Age Related Macular Degeneration

Question 1

Is ARMD the most common cause of blindness in the UK?

Answer 1

Yes

Question 2

Are changes usually bilateral or unilateral?

Answer 2

Bilateral

Question 3

What is the key feature of ARMD?

Answer 3

Degeneration of the central retina (macula)

Question 4

There are traditionally two forms of macular degeneration. What are they?

Answer 4

Dry (90%) - atrophic

Wet - exudative

Question 5

Does dry or wet macula degeneration carry the worst prognosis?

Answer 5

Wet

Question 6

What is the average age of presentation?

Answer 6

Over 70

Question 7

What is the male to female ratio?

Answer 7

1:2

Question 8

Describe dry macular degeneration

Answer 8

Macular degeneration characterised by drusen - yellow round spots in Bruch’s membrane
Slow and progressive visual loss compared to wet
Near and distant vision affected
Loss often symmetrical
Can progress to wet

Question 9

Describe the wet type

Answer 9

Vascular proliferation under the retina (choroidal neovascular membranes) - these can spontaneously bleed or leak fluid
Vision can deteriorate rapidly
Distortion is key feature - straight lines seem curved, central blank patch or blurring of vision
Decreased visual acuity with central scotoma
Peripheral vision remains normal

Question 10

Is treatment available for wet ARMD?

Answer 10

Yes, unlike dry type

Question 11

What are red flags for ARMD?

Answer 11

Decrease in central vision
Distortion of vision e.g distorted lines, letter missing when reading
Previous visual loss in other eye from macular degeneration

Question 12

What is the typical presentation for ARMD?

Answer 12

Decline in visual acuity - mainly central vision (difficulty reading, watching TV, recognising faces)
Distortion of vision
Difficulty with night vision and changing light conditions
Fluctuations in visual disturbance which may vary significantly from day to day
Normal visual fields
Normal red reflex
No pupillary defects

Question 13

What are some risk factors for ARMD?

Answer 13

Increasing age
Smoking 
FH of macular degeneration 
DM 
Cardiovascular disease 
Cataract surgery

Question 14

What do optic nerve drusen signify?

Answer 14

Optic nerve head axonal degeneration
Abnormal axonal metabolism -> mitochondrial calcification. Some axons rupture and mitochondria extruded. Calcium deposited and drusen form

Optic disc edge made irregular by the lumpy yellow matter
Optic cup absent
Abnormal branching of vessels

Question 15

What are some signs of ARMD?

Answer 15

Distortion of line perception on Amsler grid testing
Fundoscopy: drusen - yellow areas of pigment deposition in macular area, which may be confluent in later disease to form a macular scar
In wet ARMD red patches may be seen - intra retinal or sub retinal fluid leakage or haemorrhage

Question 16

What causes dry ARMD?

Answer 16

Aging and thinning of macular tissue
Deposition of pigment in the macular
Or combination of the two processes

Question 17

How is dry ARMD treated?

Answer 17

Prevention - no method exists to treat
Eat healthy, exercise, wear sunglasses
Antioxidant vitamins and mineral supplements - vitamin A, C and E, zinc, lutein

Question 18

What investigations should be done?

Answer 18

Slit lamp microscopy - identify any pigmentary, exudative or haemorrhagic changes affecting retina
Colour fundus photography - provide baseline
Fluorescein angiography if neovascular ARMD suspected - can guide intervention with anti-VEGF therapy
Ocular coherence tomography - visualise the retina the 3D (real areas of disease that are not visible using microscopy alone)

Question 19

What is VEGF?

Answer 19

A potent mitogen that drives increased vascular permeability

Question 20

How is wet ARMD managed?

Answer 20

Anti-VEGF e.g bevacizumab injections every 4 weeks
- to reduce cell proliferation, reduce formation of new blood vessels, reduce vascular leaks and therefore increase acuity

Laser photocoagulation - slows down ARMD where there is new vessel formation