Eccentric Vision Training
Eccentric Viewing is a technique taught to reduce the impact of central vision loss. The majority of central vision loss is caused by some dysfunction of the macula; the most common for children is Stargardt’s Disease (Juvenile Macular Degeneration). The functional implications of central vision loss are poor visual acuity, poor colour discrimination, slow light adaptation and photophobia.
In 1998, Professor Jill Keeffe and colleagues from the Centre for Eye Research conducted a study that highlighted common problems associated with central vision loss. They included:
- inability to recognise faces
- difficulty reading print
- difficulty with common every day tasks
- social isolation
Traditionally we have assumed that an effective way to reduce the impact of this loss is to introduce magnification. Indeed there are several studies that indicate it is much easier to see a large blurred image rather than a small blurred one (Dudley,1990; Virtanen & Laatikainen, 1991). But it may not always be practical to provide enlargement e.g. Nanna’s face.
Eccentric viewing compliments magnification. The impact of sight loss caused by central field loss can be ameliorated with the use of eccentric viewing (Goodrich, 1986; Collins, 1990; Cullam, 1990; Nilsson and Nilsson, 1994; Fitzmaurice, 1994; Jose, 1995).
What is eccentric viewing?
Eccentric viewing is a technique which enables persons with central field loss to make the most efficient use of their remaining peripheral vision – and is not only used to access print.
It is a technique that some people with central field loss will use without direct teaching. For others, being taught the technique will assist – and the skill will become automatic with practise.
Who can benefit from this technique?
The child with central field loss must:
- be able to follow instructions
- have sufficient short term memory to retain these instructions
- be fully corrected when undertaking this program; reading glasses are preferable to bi-focals
- strong motivation to improve functional vision will assist during the training period
What is the technique?
Pre-training assessment is required before starting the program. This assessment is completed by an experienced orthoptist who will determine the preferred retinal locus, i.e. the part of the retina that will give the student the best vision.
Once the preferred retinal locus is established the children are made aware of the potential acuity of this point. They are then taught to locate one object/stimuli make it disappear and to see another stimuli. They are taught the direction and re-fixation movement that will maximize their preferred retinal area.
The aim of the program is to ensure that the children are using their residual vision efficiently. For some children this will mean an increase in their environmental awareness and thus increase their mobility skills; and for other children it will mean a reduction in the size of print needed. This is not an easy task, initially it can be frustrating and tiring.
Dr Kerry Fitzmaurice, Dean of the School of Orthoptics at La Trobe University, has developed a computerised training program that systematically works through a series of modules that facilitates eccentric viewing:
- Module 1 is eccentric awareness and eccentric practice
- Module 2 offers more advanced activities
- Module 3 has extension activities other than reading
- Module 4 focusses on text reading
This technique will not stop the progression of any condition, nor will it restore any vision lost but what it will do is make the children aware of where their best viewing position is, and with practice, it can become an additional strategy to maximising residual vision.
In 2003, Associate Professor Kerry Fitzmaurice conducted an eccentric viewing assessment and introduction to eccentric viewing techniques for a number of students with a bilateral central vision loss at the Statewide Vision Resource Centre.
The response from the students and Visiting Teachers was very positive with one student describing the technique as “like a blind going up” – a light bulb moment indeed!
We hope to conduct more of these sessions in the future with Professor Fitzmaurice and hope that more students can be involved. The sessions take around 45 minutes with time for any questions the students or parents/carers might have. There is no cost to the family.
Report by Annette Godfrey-Magee, Educational Vision Assessment Clinic, SVRC
For more information visit: Vision and Vision Impairment.