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Astigmatism and its prevalence
Astigmatism ‐ prevalence, insights & opportunities
Spherical or </=0.50DC
November 2012 24% 53% 23%
Anna Sulley BSc (Hons) MCOptom FBCLA FAAO Medical Affairs Associate Director EMA
>/=0.75DC in one eye only >/= 0.75DC in both eyes (N=11,624)
Young G, Sulley A and Hunt C. Prevalence of Astigmatism in Relation to Soft Contact Lens Fitting. Eye & Contact Lens 2011; 37 (1): 20‐25
Prevalence eyes with various levels astigmatism 30%
Prevalence astigmatism increases with age 30%
Hyperopes Myopes
25%
0.50DC or less >/= 0.75DC at least one eye
25%
All 31.7% myopes >0.75DC
15% 15.7% hyperopes >0.75DC
10% 5%
15%
10%
5%
0% 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 >2.50 Cylinder (D)
Young G, Sulley A and Hunt C. Prevalence of Astigmatism in Relation to Soft Contact Lens Fitting. Eye & Contact Lens 2011; 37 (1): 20‐25
50 45 40 35 30 25 20 15 10 5 0
0% 8‐19
20‐29
30‐39
40‐49
50‐59
60‐70
Age range (Years) Young G, Sulley A and Hunt C. Prevalence of Astigmatism in Relation to Soft Contact Lens Fitting. Eye & Contact Lens 2011; 37 (1): 20‐25
Prevalence Astigmatism vs. Fits Data
Percentage (%)
20%
Prevalence
Prevalence
20%
Although toric soft CL prescribing increasing ‐ not to levels expected if all astigmats fully corrected
Astigmatic Drop Outs A high percentage of CL drop‐ outs are astigmats 65% of drop‐outs: ≥ 0.75DC in one eye
47 20
Prevalence Toric fits UK ‐ Industry astigmatism (≥0.75D data 2 at least 1 eye) 1
19
Norway 3
Young, Veys, Pritchard & Coleman Ophthal Phsiol Opt 2002; 22: 516‐52
• Astigmats over represented among CL drop‐outs • Poor vision due to uncorrected cylinder contributing factor in CL discontinuation
1. Young G, Sulley A & Hunt C. Prevalence of Astigmatism in Relation to Soft Contact Lens Fitting; Eye & CL, 2011: 37: 20‐25 2. GfK Fit Audit FY 2011 3. 19.4% CL wearers use torics – Internal data, 2012
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Studies to gain key insights into astigmatic patient behaviour, awareness and needs
1. Non‐toric Use Clinical Study No. of subjects Spherical wearers: 67 CL Drop‐outs: 72 Neophytes: 61
Spherical Wearers
1 – Non‐toric User Clinical Study
2 – Qualitative Interviews
3 ‐ Astigmatism Awareness Survey
4 – Usage & Attitude Survey
Background questionnaire to evaluate ease of fitting non‐toric CL users & clinical performance 2 ASD torics
Interviews and focus groups
1‐month, open label, randomised, DW study
Practitioners and astigmats (lapsed, current spherical, neophytes)
Consumers aged 18 to 54 (n=819)
200 astigmats
60 each group
Spectacles/CL wearers (n=538)
n=3525 (n = 1018 astigmats)
UK, 16 sites
UK & Italy
UK
9 countries in Europe
On‐line survey ‐ Independent MR agency
On‐line survey – Independent MR agency
Drop-outs Neophytes
CL wearers Aged 16‐54 years Representative CL population by age, gender, modality
Neophytes – key reasons for not wearing CLs (n=61)
Male
Female
Sulley A, Young G, Osborn K, et al. A multi‐centre study of astigmatic nonusers of soft toric contact lenses. BCLA Conference 2011, Poster Presentation.
Drop‐outs – key reasons for discontinuation (n=72)
Spectacles more convenient
39%
Concerned about comfort
33%
Haven't got round to it
33%
Cost
30%
Never thought about it
39% 35%
Poor vision
31%
Don't like thought of putting CLs in eye
Discomfort Spectacles more convenient 31%
Dryness
24%
23% Cost
Get lost in eye
21%
18%
Irritation/infections
15%
CLs too much trouble to care for
15%
Handling
15%
Reasons wider beliefs of non‐ lens wearers
Sulley A, Young G, Osborn K, et al. A multi‐centre study of astigmatic nonusers of soft toric contact lenses. BCLA Conference 2011, Poster Presentation.
Ran out of CLs and didn't get round to getting more
15%
CLs too much trouble to care for
15%
Key factor was CLs did not meet specific vision needs
Sulley A, Young G, Osborn K, et al. A multi‐centre study of astigmatic nonusers of soft toric contact lenses. BCLA Conference 2011, Poster Presentation.
Background questionnaire ‐ Spherical wearers – key reasons for not wearing toric CLs (n=67)
2. Qualitative interviews Lapsed Wearers
Unaware there were lenses for astigmatism
Current Lens Wearers
28%
Unaware I had astigmatism
22%
Cost
18%
Practitioner never offered me toric CLs
12%
Astigmatism didn't warrant toric CL
12%
Main reason for not wearing ‐ ‘lack of awareness’
Non wearers
1 in 10 said TSCLs not offered Sulley A, Young G, Osborn K, et al. A multi‐centre study of astigmatic nonusers of soft toric contact lenses. BCLA Conference 2011, Poster Presentation.
Astigmatism qualitative interview s, UK & Italy, 60 practitioners, 60 patients, 2011
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Do we always communicate about astigmatism, the implications and the options? Torics are hard to fit, with limited Rx & take up too much chair‐time
3 ‐ Astigmatism Awareness Survey
What is astigmatism? Are CLs are Ok with astigmatism?
I am not sure I have the skills needed to fit them
Low awareness
•
•
If there is an alternative, my practitioner will tell me
My patients just want low cost – if not, they’d ask for something else Practitioner
If I know a little more about the options, I might try toric CLs
Astigmat
Can astigmatism can be corrected with CLs?
Nearly 4 out of 10 (38%) don’t know what astigmatism is
Net don’t know / no = 57%
15%
Happy to switch if vision with toric CLs as good as spex
‘What’s in it for me’ – and CLs are less profitable
Yes
‐ recommended as most suitable lens 50
77%
30 %
7%
42
20 N=161
1%
10
N=538
0 Astigmats
Non‐astigmats
On‐line survey in 9 countries across Europe (n=3525), 2011, Independent MR agency UK, France, Germany, Italy, Spain, Sweden, Russia, Poland & Saudi Arabia
4. European Usage & Attitudes Survey
Do patients know about astigmatism and toric lenses? Low toric CL penetration vs astigmatism prevalence
Satisfaction levels with vision correction P<0.05
Benefits & opportunities
Spherical wearers – key reasons for not wearing toric CLs
Successfully completed 1‐month
Unaware there were lenses for astigmatism
P<0.05
60
Lack of awareness and other barriers
28%
Unaware I had astigmatism
22%
Cost
50 68
58 50
20
Percentage (%)
50 40 30 20 10
47 20
18%
Practitioner never offered me toric CLs
12%
Astigmatism didn't warrant toric CL
12%
Can astigmatism can be corrected with CLs?
Toric soft CL Astigmats wearing wearers (n=1018) spectacles (n=205)
Lapsed wearers (n=242)
On‐line survey in 9 countries across Europe (n=3525), 2011, Independent MR agency UK, France, Germany, Italy, Spain, Sweden, Russia, Poland & Saudi Arabia
92
94
94
Overall (183/200)
Spherical CL wearers
Lapsed wearers
86
80 60 40 20 0 Neophtyes
9 / 10 want practitioners to discuss CLs as an option for astigmatism 33%
57% Prevalence Toric fits UK ‐ astigmatism Industry data (≥0.75D at 2 least 1 eye) 1
0
100
Net don’t know / no = 57%
0
10
Proportion subjects (%)
Data on file, JJVC, 2012, UK adults aged 18‐54, Independent MR agency
Satisfaction with VC (%)
32
1%
No
Very important Somewhat important Neither important nor unimportant Not very important Not at all important
30
Practitioner recommendation – critical factor in choice of vision correction
P<0.05 40 33%
23%
40
N=538
Reason why people wear current lens
9 / 10 important that practitioners discuss CLs as an option to correct astigmatism
57%
70
Don't know
4. European Usage & Attitudes Survey
3 ‐ Astigmatism Awareness Survey Only 1 in 4 non CL wearing astigmats have discussed CLs as an option with their practitioner
No
Data on file, JJVC, 2012, UK adults aged 18‐54, Independent MR agency
Astigmatism qualitative interview s, UK & Italy, 60 practitioners, 60 patients, 2011
Yes
42%
43%
15%
42%
7%
43%
1. Zikos GA, Kang SS Ciuffreda KJ et al. Optom Vis Sci 2007;84:11 1039‐45 Yes No Don't know
1% Very important Somewhat important Neither important nor unimportant Not very important Not at all important
1%
3. Young G, Mcllraith R. Optom Vis Sci 2008; E-abstract 85051
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Low Astigmats
Range of options for astigmats • Toric soft lenses
• Astigmatism, not fully corrected, leads to:
– Wide range materials, modalities and replacement frequencies
– Loss visual performance at low‐contrast – Ocular discomfort with accommodative problems with NV or PC work (asthenopia)
• Manufacturing advances • Wide range parameters and powers
• RGPs
• Do thicker or higher modulus spherical CLs mask astigmatism?
– Corneal astigmatism‐ spherical – High corneal toricity – BS toric – Large diameter RGPs
– No significant masking effect with either 1‐4
• Do aspheric soft CLs improve visual performance in low cylinders vs spherical CLs?
• Hybrid lenses • Scleral lenses • Multifocal RGPs
– Scant evidence ‐ for typical pupils (4mm & 6mm), vision superior with toric soft CLs and spectacles5
– Translating or aspheric
1. 2. 3. 4. 5.
• Toric soft multifocal lenses
Cho PC and Woo GC. Vision of low astigmats through thick and thin lathecut soft contact lenses. Cont Lens Anterior Eye 2001;24:153‐160. Bernstein PR, Gundel RE and Rosen JS. Masking corneal toricity with hydrogels: does it work? Int Contact Lens Clinic 1991;18: 67‐70. Edmondson LL, Edmondson W and Price R. Masking astigmatism Ciba Focus Night & Day vs Focus Monthly. Optom Vis Sci, 2003;80 (supp) 184. Snyder C. Masking of astigmatism with selected spherical soft contact lenses. J Am Optom Assoc 1989 Oct;60(10):728‐31. Morgan PB, Efron SE, Efron N et al. Inefficacy aspheric soft CLs for correction of low levels of astigmatism. Optom Vis Sci 2005;82:9 823‐828.
Lid Movements
Toric Soft Behaviour Anatomical Variations
• Patient variables – Inter‐canthal Angle – affects rotation – Palpebral Aperture Size – affects orientation – Degree Myopia – affect orientation
• Effect lids – – – –
θ2
θ3
Position and lid angles Angle lids – affects orientation Lid tension – affects instability Force and direction blink
Young G et al. Clinical Evaluation of Factors Influencing Toric Soft Contact Lens Fit. Optom Vis Sci 2002; 79 ; 1, 11‐19.
θ1
θ6
θ4 θ7
θ5
Lid position / Angles & Apertures
Dynamic forces acting on a toric soft lens ‐ High‐speed video recording pre & post blink Palpebral aperture & Lid tension
Challenges to toric lens stability
Soft Toric Lens Behaviour • Lens effects
Blink
Blinking
Versional tasks
8 Cardinal Directions
Eye movements
Saccadic Diagonal Gaze
Gravity
Head movements
– Interaction between CL & lids controlled by lens mass profile • thickness, material, elasticity, power
– BVP effects depend on lens design and influence fit – Different orientation position and rotational stability on same eyes with different designs * Young G et al. Clinical Evaluation of Factors Influencing Toric Soft Contact Lens Fit. Optom Vis Sci 2002; 79 ; 1, 11‐19.
Hanks et al. Contact lens forum. 1983 819: 31-35
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How do the latest soft toric designs perform?
Accelerated Stabilisation Design (ASD)
• Recent literature review toric soft developments and performance – Prism‐ballast, periballast, thin zone (double slab‐off / dynamic stabilisation), truncation, back surface and front surface torics – Newer lens designs reduce lens rotation & improve rotational stability – Better reproducibility, more frequent replacement schedules, expanded parameters, high permeability and better wetting characteristics contributed to increased success
Edrington TB. A literature review: The impact of rotational stabilization methods on toric soft contact lens performance. CLAE 2011;34:3 104‐110.
Rotational stability toric soft CLs during natural viewing conditions
Eye tracker tasks • 15 minutes settling
Settling Newspaper Reading Visual search task Extreme version
Zikos GA, Kang SS Ciuffreda KJ et al. Optom Vis Sci 2007;84:11 1039‐45
• Paper reading 12 ‐ 30o & return to primary gaze • Blink with metronome every 1.5 seconds • Gaze change every 20 seconds • Up, down, left & right over 40o horizontal & 32o vertical range
Zikos GA, Kang SS Ciuffreda KJ et al. Optom Vis Sci 2007;84:11 1039‐45
Standard deviation lens rotation for 4 visual tasks with 2 toric soft designs
Eye movements ‐ Settling Average rotation during 15 mins post insertion
P<0.01
10
ASD lens Prism‐ballast lens
5
Rotation
10 9 8 Standard 7 Deviation 6 (degrees) ‐ lower 5 numbers mean 4 less variability in 3 2 rotational 1 position 0
• 40cm, 40o horiz & 15o vertical
0 0.5 ‐5
1
3
5
10
15
ASD Prism Ballast
‐10
Zikos GA, Kang SS Ciuffreda KJ et al. Optom Vis Sci 2007;84:11 1039‐45
Zikos GA, Kang SS Ciuffreda KJ et al. Optom Vis Sci 2007;84:11 1039‐45
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Effect of gravity and gaze direction on toric lens orientation and VA
Results
ACUVUE® OASYS® for ASTIGMATISM Proclear® Toric
Accelerated Stabilisation Design
AIR OPTIX® for Astigmatism PureVision® Toric
Prism Ballasted Design
McIlraith R et al, Toric lens orientation and visual acuity in non‐ standard conditions. CLAE 2010 Feb;33(1):23‐6;
McIlraith R et al, Toric lens orientation and visual acuity in non‐ standard conditions. CLAE 2010 Feb;33(1):23‐6;
VA Fluctuations During Wear
Chamberlain P et al. Fluctuation in visual acuity during soft toric contact lens wear. Optom Vis Sci 2011 Apr;88(4):E534‐8.
Chamberlain P et al. Fluctuation in visual acuity during soft toric contact lens wear. Optom Vis Sci 2011 Apr;88(4):E534‐8.
Simulating the “Real World” in a laboratory setting….
Fitting Torics – Never Easier! Enhanced designs
Improved manufacture Better materials Convenience Zikos GA, Kang SS Ciuffreda KJ et al. Optom Vis Sci 2007;84:11 1039‐45
Young G, Mcllraith R. Optom Vis Sci 2008; E‐ abstract 85051
Chamberlain P, Morgan P, Moody K Maldonado‐ Codina C,. Optom Vis Sci 2011;88(4):1
Rx
– – – –
Thin, comfortable Fast, consistent stabilisation Predictable orientation Stable, clear vision
– Reproducible – Wetting agents, SiHs – Reusable or daily disposable – Wide parameter range
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Number of trial fit attempts
Lens orientation at 1‐week 85% 1DAMfA within 5° of zero 82% AOfA within 5° of zero
Most lenses minimal rotation (55% 1‐wk)
100
No sig differences in orientation between dispensing & follow‐ ups
80
% Eyes
SW
DO
Neo
94
60
86
84
40 16
20
14
5
0.7
0
0
0 1
2
3
No. of Trial Fits
• 88% eyes successfully fitted on 1st attempt Sulley A, Young G, Osborn K, et al. A multi‐centre study of astigmatic nonusers of soft toric contact lenses. BCLA Conference 2011, Poster Presentation.
Sulley A, Young G, Osborn K, et al. A multi‐centre study of astigmatic nonusers of soft toric contact lenses. BCLA Conference 2011, Poster Presentation.
Key Features of a Successful Fit
What is the process? Convert spec Rx to ocular Rx (BVD)
Accurate, up to date refraction
Successful fit
Loose vs tight fit *
• Good physical fit
• Tighter
– Same as spherical lens
• Stabilisation
ֳcyl if there is choice; leave axis unchanged
Trial lens cylinder & axis close to Rx
– Speed to stabilise – Consistency of orientation
• Orientation – Quantity & Rotational Stability – Orthogonal eye movements
Allow settling – assess fit & orientation
If necessary, change lens to allow for rotation
Poor Vision Problem Solving
⇒ more stable orientation position
• Looser ⇒ faster reorientation
• Need balance fitting characteristics – Reasonable stability with enough rotational movement for correct orientation * Young G et al. Clinical Evaluation of Factors Influencing Toric Soft Contact Lens Fit. OVS2002; 79 ; 1, 11‐19.
Explaining Poor Vision
Poor VA
• Rotate lens to correct position and recheck vision
Is lens rotationally stable?
– Confirms whether mislocation is sole cause
• Toric soft mislocation ‐ rules of thumb
Yes
No
Is lens orientating as expected?
Is fitting otherwise correct?
Yes
No
Yes
No
Return Lens
Rotational direction?
Use different lens design
Alter fit
Clockwise add
Anti-clockwise subtract
Re-order
Re-order
– Induced cyl = 2x induced sphere – Axis induced cyl = opposite direction to mislocation – Induced cyl = 1/3 correcting cyl for every 10° rotation (up to 30°)
• Computer programmes
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Binocular VA at 1‐week vs. baseline Poorer VA
Remember Comfort and Physiology • Astigmats deserve same benefits as others
P<0.0001
Vision
Comfort
Health
• Consider lens material characteristics
(6/6)
– Wettability, oxygen delivery, lubricity and modulus – SiH 1st choice reusable? – Convenience benefits DDs
Better VA
Sulley A, Young G, Osborn K, et al. A multi‐centre study of astigmatic nonusers of soft toric contact lenses. BCLA Conference 2011, Poster Presentation.
92
94
94 86
100% 90%
Typical Confidence interval
80% 70%
*
60% 50% 40% 30% 20% 10%
Sulley A, Young G, Osborn K, et al. A multi‐centre study of astigmatic nonusers of soft toric contact lenses. BCLA Conference 2011, Poster Presentation.
N
o
M ed
s M ed s
H i As Ast g. tig .< 1. 50
M yo p y p es er op es
<4 5 >= 45
e
Lo
Spherical Lapsed Neophtyes CL wearers wearers
H
Overall (183/200)
Ag
M al e m ale
0% Fe
100 90 80 70 60 50 40 30 20 10 0
Success rates by pre‐determined criteria
Success rate (%)
Proportion subjects (%)
Successfully completed 1‐month
* Significant for AOfA, P=0.03
Sulley A, Young G, Osborn K, et al. A multi‐centre study of astigmatic nonusers of soft toric contact lenses. BCLA Conference 2011, Poster Presentation.
Wide range of successful options ….
Enhance communication with astigmats and adopt proactive approach to discussing toric soft lenses and their benefits
• Wide range options •Stable, predictable designs •Range materials, Rx, replacement • Ease & speed of fitting • High success rates • Excellent vision & comfort performance
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