Welcome to the Low Vision area of the BIOS website. We hope you will find the following information useful.
What is Low Vision?
When someone has visual loss that cannot be corrected with glasses or contact lenses and which is not remediable with medical treatment, we say they have Low Vision. Low Vision may affect the central part of the vision, called the macula, which is used for clear and detailed vision. In this case, the person has difficulty with reading, finding that print is distorted, blurred, or incomplete. They may experience difficulty recognising faces, watching television, looking at photographs, and carrying out tasks and hobbies they have previously enjoyed. Low Vision can also affect the peripheral vision, also known as the field of vision. This results in problems negotiating busy areas, obstacles and steps, and may sometimes be worse in the evening or at night time. In some cases, the person may experience problems with both central and peripheral vision.
Orthoptists’ involvement in Low Vision
Orthoptists with a role in Low Vision are part of a wider multi-disciplinary team involving sensory Rehabilitation Officers based within local authorities, eye clinic Liaison Officers, local voluntary societies for people with sight loss and national support organisations, which together provide advice and practical support for the client. In some hospitals, Orthoptists undertake Low Vision Assessments, while in other areas this role is fulfilled by Optometrists or other suitably trained professionals.
Low Vision Assessment – what does it involve?
A Low Vision Assessment is a specialist assessment of visual function for people with sight loss. The assessment takes a holistic approach to the client’s needs and is often longer than a standard Orthoptic appointment (up to an hour).
The Orthoptist will discuss the client’s eye condition and their understanding of it with them, aiming to address any concerns and questions they may have. She or he will then determine the person’s daily difficulties and what sort of tasks they are aiming to achieve, thereby adapting the assessment appropriately. Through a variety of aids, techniques and advice, the Orthoptist aims to enable the client to use their remaining vision to its greatest potential.
As well as measuring distance and near vision, the effects of glasses, lighting, colour and contrast are also considered. Usually a range of low vision aids (magnifiers) is offered to the client for trial, while further training in specialised techniques (as listed below) may be introduced to back up the use of magnifiers. In most cases low vision aids are given out free of charge on long-term loan from the hospital.
a. Focusing and positioning of the magnifier– using magnifiers can be tricky as they require precise positioning and careful handling. Often they have a small field of view, making it difficult to follow lines of print quickly or take in a whole picture. The Orthoptist will support the client in overcoming these problems.
b. Eccentric Viewing – this involves identifying and utilising the remaining healthy part of the eye closest to the macula. For the person who has lost central vision, it will be a non-central or “eccentric” part.
c. Steady Eye Strategy– with central vision loss it is hard to scan across the page as the central missing or blurred area continually blocks out the words. This strategy aims to teach the client to keep their eyes still and move the page from right to left across the best part of their vision. This improves the accuracy and speed of reading.
- Tracking - when you get to the end of the line and try to jump to the beginning of the new line, it may be difficult to judge which line you are on. In order to improve tracking, the person needs to look at the line below the one they have just read, follow it to the beginning then read the new line.
Any additional needs can be discussed with the Orthoptist during the assessment. She/he will be well equipped with information to pass on about things such as audio books/newspapers, puzzle books, and adaptive equipment to help with hobbies and daily activities.
2. Visual Impairment in Children
Orthoptic Assessment of Children with suspected Visual Impairment
During visits to the Ophthalmology (Eye) clinic children with suspected visual impairment are often seen by the Orthoptist. Orthoptic assessment comprises various observations and tests to gather information about the child’s visual acuity (eyesight) and possible presence of a squint.
Tests of visual acuity for babies and toddlers utilise flashcards with gratings (black and white stripes) and line drawings; the Orthoptist observes the child’s eye and head movements to evaluate visual acuity. For older children, picture and letter matching or naming tests are used. In addition to formal tests, a variety of techniques is used to gain information about how the youngster sees, including interpreting their response to lights, reflective materials and toys. Quiet toys are used so that reactions to sound are not interpreted as a visual response.
Many children with low vision have involuntary to and fro eye movements called nystagmus. The Orthoptist carefully observes the eye movements, as well as any unusual position of the head adopted by the child to compensate for the nystagmus.
As a reasonable amount of co-operation is required when assessing children’s vision, it can take time and many visits to build a full and accurate picture of how well they see. However, when low vision is suspected or confirmed in a youngster, help and advice is available to parents and carers.
Support for Families of Children with Visual Impairment
Diagnosis of the disorder causing the vision problem is normally made by the Ophthalmologist (Eye Doctor). This may not be possible early on, due usually to insufficient information because of the child’s age or co-operation. Certain special tests, for example electro-diagnostic tests, cannot be conducted accurately until the child is old enough.
When given a diagnosis, parents can expect to receive information about the likely long term impact on vision, but it is important to note that there may be a large variation in the outcome for individual children. In cases of nystagmus, for example, eyesight can range from virtually normal to very poor, with all levels in between. Sometimes the final visual acuity may be impossible to predict, especially if the child has additional learning disabilities. It is often necessary to wait to see how the sight develops.
Whilst it can be devastating to hear that your child has or is suspected of having low vision, it is important to be aware that children’s eyesight develops over several years and there is much that can be done to ensure he/she uses their vision to its full capacity. In the rare cases of extremely limited or no eyesight, the input of other professionals will enable the child to develop full use of other senses.
Information and Advice
Following diagnosis, a member of the eye care team, often the Orthoptist or an Eye Clinic Liaison Officer, should be able to give parents information about the condition or help them to find such information. Details of local and/or national support organisations for children with the condition or with sight impairment generally may also be provided.
A team-working approach is recommended to support visually impaired (VI) children and their families. One important team member who may become involved is a Qualified Teacher of the VI, a teacher with an additional qualification who works with VI children from babyhood to school-leaving, supporting and advising both the family and other teaching staff. Later the child may be assessed for using low vision aids, comprising equipment such as magnifiers, binoculars and telescopes. These allow easier access to educational materials and to the world around them. Where appropriate, the Ophthalmologist will arrange to register the child as sight impaired or severely sight impaired. This is a voluntary process which can help to ensure the child and/or family receive appropriate benefits. In general you should find that the aim of all involved with the child is to provide the best care and service, working with the family to help the child reach their full potential.
Useful Websites and Documents
There are many sources of information on the internet. The following websites and documents are particularly useful for parents/carers of VI children.
LV Resources for CYP with vision impairment.pdf
Royal National Institute of Blind People (RNIB)
Visually Impaired Children Taking Action (VICTA)
The Clinical Trial website lists all clinical trials http://clinicaltrials.gov/ and it has a section for parents and families. To find out about relevant local research projects, contact the Research Department at the Hospital where your child is registered with.
3. Adults with Learning Disability and Visual Impairment
People with learning disabilities are ten times more likely to have serious sight problems than other people, with around 60% needing to wear glasses. If glasses have been prescribed they should be considered important; even if the person does not read, glasses may help with close up activities such as eating and crafts. Glasses can be labelled with the person’s name if they live in a shared setting, along with their purpose (near or distance wear). It is a good idea for them to choose different shaped or coloured glasses if they need separate pairs for near and distance.
For those with sight problems not fully correctable with glasses, assessment at a Low Vision clinic may be recommended. Within hospitals there is usually a Learning Disability Liaison Team, which can be contacted for advice if an appointment for a low vision assessment has been made. They may be able to send relevant information in a format that suits the individual, such as using large bold print or pictures to explain what to expect.
Some individuals may require a longer than usual appointment, whereas others may need a shorter first appointment to enable them to get used to the environment, followed by another appointment for the assessment. A quiet waiting room may be a possibility, or an option given to arrive and be seen straight away to avoid anxiety.
Before a hospital appointment, prepare the service user by looking at the information offered by such websites as http://www.seeability.org/eyecare_hub/ and/ www.mencap.org.uk about what to expect. They also give descriptions of different eye conditions.
At the Low Vision Assessment
Orthoptists are experienced in assessing vision in people of all ages and abilities and will try to find the optimum way to communicate with and assess the service user. They will usually begin by asking some questions of the service user and their carer about any concerns they have about the level of vision, any particular problems experienced, and any changes noticed, such as activities that the person now finds difficult.
If letter naming is not possible, matching letters, naming or matching simple pictures or shapes or signing are useful ways to assess vision. The carer may have useful observations of the person’s visual behaviour to report.
Magnifiers will be shown to the service user and his or her response assessed. As with glasses, they may be useful even if reading is not possible as there are many types of simple and lighted magnifiers that could allow enjoyment of magazines and photographs.
Thought will be given to the best aid for the individual to manage e.g. hand-held or hands-free magnifier. The aids are normally provided on a free of charge long-term loan basis. A follow up appointment is usually offered, to reinforce techniques and ensure the aid is useful.