| Sumario: | Background: Severe peripheral visual field (PVF) loss can negatively impact a person's functional performance with activities of daily living, particularly mobility. The inability to navigate safely and efficiently has been associated with an increased risk of falls and injuries, as well as feelings of depression and isolation. Although no curative treatment is available for PVF loss, compensation is possible with visual field enhancement therapy (VFET). VFET using sectoral Fresnel prisms is a concept that has been documented as a viable treatment option for improving PVF awareness. Sectoral Fresnel prisms displace images from the patient's non-seeing field into their seeing field, making potential hazards more visually accessible. As a result, sectoral Fresnel prisms have the potential to improve motor performance and to enhance the overall quality of life in those suffering from visual field loss. Case Reports: Two cases are discussed demonstrating the West Haven Veterans' Administration protocol and techniques used when fitting sectoral Fresnel prisms in both conventional and non-conventional clinical cases. The first case is a conventional sectoral Fresnel prism fit on a patient with a left homonymous hemianopsia. The second case demonstrates a challenging fit on a monocular patient with end-stage glaucoma having an overall severely constricted field. Both patients were successfully fit with sectoral Fresnel prisms, and after training, they were able to achieve their primary goal of safe and independent travel. Conclusion: Sectoral Fresnel prisms have historically been a clinically accepted tool for rehabilitating patients with PVF loss. Recognizing functional difficulties secondary to PVF loss and identifying appropriate candidates for sectoral Fresnel prism therapy is critical to helping these patients. However, conflicting opinions regarding patient-selection criteria, prism power, and prism placement have resulted in a lack of clinical guidance or a standardized protocol for evaluating and treating these cases. Successful outcomes with sectoral Fresnel prisms are dependent upon patient selection, patient education, demonstration, fitting technique, and training. This paper serves as an overall guide by discussing a model successfully used in the WHVA for evaluating and prescribing sectoral Fresnel prisms. Emphasis is placed on the importance of interdisciplinary training to ensure safe use and long-term prism acceptance.
|
|---|