Epidemiology and demographic of visual impairment: Flashcards

1
Q

What is visual impairment

A

*Reduced binocular visual acuity, which cannot be improved even with best optical correction provided by conventional lenses
*Conventional lenses include the required distance correction and near vision additions up to +4DS

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2
Q

What are conventional lenses

A

The required distance correction and near vision additions up to +4DS

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3
Q

Example of someone who doesn’t have reduced VI

A

*If 6/6 in RE and 3/60 in LE with a binocular visual acuity of 6/6
*Then this individual would not be classified as having a visual impairment?
*Cause their binocular visual acuity is 6/6, which would not be classified as a visual impairment.

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4
Q

Why is it important to define a visual impairment:

A

*It’s important to define a visual impairment because there are certain benefits associated with being visually impaired
*Best corrected VA i.e with glasses
*For example:
oFinancial help
oSocial help
*Because someone with a visual impairment might have difficulties with their activities of daily living e.g. reading, and might have a decline in quality of life.
*It’s also important in terms of epidemiological studies to understand what visual impairment is.
oSo when doing a large-scale study and want to know how many people don’t see particularly well in your area or in your country.

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5
Q

What are the benefits associated with VI

A

*Financial help
*Social help

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6
Q

What are difficulties of someone with VI

A

*Activities of daily living e.g. reading
*A decline in quality of life.

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7
Q

How many definitions are there of VI

A

65

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8
Q

What are the different terms used for vi

A
  • Blind
  • Partial sight
  • Low vision
  • Subnormal vision
  • Visual impairment
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9
Q

WHO vi

A

Presenting VA in better eye cause hard to get glasses so cause don’t have glasses, they might be visual impaired cause of that

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10
Q

Mild VI

A
  • 6 / 12 – 6/18
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11
Q

Moderate VI

A
  • 6/18 – 6/60
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12
Q

Severe VI

A
  • 6/60 – 3/60
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13
Q

Blindness

A

> 3/60 E.G. if someone had VA of 2/60 and presenting VA in better eye was 2/60 then theyd be blind

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14
Q

Near VI

A

Near vision worse than N6 or N8 at 40cm and best corrected VA better than 6/12

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15
Q

What are the 2 categories of vi registration

A

*Severely sight impaired / blind
*Sight impaired / partially sighted

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16
Q

Severely sight impaired / blind

A
  • Blinds person act 1920 and National Assistance Act 1948
  • Blind as unable to perform any work for which eyesight is essential
  • There is no reference to near vision, occupation or any particular occupation or disability
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17
Q

Severely sight impaired / blind guidelines

A
  • 1.Acuity in better eye was below 3/60
    1. Above 3/60 but below 6/60 with significantly contracted field ( cause can cause difficulties with activities of daily living )
    1. Acuity better then 6/60 but with substantially contracted fields especially inferior
    1. Note blind category was changed to severely sight impaired 2003
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18
Q

Sight impaired / partially sighted guidelines

A
  • There is no legal definition.
  • Substantially and permanently handicapped by defective vision caused by congenital defect, illness or injury.
  • NOTE: Partial sight category was changed to sight impaired in 2003
    1. 3/60 to 6/60 with a full field
    1. Up to 6/24 with moderate restriction of the field, opacities or aphakia
      *If have corneal opacities, hard to correct with glasses so might need cl’s but these opacities can cause abrasions and VA not good
    1. 6/18 or better with a gross field defect i.e stroke or hemianopia or glaucoma or retinitis pigmentosa
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19
Q

What is aphakia

A
  • Cataract done and intraocular lens implanted in eye
  • If emmetrope before cataract surgery, you end up with high plus glasses so become hyperopic = magnified = not good depth perception and poor va and hard judging distances
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20
Q

Guidelines for children

A
  • Children can be born with a visual impairment, or can develop it later on in their childhood.
  • Children, unless they’re obviously blind, should always be classified as being sight impaired.
  • At the age of 4 and over, its better to use binocular visual acuity when making a decision as to which category the child should be placed under.
  • Children with visual acuity of 6/24 or better, as long as all that’s wrong with them is that they’ve got a visual impairment should be considered candidates for mainstream schooling.
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21
Q

History for certification process

A

Prior to 2003 certification via
* BD8 form England & Wales.
* Scotland BP1 form ,
* Northern Ireland A655 form

Changes brought about in 2003
* Cause not everyone who was eligible was being registered and have help as having VI as forms were complicated so system changed
* Early identification of sight loss for social care
* Improved access to social care
* Increase registration
* Improve accuracy of data collection

Registration is voluntary

22
Q

What happened from November 2003

A

*Can be certified OR if not eligible for certification but needed help
*Can only be certified as having VI via Certificate of vision impairment (CVI form )- standard across UK

  • Low Vision Leaflet (LVL) Previously Letter of visual impairment (LVI).
    *Usually available from primary care community practices for patients to self refer to Social Services e.g. high street practice
    *Not certify you as having low VI but its for those pxs who have difficulty but don’t meet criteria for VI
    *So can get help from social services
  • Referral of Vision Impairment (RVI)
    *For eye clinic to refer patient to social services.
    *Should be done as soon as social needs become apparent, but where certification is not currently appropriate or cannot be carried out, for example if they are not being seen by a consultant.
23
Q

What do you use if you want to register someone as VI in UK

A

CVI form i.e certificate of visual impairment

24
Q

What are LVL and RVI forms for

A

Getting people help from social services but px cant be registered or certified as having VI

25
Q

What is certification and what does it do

A

CVI formally certifies a person as SI or SSI.
*Provides a pathway for someone with sight loss to be brought to the attention of social services.
*Epidemiological analysis provides information on the prevalence of visual impairment.

26
Q

Where does registration of VI happen and how does it work

A

*At social services
*Fill out from to certify px VI and it goes to social services
*Social services register that someone has SI or SSI

27
Q

Features of registration

A

*Care Act 2014 requires local authorities to establish and maintain a register of people who are sight impaired or severely sight impaired.
*The Care and Support (Sight-impaired and Severely Sight-impaired Adults) Regulations 2014 provide for a person to be treated as being sight impaired or severely sight impaired if the person is certified as such by a consultant ophthalmologist
*help local authorities plan and provide services for people who are visually impaired.
*registration is voluntary

28
Q

Certificate of Visual Impairment

A

*Part 1 Patient details i.e name, address, NHS number and social services they fall under, Category of registration, Patient awareness-Information booklet sight loss & Contact with ECLO?
*Part 2 – Visual Function (best corrected VA in RE, LE and BE, visual fields, has px been to LV clinic )
*Part 2a – Diagnosis (18 years and over only)
*Part 2b – Diagnosis (under 18 years) – whats causing sight loss
*Part 3 – Additional information such as does the patient live alone, communication needs
*Part 4- Consent and information sharing, Ethnicity
*Information for Driving Licence holders and general information about CVI

29
Q

CVI

A

*Certification only via Consultant Ophthalmologist I.E optom cant but if you think they need to be registered as SI, then refer to gp, gp refer to hospital eye system and seen by Consultant Ophthalmologist and certify that they reigester

Copies for
* Patient
* Hospital
* General Practitioner
* Local council/Care Trust
* Epidemiological analysis @ Royal College of Ophthalmologists Certifications office at MEH

30
Q

LVL

A
  • For those who don’t meet criteria to be certified as VI
    *E.G. wet AMD – struggling with reading cause of AMD but cause 6/12 vision after injections and small visual field loss, theyre not classified as VI but still need help
  • Px fills in leaflet and sends to social services
  • Mechanism of self referral
  • Live alone?
  • Responsiblities as carer?
  • Difficulties
  • Concerns
31
Q

Referral of VI

A

Form similar to LVL
* Patient consent cause sending it on pxs behalf
* Filled in by hospital staff
* Copy to GP and to social services
* Urgency of referral

32
Q

Benefits of SSI Registration

A
  • Blind person’s personal income tax allowance
  • Reduction of 50 per cent on the television licence fee
  • Car parking concessions: the Blue Badge Scheme
  • Free postage on items marked “articles for the blind”
  • free permanent loan of radios, cd radio cassette players.
  • help with telephone installation charges and line rental.
  • Free NHS sight test
  • Other NHS costs
  • Discounted rail travel
  • Local bus schemes
  • Exemption from BT Directory Enquiry charges
  • Information in accessible formats
  • Leisure concessions
  • Council tax disability reduction
  • Welfare benefits
  • Attendance Allowance
  • Disability Living Allowance
  • Carer’s Allowance
  • Employment and Support Allowance
  • Tax Credits
  • Pension Credit
  • Housing Benefit and Council Tax Benefit
  • Help from specially trained social services staff, usually called Rehabilitation Workers or Rehabilitation Officers
  • Protection under the disability discrimination act
33
Q

Access to work scheme

A
  • Employer or Visually Impaired person should contact job centre
  • Important for VI person working and eyesight changed making it harder to carry out job
  • For other disabilities too
  • Assist disabled people by providing practical support and helping to meet additional costs associated with overcoming work related obstacles resulting from disability

Examples of what may be done
* Adaptations to Premises and Equipment. E.g. Zoom text for Computer
* Special Aids and Equipment. E.g. CCTV
* Travel to Work. E.g. Cost of a taxi if applicable reimburse

34
Q

Visually Impaired Children

A

Formal system in place to help children with visual impairment

Children’s Act 1998/2004
* Help should be available to all ‘children in need’
* Registration not necessary
* Even if not registered, have to be prioritised
* Schools and education authorities need to provide help to all visually impaired children
* Local Education Authorities identify all children recognised with special educational needs from age of 2 (up to age 19 if they are in full time education)
* SENCO
* Help VI person in class

35
Q

What is epidemiology

A
  • The study of the distribution, determinants and control of disease in human populations
  • In order to set policies and priorities and to evaluate global eye health
36
Q

What is prevalence

A
  • Measure of disease frequency
  • Number of people with a disease at a given time
  • Typically expressed in terms of a proportion (usually %)
37
Q

Equation for prevalence:

A

Prevalence = No. of cases or events / Total population at risk

38
Q

What is incidence

A
  • Number of cases occurring in a specified time
  • Sometimes expressed as a rate: the number of new cases occurring over a given time frame in relation to the total number of persons at risk during the same time frame
39
Q

Equation for incidence

A

Incidence = No. of new cases over a given time interval / Total population at risk at the beginning of the specified time

40
Q

Visually impaired statistic

A

Of the 253 million people in the world who are visually impaired
o 55% are women (139 million).
o Approx. 203 million, representing 80%, are aged 50 years or older.

41
Q

Global causes of Blindness and MSVI (all ages)

A
  • Cataract: 25.8%
  • Refractive Error: 48.99% - most common cause of VI – easily corrected by glasses
  • Glaucoma:2.78%
  • Age Related Macular Degeneration: 4.10%
  • Corneal Opacities:1.65%
  • Diabetic Retinopathy: 1.16%
  • Trachoma:0.79%
  • Other: 14.71%
42
Q

Change in prevalence of visual impairment from 1990 to 2015

A

*Decline observed in prevalence of visual impairment for most eye conditions except Diabetic Retinopathy and the ‘Other’ category.
*Related to increase in the prevalence of diabetes CAUSING INCREASE IN VI

43
Q

Global Incidence of Visual Impairment:

A
  • Incidence varies with age
  • Not many studies
  • Priverno Eye Study (Cedrone et al, 2003)
    *Blindness 0.1%
    *Low Vision 1.3%
44
Q

Risk Factors for Sight loss in the UK:

A
  • Old Age
    * 31 per cent aged 85 years and over
  • Low Income
  • Diabetes
  • Smoking
  • Learning Disabilities
  • Ethnic Minority Groups
  • Other health conditions E.G HTN
45
Q

Prevalence of Visual Impairment in the UK:

A
  • 149,938 people: SSI register (England & Wales) (2017)
  • 157,531 people: SI register (England & Wales) (2017
  • Registration is voluntary so not everyone who has VI will appear on these registers so data is underestimating number of people with VI 2 million VI across UK
46
Q

UK Incidence of Visual Impairment:

A
  • Incidence varies with age
  • 20605 new registrations on the SI and SSI register(2016/17)
47
Q

Prevalence of childhood VI in the UK:

A
  • Approx. 12,000 SI and SSI children between the ages of 0–16
  • Around half have additional disabilities and/or special educational needs
  • SSI Register (2017)
  • 0- 4 years: 637 children
  • 5-17 years: 4,651 children
  • SI Register (2017)
  • 0- 4 years: 604 children
  • 5-17 years: 5675 children
48
Q

Incidence of childhood blindness in the UK: New registrations:

A

SSI register (2017)
* 0- 4 years: 200 children
* 5-17 years: 205 children
SI Register (2017)
* 0- 4 years: 175children
* 5-17 years: 310 children

49
Q

Common Causes of Visual Impairment UK: Adult Population:

A
  • Glaucoma (30%)
  • Diabetic Retinopathy (8%)

Other less common causes
* Cataract
* Myopia
* Optic Neuropathies

50
Q

Causes of VI: Working population:

A

*Diabetic Retinopathy Eye (2004) 18, 257–261
But recent findings Liew et al 2014 have found that no. of registrations due to DR/DM has decreased and overtaken by hereditary retinal disorders
*Other causes hereditary retinal disorders & optic atrophy

51
Q

Common cause of Visual Impairment UK: Children:

A
  • Cerebral Visual Impairment 39%
  • Hereditary Retinal Disorders 22%
  • Optic Nerve pathologies 22%
  • Congenital Cataract 4%