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Chronic Visual Loss

Chronic Visual Loss. A global and Australian perspective Dr Nicholas Cheng (HMO2). Worldwide Causes of Blindness and Visual Impairment. Key Facts 285 million visually impaired 39 million blind 246 million with low vision Major causes: Uncorrected refractive error 42% Cataract 33%

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Chronic Visual Loss

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  1. Chronic Visual Loss A global and Australian perspective Dr Nicholas Cheng (HMO2)

  2. Worldwide Causes of Blindness and Visual Impairment Key Facts • 285 million visually impaired • 39 million blind • 246 million with low vision • Major causes: • Uncorrected refractive error 42% • Cataract 33% • Glaucoma 2% • 90% live in the developing world 80% of visual impairment can be avoided or cured World Health Organisation. Visual Impairment and Blindness. June 2012. Available from http://www.who.int/mediacentre/factsheets/fs282/en/

  3. Worldwide Causes of Blindness and Visual Impairment World Health Organisation. Global data on visual impairments 2010.. Available from http://www.who.int/blindness/GLOBALDATAFINALforweb.pdf

  4. Who is this?

  5. Australian Causes of Blindness and Visual Impairment Eye Research Australia – Clear Insight. The economic impact and cost of vision loss in Australia. Available from http://www.cera.org.au/uploads/CERA_clearinsight.pdf

  6. Case 1 • Inspired by a recent ophthalmology lecture, you decide to undertake a volunteering role with a non-profit eye health organisation. • With the aid of an interpreter you interview your first patient. • A 65yo man presents complaining of gradually increasing difficulty with both near and distance vision. • He has been experiencing glare around lights and feels he needs stronger glasses. • PHx: Type II diabetes, HTN

  7. Cataract Symptoms: • Slowly progressive over years • Glare, haloes, worsening myopia • Risk factors: • Daylight (UV), Degeneration (Age), Diabetes, Drugs (cigs + steroids), Damage (Trauma) • Congenital cataract – Autosomal dominant, birth trauma, maternal infection, galactosaemia Signs: Lens opacity

  8. Types of cataract Batterbury M, Bowling B. Ophthalmology: An illustrated colour text. 3rd ed. Edinburgh: Churchill Livingstone; 2009.

  9. Management of Cataract Modern phacoemulsification cataract surgery • Timing depends on degree of functional impairment • Sometimes medical indications such as visualising fundal pathology • Preop evaluation • VA, screen lids/ocular adnexa, cornea, fundoscopy

  10. Management of Cataract Modern Phacoemulsification Surgery

  11. Management of Cataract Modern Phacoemulsification Surgery • Anaesthesia • Majority LA + peribulbar/sub-Tenon block • Can do GA or topical • Intraopcomplications • Rupture of lens capsule • IOL dislocation • Choroidal rupture • Postop complications • Most devastating is endophthalmitis – Wary of acute painful red eye postop • Posterior capsule opacification

  12. Case 2 • Still overseas, a family brings in a blind man asking if anything can be done. • The man describes recurrent episodes of red eye, irritation and mucopurulent discharge over many years taking days-weeks to resolve Previously Now

  13. Chlamydial Conjunctivitis • Symptoms: Chronic conjunctivitis – Subacute • Signs: Mucopurulent discharge, Large follices predom in inferior fornix • Ix: PCR • Rx: Azithromycin 1g single dose, reportable disease

  14. Trachoma • Chronic conjunctivitis • Common cause of blindness worldwide and in Aboriginal communities of Australia • Cxs: • Cicatricial change with entropion, trichiasis, dry eye and secondary corneal ulceration and scarring • Rx: WHO SAFE – Surgery, Abx, Face washing, Enviro improvement

  15. Case 3 • You return home from your trip, exhausted but happy. No more eyes for a while. • While discussing your trip with your aunt, she mentions that she too is having some eye problems. • She has been noticing increasing difficulty reading the newspaper, with distortion of the writing. Her distant vision seems to be ok though.

  16. Age-Related Macular Degeneration (AMD)

  17. Dry AMD Drusen Geographic atrophy Geographic atrophy responsible for majority of visual loss

  18. Wet AMD Choroidal neovascular membrane

  19. Wet AMD Batterbury M, Bowling B. Ophthalmology: An illustrated colour text. 3rd ed. Edinburgh: Churchill Livingstone; 2009.

  20. Age-Related Macular Degeneration (AMD) Management

  21. Age-Related Macular Degeneration (AMD) Management High-dose multivitamins • New Study AREDS2 • No benefit in early AMD, but can retard progression in moderate to severe AMD • 25% decreased progression over 5 years Components • Beta carotene – Now could be substituted for lutein/zeaxanthin • Vitamin C • Vitamin E • Zinc oxide

  22. Case 4 • A 60yo woman initially presents to her optometrist complaining of gradual worsening of her peripheral vision. The optometrist performs this test and refers her to you, her GP, for a referral to an ophthalmologist. What is this test?

  23. Case 4 • You are tempted to just write the referral, but glance up to see your direct ophthalmoscope in the corner of the room. • You decide you will have a look at her fundus to see the cause of her problem.

  24. MCQs • Which of these can be used as mydriatics? • Tropicamide 0.5% • Phenylephrine • Cocaine 10% • Cyclopentolate • Atropine Parasymp Antagonist – 2-6hours Sympathetic Agonist Sympathetic Agonist Parapsymp Antagonist – 24hours Parapsymp Antagonist – 7-14days

  25. Case 4 • You are tempted to just write the referral, but glance up to see your direct ophthalmoscope in the corner of the room. • You decide you will have a look at her fundus to see the cause of her problem.

  26. Glaucoma Essentially a characteristic optic neuropathy Triad of: • Raised IOP • Normal IOP 10-21mmHg • Optic disc cupping – • Normal <0.3 but variation, look for asymmetry ≥0.2 • Peripheral field changes

  27. Glaucoma MiVision. Glaucomatous Discs. 2009. Available from http://www.mivision.com.au/the-optometrist-s-practitioner-patient-manual-glaucomatous-disc/

  28. Glaucoma Symptoms: • Largely asymptomatic until late • Peripheral field loss • Risk factors: • High IOP, Diabetes, Age, High myopia, Thin corneas, FHx, Sterioids Evaluation: • Fundoscopy • Optic disc cupping – “ISNT” Inferior rim usually biggest • Tonometry • Raised IOP • Perimetry • Visual field testing

  29. Measuring IOP Tonopen (contact) Goldmann tonometer (contact) Pneumotonometry (non-contact)

  30. Anatomy of Glaucoma Name the structure Canal of Schlemm Trabecular meshwork (a+b) Kanski JJ. Clinical ophthalmology: A systematic approach. 6th ed. Edinburgh; New York: Butterworth-Heinemann/Elsevier; 2007.

  31. MCQs • Aqueous humor: • Is produced by the ciliary processes • Is produced by the trabecular meshwork • Is produced by the canal of Schlemm • Is responsible for glaucoma • Exits the eye through the posterior chamber

  32. MCQs • A man is worried about developing glaucoma, as his uncle has just been diagnosed. Which of the following is true? • If he has a pressure IOP of 18mmHg he cannot have glaucoma • Field loss is confirmative of glaucoma • A raised IOP is confirmative of glaucoma • Visual loss in glaucoma is related to nerve fibre damage

  33. Glaucoma Mysteries Ocular hypertension = Raised IOP without symptoms (visual field loss) or signs (optic disc cupping) of glaucoma Normal tension glaucoma = Symptoms and signs of glaucoma without a rise in IOP

  34. Pathogenesis of Glaucoma • Retinal ganglion cell death • Exact mechanism still uncertain • Mechanical (high IOP) vs Ischaemic vs Both • Mechanical • Raised IOP directly damages nerve fibres • Ischaemic: • Compromise of microvasculature US Pharmacist. An Overview of Glaucoma Management for Pharmacists. 2010. Available from http://www.uspharmacist.com/continuing_education/ceviewtest/lessonid/106698/

  35. Types of Glaucoma • Primary • Open angle • Angle closure • Secondary • Open angle – eg. neovascular, pigmentary • Congenital

  36. Types of Glaucoma • Primary open angle glaucoma (POAG) = Chronic – Most common • Primary angle closure glaucoma (PACG) = Acute Kanski JJ. Clinical ophthalmology: A systematic approach. 6th ed. Edinburgh; New York: Butterworth-Heinemann/Elsevier; 2007.

  37. Glaucoma Management Aim: Either decrease production or increase drainage of aqueous humor • Pharmacological - ABCPP • Alpha-agonists • Beta-blockers • Carbonic anhydrase inhibitors • Prostaglandins • Parasympathetic agonists • Surgical • Trabeculoplasty • Trabeculectomy

  38. Glaucoma Management - Pharm

  39. Glaucoma Management - Surgical Laser Trabeculoplasty • Laser to trabecular meshwork to increase outflow Trabeculectomy • Surgical fistula between anterior chamber angle and sub-Tenon’s space • Creation of drainage bleb

  40. Case 5

  41. Diabetic Retinopathy

  42. Background DR Flame haemorrhages Microaneurysms Dot and blot haemorrhages Glycosmedia. Diabetic retinopathy. 2000. Available from http://www.glycosmedia.com/education/diabetic_retinopathy/aims.php

  43. Pre-proliferative DR Cotton wool spots Venous changes Glycosmedia. Diabetic retinopathy. 2000. Available from http://www.glycosmedia.com/education/diabetic_retinopathy/aims.php

  44. Proliferative DR New vessels at the disc (NVD) New vessels elsewhere (NVE)

  45. MCQs • What is the most common cause of visual disability in diabetics? • Macular ischaemia • Vitreous haemorrhage • Macular oedema • Glaucoma • Retinal detachment

  46. Maculopathy Macular oedema + hard exudate Angiogram

  47. Maculopathy Macular oedema Normal OCT

  48. Diabetic Retinopathy Risk Factors: • Duration of diabetes, poor metabolic control, HTN • After 10 years – 50% DR • After 30 years – 90% DR Pathogenesis: • Microangiopathy • Microvascular occlusion and leakage • Subsequent neovascularisation

  49. Diabetic Retinopathy NHMRC Guidelines Screening All patient with diabetes • At diagnosis and at least every 2 years High risk patientswithout DR (long duration, poor control, HTN, hyperlipid) • Screen annually Patient with NPDR • Screen 3-6 monthly

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