Want to discuss Peli Prisms?
One of our orthoptic team, Natalie, is experienced in using ‘Peli Prisms’ to assist patients who have a persistant homonymous hemianopia after stroke or brain injury. These prisms have been used for around 20 years, and can expand the visual field by up to 30 degrees beyond the midline in successfully adapted cases.
These prisms have been called a range of names including: peli lenses, field expansion prism and spot prisms, but they all represent the same thing.
The diagram below comes from the original research paper by Eli Peli and clearly shows how, over time and will training, the patient will perceive some expansion of visual field. This improvement in awareness is seen in approximately 75% of patients who trial these prisms.
What is Hemianopia?
Homonymous hemianopia, also known as homonymous hemianopsia, is a type of visual field defect seen after strokes, brain injuries and tumours and causes a loss of the visual field to one side. The picture below demonstrates the vision following a left homonymous hemianopia.
Will Peli Prisms work for me?
It is impossible to say whether Peli Prisms will work for an individual without a thorough assessment, which includes Goldmann visual fields (as recommended by Peli himself) and an in clinic trial before training/trial prisms are fitted.
Peli Prism Program
Research suggests that fitting Peli Prisms is just the first step in gaining success with this type of treatment, a staged program with prescribed exercises is best to get the most out of them.
The Peli program at Adelaide Orthoptics is clearly laid out to patients from the start, and is based firmly within the research outlined in the original and subsequent articles, along with minor adaptations made following experience of using these in the clinic environment.
