The Activities
Part 3
Screening Activities
The Role of the Screener
The Screener is responsible for competently implementing the 4 screening stations and recording the children’s results onto their individual results slip.
A general understanding of the processes and paperwork involved is also required.
Qualifications:
- Complete this online screening course
- Complete face-to-face practical training and observe at a vision screening session
- Obtain a ‘Working with Children’ clearance or equivalent
How to Interact with Screening Participants
Make it fun!
Ensure the child being examined is aware this is not a ‘test’. Perhaps by saying that we have some games for them to play.
Never be alone in a room or confined space with a child.
Have another Lion or administrator available to assist with managing participants waiting in line.
Don’t have too many lined up at one time.
Smile at the participant and make them feel comfortable.
Do not show frustration if a participant is not cooperating. If a screening is not able to be performed suggest a referral to an optometrist.
Always tell the participant they “did a great job”.
Do not touch the participant.
Give clear instructions as to what the test is doing (e.g. it works a bit like a camera to see if your eyes are working well, it is quick, it doesn’t hurt and you can’t get anything wrong).
If it seems that instructions are not being understood, try expalaining them in another or different way.
If you give out stickers to a child you should hand it to them so the child can place it on themself.
Visual Acuity (Lea Chart) Screening Instructions
Purpose
How sharp is the vision at longer distances? This is called distance visual acuity.
Set Up
Find a space on a wall, door or white board to hang the Lea Chart.
Place a mark on floor 3 metres from the chart. The centre of the chart is to be at head height for the average child being examined. Requires good room lighting but watch for glare on the chart.
May be used in presence of other children if absolutely necessary.
If a child is easily distracted and to avoid children memorising or copying answers, it is best to perform the screening without other children nearby, perhaps more than 3 metres away.
The screening can be done with just two adults in the room.
Method
With two eyes open, start with the largest symbols to give the child some confidence and to determine what the child calls each symbol (e.g. heart or apple.)
Test the top two lines in this way. Your pointer should not cover symbols but be clear which symbol is pointed to. Perhaps hold the pointer, a dark thick pen for example, directly above or below the symbol.
Cover one eye, the child may hold hand over eye but look for peeking through fingers. It is preferred to hold an occluder over the child’s eye.
From the third line test two symbols on each line for the next four lines then check 5 symbols for the next two lines ending on the 6/12 line which is 10mm high.
Cover the second eye and repeat as above.
There is no need to go to smaller symbols.
Tips
A child may call a shape by a different name, i.e. servo instead of circle. As long as they consistently identify the shape, whatever the name they use, this is acceptable.
If children don’t know the names of shapes, get them to select the same shape from the small separate shapes that come with the kit or point to it on the card that has the set of shapes.
Refer if the child misses 1 of the 10mm (6/12) symbols with either eye.
Explanation of Failed Screening Result – Visual Acuity
“When the letters become small you seem to have a little difficulty seeing them. I suggest you have a further eye test”.
The reason may be optical, e.g. Myopia or it may be a more serious fault in the eyes, e.g. Lazy Eye or opacity of the lens in the eye.
Colour Vision Screening Instructions
Purpose
Does the child perceive colour as most people do?
Set Up
Find somewhere to sit or stand where you and the child will be comfortable and the lighting is good.
The test plates can be affected by finger oils / grease etc. so it is recommended that the child does not touch the plates.
Method
May be conducted in the same room as the other tests.
Examiner is to be seated or standing 1 metre in front of the child
Requires good room lighting but watch for glare on the plates.
May be used in presence of other children but if child wishes or is distracted, do the test without other children present.
Screening to be conducted with both eyes open.
Ask for the child’s response starting from the demo chart through to chart 7.
If the child reads a letter wrongly, the plate may be checked twice.
Refer if two plates are misinterpreted.
(Chart 8 – basic colour chart, is not required as it tests for a blue yellow loss, rare in the absence of eye disease. Expected responses are written on the back of this chart. The basic colour chart could be used to check the amount of confusion a colour blind person experiences but is not for screening purposes).
Note: Avoid using the term ‘colour blind’. Instead explain that a person perceives colour differently to other people.
Tips
You could explain the screening activity by saying that we are looking for hidden numbers.
If there is no response to the first/demo plate the answer can be shown, to give the child an idea of what is required.
If the child is not confident with numbers, they can be read singularly (i.e. ‘1’ and ‘6’ rather than ’16’).
The child could also use a cotton bud or similar to trace the number outline.
It is preferable to be seated away from other children, as well-meaning friends will sometimes call out a number if a child appears to be struggling.
Explanation of Failed Screening Result – Colour Vision
“You seem to perceive colours differently to most people. You may never have noticed this but it may be worthwhile talking to an eye care professional”.
Colour blindness is a bad expression, subjects who do not see colours as others do still see colours but e.g. tan and green colours may be confused.
We will find one in ten boys with a colour vision perception different to most people.
Girls have a one in a hundred chance of colour vision loss as the colour gene is carried on the “X” chromosome. Boys have one “X” chromosome, girls have two chromosomes so both need to be affected in females.
One of the charts will define if the loss is red based (protanomoly) or green based (deuteranomoly), the red based is more significant in that stop lights and brake lights can be difficult to see and it may be difficult to work out which apples are ripe etc.
Depth Perception (Stereo Fly) Screening Instructions
Purpose
An aid in assessing the binocular function of the eyes at near tasks. This is called stereo acuity.
Set Up
Find somewhere to sit or stand where you and the child will be comfortable and the lighting is good.
Method
Requires good room lighting but watch for glare on the chart.
May be used in presence of other children but if child wishes or is distracted, do the test away from other children.
The screening is conducted with both eyes open and with the polarising spectacles being worn.
Ask the child if they see the fly standing out from the page. Perhaps have the child try to pick up the wings.
Ask which animal stands out or is jumping out from its box in each row. This can be verbal but most children will try to pick up the animal or push it back into it’s box.
Correct answers are – A: Cat B: Rabbit C: Monkey
The circle chart is used to better define the extent of any stereo anomaly but is not required for our purposes.
Try testing yourself with one eye closed to see the effect of having loss of 3D vision!
Tips
Some children are quite vocal about the difference they see, others may be shy or quiet.
Try showing the fly without the glasses, close the book, get them to put the 3D glasses on, then open the book to reveal the fly again.
The child usually indicates there is a difference by their facial expression.
They can then be encouraged to try and pick up the fly.
Explanation of Failed Screening Result – Depth Perception
“Your eyes do not seem to be working perfectly together today.”
Good clarity of vision and good eye coordination are required to perceive the stereo effect.
Some young people find stereo a difficult concept and may miss seeing the stereo even though they have good binocularity and clarity of vision.
That is why we say the word ‘today’ implying that the child may have ‘normal’ stereo vision at another time and with other types of tests.
Welsh Allyn Spot Vision Screener (Camera) Instructions
Purpose
Are there any abnormalities with the child’s eyes?
Designed to screen for Myopia (near sightedness), Hyperopia (far sightedness), Astigmatism (blurred vision), Anisometropia (unequal refractive power), Binocular Vision (eye misalignment) and Anisocoria ( unequal pupil size).
Set Up
Find somewhere to sit or stand where the lighting is more subdued – too much light makes the pupils smaller.
Method
Select the appropriate age range for the child being screened.
It sometimes helps to place paper foot prints or a mark on the floor where you want the participant to stand, or the participant may sit in a chair.
Using a camera tripod does not usually help. To allow for subtle adjustments it is easier to hold the camera.
Be sure there are no direct lights shining on the front of the camera.
The machine has a pupil size detector and will notify you when there is an issue with pupil size. If this occurs adjust the light brighter to achieve smaller pupils or darker to achieve larger pupils.
Be sure the front of the camera is 1 metre (3.3 feet) from the participant’s eyes when conducting the screening.
Ask the child to look at the flashing lights in the camera.
Trigger the Start screening on the camera and slowly rotate the device upward to meet both of the subject’s eyes.
Adjust your distance from the subject until both eyes are clear on the screen.
Be sure the camera is level and squarely pointed at the child’s eyes at exactly the same height as their eyes.
If the camera is tilted up or down, or twisted right to left it will be difficult to obtain a good reading.
Be sure neither you nor the participant moves during the camera’s reading process. The participant and you only need to be still for 1 second, but both of you must be still.
If the distance changes due to movement slowly rock forward or backward to achieve the correct distance.
Remember you must hold the camera at the height of the participant’s eyes – do not point it down to them.
A blue screen indicates you are too close or too far from the subject.
Once the image has been taken, save it on the camera with the child’s first name and number taken from their paper results slip.
If a full eye examination is required, a copy is to be printed and provided to the facility for distribution with the parent letter.
For other actions, consult the camera instructions.
Tips
If the results are not what you expect be sure the child’s pupils are at least 4mm but not more than 8mm.
Having the child close their eyes for a short time and then open them may improve the pupil size.
Children could be asked to wait in a darkened location prior to screening with the camera and this may also help.
A copy of the Camera Manual can be downloaded here.
A copy of the Camera Quick Start Guide can be downloaded here.
Explanation of Failed Screening Result – Spot Vision Screener (Camera)
Myopia (Near sighted)
“You have no problem seeing close things, but perhaps your long distance vision could be improved.”
The myopic eye is a little too large for the optical surfaces of the cornea and lens behind the iris. A negative lens is required to push the focus back to the retina. When you read the nearness of the task pushes the focus back so writing is clear.
Hyperopia (Long sighted)
“You see clearly but your eyes have to focus harder to see.”
The eye is a little short so the subject has to ‘zoom’ in forcibly to see. Because of the extra focussing effort, the subject has strain on the eyes especially at near distance. The extra need to focus can cause the eyes to converge, (see strabismus below).
For those over 45 years old, a related condition, (presbyopia,) means reading becomes difficult as the lens situated just behind the iris is losing its flexibility and the ring of muscles just behind the iris, which is involved in focussing, can’t flex the lens to give the power needed for reading.
Astigmatism
“Your eyes are a little out of shape, this may require correcting with glasses so a further test is recommended.”
The eye should be round like a soccer ball, the astigmatic eye is more like an Aussie Rules football. When looked side on, the football has more curve up and down than it has horizontally. Vertical lines may be clearer than horizontals for example.
The readout on ‘Spot Vision Screener’ may say e.g. 65 degrees, this means the more curved surface is aligned along the 65 degree axis.
Anisometropia
“One eye is a little different to the other, this may require correcting with glasses so a further test is recommended.”
This can be a difference in myopia, hyperopia or astigmatism. One eye may be perfect in focus but the other needing glasses, a danger here is that one eye may become ‘lazy’.
Binocular Vision (Gaze) e.g. Strabismus
“Your eyes are not quite parallel when relaxed so a further examination is recommended in order to see if this is significant.”
Each eye has 6 muscles controlling alignment. Only one needs to be over or under-acting! More common is slight misalignment e.g. as mentioned in hyperopia above an over-convergence of the eyes is seen and the child may want to hold the reading task too close.
Anisocori
“Your pupils, the holes letting light into your eyes, seem to be different sizes. There can be many reasons for this and it is probably just the way you are. However a further examination is recommended.”
Complete text books are written about the nerve innervation to the eyes, the size of pupils and the way they react to light is very important. The shape of the pupil is also significant.
These explanations of the conditions detected by the camera are also contained in the Children’s Vision Screening Screener Manual.
Welsh Allyn Spot Vision Screener Screens
Home Screen
- Age Range
To begin instant screening, with no personal subject data, select an age range of the subject from the Home screen. You will be able to enter subject data after the screening if desired. - Start Button
The Start button will allow you to:
Enter subject information such as ID, First and Last Name, Gender and Date of Birth (DOB)/Age (Required)
Find queued subjects (exact match on the ID screen)
Begin the screening process (Binocular and Monocular available)
Review and print screening results - Icons on Bottom of Screen
Queue (View, select or search for queued subjects from a list to begin the screening process)
History (View completed records of already screened subjects)
Tools (A variety of options to customize the vision screener)
Tools Screen
- Display software application version and serial number and important vision screener features, including memory storage levels of the device.
- View the age-based criteria settings used for exam recommendations that are currently active on the vision screener.
- Set the current date and time for your vision screener.
- Import and export using an inserted USB storage device.
- Set a location for a screening and all subjects will be tied to that location.
- Connect the vision screener to a wireless network. From this page you can view and change your TCP/IP settings.
- Configure a network printer and print a test page. It also lets you view printer status.
- Configure how data is displayed on the ‘Results’ screen when a screening is complete.
- Set a security PIN for your device for added security. If enabled a PIN will be required whenever you start the device or upon waking it.
- Activate the license on the device.
- Allow you to select the language that will display on the vision screener.
- Change the parameters the unit uses for assessing normal results.
All Measurements in Range Screen
No Referral required.
Error Detected Screen
Referral for a Full Eye Examination recommended.
Returning the Equipment
After the screening ensure that the camera is packed in its protective case where possible and that other items are packed securely.
A special ‘sensitive’ courier service is required to return the screening equipment, unless it is being transported between locations by Lions.
Within one week of completion of the screening contact the National Program Manager, or District Co-ordinator, who will assist with arranging the safe return of the screening kit.
