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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

Chronic Visual Loss

A global and Australian perspective

Dr Nicholas Cheng (HMO2)

worldwide causes of blindness and visual impairment
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/

worldwide causes of blindness and visual impairment1
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

australian causes of blindness and visual impairment
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

case 1
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
cataract
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

types of cataract
Types of cataract

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

management of cataract
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
management of cataract1
Management of Cataract

Modern Phacoemulsification Surgery

management of cataract2
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
case 2
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

chlamydial conjunctivitis
Chlamydial Conjunctivitis
  • Symptoms: Chronic conjunctivitis – Subacute
  • Signs: Mucopurulent discharge, Large follices predom in inferior fornix
  • Ix: PCR
  • Rx: Azithromycin 1g single dose, reportable disease
trachoma
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
case 3
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.
dry amd
Dry AMD

Drusen

Geographic atrophy

Geographic atrophy responsible for majority of visual loss

wet amd
Wet AMD

Choroidal neovascular membrane

wet amd1
Wet AMD

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

age related macular degeneration amd management1
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
case 4
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?

case 41
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.
slide25
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

case 42
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.
glaucoma
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
glaucoma1
Glaucoma

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

glaucoma2
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
measuring iop
Measuring IOP

Tonopen (contact)

Goldmann tonometer (contact)

Pneumotonometry (non-contact)

anatomy of glaucoma
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.

slide32
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
slide33
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
glaucoma mysteries
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

pathogenesis of glaucoma
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/

types of glaucoma
Types of Glaucoma
  • Primary
    • Open angle
    • Angle closure
  • Secondary
    • Open angle – eg. neovascular, pigmentary
  • Congenital
types of glaucoma1
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.

glaucoma management
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
glaucoma management surgical
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
background dr
Background DR

Flame haemorrhages

Microaneurysms

Dot and blot haemorrhages

Glycosmedia. Diabetic retinopathy. 2000. Available from http://www.glycosmedia.com/education/diabetic_retinopathy/aims.php

pre proliferative dr
Pre-proliferative DR

Cotton wool spots

Venous changes

Glycosmedia. Diabetic retinopathy. 2000. Available from http://www.glycosmedia.com/education/diabetic_retinopathy/aims.php

proliferative dr
Proliferative DR

New vessels at the disc (NVD)

New vessels elsewhere (NVE)

slide46
MCQs
  • What is the most common cause of visual disability in diabetics?
    • Macular ischaemia
    • Vitreous haemorrhage
    • Macular oedema
    • Glaucoma
    • Retinal detachment
maculopathy
Maculopathy

Macular oedema + hard exudate

Angiogram

maculopathy1
Maculopathy

Macular oedema

Normal OCT

diabetic retinopathy1
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
diabetic retinopathy nhmrc guidelines
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
diabetic retinopathy management
Diabetic Retinopathy Management

General

  • Good glycaemic control, control HTN, hyperlipidaemia
  • Regular screening

Severe preproliferative DR / Proliferative DR

  • Pan-retinal photocoagulation

Macular oedema

  • Focal argon laser photocoagulation
  • New treatments: anti-VEGF (Lucentis = ranibizumab, Avastin = bevacizumab) in sub-population (central retinal thickness >400microm) NICE Guidelines
case 6
Case 6
  • 29yo man presents with difficulty seeing at night, and feeling he is losing peripheral vision
retinitis pigmentosa
Retinitis Pigmentosa
  • Retinal dystrophy affecting rods more than cones
  • Prevalence 1:5000
  • Hereditary - Can be AD, AR, X-linked
  • Sxs:
    • Bilateral loss of peripheral vision
    • Difficulty with night vision
    • Glare (cataract)
  • Ex: Triad of:
    • Arteriolar attenuation
    • Bone-spicule pigmentation – RPE changes
    • Waxy disc pallor
retinitis pigmentosa1
Retinitis Pigmentosa
  • Mx:
    • No current cure
    • Supplemental Vit A may retard progression
    • Bionic Eye
summary
SUMMARY
  • Chronic visual loss causes a high burden globally
  • Predominant causes of chronic visual loss vary across the world
    • AMD, DR, Glaucoma, Cataract in developed world
    • Cataract, refractive error, corneal opacities in developing world
  • Exciting new treatments for previously untreatable conditions
    • Anti-VEGF
    • Bionic Eye
case 43
Case 4

LE

RE

Medrounds. Peripheral vision. 2006. Available from http://www.medrounds.org/glaucoma-guide/2006/08/section-6-d-peripheral-vision-visual.html

acute angle closure glaucoma
Acute Angle Closure Glaucoma
  • Signs: VA 6/60 – Think outside in
    • Cornea – cloudy
    • Anterior chamber – shallow, aqueous flare and cells
    • Pupil - mid-dilated non-reacting
    • High IOP
  • Rx: Acetozolamide 500mg IV or PO, topical timolol 0.5%, pilocarpine 1%
  • Definitive Rx: YAG laser iridotomy