Tunnel Vision Prismatic Field Expansion: Challenges and Requirements

Apfelbaum, Henry L.; Peli, Eli

doi:10.1167/tvst.4.6.8

Cited by 30 publications

(35 citation statements)

References 26 publications

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“…No solution using conventional prisms has met lasting acceptance (as reviewed in Apfelbaum & Peli 2 ). If the peripheral field loss patient has only one functional eye, the apical scotomas associated with conventional prisms are a poor tradeoff for field expansion.…”

Section: Resultsmentioning

confidence: 99%

“…Their perimetric results were used to verify our calculated perimetry. Apfelbaum and Peli 2 have pointed out that failures to conduct such verification resulted in incorrect assertions of field expansion effects in a number of prior publications. The prism prescriptions used here were not necessarily optimized for the subjects’ particular needs (in term of prism powers or contrast ratio), so these should not be considered clinical case studies.…”

Section: Methodsmentioning

confidence: 99%

“…(A) An image of the savannah cartoon (Fig. 1A in Apfelbaum & Peli 2 ) without the prisms. Blue rectangle indicates the portion of the scene within the see-through view, spanning 48° horizontally.…”

Section: Figurementioning

confidence: 99%

“…This superimposition results in visual confusion, seeing two different things in the same apparent direction (as illustrated in Fig. 1 of Apfelbaum & Peli 2 Introduction).…”

mentioning

confidence: 98%

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Multiplexing Prisms for Field Expansion

Peli

Jung

2017

Optom Vis Sci

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Purpose Prisms used for field expansion are limited by the optical scotoma at a prism apex. For a patient with two functioning eyes, fitting prisms unilaterally allows the other eye to compensate for the scotoma. A monocular patient’s field loss cannot be expanded with a conventional or Fresnel prism due to the apical scotoma. A newly invented optical device, the multiplexing prism (MxP), was developed to overcome the apical scotoma limitation in monocular field expansion. Methods A Fresnel–prism-like device with alternating prism and flat elements superimposes the shifted and see-through views, thus creating the (monocular) visual confusion required for field expansion and eliminating the apical scotoma. Several implementations are demonstrated and preliminarily evaluated for different monocular conditions with visual field loss. The field expansion of the MxP is compared with the effect of conventional prisms using calculated perimetry and measured visual field. Results Field expansion without apical scotoma is shown to be effective for monocular patients with hemianopia or constricted peripheral field. The MxPs are shown to increase the nasal field for a patient with only one eye and for patients with bitemporal hemianopia. MxPs placed at the far temporal field are shown to expand the normal visual field. The ability to control the contrast ratio between the two images is verified. Conclusions A novel optical device is demonstrated to have the potential for field expansion technology in a variety of conditions. The devices may be inexpensive and can be constructed in a cosmetically acceptable format.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Figurementioning

confidence: 99%

“…This superimposition results in visual confusion, seeing two different things in the same apparent direction (as illustrated in Fig. 1 of Apfelbaum & Peli 2 Introduction).…”

mentioning

confidence: 98%

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Multiplexing Prisms for Field Expansion

Peli

Jung

2017

Optom Vis Sci

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“…Apfelbaum and Peli have noted that an ideal LVA for PFL would result in field expansion in primary gaze without obstructing central vision. 21 …”

Section: Current Low Vision Aidsmentioning

confidence: 99%

Head-Mounted Display Technology for Low-Vision Rehabilitation and Vision Enhancement

Ehrlich

Ojeda

Wicker

et al. 2017

American Journal of Ophthalmology

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Purpose To describe the various types of head-mounted display technology, their optical and human factors considerations, and their potential for use in low vision rehabilitation and vision enhancement. Design Expert perspective. Methods An overview of head-mounted display technology by an interdisciplinary team of experts drawing on key literature in the field. Results Head-mounted display technologies can be classified based on their display type and optical design. See-through displays such as retinal projection devices have the greatest potential for use as low vision aids. Devices vary by their relationship to the user’s eyes, field of view, illumination, resolution, color, stereopsis, effect on head motion and user interface. These optical and human factors considerations are important when selecting head-mounted displays for specific applications and patient groups. Conclusions Head-mounted display technologies may offer advantages over conventional low vision aids. Future research should compare head-mounted displays to commonly prescribed low vision aids in order to compare their effectiveness in addressing the impairments and rehabilitation goals of diverse patient populations.

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