Download Cataracts and Age-Related Macular Degeneration

TOBACCO AND THE AGING EYE (CATARACTS
AND AGE-RELATED MACULAR
DEGENERATION)
Mini Lecture 2
Module: Tobacco and Sensory Organs
Objectives of the Mini Lecture
GOAL OF MINI LECTURE: Provide students with
knowledge about the relationship between tobacco use and
cataracts and macular degeneration.
LEARNING OBJECTIVES
Students will be able to:
• List the eye diseases impacted by tobacco use
• Understand how tobacco causes different types of eye
diseases
• Understand the importance of smoking cessation in
reducing the risk of eye diseases
Contents
Core slides
1. Global Epidemiology: Blindness
2. Epidemiology: Blindness (Indonesia)
3. Epidemiology: Blindness (India)
4. Impact of Smoking on the Eye
5. Tobacco and Cataract: Evidence from
India
6. Smoking and Cataract: Suggested
Mechanisms
7. Smoking Cessation and Cataract
8. Smoking and Age-Related Macular
Degeneration (AMD)
9. Smoking and AMD Mechanisms
10. Smoking Cessation and AMD
11. Cessation Messages
Optional slides
1. Cataract Management
2. Smoking and Graves’
Ophthalmology (GO) or Thyroid
Eye Disease (TED)
3. Smoking and Graves’
Ophthalmology: Mechanism
4. Cessation and Graves’
Ophthalmology (GO) or Thyroid
Eye Disease (TED)
CORE SLIDES
Tobacco and the Aging Eye (Cataracts
and Age-Related Macular Degeneration)
Mini Lecture 2
Module: Tobacco and Sensory Organs
Global Epidemiology: Blindness
• Leading cause for global disability
• 45 million people in 2000; 76
million by 2020
• 135 million people have severely
impaired vision in both eyes
• Cataracts are the major cause of
blindness
• Representing 48% of global
blindness.1
1. Foster and Resnikoff 2005
www.answers .com/topic/cataract
Indonesia
Epidemiology: Blindness1
• National figure for blindness proportion: 0.9%
• Range from:
• The lowest: 0.3% (East Kalimantan Province)
• The highest: 2.6% (South Sulawesi Province)
• National figures for cataract in individuals aged 30>:
17.3%
• Already diagnosed with cataract: 1.8%
• Persons with main symptoms of cataract (blurred
vision and increased sensitivity to light): 15.5%
1. RISKESDAS 2007
India
Epidemiology: Blindness
• India has a large cataract burden
accounting for 44% of total
blindness.1
• The annual incidence of cataract
blindness is about 3.8 million.2
• The cost of treating all cases of
cataract blindness in India is Rs. 5.3
billion.3
1. Dandona et al. 2001; 2. Vajpayee et al. 1999; 3. Shamana et al. 1998
Impact of Smoking on the Eye
• Smoking is an independent and modifiable risk factor
for development of a range of eye diseases, including:
• Cataract
• Age-related macular degeneration (AMD)
• Graves’ ophthalmology (GO) or thyroid eye disease
(TED).1
• Smoking is a modest risk factor for the development of
nuclear cataract.2
• Current smokers are three times more likely to
develop cataracts than never smokers, with the risk
increasing with number of cigarettes smoked.3
1. Astbury 2006; 2. Tan et al. 2008; 3. Kelly et al. 2005
India
Tobacco and Cataract:
Evidence from India
• Compared with never smokers, cigarette
smokers had a higher prevalence of any
cataract and were more likely to report a prior
history of cataract surgery.1
• Smokers develop cataracts at an earlier age
than non smokers.2
• Smokeless tobacco use was more strongly
associated with cataracts.2
1. Krishnaiah et al. 2005; 2. Raju et al. 2006
Smoking and Cataract:
Suggested Mechanisms
Exact mechanism remains unclear:
• Free radicals in tobacco smoke cause oxidative
damage to the retina and reduce choroidal blood
flow.
• Oxidative stress on the lens through reduction of
antioxidant levels.
• Morphological and functional changes to the lens
and retina by atherosclerotic and thrombotic effects
on ocular capillaries.
• Heavy metals in tobacco cause direct toxicity.
1. Kelly et al. 2005; 2. Astbury 2006; Krishnaiah et al. 2005
Smoking Cessation and Cataracts
• Ex-smokers have lower risk of cataract, indicating
beneficial impact of cessation.1
• Smoking cessation has a protective effect for
cataract development.2
• Those who stopped smoking for >25 years had a
20% lower risk for cataract.3
• Promoting tobacco cessation among ophthalmic
patients could contribute to significant improvements
in eye health.4
1. Kelly et al. 2005; 2.Christen et al. 2000; 3. Weintraub et al. 2002; 4. Krishnaiah et al. 2005
Smoking and Age-Related Macular
Degeneration (AMD)
A 3-4 fold increase in risk of
AMD among current smokers
compared with never
smokers.1
• Risk of developing any type
of AMD was 2–3 times
higher among smokers
compared with never
smokers.2
• Risk of developing neovascular AMD was 4 times
higher among smokers
compared with never
smokers.3
http://topnews.us/images/Smoking-deteriorates-AMD.jpg
1. Smith et al. 2001; 2.Thornton et al. 2005; 3. Khan et al. 2006
Smoking and AMD Mechanisms
Suggested mechanisms:
• Reduced macular pigment and antioxidants
leading to increased oxidative stress on the
macula impairing its defense mechanisms.
• Interference in the nutrient exchange between the
retinal pigment epithelium and its blood supply.
• Vascular insufficiency.
1. Smith et al. 2001; 2. Thornton et al. 2005; 3. Khan et al.2006
Smoking Cessation and AMD
Cessation:
• Risk of developing AMD
among ex-smokers who
had not smoked for 20
years was reported to be
similar to never smokers,
indicating benefit of
cessation.
1. Smith et al. 2001; 2. Thornton et al. 2005; 3. Khan et al.2006
historyfilms.net/health_and_wellness/index.htm
Cessation Messages
• The general public, including teens, need to become
aware of the ocular risks of cigarette smoking.1
• Importantly, even the majority of eye patients remain
largely unaware of the strong link of tobacco with
blindness.2
• The fear of going blind may be more motivational to
help people quit smoking than health warnings and
advice from ophthalmologists. Messages about
blindness could potentially facilitate cessation.3
1. Moradi et al. 2007 2. Kelly et al. 2005; 3. Astbury 2006
OPTIONAL SLIDES
Tobacco and the Aging Eye (Cataracts
and Age-Related Macular Degeneration)
Mini Lecture 2
Module: Tobacco and Sensory Organs
Cataract Management
• No medical treatment exists to prevent, delay, or
reverse cataract development in healthy individuals.
• Cataract management:
• Surgical extraction with intraocular lens
implantation.
• Significant health resource consumption for
individuals and societies.
• Modifiable risk factors such as tobacco use
could potentially help in prevention.
1. Kelly et al. 2005; 2. Krishnaiah et al. 2005
Smoking and Graves’ Ophthalmology
(GO) or Thyroid Eye Disease (TED)
Recent metanalysis reported substantial evidence that
smoking causes GO:
• Smokers have 1.3 times increased risk of
developing GO.
• Smokers have higher risk of progression to more
advanced GO.
• Smokers were also more likely to experience
disease progression or poorer outcome of
treatment.
1. Thornton et al. 2006; 2. Pfeilschifter et al.1996
Smoking and Graves’
Ophthalmology: Mechanism
Suggested mechanisms:
• Increase in tissue hypoxia
• Alterations in immune
surveillance, resulting in
decreased control of naturally
occurring clones of T-helper cells
that are directed against thyroidal
or orbital antigens
• Proliferation of retro-ocular
fibroblasts, causing orbital
oedema
1. Thornton et al.2006; 2. Pfeilschifter et al.1996
www.revophth.com/index.asp?page=1_14136.htm
Cessation and Graves’ Ophthalmology
(GO) or Thyroid Eye Disease (TED)
Cessation:
• Ex-smokers have lower risk of
developing GO than current
smokers.
• Response to treatment delayed
and poorer among continuing
smokers with GO.
• Lower risk of GO in those
Graves’ Disease (GD) sufferers
who have quit smoking before
the manifestation of GD
compared to current smokers.
www.revophth.com/index.asp?page=1_14136.htm
1. Thornton et al.2006; 2. Pfeilschifter et al.1996.
The most important health message a doctor can
give to patients is to quit smoking.