

Answer 35

Background diabetic retinopathy Pre-proliferative retinopathy Proliferative retinopathy Advanced retinopathy

Question 36

Background diabetic retinopathy

Answer 36

- Microaneurysms (outpouchings of capillaries that leak plasma constituents into the retina) - Dot + blot haemorrhages (from bleeding capillaries in the middle layers of retina)

Question 37

Pre-proliferative diabetic retinopathy

Answer 37

Presence of retinal ischaemia represents progression from background to pre-proliferative - Cotton wool spots

Question 38

Proliferative diabetic retinopathy

Answer 38

Insufficient retinal perfusion results in production of VEGF --> development of new vessels on retina (neovascularisation) - New vessels at the disc NVD - New vessels elsewhere NVE

Question 39

Advanced diabetic retinopathy

Answer 39

- Recurrent vitreous haemorrhage from bleeding areas of NV - Tractional retinal detachments as areas of NV grow into vitreous + form fibrous bands suspending the retina - Rubeosis as NV occurs at iris + drainage angle result in increased intraocular pressure + progression to glaucoma

Question 40

Pan-retinal photocoagulation (PRP)

Answer 40

Primary tx for proliferative diabetic retinopathy | - Reduces VEGF