General Disease

Question 1

Why is diabetes mellitus significant to the eye?

Answer 1

2nd leading cause of blindness in <65s in Western World (1st = genetics).

Visual loss may occur through:

1. Diabetic retinopathy
2. Cataract
3. Glaucoma
4. Ischaemic optic neuropathy
5. Retinal vein + artery occlusions
6. CN III/IV/VI palsy

Question 2

History suggestive of diabetic eye disease?

Exam?

Answer 2

Polyuria, polydipsia, fatigue, blurred vision, persistent dark specks in visual field (floaters), visual distortion

Mild non-proliferative diabetic retinopathy: may see fatty exudates, microaneurysms, haemorrhages. Chronic hyperglycaemia leads to biochemical + inflammatory changes in the retina that result in:

• Leakage
• Occlusion
• New blood vessel growth (if proliferative retinopathy)

May have very good vision (6/6) unless exudates are very central! Therefore screening needed to pick up early.

Question 3

How is diabetic retinopathy classified?

Answer 3

Background
Pre-proliferative
Proliferative
Advanced proliferative

Question 4

What signs are there in background diabetic retinopathy?

Answer 4

Microaneurysms (localised outpouchings of capillaries that leak plasma constituents into the retina) - may be clinically indistinguishable from small dot and blot haemorrhages (also found in pre-proliferative retinopathy and arise from bleeding capillaries in middle layers of retina)

Question 5

What signs are there in pre-proliferative diabetic retinopathy?

Management?

Answer 5

Retinal ischaemia distinguishes it from background retinopathy

Cotton wool spots (small, fluffy, superficial) - accumulations of dead nerve cells from ischaemic damage

Venous changes and intraretinal microvascular abnormalities (IRMA)

Overall: small haemorrhages, hard exudates and cotton wool spots. If severe: widespread haemorrhages.

Annual follow up, if severe 6/12 follow up

Question 6

What signs are there in proliferative diabetic retinopathy?

Answer 6

Insufficient retinal perfusion> VEGF production > new vessels on the retina (neovascularisation).

New vessels may be at the disc: “new vessels at the disc” (NVD), or over the other areas of the retina “new vessels elsewhere” (NVE).

Question 7

What signs are there in advanced diabetic retinopathy?

Answer 7

Recurrent vitreous haemorrhage from bleeding areas of neovascularisation

Tractional retinal detachments as areas of neovascularisation grow into the vitreous and form fibrous bands suspending the retina

Rubeosis as neovascularisation occurs at the iris (NVI) and drainage angle resulting in increased intraocular pressure and progressive glaucoma

Question 8

What is diabetic maculopathy?

Mgmt?

Answer 8

Hard exudates and/or macular oedema at the macula

Unlikely to be asked to identify oedema as it is hard to visualise using a direct ophthalmoscope

Hard exudates = waxy yellow lesions, distinct margins, clumps or rings, often surrounding leaking microaneurysms (lipid/protein material in outer retinal layers).

Refer to opthalmology

Question 9

Overall mgmt of diabetic retinopathy?

Answer 9

Pan-Retinal Photocoagulation (PRP) - primary Tx for PROLIFERATIVE diabetic retinopathy - reduces production of VEGF by reducing the oxygen demand from the peripheral retina- clinically it is seen as clusters of burn marks on the retina.

About 10-15% people with heavy lasers may lose enough vision to lose driving lisence

Glucose tolerance test, retinal photographs to monitor progression, fluorescein angiography to look for leaking vessels

Optimise glycaemic control, BP and hyperlipidaemia, lifestyle modifications (e.g. smoking cessation), be aware of higher risk of cataracts and glaucoma

For maculopathy: AntivegF injections (ranibizumab, aflibercept) can last 2-3 months, steroids can last 3 years? (implant?)

Vitreoretinal surgery possible if large amount of blood has collected, extensive scar tissue that’s likely to cause, or has already caused, retinal detachment

Question 10

What is the significance of HTN on the eye?

Answer 10

Acute hypertensive retinal changes
o Acute ischaemia in choroid
o Optic disc swelling

Chronic hypertensive retinal changes (more common)
o Arteriosclerosis
o AV nipping, right angle changes
o Copper and sliver wiring
o Retinal haemorrhages

Question 11

What is hypertensive retinopathy?

Answer 11

Retinal damage due to chronic hypertension

Asymptomatic although some report worsening headaches.

Exam: cotton wool spots indicating ischaemia, flame haemorrhages, papilloedema if advanced malignant HTN

Tx underlying HTN as an emergency if malignant HTN

Question 12

Grades of hypertensive retinopathy?

Answer 12

Grade 1 – changes of early hypertensive retinopathy are subtle, with generalised arteriolar narrowing.

Grade 2 – development of areas of focal narrowing, and compression of venules at sites of arteriovenous crossing (AV nipping).

Grade 3 disease – development of features similar to those of diabetic retinopathy, namely retinal haemorrhages, hard exudates and cotton wool spots.

grade 4 - optic disc swelling (malignant HTN)

Question 13

What is malignant HTN

Answer 13

Typically presents with grade 4 hypertensive eye disease, which includes all the features of grade 3, with the addition of optic disc swelling.

Other features: headaches, eye pain, reduced visual acuity and focal neurological deficits. may have also have ring of exudates around the macula (macular star).

Initial management typically involves antihypertensives and emergency hospital admission.

Question 14

What is thyroid eye disease

Answer 14

Organ specific autoimmune condition, usually seen in Grave’s disease where anti-TSH receptor antibodies target extra-ocular muscles as well as TSH receptors

Irritable red eyes, aching, pain on eye movement, double vision, ‘staing’ appearance of eyes, systemic symptoms of hyperthyroidism

More common in middle aged females
Association with smoking

Exam: limitation of eye movements, proptosis (look from top of their head), lid retraction, positive lid lag sign, systemic signs of hyperthyroidism

Ix: thyroid function tests, anti-TSH receptor antibodies, CT for extra-ocular muscle swelling

Tx: eye lubricants, liase with endocrinologist to Tx underlying thyroid problem, immunosuppression, surgical decompression of orbit

Question 15

What is Sjorgen’s syndrome?

Answer 15

Autoimmune destruction of lacrimal + salivary glands - commonly associated with autoimmune inflammatory conditions e.g. RA + SLE

Symptoms: burning gritty eyes, dry mouth, difficulty swallowing

Ix: Schirmer’s test using absorbent paper to assess tear production

Tx: lubricants, treat underlying autoimmune condition

Question 16

Scleritis vs episcleritis?

Answer 16

Episcleritis (below conjunctiva, above sclera): non-painful (gritty / mild discomfort), red watering eye, photophobia. Exam - MOBILE hyperaemic vessels, rarely associated with systemic disease, self-limiting - reassurance and lubricants for comfort

Scleritis: vasculitis of sclera commonly associated with inflammatory conditions (RA, SLE, Wegener’s granulomatosis) - rarely thinning of sclera can cause globe perforation if untreated. IMMOBILE hyperaemic vessels. Mgmt: lubricants, oral NSAIDs, may need oral steroids

Question 17

What is exopthalmos?

Answer 17

Exopthamlos (proptosis i.e. protruding eyes): in most people eyelid covers up to cornea, in exophthalmos see white at top (in exam cant just diagnose exophthalmos – have to measure – but can say lids are retracted).

Question 18

Grades of hypertensive retinopathy?

Answer 18

I Arteriolar narrowing and tortuosity
Increased light reflex - silver wiring

II Arteriovenous nipping

III Cotton-wool exudates
Flame and blot haemorrhages

IV Papilloedema