1. Age-Related macular degeneration & retinitis pigmentosa Ayesha S abdullah

2. Learning outcomes
By the end of this lecture the students would be able to
Describe the epidemiology of ARMD
Correlated the clinical presentation of age-related macular degeneration (ARMD) with the underlying pathophysiology
Outline the principles of treatment of ARMD
Describe the epidemiology and clinical presentation of retinitis pigmentosa

3. Case
A 72 year old man presented to the OPD with the complaints of difficulty in recognizing faces and distortion of vision for the last one year.
When he reads the words seem distorted and wavy with the left eye.
He is a known hypertensive and smoker for the last 40 years. His elder brother has similar problem.

4. Physical examination VA: 6/12 OD 6/24 OS
Anterior segment: bilateral early cataract
Pupils : normal
Posterior segment: fundus photograph
Defect on Amsler Grid

7. How is ARMD caused? What is the function of RPE?
Absorb light, transport oxygen & nutrients to the outer retina
Transport cellular wastes from the outer retina to choroid
In ARMD RPE dysfunction leads to accumulation of the waste products under the retina at the interface between the Bruch’s membrane and RPE in the form of yellowish deposits
They can be seen on ophthalmoscopy as “Drusen”

9. Aaetiology Known risk factors Oxidative damage Microvascular disease
Genetic predisposition

11. Choroid
Bruch’s
RPE

14. Choroid
Bruch’s
RPE

15. Choroid
Bruch’s
RPE

19. It is a slow process
RPE continues to slow down transport of nutrients and wastes
Overlying photoreceptors and RPE get atrophic
It may continue as a slowly progressive “dry” form of the disease
In some it assumes a more aggressive “wet form”
New vessels grow from the choroid underneath the retina forming a neovascular membrane.
It leaks and can bleed
Resulting in severe visual damage
The macula may undergo fibrosis and scarring- “diskiform scar”

26. Epidemiology What is the magnitude of ARMD?
Leading cause of blindness in developed countries over the age of 50 years
Whites are twice at risk as compared to blacks

27. Who is at risk?
Homework

28. Can it be prevented? No
Risk modification

29. How can it be treated Risk modification Monitoring – Amsler Grid
Diet . Age-Related Eye Disease Study (AREDS), showed that those who are at high risk for developing advanced age-related macular degeneration, may be helped by taking a specific combination of antioxidants and zinc.
Vitamin C, Vitamin E, Vitamin A as beta-carotene*, Zinc , Copper in a specific dose
*with caution in smokers, increases the risk of lung cancer

30. Specific treatment Anti-VEGF intravitreal injections
Photodynamic therapy
Thermal Laser treatment
Surgical excision of the membrane
Photodynamic compounds, which react with water to create oxygen and hydroxyl free radicals, are stimulated with a specific light wavelength; the intensity of which is low enough to spare the irradiated tissues from thermal damage. The free radicals intern react with cell membrane of the endothelium and blood cells to induce massive platelet activation and thrombosis

31. Rehab
Low vision aids

33. Electronic devices

35. Directions for using the Amsler grid
If you wear reading glasses, put them on for this test.
Hold this book at a comfortable reading distance.
Cover one of your eyes.
Look at the grid. Keep your eye focused on the white dot at the center of the grid throughout the test.
Without moving your eye from the center dot, notice the lines that make up the grid. All of the lines should be straight and all of the squares should look the same.
There shouldn’t be any blank, dark, or distorted areas on the grid.
Call your eye doctor right away if you notice anything unusual or abnormal in your vision.
Use the same procedure to test your other eye.

36. Retinitis pigmentosa A degenerative retinal disease
Varying pattern of inheritance
Autosomal dominant. 20% of cases (AD)
Autosomal recessive (AR)
X- linked. Rare with worst prognosis (XL)
Isolated cases
Photoreceptor dysfunction primarily affecting rods
Systemic associations and deafness
1:5000 prevalence
Can have a typical or atypical clinical presentation

37. How can it be diagnosed? WAB Bilateral involvement Night blindness
Loss of peripheral vision
Signs
Arteriolar narrowing
Bone specule pigmentary changes
Waxy pale disc
ERG
Perimetry
WAB

40. How progressive is the visual loss
Starts in childhood
Progresses very slowly
Rarely the person is blind by the age of 30 year ( X- linked)
Rarely proceeds to complete blindness
AD-best prognosis with retention of central vision beyond the 6th decade
XL has the worst prognosis with severe visual loss by the 4th decade

41. Ocular associations
Homework

42. Is it treatable? No The associated ocular diseases can be treated
The person would be needing low vision aids when the visual field loss becomes more.
Needs to be differentiated from certain drug induced retinopathies ( chloroquine & thioridazine), infections (syphilis) and severe posterior uveitis