Presentation of Dr. Detlev Breyer at the World Ophthalmology Congress in Barcelona, 2018: Evaluation of Stereopsis for Blended Vision Variants with Refractive MIOL compared to Phakic Eyes

1. Breyer, Kaymak & Klabe Eye Surgery and Premium Eyes are Consulting, Study Center & MAB for:
Abott, Alcon, AlimeraSciences, Allergan, AMO, Bayer, Carl Zeiss Meditec, Ellex, Fluoron, Geuder,
iOptics, LensAR, Medicem, Novartis, Oculentis, Oertli, Revision Optics, Santen, Staar Surgical,
Sifi Medtech, Thea, Topcon, Visufarma, Ziemer
Evaluation of Stereopsis for Blended Vision Variants with
Refractive MIOL compared to Phakic Eyes
P. Hagen, D. Breyer, H. Kaymak, K. Klabe, T. Ax, F. Kretz, G. Auffarth
Breyer, Kaymak & Klabe Eye Surgery and Premium Eyes are Consulting, Study Center & MAB for:
Abott, Alcon, AlimeraSciences, Allergan, AMO, Bayer, Carl Zeiss Meditec, Ellex, Fluoron, Geuder,
iOptics, LensAR, Medicem, Novartis, Oculentis, Oertli, Revision Optics, Santen, Staar Surgical,
Sifi Medtech, Thea, Topcon, Visufarma, Ziemer

2. Background
• Stereoacuity measured with random dot stereograms is
heavily affected by visual acuity of poorer eye
 Question:
How is stereo vision affected in case of different bilateral
implantation variants with EDOF IOLs
(Emmetropic Vision vs. Blended Vision)?
• Numerous mechanisms of depth perception are known,
such as:
 Monocular cues:
Accomodation, Motion Parallax, …
 Binocular cues:
Motoric Fusion (Convergence), Binocular Parallax
(Stereopsis), …
 Fun-Fact: Many of them are in principle analogous to
distance measuring in astronomy

3. Binocular Parallax (Stereopsis)
OD
OS
Distant
background
ObjectBinocular
obsever
Difference in horizontal visual angles (disparity)
allows for relative distance measurement

4. LENTIS Comfort MF15 (Emmetropic/Blended Vision)
Implantation variant Comfort EV Comfort BV
Target refraction [D]
(non-dominant eye)
0.0 -1.5
number of patients 344 192
M:F [%] 48:52 43:57
Age [years] 69 ± 9 64 ± 11
Retrospective
data analysis
Distance [cm] 33 40 50 67 100 200 oo
Defocus [D] -3 -2,5 -2 -1,5 -1 -0,5 0
Emmetropic Vision
Blended Vision
Purely refractive EDOF (bifocal with transition zone) optic:
 Sector-shaped segment with +1.5D addition
for improved intermediate vision

5. Results: Monocular Near Visual Acutiy
Number of
Eyes
Target refraction
[D]
bestcorrected
for
CNVA
[logMAR]
63 0.0 Far 0.54 ± 0.19
63 -1.5 Intermediate 0.10 ± 0.12
• Eyes with target refraction -1.5D have significantly (p<0.001) better
mean near VA as those with emmetropia
 Difference: approx. 4-5 Snellen lines
• Presumption: In case of EV as well as BV stereo acuity will be
dominated by the poorer eye (the one with target refraction
emmetropia)
 No difference in stereo acuity expected between both variants
Target refraction [D]

6. Titmus Stereo-Fly-Test
• Contour-based stereotest
• 9 arrangements with 4 ring structures each
• Polarization glasses filter out the particular
image for each eye
• Distance to chart D = 40cm

7. Minimum Angle of Stereopis
no glasses, binocular with glasses, OD with glasses, OS
• One of the inner rings per arrangement has offset ∆x
• Analogous to visual acuity:
Results can be expressed as minimum angle of stereopsis
(MAS) and stereo acuity (SA)
 for statistical calculations taking logarithm is useful:
Arrangement
(correct answer)
MAS
(D=40cm)
SA
decimal logMAS
1 (bottom) 800‘‘ 0.075 1.12
2 (left) 400‘‘ 0.15 0.82
3 (bottom) 200‘‘ 0.3 0.52
4 (top) 140‘‘ 0.43 0.37
5 (top) 100‘‘ 0.6 0.22
6 (left) 80‘‘ 0.75 0.12
7 (right) 60‘‘ 1.0 0.00
8 (left) 50‘‘ 1.2 -0.08
9 (right) 40‘‘ 1.5 -0.18
offset ∆x

8. Results: Titmus Stereo-Fly-Test at near
n = Number of patients
EV = Emmetropic Vision
BV = Blended Vision
Phak = Phakic eyes
Group
SA [logMAS]
Median Mean SD
EV 0.37 0.34 0.39
BV 0.00 0.12 0.35
Phak -0.18 -0.03 0.30
• 67% of phakic eyes have SA of 1.5 or better
(comaprable to „80% have SA of 2.0 or better“)
 SA > VA
• Significant (p<0.05) differences between medians of groups:
BV significantly better than EV (unexpected!)

9. Spatial Frequency vs. Difference in Snellen Lines
~8mm
Estimation of spatial frequency
• At low spatial frequencies (e.g. 2cpd):
 Only low dependence of stereo acuity on visual acuity of
poorer eye
 Stereo acuity remains relatively high even when poorer eye
has VA of 4-6 Snellen lines lesser than better eye
• Qualitative agreement with our results
Dn = Difference of n Snellen
lines between both eyes

10. Possible Explanation Model
Disparity easy to recognize still recognizable barely recognizable
both eyes with good VA only one eye with good VA no eye with good VA
Matching of rings and identifying ring offset apparently
even works if one of both images is blurred
(more difficult in case of random dot tests)

11. Summary & Outlook
• Numerous mono-/binocular mechanism of depth perception
 Many of them unaffected by mild degradation of visual acuity
• Contour-based „Stereo-Fly-Test“ at near (40cm):
 Comfort Blended Vision significantly better than Comfort Emmetropic Vision
 Not only near VA is improved by BV but also near SA
• Further tests with both implantation variants required:
 More data
 Vary distances
 Compare with random dot tests
 Which test better represents natural everyday visual impression?

12. Thank you very much for your attention!
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