How the Peli Lens Works

Using high-powered prisms, the Peli Lens helps patients with peripheral vision loss attributed to Homonymous Hemianopia by expanding a hemianopic patient’s awareness of their blind side by over 30 degrees. This awareness enables patients to better detect obstacles and navigate around them. On this page, you’ll learn more about the Peli Lens, how it works, and how to get it for your patient.

How Homonymous Hemianopia Looks

Homonymous Hemianopia, often caused by stroke, occurs when a patient loses visual field in the same half of each eye.

The images below show how a normal visual field looks compared to the visual field of a patient with homonymous hemianopia.

Normal Visual Field

Hemianopic Visual Field

How the Expanded Visual Field Appears

The goal of the Peli Lens is to help patients make the most use of their remaining vision.

By placing peripheral prisms in the patient’s blind side, they can notice movement and contrast from their missing visual field. This often enables patients to significantly increase their awareness of their blind side.

Below you’ll see a view from above of how a hemianopic patient’s visual looks normally and how the field looks while wearing the Peli Lens.

View from Above

Below you’ll see a view from above of how a hemianopic patient’s visual looks normally and how the field looks while wearing the Peli Lens.

Homonymous Hemianopia Visual Field

Homonymous Hemianopia with the Peli Lens

Video Simulations

The videos below provide simulations of how homonymous hemianopia patients may perceive certain scenarios while wearing the Peli Lens.

Normal vs Hemianopic vs Expanded Visual Fields

Here’s another way to visualize the difference between normal vision, hemianopic vision, and vision using the Peli Lens.

Full Visual Field

Hemianopia Visual Field

Expanded field with superimposed image

Peli Lens Keys for Success

Reacting to the Information from the Expanded Field

Peripheral prisms alert the patient of movement in their blind side so they know to turn and look in that direction. The information in the expanded field can be viewed by the patient moving their eyes or moving their head to focus on that area.

Adapting to Peli Peripheral Prisms

This superimposed field expansion described by Peli Lens wearers can take some getting used to. With training, patients are easily able to differentiate their regular field from the expanded field.

We recommend that a patient wear training prisms for 4-to-6 weeks and spend about 20 minutes a day performing self-training exercises to help with adaptation.

We’ve created a training protocol to help patients with this process.

Success Rates with the Peli Lens

In the initial trial of the Peli Peripheral Prisms, 74% wished to continue wear after the 6-week assessment. At the end of the first year, 47% of patients continued to wear the prisms.

Many doctors have reported success rates much higher than this when the fitting is coupled with multiple training sessions and at-home practice.