ax and mx of amd

CET CONTINUING EDUCATION & TRAINING

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Assessment and management of AMD

hyper-reflective material underlying the

RPE is clearly visible on the tomogram.

Furthermore, the local elevations of

the RPE caused by drusen are also

apparent on an OCT image (Figure 3).

When a patient is referred to the

hospital with suspected wet AMD,

fluorescein angiography is carried out

as a standard procedure to confirm

the presence and type of choroidal

neovascularisation. Fluorescein

angiography is also an important

tool in differentiating between

neovascularisation attributable

to AMD and that caused by other

conditions such as myopia and

birdshot choroidopathy, which may

require different treatment strategies.2

VA is often relatively unaffected in

early AMD, but there is evidence to

suggest deficits in other aspects of visual

function when fundus changes are still

mild. Reduced sensitivity to flicker3

and elevated cone and rod thresholds4

have been reported in individuals

with ARM before marked VA loss has

occurred. There is substantial evidence

that the rod and cone adaptation are

also delayed in very early macular

disease.5,6 The macular photostress test

is one way that cone adaptation may

be assessed quickly and easily in the

REFERRAl REFINEMENT PART 4 COuRsE CODE: C-16276 O/D

Dr Alison Binns, Bsc (Hons), PhD, MCOptom

The previous article in this series outlined the key features of age-related macular

degeneration (AMD), a condition that is responsible for more than half of all

registrations as sight-impaired or severely sight-impaired in the UK.1 A review

of treatments showed that medical intervention is currently only available

for those with the active, wet form of the disease. Although those with early

AMD (also known as age-related maculopathy - ARM), dry AMD (geographic

atrophy), and end stage wet AMD are not responsive to current medical

treatments, they still present at optometric practices requiring management.

This article provides an overview of the optometric assessment of patients with

suspected ARM and AMD, and appropriate management of these patients.

Clinical Assessment of ARM and AMDDiagnosis and monitoring of AMD in the

clinic has historically been based on the

assessment of visual acuity (VA), Amsler

chart, and fundus examination of retinal

signs. Fundus examination in recent

years has expanded to include not only

direct and indirect ophthalmoscopy,

but also imaging techniques such as

(stereo) fundus photography and optical

coherence tomography (OCT). Intra-

retinal or sub-retinal fluid accumulation

or sub-retinal pigment epithelium (RPE)

neovascular membranes will cause a

raised area of the retina, which may not

be immediately appreciated without a

three dimensional view of the fundus.

Binocular indirect ophthalmoscopy

(Volk or BIO headset) and stereo

fundus photography provide a means

of accurately identifying elevations of

the retina. OCT, which provides a cross-

sectional view of the retinal layers, not

only allows the clinician to identify

raised or thickened areas of the retina,

but also allows some visualisation of the

nature of the material that is causing the

elevation. For example, Figure 1 shows

a serous pigment epithelial detachment

(PED), where the fluid under the RPE

is seen as black due to its low relative

optical reflectivity, whilst Figure 2 shows

a fibrovascular membrane, where the

Figure 1 Fundus photograph (left) and OCT image (right) of serous PED. Black arrow indicates location of OCT scan. Note the bright band of OCT image corresponding to the RPE (marked with a green arrow) shows dome-shaped elevation with accumulation of fluid beneath, seen as a dark region due to its low relative optical reflectivity. Images courtesy of Ashley Wood, Cardiff University

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clinic. Margrain and Thomson7 found

the technique to be most repeatable

after exposure of the macula to an

ophthalmoscope light for 30 seconds,

followed by assessment of the time taken

for VA to return to within one line of its

pre-bleach level. Their data suggest that

a healthy 60-year-old person should

have a recovery time of less than about

60 seconds, and that any delay beyond

this may be considered abnormal.

There is also evidence that patients

who are at higher risk of developing

choroidal neovascularisation will

have more marked delays on the

macular photostress test.8 This may

provide a useful adjunct to the Amsler

chart, which is commonly used to

look for central visual distortions in

patients at risk of wet AMD (Figure 4).

Optometric management of ARM and AMDAge-related maculopathy

On identifying drusen or pigmentary

changes in the retina, a key role of

the optometrist is to exclude the

possibility of neovascular changes

through thorough fundus examination

and checking for marked central visual

field distortions using the Amsler chart

(bearing in mind that drusen may

themselves cause small distortions).

These patients should be referred for

urgent ophthalmological assessment

if they have noticed a sudden onset

of blurring or distortion of the central

vision. Not all patients with drusen will

imminently develop severe visual loss

(one study observed that nine out of 49

patients with bilateral drusen developed

severe sight loss in at least one eye

over a period of about five years).9

However, patients should be made

aware of the risks of developing late

AMD and the symptoms of wet AMD.

Patients with risk factors for developing

choroidal neovascularisation (eg,. lots of

large soft and confluent drusen and/or

focal hyperpigmentation, or wet AMD

in the fellow eye) should be monitored

particularly closely. Amsler charts

may be given to patients to take home

so that they can check for distortions

in their vision on a daily basis. It is

important that the patient understands

how to carry out the test (for example,

the importance of checking each eye

separately), and it is also vital that

they understand the need for prompt

assessment should any changes

in their vision become apparent.

The optometrist should consider

giving advice to patients with ARM

about lifestyle changes which may

reduce their risk of developing

advanced AMD. Epidemiological10

and longitudinal11 studies have

consistently reported that smoking is

the strongest modifiable risk factor for

the development of late AMD, which

gives a firm basis for recommending

that patients with ARM stop smoking.

Some population-based studies have

indicated that increased light exposure,

especially to short wavelength (blue)

light, may also be a risk factor for

AMD.12-17 Although this finding has

not been universal,18,19 it may be wise

to advise individuals at risk of AMD

and those with early fundus changes

to wear protective sunglasses when

outdoors, especially on bright days.

Other nominated modifiable risk factors

such as elevated body mass index

(BMI), lack of physical activity and

excessive alcohol consumption are less

consistently significant across studies.20

Nutritional supplements

The efficacy of nutritional supplements

in preventing or delaying the onset of

late AMD has been a matter of some

debate. The first large randomised

controlled trial of the benefits of

supplementation for people with early

ARM was the Age-Related Eye Disease

Study (AREDS).21 This study reported

a 28% risk reduction in progression

from intermediate to late AMD over five

years in people taking a combination of

zinc plus antioxidants (high dosage of

vitamins C, E and beta carotene). There

was evidence of a beneficial effect in

those who had at least one large druse,

multiple intermediate sized drusen,

parafoveal geographic atrophy in one or

both eyes, or unilateral advanced AMD

(individuals with only small drusen

did not benefit). There is, therefore, a

strong case for recommending vitamin

supplements conforming to the AREDS

formulation for people who fall into

this ‘intermediate AMD’ category.

Figure 2 Fundus photograph (left) and OCT image (right) of choroidal neovascular membrane resulting in PED. Black arrow indicates location of OCT scan. Note disruption of RPE on OCT image, and reflective material beneath (red arrow). Images courtesy of Ashley Wood, Cardiff University

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advanced AMD.22 There was also an

apparent decrease in the risk of early

AMD with regular fish consumption.

The carotenoids lutein and

zeaxanthin, which are the main

constituents of macular pigment, have

also been the subject of much interest

given their protective antioxidant

and short wavelength absorption

characteristics. Large epidemiological

studies have found a reduced incidence

of intermediate and advanced AMD

in those individuals with the highest

dietary intake of these dietary factors,

suggesting that they may indeed have

a protective effect in individuals

predisposed to AMD.23 Green, leafy

vegetables such as kale and spinach

are a particularly good source of

these carotenoids. On the basis of the

evidence, advising patients to include

regular fish and green, leafy vegetables

in their diet is a reasonable precaution

to take, but it should be noted that

the protective effect cannot be fully

determined until large, randomised

controlled trials have been carried out.

Wet AMD

Patients who require urgent referral

to the hospital eye service (HES) by

the optometrist are those who present

with newly developed wet AMD. These

patients are at risk of rapid development

of visual loss, and are also the patients

who could potentially benefit from

medical intervention, particularly

the anti-VEGF therapy ranibizumab

(‘Lucentis’; Novartis Pharma AG,

Switzerland and Genentech, California).

There are guidelines provided by the

College of Optometrists for referral of

AMD cases, but these were published

in 2005, pre-dating the widespread use

of therapies based on growth factor

inhibitors.24,25 Other referral guidelines

have been published since, for example

by Novartis, with specific reference to

anti-VEGF treatments.26 The key features

of these documents are the same; newly

developed wet AMD warrants urgent

attention by an ophthalmologist. Delayed

treatment for wet AMD has been strongly

associated with a poorer visual outcome,

so time is of the essence.27 Some health

authorities now employ a direct referral

scheme for these patients,

for example hospitals in

Wales use an AMD direct

referral pad, adapted

from the Thames Valley

Macular Group Referral

Pad, which allows urgent

and direct referral straight

to the local macular

specialist. In a different

scheme, Manchester

Royal Eye Hospital

runs an optometry-led

Contraindications for the AREDS

supplements include smoking, anaemia

and Alzheimer’s disease.20 Some

supplements that are currently available

commercially lack beta carotene and so

are less hazardous to current smokers.

However, there is less rigorous

evidence available regarding the efficacy

of such non-AREDS formulations.

Evidence for the beneficial effects

of other dietary factors is less robust.

Omega-3 long chain polyunsaturated

fatty acids are required to maintain

healthy photoreceptor outer segments,

and may be associated with preventing

oxidative, inflammatory and age-related

damage to the retina. Oily fish such as

salmon and tuna are rich in omega-3

fatty acids, and other sources include

nuts, seeds and olive oil. A recent

systematic review of nine studies that

had evaluated

the benefits of

omega-3 fatty

acid intake (and

included a total

of 88,974 people)

found that a high

dietary intake

of omega-3 was

associated with

a 38% reduction

in the risk of

d e v e l o p i n g

Figure 3 Fundus photograph (left) and OCT image (right) of drusen. Black arrow indicates location of OCT scan. Note bright band of OCT image corresponding to RPE (marked with a green arrow) is raised by underlying drusen (red arrows). Images courtesy of Ashley Wood, Cardiff University

Figure 4 Image showing the Amsler chart as it may be perceived by a patient with distortions due to wet AMD. Images courtesy of National Eye Institute, National Institute of Health

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include metamorphopsia, recent onset

blurred central vision, VA loss and

uniocular hyperopic shift. Clinical

trials suggest that baseline VA does not

influence the outcome of ranibizumab

treatment within the range of 6/12 to

6/48, and NICE guidelines support

medical intervention if presenting VA

is within the range of 6/12 to 6/96.2

Advanced AMD

When AMD has advanced to a stage

where VA is markedly reduced (to less

than 6/96), as a result of geographic

atrophy or advanced wet AMD including

fibrosis or disciform scarring, treatment

is unlikely to result in a positive

outcome.2 These patients should still be

referred to the HES on a non-urgent basis

for assessment of the fellow eye, and also

to determine whether they may benefit

from other services available. A low

Fundus Features Functional status Optometric Action

Dry ARM • Drusen (several small hard drusen are considered a normal ageing change)• Focal Hyperpigmentation

• Slight distortion on Amsler grid, corresponding to location of drusen• Gradual reduction in VA

Monitor, advise on lifestyle changes (eg, stopping smoking and nutritional supplements) and provide Amsler grid for self-assessment.

Wet AMD(suitable forTreatment)

• Haemorrhage (sub-RPE, sub-retinal, intra-retinal)• Exudates (requires urgent referral as it is a sign of leakage from new vessels)• Visible retinal elevation• Sub-retinal fluid or pigment epithelial detachment• Sub-retinal neovascular membrane may be seen as greenish grey lesion

• Presence of markedly distorted, blurred, or absent lines on Amsler grid• Recent onset marked reduction in VA (6/12 to 6/96)• Hyperopic shift in Rx

REFER URGENTLY (via rapid access referral route if available locally)

Advanced AMD

• Geographic atrophy• Disciform scar• Extensive exudates, haemorrhage, fibrosis, macular elevation

• Central scotoma on Amsler chart• VA reduced to below 6/96

Refer non-urgently to assess fellow eye, and consider LVA assessment and training, visual impairment counselling and registration.

Table 1 Summary of the clinical features of ARM, wet AMD and advanced AMD, and appropriate action for optometrists

vision assessment, visual impairment

counselling and/or registration as sight

impaired or severely sight impaired may

be appropriate. If they have only early

changes in the fellow eye, provision

of an Amsler grid for self-assessment,

and advice on lifestyle changes

should also be given (eg, stopping

smoking, nutritional supplements).

For patients with an AMD-related

visual impairment who are not

amenable to treatment, the optometrist

can also give useful advice on

household modifications that may help

with performance of daily activities.

Generally increased lighting levels,

with directional lighting when reading,

can be particularly beneficial. Advice

on improving contrast can also be

helpful, for example suggesting that

the patient use a thick black felt tip

pen when writing. Later articles in this

fast-access direct referral clinic, in

which optometrists and GPs may refer

patients directly to a referral refinement

optometrist, who can then re-direct

either to the retinal specialist clinic

for treatment, or to alternative clinics/

discharge.24 It is of great importance

that all optometrists familiarise

themselves with the local protocols for

normal referrals and fast track referrals.

Signs and symptoms of wet AMD

requiring urgent treatment are

summarised in Table 1. The key retinal

features are: intra-retinal/sub-retinal

or sub-RPE haemorrhage, the presence

of exudates (which suggests leakage

from the vessels, indicating a need

for urgent treatment), intra-retinal or

sub-retinal fluid, PED, raised central

retina, and/or visible neovascular

membrane (often seen as a greenish

or greyish lesion). Functional changes

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series will look at the management of

patients with low vision at greater depth.

summaryPatients with active wet (neovascular)

AMD require urgent medical treatment to

prevent rapid visual loss occurring. It is

important that all optometrists are aware

of the urgent referral pathway for these

patients in their area. Those individuals

with early AMD may benefit from

guidance about modifiable risk factors,

particularly with respect to smoking and

the potential positive effect of dietary

supplements. Even if the presence of

wet AMD has been excluded, advice on

monitoring for symptoms of choroidal

neovascularisation and the provision of

Amsler charts is advisable, especially

for those patients with risk factors for

development of wet AMD (such as

choroidal neovascularisation in the fellow

eye, or lots of large soft and confluent

drusen or focal hyperpigmentation of

the retina). Patients with end stage AMD

(geographic atrophy/disciform scarring)

should be referred non-urgently to check

the status of the fellow eye, and for low

vision aid provision and training, or

registration as sight impaired or severely

sight impaired. As new treatments

become available, referral guidelines

are likely to be reviewed in the future.

Five key points to remember:

• Patients with early AMD should

be thoroughly examined to exclude

possibility of wet AMD and given

an Amsler chart to self-monitor.

• Stopping smoking, taking AREDS

formulation dietary supplements

(to non-smoking patients only),

and the use of sunglasses on bright

days should be recommended.

• If a patient has any signs of wet AMD

(Table 1), has noticed a sudden onset

of blurring or distortion of the central

vision, or shows marked distortion

on the Amsler grid, refer urgently

for ophthalmological assessment.

• Referral pathways vary between

areas, and it is important for all

optometrists to know their local system.

• When AMD has advanced to end-

stage disciform scarring or geographic

atrophy, refer non-urgently for low

vision assessment and evaluation of the

fellow eye. Advise on the importance

of improving lighting and contrast.

About the author Dr Alison Binns is an optometrist

and a lecturer at the School of

Optometry and Vision Sciences, Cardiff

University. Her main research interests

include the early detection and monitoring

of age-related macular degeneration and

electrophysiology of the visual system.

ReferencesSee http://www.optometry.co.uk

clinical/index. Click on the article title

and then download "references".





Course code: C-16276 O/D1) Which of the following is NOT an advantage of OCT when assessing AMD?a) It allows visualisation of changes to different retinal layersb) It helps differentiation between different types of PEDc) It allows differential diagnosis of classic and occult choroidal neovascularisationd) It helps to identify areas of retinal thickening due to oedema

2) The ‘macular photostress test’ provides a rapid assessment of:a) Speed of cone adaptationb) Speed of rod adaptationc) Cone absolute thresholdd) Rod absolute threshold

3) If a patient presents with bilateral soft drusen in the macular area and VA of 6/6 in both eyes, what is the MOsT appropriate course of action?a) Refer for urgent ophthalmological assessmentb) Advise on lifestyle changes and monitorc) Refer for non-urgent ophthalmological assessmentd) Refer for low vision assessment

4) If a patient presents with recent loss of central vision in their right eye, accompanied by haemorrhage and oedema in the macular region, and the best VA is 6/36, what is the MOsT appropriate course of action?a) Refer for urgent ophthalmological assessmentb) Advise on lifestyle changes and monitorc) Refer for non-urgent ophthalmological assessmentd) Refer for low vision assessment 5) Which of the following statements about dietary supplements for AMD is TRuE?a) Low dose vitamin C and E taken daily reduces risk of progression from early to late AMDb) High dose vitamin C and E and beta carotene plus zinc taken daily reduces risk of developing early AMD within five years, in healthy individuals c) High dose vitamin C and E and beta carotene plus zinc taken daily reduces risk of progression from intermediate to late AMD within five yearsd) High dose vitamin C and E and beta carotene plus zinc taken daily reduces risk of further visual loss in those patients with bilateral wet AMD 6) Which of the following statements about the referral of patients with wet AMD is FAlsE?a) Urgent referral is only necessary if VA is poorer than 6/18b) Urgent referral is not necessary if VA is poorer than 6/96c) Sudden onset report of central scotoma should be referred urgentlyd) Sudden onset report of blurred central vision should be referred urgently even in the absence of choroidal neovascularisation

PlEAsE NOTE There is only one correct answer. All CET is now FREE. Enter online. Please complete online by midnight on June 17 2011 - You will be unable to submit exams after this date – answers to the module will be published on www.optometry.co.uk. CET points for these exams will be uploaded to Vantage on June 27 2011.

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ax and mx of amd

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