SVA

S P O R T S V I S I O N A S S O C I A T I O N

NEWSLETTER

May 1998

TABLE OF CONTENTS

Sports Vision Association Committee of Management .................... 1

Editorial ........................................................................................... 2

International Conference ................................................................. 3

Services Available to Members ....................................................... 4

Visual Performance in Cricket ......................................................... 5

Eye Dominance ............................................................................... 9

The Norville Symposium ................................................................. 12

Reaction Testing of Peripheral Visual Stimuli in Sports ................... 13

Visual Field and Protective Appliances ........................................... 14

Vision and Action in Volley Ball ....................................................... 15

A New Dynamic Visual Acuity Test ................................................. 16

Visual Needs of the Referee ........................................................... 18

Official Visual Requirements for Referees and Other Sports

Officials ........................................................................................... 20

Visual Performance and Soccer Skills in Under 14 Players ............ 22

1

Editor Geraint Griffiths Tan-y-Coed 31 Birdhill Road Woodhouse Eaves LEICESTER LE12 8RP Fax and Phone 01509 891089

Sports Vision Association Committee of Management Chairman

Don Loran

Members

Brian Ariel

Nick Atkins

Ian Cockerill

Geraint Griffiths

David King

Andrew Merry

Frank Norville

Henri Obstfeld

Secretary Peter Smith

EDITORIAL

Great achievement often comes in spite of adversity

2

There is a vigorous debate (see visual performance in cricket) emerging

about the purpose of Sports Vision. The SVA is clear that it is visual

enhancement through the protection and correction of eye sight in sport.

Research suggests (Bausch and Lomb in the cricket report) there is plenty to

be done in this area even amongst elite athletes. This work has a solid base

in existing scientific knowledge. A further aim of the association is to advance

this knowledge through research, publications and peer debate.

PRESSURE FROM ATHLETES

From athletes themselves, who equate increased performance with training

there is a demand for eye exercises, the logic of basic optometric principles

often, understandably escaping the lay public. It is important that the

profession is not too easily swayed by this pressure.

We know from the sequelae of extra ocular muscle palsy and the orthoptic

training of muscle balance anomalies that the status quo can be altered in

manifest pathology. Sporting coaches know that fitness training in sport

improves performance.

It may be logical to assume that eye exercises will improve the performance

of the extra-ocular muscles of the healthy eye, but it has not been

scientifically proven that this will lead to more goals or jumping higher.

Indeed, it could be argued that great achievement often comes in spite of

adversity as is so often seen in blind athletics. Practitioners who nail their

colours too firmly to the mast of eye exercises before any rigorous scientific

investigation, risk being discredited in the eyes of the scientific community.

It is worth remembering that such esteem in which optometry is held is due to

established scientific fact. If credibility is lost no amount of enthusiasm or

overwhelming anecdotal evidence will bring it back.

Sports Vision is a vast unexplored area of visual science, SVA chairman Don

Loran now emphasises that it is up to each individual practitioner to do his or

her bit to advance our knowledge, encouraged and supported by the Sports

Vision Association.

INTERNATIONAL CONFERENCE

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The First International Conference of the Sports Vision Association

"Focus on Sports Vision" is to be held in Manchester from the 24 - 26

September 1999

Manchester with its considerable and soon to be Commonwealth sporting

connections is an ideal setting for this prestigious International Conference.

The purpose-built conference centre at UMIST has state of the art lecture

facilities and comfortable style hotel accommodation. Guests will be able to

visit the city on organised tours and there will be a grand banquet on

Saturday night. UMIST's sports vision centre of excellence, will be open to

delegates for workshops on Saturday afternoon.

Sponsors Support

The response from potential sponsors has been very encouraging and is an

indications of the growth in interest industry is expecting in Sports Vision.

Please register interest on the enclosed form for priority booking of

conference and limited special rate hotel space

Programme (divided into themed sessions, headed by international guest

speakers):

Topics

• Eye injuries, their prevention and implications for coaching practice

• Vision screening, sports vison in optometric practice and workshops

• Vision enhancement in sport, reality or myth?

• Sports science and research

• Free papers

Full Conference package Thursday lunch to Sunday afternoon including

dinner, bed and breakfast and the conference banquet will be available.

SERVICES AVAILABLE TO MEMBERS

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Knowing where to start can be a problem, these services are designed to help the practitioner who wants to extend an interest in sports vision.

The Newsletter to members

free

The SVA manual Which gives instruction in the use of the basic sports vision tests and a summary of normative data as well as protocols, data sheets, current fee guidelines and how to analyse the results.

£30

The Appliance Review Compiled and updated by Debbie Burns, this is an exhaustive summary of sports vision appliances currently available.

£10

Screening Report This is an abridged version of a recent SVA visual assessment (no names included, to comply with confidentiality requirements)

£20

Transactions These are edited reports from conferences and courses.

Vary

Apply

Slides library for individual member's presentations • History and development • Sports Vision Prescribing • Screening

£5

"T" Shirts, SVA Embossed

£9

Certificate of Advanced Studies in conjunction with UMIST 3 part course, 30 hours

Guide £350

Professional Services • Evening Lectures • Conferences • Vision Screening Services • Referral Centre of Excellence at UMIST • Training of Screening Team Leaders

Cost on application

Equipment • On site Screening set. Sussex Vision 01903 851951 • Acuvision 1000. Paul Richards 0181 870 9706 • Dynamic Fixation Test. Paul Adler 01462 732 393

Price on request

direct from supplier

Name Address Phone

Total

Cheques with order payable to the Sports Vision Association, or for inquiries Please return to:

Mr Peter Smith, Sports Vision Association 17 Greenhead Rd., Huddersfield

W Yorkshire HD1 4EN

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VISUAL PERFORMANCE IN CRICKET

Based on the visual assessment of the Scottish Cricket Team

Richard Morwood and Geraint Griffiths

Part 2 (Reprinted with permission from "Optician")

• The Effects of Light in the Sporting Situation

• The Sports Vision Profile of the Scottish Cricket Team (Normative

Data)

In Part 1 (October 1997 newsletter) the significance of the basic

measurement of vision was considered as well as muscle physiology and its

relationship to some of the standard sports vision tests.

EFFECTS OF LIGHT IN THE SPORTING SITUATION

A second area of consideration is the visual demand made on the eyes in the

sporting situation, this takes the effect of light and movement more into

account.

• Contrast Sensitivity. Corrections of small amounts of short sight in one or

both eyes as well as proper maintenance of contact lenses will help to

maintain visual acuity. The results were generally very good, only three

scoring below 5 on the tester (Vector Vision CVS 1000, Contrast Sensitivity

Test). Where the reading is low, the measure of high and low contrast static

vision in each eye will give a clue to the cause.

• Glare Recovery. This is where comfort and visual performance are reduced

by a relatively bright light source in the visual field. Recovery to a 6/6 line of

letters at 3m was timed after the flash from an ordinary camera flash bulb

held at 2/3 metre. In situations of glare there is loss of vision and this varies

considerably from one individual to another. Maximum time was 17 seconds

and the minimum of 5 seconds in players without sun glasses. Where

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possible the eyes should be protected before and after the match, during

training and even during the match with tinted contact lenses, particularly in

players who are shown to be susceptible5. Recovery from glare was shown to

be quicker in both light and dark eyes with the sunglasses than without. The

proportion of dark eyes to light was about 50:50

The results do show however that there can be a considerable time delay

after the flash from the sun or a floodlight before the eyes can see again, let

alone make the fine judgements required in hitting and catching.

It is also interesting that on average, without the visor, the dark eyes (11.33

secs) recover more slowly from the effect of the flash (blue eyes 8.17

seconds). In general, dark eyes are better protected against the sun but it is

possible that if they are surprised by a flash of light when the pupil is wide,

that the usually better protected and more sensitive retina takes longer to

recover. It follows from this that the blue eye is continually coping with more

light than the brown eye.

Poorly placed floodlights as well as Solar radiation can cause glare

problems. Exposure to ultra-violet radiation in sunlight (UV) can lead to

cataract formation and macular degeneration in later life5, especially in fair-

skinned blue-eyed people who have less natural pigment in the iris and on

the retina. Infra-red radiation (heat) will tend to dry the cornea and diminish

its optical properties (sharpness of vision and depth perception).

Consequently, sports people should be encouraged to wear sun protection

(the yachtsmen are considering the use of tinted UV protected contact lenses

4).

• Visualisation. This is the ability to imagine and mentally rehearse sporting

actions and responses. Deficits can hinder the best response in the game

situation and make it difficult for the athlete to learn from mistakes.

Visualisation is used by 80% of the cricketers compared with British Ladies

Hockey Team 4 (89.5%) and the Nottingham Forest U14 squad 4 (41.67%).

• Basin Anticipation Timer. This instrument measures how well subjects can

time the arrival of an object travelling towards them at speeds of 5, 10 and 15

miles per hour. Negative results show a late response and positive an early

response.

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These relatively low speeds were used (compared with the speed with which

the ball is bowled) because the apparent speed of the ball moving straight to

the batsman is governed by the rate at which it is falling vertically or swerving

horizontally. The components of the speed in these directions is much slower

than the actual speed of the ball towards the bat. The forward movement of

the bat may be a simple reaction to the release of the ball from the bowler’s

hand, but sideways and vertical movement in flight can, up to a point, be

followed.

This is arguably one of the most important tests for cricket and shows quite a

wide variation of results. Some of the weaker measurements do seem to be

associated with vergence and accommodation problems which could make

the possibility of boosting control with eye exercises significant. Consistently

late responses could indicate a problem with convergence for example.

It is interesting to see that the best performances were at the low and high

speeds. The two lower speeds probably give a real reading of timing ability,

which is harder for the faster speed. Once the speed goes over 10 miles per

hour the test becomes a reaction to the first light in the sequence, rather than

following the sequence of lights to the end.

CONCLUSION

With the basic set of screening equipment6 and 3 or 4 specialist items an

interesting profile emerges of the visual demands in cricket (see Fig 1 Sports

Vision Profile). This information may help practitioners to talk to cricketers of

all abilities to help them enjoy the game more.

Sports Vision Profile (after D.F.C. Loran) Scottish Cricket Squad

Fig 1 TEST RESULTS

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May Need

Attentn Below Av Av Above Av Excellent SD

Vision 0.9 R 0.24 0.1 -0.04 -0.18 -0.32 0.14

L 0.19 0.07 -0.05 -0.17 -0.29 0.12

0.1 R 0.64 0.45 0.26 0.07 -0.12 0.19

L 0.54 0.38 0.22 0.06 -0.1 0.16

Vernier Acuity 2.17 3.44 4.71 5.98 7.25 1.27

Vergence (cycls / Min) 13.03 18.23 23.43 28.63 33.83 5.2

Focus (Cycls / Min) 5.04 12.59 20.14 27.69 35.24 7.55

Dynamic Fixation (Secs) 24.74 21.26 17.78 14.3 10.82 3.48

Dynamic Acuity Revs/Min) 67.98 77.05 86.12 95.19 104.26 9.07

Contrast Sensitivity 3.79 4.75 5.71 6.67 7.63 0.96

(Graded 1 -8)

Peripheral Awareness C (Secs)

0.93 0.8 0.67 0.54 0.41 0.13

Hand - Eye Co-ordination (Score in 30 secs)

Proaction 39.24 44.37 49.5 54.63 59.76 5.13

Reaction 31.21 34 36.79 39.58 42.37 2.79

Eye / Foot Response Time 27.81 32.65 37.49 42.33 47.17 4.84

(Score in 30 Secs)

Glare Recover With 13.27 10.06 6.85 3.64 0.43 3.21

(secs) Without 17.08 13.15 9.22 5.29 1.36 3.93

Stereopsis Minutes of Arc 147.46 103.73 60 16.27 -27.46 43.73

Time (Secs) 10.97 7.76 4.55 1.34 -1.87 3.21

Anticipation 15.35 11.2 7.06 2.92 -1.22 4.14

(Seconds x 100)

May Need

Attentn

Av

May Need

Attentn

SD

Muscle Balance

Near Cover Test -3.87 -2.22 -0.57 1.08 2.73 1.65

Wing -5.71 -3.86 -2.21 -0.36 1.49 1.85

Brock String -2.48 -1.82 -0.17 0.49 1.15 0.66

ACKNOWLEDGEMENTS: Richard Morwood Project Instigator, Jim Love

Director of Scottish Cricket, Sponsors Lizars Opticians.

REFERENCES (Parts 1 & 2):

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1. Griffiths G.W. 1996 Dynamic Fixation, Its Use in The Measurement of

Athletic Potential. MSc Dissertation Dept of Optometry UMIST (Test available

through Paul Adler 01462 732393)

2. Pickwell D 1989 Binocular Vision Anomalies Pub Butterworths

3. Acuvision 1000: British Agent Paul Richards, Wheeler and Kirk Opticians,

Wimbledon 0181 870 9706

4. Elite visual assessments reports available through the Sports Vision

Association: Sec Peter Smith 01484 423704

5. 1. Bergmanson Et Al 1996. A Sting in The Rays. Optician July 19 1996 No

5560 Vol 212

6. On Site Screening Set, and Sports Vision Screening Manual, available

through Sussex Vision 01903 851951.

EYE DOMINANCE

It is interesting to compare the incidence of eye dominance in different

sports and speculate on the importance of this information

Geraint Griffiths

In archery problems with weak dominance, aiming with the non-dominant eye

or loss of dominance due to tiredness can affect scores. This information is

based on conversations with members of the British National Archery Squad

and with coaches at the National Coaching Conferences in 1995 and 1996.

Two senior coaches were asked for their estimate of the incidence of the four

combinations of hand and eye dominance amongst their archers and this was

compared with actual occurrence amongst delegates at the conference and

the National Archery Squad (see Fig 1).

Fig 1 Occurrence of Hand Eye Dominance in Archery

Eye

Dominance

Hand

Dominance

% Estimated

Occurrence

Occurrence in

Delegates (%)

% National

Archery Squad

Right Right 70 84.3 60

Left Left 20 10 20

10

Left Right 9.5 2.9 6.7

Right Left 0.5 2.9 13.3

(N = 70) (N = 15)

Ref: Claire and Doug Stamford (Lilleshall 9.11.96) and SVA Visual

Assessment of the National Archery Squad (Lilleshall 11.3.95)

It could be argued that in cricket, because the bat is aimed at the ball, (or

where the ball is likely to be when it arrives at the point of hitting) as the arrow

is aimed at the gold in archery, eye dominance is also important in cricket.

In the squad of fifteen players, all four of the leading batsmen in the Scottish

National cricket squad were right eye, right hand dominant (uncrossed) and

favoured a full-on stance and straight head, unlike the sideways stance

favoured in baseball (MORWOOD AND GRIFFITHS 1998). It seems that

binocular vision is important in batting and that the dominant right eye should

not be hindered by facial features or head tilt (WALLER 1997) as it would be

in a sideways stance.

The incidence of cross dominant players (46.7%) compared with archery

(30%), suggests that at least one aspect of the playing cricket favours this

configuration (the side on delivery of the bowler?)

MUSCLE BALANCE

It is possible that the timing of a shot or the closing of the fingers round a ball

for a catch is related to distance judgement. Distance judgement based on

stereopsis is related to binocular balance which is more likely to cause

problems if it is decompensated (MALLET R.F.J. 1964). Phorias, vergence

facility and dynamic fixation are measured routinely and may give clues to the

endurance and flexibility of muscle control, but the assessment would not be

complete without a measure of fixation disparity, especially in such a visually

dependent sport as cricket. If there is a difficulty with timing, a

decompensated phoria which could be associated with asthenopia, would

need to be investigated.

MEASUREMENT OF DECOMPENSATION

This can be done with near and distance Mallet Units using the large targets

on the near Mallet Unit for extended near points. The Brock string can also be

used to investigate decompensation at near and intermediate distances. Any

correlation between the techniques would be interesting.

11

Recently work has been done by WALLER 1997 using a new test (SHAPIRO

1998), on muscle compensation and the effect of head tilt, looking to the

position of bowler's hand at the point of delivery, with the subject in the

batting position.

He noted that in a sideways stance favoured by some batsmen (and all

baseball players), it is very difficult to keep the head straight and the eyes

level, which readily induces a vertical fixation disparity and may disturb the

relationship between the dominant and non-dominant eye.

POST SCRIPT

Senior archery coach Claire Stamford has now taken up crown green bowls

and was surprised to find that coaches do not allow for or understand the

significance of the dominant eye in their sport.

Claire reports that one lady beginner was left eye dominant and came from a

period when naturally left-handed children were often forced to use their right

hand. This beginner has developed an ability to use her right hand even

though she is left handed for many things. She is now on the point of giving

up the sport because her bowling is so inconsistent. Her coach insists that

she bowls right handed because this is standard practice. This would be

correct for the majority of people who are right handed and right eye

dominant.

REFERENCES

1. Morwood and Griffiths. Visual performance in cricket. OPTICIAN 1998

No 5639 Vol. 215

2. Waller D.I. 1997. Ocular motor balance of cricket batsmen. Transactions

of the Accreditation Course in Sports Vision UMIST 24.9.97

3. Mallet R.F.J. The investigation of heterophoria at near and a new fixation

disparity technique. OPTICIAN 1964 148:547-51

4. Shapiro J. A new instrument and technique of refraction and binocular

balance. (Parallel Testing Infinity Balance PTIB) OPTICIAN 1998 No 5643

Vol. 215

Instrument available through Evans instruments Ltd (01842 766004)

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THE NORVILLE SYMPOSIUM

A healthy turnout for the first Norville symposium shows growing

interest amongst students

Thanks to generous sponsorship from Norville Optical the SVA was able to

organise a symposium of research carried out by undergraduate and post

graduate students at Aston University. The conference was chaired by Ian

Cockerill whose original idea it was.

Paul Walden speaking on behalf of Norvilles said that sports vision had an

exciting future in this country which is likely to be driven by public demand

and imminent regulations such as mandatory protection in under 19 squash

players. Technically manufacturers are ready to meet this demand in terms of

specialist optical appliances and lenses and the study of vision in sport will

help optometrists understand their application. (the new British Standard for

eye protectors for squash is expected shortly. ED.)

The next four articles are abstracts from the symposium

REACTION TESTING OF PERIPHERAL VISUAL STIMULI IN SPORTS

Peripheral vision is important in many sports including basketball and

ice-hockey

Urban Niederoest

The purpose of this study was to:

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• Find the currently best standardised method of testing peripheral visual

reaction time

• Find whether any difference in reaction-time exists between athletes and

non-athletes

• Provide feedback on Sports Vision to Swiss athletes

• Determine the general demand for Sports Vision in Switzerland

The athlete group consisted of eight top-level Swiss basketball players:

• 5 males, 3 females, average age = 26.6 years

• 4 uncorrected, 1 spectacle wearer and 3 contact lens wearers

The following visual abilities were tested:

• Peripheral visual reaction time (peripheral awareness trainer -PAT

• Refractive state (retinoscopy)

• Visual acuity (high and low contrast)

• Stereo acuity (TNO - test)

• Colour vision (Ishihara plates)

• Tachistoscopic span of recognition

The peripheral visual reaction times were compared with a group of 30

optometry-students.

CONCLUSION

Contrary to expectation, the non-athletes showed statistically significantly

faster reaction times than the athletes, which could have been due to the

number of vision-related deficiencies encountered:

• Uncorrected refractive errors (5 athletes)

• Relatively lower contrast sensitivity due to uncorrected

astigmatism

• Dirty soft contact lenses

• Binocular vision problems

There was a high level of general interest in the study, in particular in all

aspects of contact lens wear. 5 athletes left their addresses for feedback and

one athlete is currently training with the PAT. The study has shown that there

is a demand for more on-site screenings, and information for athletes and

coaches about contact lenses and safety eye-wear.

14

VISUAL FIELD AND PROTECTIVE APPLIANCES

In basketball movement off the ball is very important. Do protective

goggles hinder performance?

A Ojosipe

INTRODUCTION

For the sake of the study the following criteria were laid down:

• Vision 6/6 or better

• Full field of view, the normal visual field monocularly is:

-60° Nasal and superior

-70° - 75°iInferiorly

-100° temporally

• Normal colour vision, for the red stimulus

• No physical disability

METHOD

The subjects were 17 City University students. Each underwent a normal eye

examination and their fields were tested using a Henson field screener.

Normal binocular vision was confirmed with a Bagollini lens.

The Wayne Saccadic Fixator was used on self-pacing mode. The subject

stood at 2/3 of arm length from the machine and depressed the central

fixation button after 100ms a peripheral stimulus illuminated. The time taken

to reach this was recorded. 5 trials were given to reduce the learning effect

and avoid systematic errors.

Subjects were assessed with and without ten sets of sports and safety

goggles.

RESULTS

Four out of the ten sets of goggles showed some significant reduction in

visual performance, with the greatest reduction in the inferior field. The

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goggles which tended to cause problems either had a large vertex distance or

a small eye size of 45mm or less.

Some goggles caused diplopia in the periphery and steaming up also

affected results.

VISION AND ACTION IN VOLLEY BALL

A psychological approach to understanding how information is

processed to achieve perception

Gert-Jan Pepping

In sports like volley ball the athlete needs information about the time to

contact when he is preparing to catch a ball.

Optometrists would consider:

• Increasing magnification

• Rate of change of accommodation and vergence

• Ease with which the ball in followed

• Change of contrast

• Rate of vertical and lateral movement

• Parallax

• Stereoscopic depth perception

In sports psychology two different approaches to understanding visual

perception are considered, Cognitive and Ecological.

Cognitive Ecological

Distinction between animal and its

environment

Animal and environment mutually

dependent

Dualism between mind and body Perception and action are

intrinsically coupled

Static retinal image is the source of

visual information

Transforming optical array is the

source of visual information

Stimulus poor Environment is information rich

Perceiver is passive Perceiver is active

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Perception is indirect Perception is direct

Cues have to be processed into

information

Information is available

Using one or other of these models, psychological hypotheses can be tested.

The parallels with visual science were hinted at and the audience and

presenter understood that a mutual interest in sport could form a bridge

between the two disciplines.

Gert-Jan Pepping is a PhD student in sports psychology at Birmingham

University and a detailed understanding, of his presentation, is beyond the

scope of this newsletter. This seems to illustrate two points:

1. How important communication between disciplines is.

2. How much each of us takes our expertise for granted.

Points worth considering when talking to coaches, athletes and

administrators within sport. ED.

A NEW DYNAMIC VISUAL ACUITY TEST

Present methods of measuring Dynamic Visual Acuity are unreliable

and give poor correlation to athletic performance

Peter Greedy

INTRODUCTION

The aim of this presentation was to demonstrate a very basic working model

of a new computer program for testing dynamic visual acuity and consider

further development options and applications of the test.

The Dynamic Visual Acuity Test (DVAT) computer program was developed to

demonstrate a method of measuring the performance of the human eye in

recognising simple moving symbols. The software was written using the

graphical development tool, Microsoft Visual Basic 4.0.

PROCEDURE

17

To initiate the test, the speed, direction, size and value of the moving symbol

are set. The subject begins the test by pressing the 'Start/Stop' button using a

pointer (or by pressing the 'Enter' or 'Space-bar' keys). As soon as the

symbol is recognised, the subject presses the Start/Stop button again and the

time is recorded by an operator.

There are several parameters used to determine the behaviour of the symbol:

• The options menu allows the direction of movement to be set.

• Velocity: measured in twips1 per cycle of the program.

• Symbol: the value of the symbol, e.g. a letter of the alphabet.

• Size: the size of the symbol, measured in standard font points.

PROGRAM FLOW

1. The Size and Value of the Symbol is set according to the settings, the

time is reset to 0 (zero), and an initial direction of motion is chosen at

random.

2. The Symbol is moved in the current direction by the number of twips

specified and the counter incremented by a fraction of a second.

3. If the Symbol reaches the edge of the active window, the direction of

motion is changed appropriately.

4. If the user presses 'Stop', the program flow is stopped. Otherwise,

control returns to step 2.

DEVELOPMENT OPTIONS

1. Symbols: non-letter; multiple; increasing in size

2. Background: patterned; scenic; static/dynamic

APPLICATIONS TO SPORTS VISION SCIENCE

Dynamic visual acuity involves a complex interaction of sensory and motor

faculties. It is postulated that programs could be developed to aid vision

training, e.g. variable velocity symbols to train eye tracking.

ACKNOWLEDGEMENTS

The author would like to acknowledge Steve Ward of Bausch & Lomb IM&T

Department for writing the program for the demonstration model.

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1There are approximately 567 twips to a logical centimetre or 1440 to a

logical inch (the length of a screen item measuring one cm or one inch when

printed)

VISUAL NEEDS OF THE REFEREE

Ken Ridden

Competitive sport is civilised society's answer to war, without

the referee it would not be possible

The county football association referees exam is in three parts:

• Written paper on the laws of the game

• A fitness test

• An eye test

Annually 6,500 new candidates are recruited, but the eye sight requirements

of the referee have not changed in 45 years.

VISUAL REQUIREMENTS

Distance vision is a priority. Colour vision is checked simply by discriminating

between 4 colours on a single sheet, Ishihara is not used. One eyed referees

are now permitted.

On the field of play, referees need to constantly monitor moving objects,

players and the ball, looking, analysing and interpreting a changing situation.

Estimation of distances has to be good in the free kick situation, any apparent

inconsistencies would quickly loose the respect of the players, which is

important to the control of the game.

Seeing is assisted by following the play and getting to a good vantage point

which is why referees have to be fit. This has implications in visual

performance from the point of view of hypoxia and blood sugar levels. In

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addition, being immediately at the scene of a misdemeanour adds presence

and lends conviction.

COMMITTING OF AN OFFENCE

Despite all the problems of fatigue movement and deception the referee has

to be acutely aware of whether an offence has been committed or not and be

able to judge its severity. He need to satisfy the law and the other players.

Instant decisions are required:

• Yellow card

• Publicly admonish

• Red card

All these judgements are further complicated by simulating fouls and feigning

injury, which can lead to teams being awarded a free kick.

ASSISTANT REFEREES

Linesmen, as they used to be known need to co-operate with the referee and

be conscious of the play situation and where the referee is. Eye contact

needs to be maintained.

One of the most difficult decisions to make can be whether a player is offside

or not. Are the attacker and defender in line or is one in front of the another,

this is more difficult to judge if the situation is not static. At the same instant

the assistant referee has to notice:

• The player’s positions

• Activities off the ball

• The referee

• See where the ball is played

OFF SIDE RULE

The goal would be allowed if the attacking player was behind the two

defenders or in line, when the ball was kicked to him.

TECHNOLOGY

Linesmen now have two note bleepers on their flags or a vibrating signal to

communicate with the referee. There has been a suggestion of electronic

20

flagging of players and goal line sensitising to judge exactly when the whole

of the ball is over the edge of the line. From 1st of July 1997 goal keepers

were permitted to move along the goal line when a penalty is taken.

CONCLUSION

The soccer referee needs thick skin and a sense of humour, as well as being

very fit with excellent sight and judgement.

All competitive sport has its origins in very basic instincts. Human beings

need it physiologically, but organised in such a way that the vanquished may

still live to fight another day. It is the referee who makes this possible. ED

OFFICIAL VISUAL REQUIREMENTS FOR REFEREES AND

OTHER SPORTS OFFICIALS

Given the visual demands on the top-flight referee it is interesting to see

what is officially required by the organising body

Steve Taylor

Some work has been done on the vision requirements in referees and it is

suggested that the requirements will be higher in the premier league than say

a Sunday league. Vision is tested using a high contrast target in which the

dots have to be counted. This test gives a fairly sharp cut off at about 6/9.

Colour vision is tested using a four square colour test and naming the

colours.

Referees retire at about 45 - 47.

IMPORTANCE OF ACUITY

21

The importance of acuity can be summarised in terms of what needs to be

seen on the pitch (See Fig 1 VA Equivalents)

Fig 1 VA Equivalents

Object

Distance VA Equivalent

The ball On half way line 6/9 ~ 5' of arc

The ball Opposite goal line 6/5

The running line Half a pitch away 6/12

The numbers on the back of players shirts should be easily seen anywhere

on the pitch by someone with 6/9 acuity.

Based on Sherman 1995, Grading of skills 1 -5, a theoretical profile for the

Soccer Referee might be drawn up (see Fig 2 Visual Skills Profile).

Fig 2 Visual skills profile

Skill

Level

Required

Measured in Referees

Visual Acuity 3 Yes

Dynamic Visual Acuity 4 No

Oculomotor Skills 5 No

Eye Body Co-Ordination 5 No

Depth Perception 5 No, other clues in monocular

Vergence Accommodation 3 No

Central Peripheral Awareness 5 No but should be in top flight

Visual Reaction Time 5 No

Visual Adjustability 5 No

Visualisation 5 No

Contrast Sensitivity Not Stated High contrast only

Colour Vision Not Stated Colour naming only

For comparison with other sports see fig 3 Visual requirement for sports

officials.

Fig 3 Visual requirements for sports officials

Sport

Requirement for Officials

22

Lawn Tennis Association 6/6 re-test every 6 months

Squash none

Boxing none

Tennis Umpire Association Practical and eye test

Football Association 6/9 and colour test

Amateur Rowing Association none

Water Skiing none

Rugby Football none

Cricket Umpire none

Reference: Sherman A 1995 Visual Requirements in Sport. In Sports Vision,

Loran and MacEwen. Pub Butterworths.

VISUAL PERFORMANCE AND SOCCER SKILLS IN UNDER 14 PLAYERS

Early research is beginning to suggest that there is a correlation

between visual performance and playing skill in football

Don Loran and Geraint Griffiths

It seems likely that visual performance will have some bearing on skill levels

in soccer. Being short sighted for example could have an immediate effect on

player recognition and anticipation and in the long term may affect physical

development through lack of confidence and inhibition of muscular effort.

VISUAL ASSESSMENT

As a first stage in the investigation a full SVA visual assessment was carried

out on the U14 players of Nottingham Forest football Club to measure

individual visual skills (see Fig 1 Visual skills measured).

Fig 1 Visual skills measured

Vision at high and low

contrast

Dynamic fixation Eye foot reaction time,

R & L

23

Stereopsis TNO Dynamic vision Eye hand response time

Vergence facility Contrast sensitivity Glare recovery

Accommodative facility Peripheral awareness

Using the data gathered a sports vision profile was compiled for the whole

group using the mean and the standard deviations for each of the vision

skills. (See Fig 2 Sports Vision profile Nottingham Forest U14 Squad and key)

Fig 2 Key

Needs

attention

More than 2 standard deviations less than the mean

Below

average

Between 1 and 2 standard deviations less than the mean

Average

Between 1 standard deviation greater or less than the mean

Above

average

Between 1 and 2 standard deviations greater than the mean

Excellent

More than 2 standard deviations greater than the mean

Fig 2 Sports vision profile Nottingham Forest Football Club

TEST RESULTS

May Need

Attentn Below Av Av Above Av Excellent SD

Vision

90% R 0.13 0.03 -0.06 -0.16 -0.26 0.10

L 0.10 0.03 -0.04 -0.12 -0.19 0.07

10% R 0.37 0.25 0.13 0.01 -0.11 0.12

L 0.25 0.19 0.12 0.05 -0.01 0.07

Stereopsis

Minutes of Arc 79.64 62.32 45.00 27.68 10.36 17.32

Time (Secs) 9.50 6.94 4.38 1.82 < 1.82 2.56

Vergence 8.70 17.15 25.60 34.05 42.50 8.45

(Cycls / Min)

Focus < 8.50 8.50 19.00 29.50 40.00 10.50

24

(Cycls / Min)

Dynamic Fixation 31.65 26.53 21.41 16.29 11.17 5.12

(Secs)

Dynamic Acuity 50.46 64.63 78.80 92.97 107.14 14.17

(Revs / Min)

Contrast Sensitivity 2.56 3.73 4.90 6.07 7.24 1.17

(Graded 1 -8)

Peripheral Awareness 1.18 0.93 0.68 0.43 0.18 0.25

(Secs)

Eye / Foot Response Time (secs)

R 16.19 13.58 10.97 8.36 5.75 2.61

L 19.20 15.08 10.96 6.84 2.72 4.12

Hand - Eye Co-ordination (secs)

Proaction 37.68 34.19 30.70 27.21 23.72 3.49

Reaction 30.45 28.68 26.91 25.14 23.37 1.77

Glare Recovery

With Visor 15.19 10.84 6.49 2.14 < 2.14 4.35

Without Visor 21.06 15.43 9.80 4.17 < 4.17 5.63

INDIVIDUAL PROFILE

Using the team profile, it was then possible to compile individual profiles for

each of the players by comparing their score with the average for the squad

(see Fig 3 Individual vision profile).

Fig 3 Individual vision profile

Name Visual Correction (estimate)

R 0

Age 13

L 0

Sport/Team Nottingham Forest Under 14 Squad

Position Centre Forward

Date of Assessment

26.11.96

25

VISUAL ABILITIES

SCALE Vision

High Low

Stere

Verge

Focus

Dyn

Dyn

Contrst

Periph

Eye/ Foot

Eye/ Hand

Glare

R

L

R

L Fix Vision (C)

R L

P (R) No Visor

Excellent

Above Average

Average - 0.1

- 0.1 0.2 60 30 25 75 4 30.6 8.82

Below Average

0.2 30.61 0.79 (28.7)

Needs Attention

16.7 21.6

RECOMMENDATIONS

Worth having full eye examination with the optometrist to check the vision in

your left eye.

Other

Good all-round visual performance. Protect blue eyes in the sun whenever

possible. Work on eye foot skills with coach.

Ranking 15 =

Score 38 (Potential 43)

SCORE

The individuals score is found by counting the squares below the line of the

bar chart. All the scores were then put in rank order, this gave the SVA

ranking of visual performance.

COACHES RANKING

After the Sports Vision Associations visual assessment of the squad and

before the individual profiles were completed four coaches at the club were

asked to grade the skill level of the players subjectively on a scale of 1 -5

(see Fig 4 basis for ranking)

Fig 4 Basis for ranking

Score Skill Level

5 International player

26

4 Premier league player

3 Full time professional

2 Sunday football

1 Not suitable for any level

The average of the four scores for each of the players was then ranked

according to the coach’s assessment of skill.

RESULTS

The two sets of data were compared to see if there was any correlation (see

Fig 5 Ranking Correlation). The results show a good correlation visually and

in statistical analysis with a probability of 99% that the results are related.

DISCUSSION

The data for the goal keepers was omitted because this had an adverse

effect on the correlation. It was argued that goal keeping is a specialist

position and these players may have different skills and visual requirements.

The correlation suggests the best players have the best visual performance.

It does not follow that players with a good visual performance will

automatically become good players, but it is tempting to say that given two

equally motivated and physically similar players the one with the better all-

round vision will become the more skillful.

Fig 5 Ranking Correlation

RANK

Name Coaches SVA

L R 3 1

D H 8 2

G H 6 4 Spearman's rho, statistical test

J J 3 4

A P 1 4 Column 1 Column 2

M O 7 7 Column 1 1

A J 13 8 Column 2 0.65 1

P R 1 8

R P 11 10 p = 0.01 One tail prediction of positive correlation

M S 11 10 (A 99% Chance that these results are correlated)

M S 15 13

P W 16 14

27

R D 8 15

M F 10 15

GOAL KEEPERS EXCLUDED

G H S P

Analysis of Non-Retained Players

The original visual assessment took place on the 9th of September 1997, it is

now eight months later. The analysis of the 5 players who are no longer with

the club (see Fig 6 Analysis of non-retained players) shows that all the

players are from the lower ranking order, with below average or poor

performances in up to 5 of the visual skills. All the players who have left the

club, had at least one visual skill which was in need of attention. The figures

have been slightly modified since their initial presentation at the May 98

Annual General Meeting, without changing the conclusions.

The means ranks of the non-retained players show good agreement between

the coaches and the SVA.

Fig 6 Analysis of non-retained players N = 5 (31%)

POSITION RANKING DEFECT SD's FROM MEAN

SVA NFFC

Striker 8 13 SA +2 (Needs attention)

PA +1 (below average)

GR +1 (below average)

Central Defender 10 11 AF +2 (Needs attention)

Mid -Field 10 11 90 % V +2 (Needs attention)

10 % V +2 (Needs attention)

DVA +1 (below average)

CS +1 (below average)

FEC` +1 (below average)

Central Mid-Field 13 15 PA +2 (Needs attention)

10 % V +1 (below average)

Striker 15 10 FEC +2 (Needs attention)

DFT +1 (below average)

10 % V +1 (below average)

PA +1 (below average)

Mean Rank 11 12

28

See Fig 7 for the key to the skills

Fig 7 KEY TO SKILLS

SA Stereo Acuity

CS Contrast Sensitivity

AF Accommodation Facility

90 % V 90 % Contrast Vision (Logmar)

10 % V 10 % Contrast Vision (Logmar)

DVA Dynamic Visual Acuity

FEC Foot-Eye Co-Ordination

PA Peripheral Awareness

DFT Dynamic Fixation Test

GR Glare Recovery

CONCLUSION

Basis for Selection in Soccer

One argument says that sports vision has to be considered in terms of more

goals or some scientifically rigorous method of measuring performance.

In reality it is the coach's or manager's subjective assessment of individual

players' skill that decides whether they play or not and at what level.

The high correlation between the SVA ranking and the Nottingham Forest

coaches ranking, suggests that visual performance could be used as a guide

to playing potential in younger players. It does not necessarily follow that

visual correction alone would have saved the players who left the club,

because other factors could have contributed to this decision. But we can say

that, visual performance may have been one factor and that all youngsters

should have access to visual screening to make sure that at least this part of

their physical development is not disadvantaged.