An update on macular pathology

Talk summary• Clinical signs

– Retinal haemorrhage and differential diagnosis– The cotton wool spot– Exudate vs Drusen

• OCT signs– Basics of OCT interpretation– When to refer– Some rare cases

Retinal haemorrhage, what depth?

• Vitreous

• Pre retinal

• Intraretinal (superficial and deep)

• Sub retinal

• Sub RPE

• More than one level

Vitreous haemorrhage

• Poor fundal view / poor red reflex

• Pulling on blood vessel– Retinal tear with PVD or trauma– Proliferative diabetic retinopathy / BRVO

• “Break through” bleeding– Severe wet AMD– Retinal macroaneurysm

Pre retinal haemorrhage(boat shaped)

Haemorrhage limited by extent of vitreous separationMasks retinal blood vessels

Superficial intra retinal haemorrhage(flame shaped)

Confined by nerve fibre layer, masks retinal blood vessels

Deep intra retinal haemorrhage(dot and blot)

May be in front of or behind the retinal blood vessels

Sub retinal haemorrhage(round)

retinal blood vessels visibleSub RPE haemorrhage similar but darker

The “cotton wool spot”

Think – Hypertension, Diabetes, SmokerRarely – HIV retinopathy, SLE

What is this?

Exudate vs drusen

If exudate is present there must be signs of leakage from abnormal blood vessels (micro or macroaneurysms, CNV)

Life is not that simpleWhat is this?

Principles of the OCT• Based on interferometry

– Interference between incident and reflected light

• Like doing a vertical biopsy of the retina– Use laser light rather than knife!

• Resolution down to 10 microns• Nerve fibre layer and RPE well defined• Good at showing swelling due to leakage• FFA still needed for showing blockage

Confusing but important terms

• Inner retina– Next to vitreous cavity– Nerve fibre layer– Interconnecting neurons

• Outer retina– Next to choroid– Rods and cones– RPE

Retina pathology often in layers

• Inner retina– Diabetic retinopathy – Retinal vein occlusion

• Outer retina– AMD– CSR

OCT pathology often in layers• Retinal surface

– Vitreo-macular traction– Epiretinal membrane

• Inner retina– Diabetic retinopathy– Retinal vein occlusion

• Outer retina– AMD – CSR

Retinal pathology in more than one layer

• Macular hole– All layers involved (full thickness)

• Lamellar hole– Usually surface and inner retina

• Severe retinal disease– Wet AMD– Diabetic eye disease– Retinal vein occlusions

• Can be difficult to assess function on thickness alone

• Normal thickness = 200 microns

• Thick retina > 250 microns– Usually due to leakage

• Thin retina < 150 microns– Atrophic with poor function

Central macular thickness

The photoreceptor integrity line

• Junction between inner and outer segments• Barely visible in histological sections• Highly prominent with OCT• Due to difference in index of refraction of the

inner and outer segments

Assess retinal function• Thick retina = oedema• Thin retina = atrophic retina• Normal thickness retina – how is it functioning?• Well demarcated IS/OS junction suggest good

photoreceptor function

• Posterior vitreous pulling on macula

• Wide range of severity

• If incidental OCT finding and patient asymptomatic – do not refer

Vitreo-macular traction

Severe Vitreo-macular traction

0.5 LogMAR“Pointed - being Pulled”

Mild Vitreo-macular traction

Inner retinal cyst0.12 LogMAR

• Posterior vitreous usually detached

• Sometimes associated with lamellar hole

• Wide range of severity

• If incidental OCT finding and patient asymptomatic – do not refer

Epiretinal membrane

Lamellar macular hole with ERM

Note ERM with “saw tooth sign”Lamellar macular holeNote healthy IS / OS junctionVisual acuity is 0.12No symptoms

Mild epiretinal membrane

0.1 LogMARLoss of foveal pit

Lamellar macular hole with ERM

0.1 LogMARAsymptomatic

ERM with lamellar hole

No symptoms-0.1 LogMAR Good IS / OS junction

Basics of diabetic retinopathy

• Retinal blood vessels involved• Inner retina first involved• Fluid

– Intra retinal (including cystoid oedema)– Sub retinal if severe– No Sub RPE fluid

• Hard exudates– Highly reflective intraretinal spots

• RPE looks ok

Basics of diabetic retinopathy

Basics of retinal vein occlusions

• Retinal blood vessels involved• Inner retina first involved• Fluid

– Intra retinal (including cystoid oedema)– Sub retinal if severe– No Sub RPE fluid

• Hard exudates– Less frequently seen than in diabetics

• RPE looks ok

Basics of retinal vein occlusions

Basics of dry AMD

Drusen“Lumpy bumpy” RPE

Basics of dry AMD

RPE atrophyHigh signal beneath RPEThin retina

Basics of Wet AMD• Blood vessels from choroid• Outer retina first involved• Fluid

– Sub RPE– Sub Retinal– Intra retinal (includes cystoid oedema)

• Usually previous dry AMD– Look at RPE line as rarely “pristine”

Basics of Wet AMD

Sub RPE fluidSub retinal fluid

Intra retinal fluidNote previous dry changes

“Burnt out” Wet AMD

Scarring and chronic leakage

Basics of CSR

• Leakage from choroid

• Fluid– Sub Retinal

• RPE– May be small PED associated– Remaining RPE looks healthy

Basics of CSR

Full thickness macular hole

Spontaneous improvement in a full thickness macular hole

0.1 LogMAR

0.0 LogMAR

Post macular hole op

0.32 LogMAR

Ask yourself

• Anything on the surface?

• Is it mainly inner or outer retina or both?

• How does the RPE look?

• How well demarcated is the IS /OS line?

Small BRVO or wet AMD at macula?

• BRVO– Inner retina (inner and outer if severe)– RPE normal– IS / OS may be preserved

• Wet AMD– Outer retina (inner and outer if severe)– RPE abnormal– IS / OS disrupted

Pre and post Ozurdex in macular oedema from vein occlusion

0.5 LogMAR

0.3 LogMAR

Pre and post Ozurdex in diabetic

Sept 2011 Feb 2012 April 2012

Ozurdex for CRVO

What is this?

Adult vitelliform dystrophy

Adult vitelliform dystrophy

0.22 LogMAR OS0.0 LogMAR ODIntact IS / OS junction

What is this and what is the vision?

Macula schisis

0.1 LogMARIntact IS / OS junction

0.0 LogMARIntact IS / OS junction

What is this?

It was due to this !

What is this?

Optic disc pit maculopathy

Retinitis pigmentosa

Pre – Sub Tenon’s steroid“Bell shape – from Below”

Post injectionNote thin retinaNo IS / OS junction