Seeing the full picture: Visual fields in macular disease

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Visual function in early macular disease

Michael Crossland PhD MCOptom DipRVI

Moorfields Eye Hospital NHS Foundation Trust

UCL Institute of Ophthalmology

LVI-Dagarna 2014, Vaxjo, Sweden, September 2014

Talk outline

• Visual function in early macular disease • Dark adapted visual function

• Visual function when a scotoma has developed • The development of the preferred retinal locus

• (Other talk) • Rehabilitation options in early macular disease

Visual function in early macular disease

Why early eye disease?

In time, everyone will have only early eye disease

SI/SSI registration in Leeds: AMD

Rostron & McKibbin, Eye 2012

Assessing early macular disease

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Structure Function Performance

Dark-adapted function in early macular disease • Structure: Rod loss in ARM

• Curcio, 1996; Curcio, 2001

• Function: Reduced scotopic sensitivity in ARM • Scholl, 2004

• Performance: Reduced dark-adapted function in ARM • Scilley, 2002

Functional measurement of dark-adapted visual function

21st century measurement of visual fields

Adaptation made to MP-1

• Shielding of stray light

• 2 log unit + short pass filters over display system

• Reduction of IR illumination for retinal imaging

• Now adopted by Nidek in MP-1S

Crossland, 2011

Optical path of

display systemOptical path of

imaging systemFilters

1: ABW (1586439) VA: 0.3 logMAR (6/12, 20/40)

CONVENTIONAL DARK-ADAPTED

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7: PF (1724597) VA: 0.6 logMAR (6/24, 20/80)


11: WR (1282157) VA: 0.22 logMAR (6/9.5, 20/32)


Dark adapted vision is worse in people with early macular disease…

…does this affect them?

Low luminance questionnaire

• Designed by Owsley for ARM

• Focus group based

• Validated: • Construct validity

• Citerion validity

• Test retest variability

• Not Rasch analysed • Owsley IOVS 2006

Low Luminance Questionnaire

INSTRUCTIONS

I�m going to read you some statements about problems that involve your vision under

different lighting conditions or feelings that you have about your vision under different

lighting conditions. After each question I will read you a list of possible answers. Please

choose the response that best describes your situation at the present time.

Please answer all the questions as if you were wearing your glasses or contact lenses (if

any). Please take as much time as you need to answer each question. All your answers are

confidential. In order for this survey to improve our knowledge about vision problems under

different lighting conditions and how they affect your quality of life, your answers must be

as accurate as possible. Remember, if you wear glasses or contact lenses for a particular

activity, please answer the following questions as though you were wearing them.

1. Do you have difficulty seeing in bright sunlight?

1- No difficulty at all

2- A little difficulty

3- Some difficulty 4- A lot of difficulty

5- Completely blind under these conditions

6- Stopped going out in bright sunlight because of your vision

7- Stopped for other reasons 1.

2. Do you have difficulty seeing in fluorescent lighting, like that found in stores and

offices?



3- Some difficulty 4- A lot of difficulty


6- Stopped going to places with fluorescent lighting because of your vision


3. Do you have difficulty seeing people�s faces in a hallway when direct sunlight is

behind them?



3- Some difficulty

4- A lot of difficulty


6- Stopped doing this because of your vision


Six domains

• Driving

• Extreme lighting

• Mobility

• Emotional distress

• General dim lighting

• Peripheral vision

• LLQ administered to 20 people with early/moderate AMD • Mean age: 75.4 years

• Mean visual acuity 0.3 logMAR (6/12; 0.5 decimal)

• Mean contrast sensitivity 1.30 log units

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LLQ performance in early AMD

0

500

1000

1500

2000

2500

3000

3500

Driving Extreme lighting Mobility Emotional

distress

General dim

lighting

Peripheral vision TOTAL

* * * * *

*

LLQ and clinical tests

Visual acuity Contrast sensitivity

R² = 0.396

0

500

1000

1500

2000

2500

3000

3500

-0.2 0 0.2 0.4 0.6 0.8

LLQ

VA (logMAR)

R² = 0.2381

0

500

1000

1500

2000

2500

3000

3500

1 1.2 1.4 1.6 1.8

LLQ

CS (log units)

LLQ and microperimetry

Conventional Dark-adapted

R² = 0.2348

0

500

1000

1500

2000

2500

3000

3500

0 5 10 15 20

LLQ

so

cre

Conventional microperimetry: Mean sensitivity (dB)

R² = 0.4299

0

500

1000

1500

2000

2500

3000

3500

0 5 10 15 20

LLQ

so

cre

Dark-adapted microperimetry: Mean sensitivity (dB)

Visual acuity Contrast

sensitivity Conventional

microperimetry Dark-adapted

microperimetry

General dim lighting 0.12 0.47* 0.37* 0.44*

Extreme lighting 0.20* 0.29* 0.23* 0.53*

Driving 0.46* 0.16 0.21 0.38*

Emotional distress 0.06 0.01 0.01 0.00

Mobility 0.36* 0.23* 0.01 0.21*

Peripheral vision 0.01 0.00 0.00 0.04

Total LLQ 0.40* 0.24* 0.23* 0.43*

Summary

• Early vision loss is becoming more common

• People with early macular disease report poor performance in low light conditions

• Early low vision intervention may be useful

• Lighting advice, consumer electronics and tints may be important to consider

• Further research is needed

After a scotoma develops: the development of the preferred retinal locus

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Preferred retinal locus (PRL)

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• Prospective, observational study

• New vision loss in better eye

• Observation of fixation position and eye movements at 0, 1, 3, 6, 12 months

• Study performed in the pre-anti-VEGF era

Rodenstock SLO-101 Development of the PRL

0

20

40

60

80

100

0 2 4 6 8 10 12

% of people

Time (months)

Crossland, Kabanarou, Culham & Rubin, Ophthalmology 2005

PRL location

0

2

4

6

8

10

12

Above Below Left Right Central

Baseline

Exit

Crossland, Kabanarou, Culham & Rubin, Ophthalmology 2005

PRL location & reading speed

Reading speed: F(df=2,24)=0.67, p=0.52

Crossland, Kabanarou, Culham & Rubin, Ophthalmology 2005 Fletcher & Schuchard, Ophthalmology 1997 Fletcher, Schuchard & Watson, J Rehab Res Dev 1999

0

10

20

30

40

50

60

Below Left Right Above

% o

f p

eop

le

Crossland 2005

Fletcher 1997

Fletcher 1999

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What does affect reading speed? Fixation stability and reading

Crossland, Culham & Rubin, Ophth Physiol Opt 2004

Fixation stability and reading

Amore, Crossland et al Ophth Physiol Opt 2013

R2=0.51

Changes in fixation stability

Crossland, Culham, Rubin 2004

Can we compensate for poor fixation stability?

PC1

read this words

eyetracker

control

Ethernet cable

PC2

« stimulus displayEYELINK I

SETUPSampling rate 250 Hz

Can we compensate for poor fixation stability? • RSVP presentation of text

• N=10, AMD, Stargardt, Best disease

• Condition 1: Baseline

• Condition 2: Stabilise all eye movements

• Condition 3: Stabilise microsaccades, drift, tremor; allow intra-word saccades

• Condition 4: Exaggerate eye movements

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Can we compensate for poor fixation stability?

Baseline Instability corrected; within-word saccades allowed

Macedo, Crossland, Rubin, 2011

Can fixation stability be improved with training?

Can fixation stability be improved with training?

• Training improves fixation stability in control subjects using peripheral fixation

(Zeevi, JOSA, 1979)

• Target shooters have better fixation stability than controls

(Di Russo, Vision Research, 2003)

• Reading speed improves after fixation training in patients

(no control groups, stability not measured) (Nilsson Optom Vis Sci 1998 ; Contestabile Eye 2002; Seiple IOVS

2005)

Fixation stability training

• Eccentric viewing training • Backman and Inde, Sweden • Goodrich and Quillman, USA

• Eye movement training • Seiple Invest Ophthalmol Vision Sci, 2005

• Intensive in-patient rehabilitation • E.g. Veterans Administration, USA

• Intensive outpatient training • E.g. Nilsson Vision Research 2003

• Training by people with MD • E.g. “Train the trainer”, Macular Disease Society, UK

• Training by exercises at home


• Is fixation training better than placebo?

• What is the best way of training the PRL?

• Should we be training people for reading? • If so, will this negatively affect performance on other

tasks?

• Is training cost-effective?


• Lack of clear evidence • EFFECT trial (Eccentric Fixation From Enhanced Clinical

Training)

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EFFECT trial

• Four arm RCT • PRL training

• TRL training

• Supervised reading practice

• Standard care only

• Outcomes • Massof Activity Inventory

• Reading speed

• Health economic analysis

Progress

• Sample size calculation: 200 participants

• Currently recruited: 140

Conclusions

• People develop a preferred retinal locus within six months of scotoma development

• Fixation instability is strongly associated with reading difficulty

• Compensating unstable fixation may improve reading ability

• Training fixation may improve reading ability

Clinical implications

• Early vision loss is becoming more common

• Rehabilitation options will be different • Tints

• Lighting

• Consumer devices…

• Fixation stability is important for people with macular disease

• Training may help people hold their fixation more steadily

Thank you for your attention

[email protected]

Seeing the full picture: Visual fields in macular disease

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