16/09/2014 1 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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Seeing the full picture: Visual fields in macular disease
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16/09/2014
1
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)
CONVENTIONAL DARK-ADAPTED
11: WR (1282157) VA: 0.22 logMAR (6/9.5, 20/32)
CONVENTIONAL DARK-ADAPTED
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?
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 to places with fluorescent lighting because of your vision
7- Stopped for other reasons 2.
3. Do you have difficulty seeing people�s faces in a hallway when direct sunlight is
behind them?
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 doing this because of your vision
7- Stopped for other reasons 3.
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