Dr Simon Barnard - irissmedical.com · A new concept in eye data acquisition Volk Eye Check and...
Transcript of Dr Simon Barnard - irissmedical.com · A new concept in eye data acquisition Volk Eye Check and...
Volk Eye CheckA new concept in eye data acquisition
and analysis of strabismus, pupil size
and eyelid position
Dr Simon BarnardPhD FCOptom FAAO FEAOO DipCLP DipClinOptom DipTh(IP)
Den Bosch,
Maandag 9 Februari
Revisiting some measurements
Despite enormous advances in technology over
the last few years we still gather some clinical
data in primary care practice using techniques
that have been around for a century, for
example, to measure
Pupil size
HVID
Eye lid position
Pupil eccentricity
Eye position
Volk Eye Check is a hand held device that
captures and fully automates, in real time, the
analysis and display of diagnostic eye data
From mm ruler to fully automated technology
• Data acquisition typically with 2 or 3 to 3 flash
photographs
• Real time analysis
• Data displayed on device and instantly
uploaded as pdf to medical record, tablet or PC
ModulesEye Check Contact Lens
Accuracy of the device
“ Volk Precision Sticker”
• Accuracy of IPD < 0.5% on average
compared to 2 experienced practitioners
• Accuracy of HVID < 1.0% on average
compared to Medmont topographer
In absolute terms:
• IPD measurement accurate to within 0.3mm on average compared to 2 experienced practitioners
• HVID accurate to within 0.1mm on average compared to Medmont topographer
Eye position• Are the eyes straight?
• Assessment of eye position to detect
strabismus is routinely carried out using three
tests
• Cover test (Clarke, 1893)
• Prism fusion test
• Hirschberg test (1885)
Cover test
• Requires skill – optometrist, orthoptist or
ophthalmologist
• Difficult to detect small amplitude strabismus – microtropia (AAPOS <8 ∆)
Prism Fusion Test
• Smaller prism for infants – 6 ∆
• As child gets older, can fuse larger
prism powers
• Look for fusion movements
• Requires patient co-operation,
skill and experience
• Difficult on babies!
• A penlight is directed towards the patient
who is gazing towards it
• The practitioner observes the position of
the corneal reflex (Purkinje image) relative
to the centre of the pupil
• Corneal reflex not usually positioned in the
centre of the pupil but decentred due to
Angle Kappa (sometimes called lambda)
• To determine the presence of strabismus,
the practitioner must detect a relative
difference in corneal reflex between right
and left eyes
• Limitation of Hirschberg is that 1 mm (and
perhaps 0.5mm) asymmetry is possible to
discern
• 1 mm = 21∆ (Brodie, 1987)
Brodie SE (1987) Photographic calibration of the Hirschberg test. Invest Ophthalmol. Vis Sci., 28, 736
Strabismus detection and measurement with the Vollk Eye Check
The present software version has a sensitivity of 84% to detect strabismus and a specificity of 98%
The next few slides show some case examples
2 year old autistic spectrum
5 year old autistic esotrope
2 year old pseudo-strabismus
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Duane syndrome LE 1. Primary Gaze
2. Gaze to the left
3. Gaze to the right
Accommodative esotropia
corrected
Pupil size
We are looking particularly for anisocoria
• Horner
• Adie
Most optometrists and ophthalmologists
measure with a millimetre ruler
Measuring pupil size can be difficult!
•Body text 28 pt Arial
Photographs of two iris/pupil colors to illustrate
the difficulty in assessing the pupil/iris border,
especially in darker colored irides
Horner syndrome
• Sympathetic denervation– Preganglionic– Post ganglionic
• Miosis• Ptosis• Anhydrosis• Heterochromic irides in congenital cases
• Preganglionic causes include lung and breast malignancy
• Postganglionic causes include neck lesions
• Acquired cases require investigation
Horner Case 1.Acquired Horner secondary to neck surgery
• 59 year-old female presented 1 week following neck surgery worried about lid appearance OD
• Patient unaware of anisocoria
• Anisocoria diagnosed with Volk Eye Check
• Consultant spinal neurosurgeon informed and requested follow-up documentation
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Written consent given by patient
Anisocoria at light index 85 (increased ambient lighting)
Anisocoria at light index 61
(reduced ambient lighting)
Introduction
Horner’s syndrome is caused by a total or partial interruption of the
sympathetic chain anywhere along its course from the
hypothalamus to the eye. The clinical signs of Horner syndrome
include ptosis and miosis. Although a possible cause of acquired
Horner’s syndrome is surgery, sympathetic injury is not a common
sequence of cervical operations (Saylam et al, 2009). Allen &
Meyer (2009) reviewed a series of 6 cases of oculosympathethetic
paresis that resulted from interventional procedures in the neck.
The Volk Eye Check is a hand-held medical camera device that
captures analyses and displays, in real time, eye measurement
data including pupil size and margin reflex distance (MRD).
Conclusions
Surgery to the cervical region of the spine is a potential cause of
Horner’s syndrome (Allen & Meyer, 2009). Measurement of MRD
and pupil sizes before and after surgery using automated photo-
documentation should be considered. The Volk Eye Check detects
subtle differences in MRD and pupil sizes between the eyes and
shows the potential to be a powerful diagnostic assistant tool for the
eye care practitioner.
References
1. Saylam CY, Ogiray E, Orhan M, Cagli S, Zileli M (2009)
Neuroanatomy of cervical sympathetic trunk: a cadaveric
study. Clin Anat. 22(3): 324-330
2 Allen AY & Meyer DR (2009) Neck procedures resulting in
Horner syndrome, Ophthal Plast Reconstruct Surg. Jan-
Feb;25(1):16-18
Acknowledgements
The research was funded by IRISS Medical Technologies Ltd,
who also acted as study sponsor. Financial Disclosure: SB, YY,
RM, MS, EJ and RL have a financial interest in the technology.
Automated documentation, using Volk Eye Check, of acquired Horner's syndrome following surgical anterior
cervical decompression
Simon Barnard 1,2 James Allibone 4,Yuval Yashiv 2, Ron Maor 2, Mike Stroud 2, Alex Levit 2, Richard London 5, Ellis Johnson2,3
1 PhD, FAAO; Department of Optometry & Visual Science, Hadassah College, Jerusalem, Israel; 2 IRISS Medical Technologies Ltd, London, UK;3 MOptom 4 FRCS; Consultant Spinal Neurosurgeon, London 5 OD, MA, FAAO, Pacific University College of
Optometry, Oregon
Case History
The patient was a 61-year-old female under the care of her
Consultant Spinal Neurosurgeon3 with a long history of neck
pain. An MRI scan in 2007 showed a significant C4/5 disc bulge
and a more modest bulges C5/6 and C3/4 . Her symptoms
gradually worsened over the next few years. In 2014 the MRI
was repeated which showed progression of the degenerative
changes and worsening of her spinal cord compression. The
indication for surgery was protection of the spinal cord. She
underwent C3/4, C4/5 and C5/6 anterior cervical discectomies
and fusion using Brantigan carbon fibre cages without a plate in
May 2014. The surgery was uneventful. Post operatively there
were no surgical issues apart from the right sided Horner’s
syndrome. Figure 1. shows pre- and post operative scans.
Two weeks after surgery she presented to her optometrist1
concerned about the appearance of her right eye. A ptosis of
the right superior eye lid was noted together with anisocoria.
The external eye features were documented with the Volk Eye
Check in two differing ambient light levels with the size of the
anisocoria increasing from 0.27mm (Figure 2) to 0.37mm in
lower ambient light (Figure 3). The difference in palpebral
aperture (MRD 1 & 2) is also shown in Figure 2.
Volk Eye Check measurements were repeated nine days later
when the patient returned reporting symptoms that mandated a
mydriatic retinal exam. Pre-dilation measurements showed no
change in ptosis or anisocoria. Measurements of pupil size
under mydriasis with phenylephrine 2.5% and tropicamide 0.5%
are shown in Figure 4. Note no significant anisocoria and the
increased MRD1 right eye due to secondary sympathetic
hypersensitivity.
Figure 1: MRIs and x-ray showing pre-op and post op
appearance of spinal cord compression
Figure 3: Anisocoria photographed in light index 61 (lower ambient
lighting) Volk Eye Check Report.
Figure 2: Anisocoria photographed in light index 85 (increased ambient
lighting) Volk Eye Check Report.
Figure 4: Volk Eye Check Report following dilation with
phenylephrine 2.5%
(a) Pre-op MRI (b) Post-op
MRI
(c) Post-op X-ray
Key points• Patient aware of ptosis but not of anisocoria
• Anisocoria increase demonstrated by changing illumination level – no need for bright and dark ?
Anisocoria at light index 85
(increased ambient lighting)Anisocoria at light index 61
(reduced ambient lighting)
Horner Case 2.Congenital Horner
• 5 month-old infant
• Mother concerned by left pupil appearing larger in room light
• More noticeable over last two or three months
• Emergency C-section + forceps
Anisocoria 0.22 mm
Light level 80 (bright)
Total relative ptosis OD
MRD1 + MRD2 = 0.87mm
Light level 66 (dim)
Anisocoria 1.04mm
Total relative ptosis OD
MRD1 + MRD2 = 0.61mm
Key points
• Confirmed diagnosis with Volk Eye Check
• Documented Horner
• Referred to ophthalmologist with documentary clinical evidence
Contact Lens Fitting• Apart from corneal Topography /Keratometry,
which parameters are important?– Pupil size– Pupil position (eccentricity)– VID (horizontal, vertical, oblique)– Inter-palpebral aperture– Distance from lower lid to pupil edge– Lower lid to lower limbus position
Contact Lens Module• Visible Iris Diameter
• Distance from pupil centre to upper and lower lid (not the same as MRD1 & MRD2)
• Pupil eccentricity
• Facility to input K’s to produce “sag” measurement
• Refines fitting procedures for CLs including multifocals and sclerals
Volk Eye CheckHorizontal Visible Iris Diameter
(HVID)White to White”
Important for:• Contact lens fitting but also
for buphthalmos
Corneal Sag
Visible iris diameter; horizontal, oblique, vertical (?)
Pupil Eccentricity
• Not measured… until now
• Important for specialist contact lenses such as
concentric and translating multifocals
Pupil Eccentricity
• Eyes with significantly decentred pupils in relation to the optical centre of the contact lenses, either due to
– eccentric anatomical position or
– a poorly fitting contact lens
will suffer loss of image quality due to induced astigmatism and comaCharman, W.N. and Walsh, G., (1988)Retinal images with centred aspheric varifocal contact lenses. Int Contact Lens Clin, 15, pp. 87-93.
Mother age 49
Daughter aged 22
Son aged 21
Pupil Diameter• Very useful for practitioners to be familiar with
the power profiles of the standard and customised lenses which they use because they will be able to fit the most appropriate design contact lenses after measuring the pupil diameter of each patient
Montes-Mico, R., Madrid-Cota, D., Dominguez-Vicent, A., Beldos-Salmeron, L. and Ferrer-Blasco, T., (2013) In vitro power profiles of multifocal simultaneous vision contact lenses. Contact lens & Anterior eye: The Journal of the British Contact Lens Association
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Courtesy AZO Optics
Courtesy AZO Optics
Simultaneous Vision Soft MF
• Most soft lens multifocal designs are manufactured with variable power with rotational symmetry about the lens centre.
• e.g., for distance vision well centred, centre near design
– Purevision multifocal lens the pupil diam > 4.8mm
– Air Optix Aqua pupil >3.4mm
(Plainis, Atchison et al. 2013)
Simultaneous Vision Soft MF
Pupil Size
Pupil Eccentricity
Soft Multifocal Custom Lens Design
• Sag information= Optimal physical fitting
• Pupil Metrics= Optimal optical design
– Streamlined design, fitting and delivery process
• Optimal clinical and business model
–Patient satisfaction
–Practitioner specialist differentiation
–Laboratory specialty status
Custom RGP MF / Bifocal Fitting
• Sag + Pupil metrics= Fitting aid
• Lid position= Optical Design aid
– Streamlined design, fitting and delivery process
• Optimal clinical and business model
–Patient satisfaction
–Practitioner specialist differentiation
–Laboratory specialty status
Summary
The Volk Eye Check is a fully automated real time data capture and analysis device that provides an eclectic range of data
General optometry
Vision therapy and orthoptics
Contact lens practise
Neuro
Oculoplastics
The Volk Eye Check is a powerful diagnostic assistance tool for all optometrists
• Strabismus screening and measurement
• Pupil measurement and diagnostic assistant
• Contact Lens determines important data to
– Save chair time in routine contact lens fitting
– Enhance multifocal choice, design and fitting for
• Presbyopia
• Myopia control