Age Related Macular Degeneration

Question 1

What is AMD?

Answer 1

Bilateral degeneration of macula and central retina- degeneration of retinal photoreceptors
=Leading cause of irreversible blindness in industrialised world

Question 2

Describe the macula

Answer 2

-Consists of small cone-dominated fovea
-Responsible for high acuity vision, Surrounded by rod-dominated parafovea and peripheral retina

Question 3

Describe rods and cones

Answer 3

-Cone= colour
-Rod= night
-Retinal pigment epithelium (RPE) nourishes photoreceptors and protects them from inflammation

Question 4

Risk factors for AMD

Answer 4

-Age
-Smoking
-Family history (complement factor H mutation)
-Obesity, dyslipidaemia, hypertension, DM
-More common in females

Question 5

Symptoms and signs of AMD

Answer 5

-Blurring or distortion of vision/ reduction VA particularly for near field objects
=Sudden/subacute would consider choroidal neovascularisation or macular oedema, gradual in dry
-Progressive central vision loss!
-Difficulties in night vision
-Fluctuations in visual disturbance varying day to day
-Scotoma/ metamorphopsia (straight lines appear wavy)
-Visual hallucinations= Charles Bonnet syndrome
-Photopsia (perception of flickering or flashing lights)
-Glare

Question 6

Clinical stages of AMD

Answer 6

-Early= lipoproteinaceous deposits (drusen) under RPE above choroid layer
-Dry AMD= RPE atrophy leading to persistent inflammation of rods and cones. 90%, yellow round drusen deposits on back of eye, geographic atrophy (vision decreased). OCT: lumpy
-Wet AMD= Neovascularisation (choroidal abnormal blood vessels), complications like subretinal haemorrhage. OCT: fluid accumulation

Question 7

Management of AMD

Answer 7

-Specialist referral
-High dose antioxidant and mineral supplementation (zinc, vit ACE)
-Monitor with fluorescein angiography and OCT

-Wet= intravitreal anti-VEGF and photodynamic therapy (PDT). Stabilises vision

Question 8

Investigation of AMD

Answer 8

-Amsler grid: determines subjective changes in central visual field (distortion in macular exudation, scotoma in atrophic areas of macula)
-Slit-lamp microscopy: pigmentary, exudative or haemorrhagic changes affecting the retina, colour fundus photography to provide a baseline against which changes can be identified over time.
-Fluorescein angiography if neovascular ARMD suspected: visualise any changes in the choroidal circulation.
-OCT: choroidal neovascularisation