Description
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Product description
- The Yoked Prism – 16 Pair (Flat) set is a clinic-ready collection of matched prism pairs (same power and base direction in both eyes) designed to create a global visual field shift without inducing fusional demand. Dropping these flat prisms into a trial frame—or holding them over habitual spectacles—lets you explore visual midline shift (VMS), posture/gait orientation, and spatial awareness in a controlled, stepwise way, while observing head/torso alignment, balance, and symptom changes in real time.
- What it is: 16 matched pairs (yoked) with consistent base orientation for symmetric field shifts (e.g., Base Left/Right, Base Up/Down)
- Primary uses: VMS evaluations, posture/gait trials, doorway/step navigation, reading orientation, and VT progressions
- Why yoked: Shifts the entire scene (not just one eye), keeping accommodation/vergence largely unchanged for clearer functional observations
- Workflow (at a glance): Insert selected Δ & base → confirm orientation → have patient walk/track/read → observe posture, head tilt, balance, and comfort → adjust power/base as needed
- Trial-frame friendly: Standard flat form is easy to handle at the chair, slit lamp, or in mobility drills; compatible with most 38 mm trial frames via adapters or holders
- Documentation cues: Record Δ power, base, activity, distance, and patient-reported effects (tilt, drift, nausea, relief)
- Safety & comfort: Start with lower Δ, monitor for dizziness; step down if symptoms persist
- Care: Clean optical faces with lens-safe solution and a soft cloth; store pairs together in the lined case to protect surfaces and keep sets organized
| Topic | Details |
| Purpose / Target Users | The Yoked Prism – 16 Pair Flat Set is used in vision therapy and binocular vision assessment to shift the visual field in the same direction for both eyes simultaneously. Yoked prisms help evaluate and train visual spatial awareness, posture, balance, and visual processing, and are often used in rehabilitation therapy or specialized binocular vision programs. The primary users include optometrists, ophthalmologists, vision therapists, orthoptists, and optometry students, as well as patients undergoing visual rehabilitation or therapy. |
| Optotypes / Symbols | The prisms themselves do not contain optotypes or symbols. They are used together with external visual targets such as fixation lights, letter charts, reading material, or therapy targets while the prisms alter the perceived visual field direction. |
| Scaling / Spacing | The set typically includes multiple prism powers arranged in incremental prism diopters (Δ), often ranging from approximately 0.25Δ to around 30Δ. Each pair is clearly labeled with its prism power to allow clinicians to select the appropriate level during testing or therapy. |
| Range of Acuity / Line Sizes | Not applicable. Yoked prisms do not define acuity or line sizes. They are used with external fixation targets or visual tasks, and the optical clarity of the prisms ensures that these targets remain visible while the visual field is shifted. |
| Testing Distance | Yoked prisms may be used at near, intermediate, or distance viewing conditions depending on the therapy protocol or clinical assessment being performed. They are commonly used during visual-motor tasks, balance exercises, or reading activities in vision therapy. |
| Physical Size & Dimensions | Each prism is typically manufactured as a flat optical lens mounted in a standard rim or frame suitable for handheld use or insertion into trial frames. Exact dimensions may vary depending on the manufacturer, but they are designed to be compact and easy to handle during clinical procedures. |
| Mounting / Display Features | The prisms are designed to be placed in front of both eyes simultaneously, often using trial frames or handheld holders. In yoked prism use, both lenses have the same prism base direction, producing a uniform shift of the visual field for therapeutic or diagnostic purposes. |
| Included Accessories / Extras | The set typically includes 16 pairs of flat yoked prisms of increasing powers. They are usually supplied in a protective storage case to keep the lenses organized and protected during transport or storage. |
| Durability / Material Qualities | The prisms are typically made from optical-grade glass or high-quality acrylic, with polished surfaces for minimal optical distortion. The rims or holders are constructed from durable plastic or metal, ensuring stability and long-term clinical use. |
| Usability / Marker of Quality | A high-quality yoked prism set features accurately calibrated prism powers, clear labeling, high optical transparency, and minimal chromatic distortion. Durable construction and a protective storage case ensure reliable performance during vision therapy, visual rehabilitation, and binocular vision assessment. |
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