Age-Related macular degeneration & retinitis pigmentosa Ayesha S abdullah

1. Age-Related macular degeneration & retinitis pigmentosaAyesha S abdullah 17.01.2014

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. EpidemiologyWhat 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? • Age • Family history • Smoking doubles the risk • Hypertension • Cardiovascualr disease • Hyperlipidemias • Variants of complement factor H • Excessive exposure to sunlight

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

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) • Autosomalrecessive (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? • Bilateral involvement • Night blindness • Loss of peripheral vision • Signs • Arteriolar narrowing • Bone speculepigmentary changes • Waxy pale disc • ERG • Perimetry

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 • Cataract • Glaucoma • Myopia • Keratoconus • Macular oedema • Vitreous changes • Optic disc drusen • Coats-like disease with exudative RD

42. Is it treatable? • No • The associated ocular diseases like, cataract, macular oedema , myopia and glaucoma 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