1. Age-Related Macular Degeneration Dr Charlotte Hazel

2. Introduction

Leading cause of blindness in the Western World

Common in Caucasian populations

Bilateral disease

60% bilateral within 5 years of visual loss in first eye

Earliest signs rarely visible before 45 years.

3. Anatomy

Macula

• Diameter 5 mm

• 4 mm temporal, 0.8 inferior to optic disc

Fovea

• Depression of ~1 disc diameter (1.5 mm) at centre of macula

4. Anatomy

Foveola

• Central point of fovea

• 0.35 mm in diameter

• Thinnest part of retina

• Cones only

• High levels of visual acuity

5. Anatomy Choroid RPE Foveola 6. Anatomy 7. Definitions

• Two forms:

• Non-exudative (dry)

• • Most common (90%)

• • Geographic atrophy

• Exudative (wet)

• • Neo-vascularisation

• • Causes more devastating and sudden vision affects

8. Pathophysiology

• Progressive thickening of Bruchs membrane with age

• Interferes with RPE - photoreceptor metabolism

• Metabolites from photoreceptors accumulate on Bruchs membrane

• Like debris!

9. Pathophysiology

Drusen (colloid bodies)

• Earliest clinical sign

• Lipid or collagen rich deposits (waste)

• Lie between Bruchs membrane and RPE

• Further disruption of RPE/photoreceptor metabolism

• Cause variable amount of depigmentation and eventually atrophy of overlying RPE

10. Pathophysiology Drusen Bruchs Membrane RPE Photoreceptors Choroid 11. Pathophysiology

Hard Drusen

• Small localised collection of hyaline material within or on Bruchs membrane

• Sharp, well demarcated boundaries

Soft Drusen

• Involve overlying focal RPE detachment

• Poorly demarcated boundaries

• Larger/commonly become confluent

12. Hard Drusen 13. Soft Drusen 14. Pathophysiology

Drusen

• Can become calcified (glistening appearance)

• Can become confluent representing widespread RPE abnormality

• • Increase risk of vision loss!

• Can be inherited as a dominant trait

• • Hard Drusen

• • No progression / consequence

15. Confluent Drusen 16. Calcified Drusen 17. Pathophysiology

RPE degeneration, seen as:

• Focal areas of hypo- and hyper- pigmentation (stippling)

• Eventually areas of atrophy of the RPE revealing underlying choriocapillaris

• • Geographic atrophy = end stage

18. RPE Degeneration 19. RPE Degeneration 20. Summary

Age-related thickening of Bruchs membrane

Interferes with photoreceptor/RPE metabolism

Causing deposition of metabolites / formation of drusen

Damage to overlying RPE/photoreceptors and underlying choriocapillaris

21. Non-Exudative AMD

Gradual mild to moderate impairment over months or years

Cause:

• Slow/progressive atrophy of RPE and photoreceptorsor

• Collapse of an RPE detachment overlying soft drusen

Advanced form = Geographic Atrophy

22. Geographic Atrophy (GA)

Clinical Features:

• Soft drusen present in early stages (significant risk factor for GA due to RPE detachment)

• Decreased retinal thickness and increased visualisation of choroidal vessels

• Sharply demarcated pale area

• Choroidal vessels sometimes white

23. Geographic Atrophy (GA) 24. Geographic Atrophy (GA) 25. Geographic Atrophy (GA)

Signs/Symptoms:

• Marked decrease VA (unless foveal sparing)

• Central field loss (positive scotoma)

• Difficulty recognizing faces

• Difficulty reading if large scotoma

• Difficulties in dim light / adapting

26. Exudative AMD

Clinical Features:

• Choroidal neo-vascularisation

• Exudative detachment of RPE and/or retina

• Disciform scar

27. Choroidal Neovascularisation

• Proliferations of fibrovascular tissue from choriocapillaris through defects in Bruchs membrane

• Sub-RPE or sub-retinal

• Membranes have a greyish/green or pinkish/yellow hue in late stages

28. Choroidal Neovascularisation

• Tendency to leak

• • Serous and blood

• • Distorted or blurred vision

• • Red if sub-retinal, darker if sub-RPE

• • Rarely vitreous haemorrhage

• Cause RPE and retinal detachments

29. Choroidal Neovascularisation

• Fibrous tissue proliferation scar development (Disciform scar)

• • Permanent vision loss

• Further bleeding

• • risk of exudative retinal detachment

30. Choroidal NeovascularisationRPE BruchsMembrane Photoreceptors Choroid 31. Choroidal Neovascularisation 32. Choroidal Neovascularisation 33. Choroidal Neovascularisation 34. Disciform Scar 35. Investigation

History

• Gradual change = non-exudative

• Sudden change = exudative

• Difficulties reading/recognising faces

• Difficulties with changing light / adapting after bright light (remember when assessing!)

• Distortion = exudative change!

36. Investigation 37. Investigation

Visual acuity

• Distance and near

• No improvement (worse?) with pin-hole

Amsler-grid

• Field test for central 20 degrees

• Show scotoma/distortion

• Monocular/ correct add for WD!

• No varifocals/bifocals!!!!

38. Amsler Chart 39. Amsler Chart 40. Amsler Chart 41. Investigation

Fundus Examination

• Binocular view detect elevation

• VOLK or contact lens

42. Management

Urgent refer any suspected neovascular membrane or sub-retinal fluid

• Fluorescein angiography

Absence of previous drusen sub-retinal fluid(?)

Non-exudative no surgical treatment

43. Mx. Non-exudative

Advice and support

• Likely to progress

• Central vision only

Advice re. Lighting

High add or LVAs

44. Mx. Non-exudative

Amsler Chart self monitoring

Low Vision referral

• Daily living skills

• LVAs

• Eccentric fixation training?

Registration

• Social Service - advice and benefits

45. Mx. Exudative

Argon laser photocoagulation

• Extrafoveal/Juxtafoveal CNV

• Subfoveal?

• Immediate loss of VA

• Slow progression NOT improve

• Possible recurrence (up to 50%)

46. Fluorescein Angiography CNV Pre- and Post- Laser Tx CNV Pre-Laser CNV Post-Laser 47. Laser Scars 48. Recurrence 49. Mx. Exudative

Photodynamic therapy

• Photosensitizer dye accumulates in proliferating tissues

• damaged by appropriate wavelength light

• More specific than laser only destroys tissue with photosensitive dye

• High cost!!

50. Mx. Exudative

Radiation Therapy

• Not conclusive

Surgical translocation

• Still experimental

Membrane removal

• Suitable for young not old

• RPE transplantation?

51. Risk Factors

Fair skin/blue eyes

Female

Obesity

Hypertension

High-fat diet / High cholesterol

Long-sighted

52. Risk Factors

Smoking

• Accelerate development of wet form - twice the risk

Sunlight

• short wavelengths accelerate degeneration

• History of out-door life

• Sunglasses/polaroids?

53. Prevention

Supplements

• Carotenoid pigments green leafy vegetables

• Zinc mixed results

• Anti-oxidants Vit A and C (particularly combined with Zinc)

• Selenium

• Problems with side-effects

54. Prevention

Age-Related Eye Disease Study (AREDS) 2001

• Vit C 500mg

• Vit E 400 mg

• Vit A 15 mg

• Zinc 80 mg (Copper 2mg)

• Did not help early stages; reduced risk of progression to advanced forms.

55. PreventionUS$ 68.95 per 500ml bottle 56. References

• www. rcophth .ac. uk /publications /guidelines/ armd .html

• • Mx, prognosis, aetiology etc

• Kanski, Clinical Opthalmology

• Various ophthalmology textbooks or atlases

• Berger et al. Age-related macular degeneration