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

21

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