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For Extended Field of Vision

Prisms has been used over the years for expanding the visual fields for patients suffering a visual field loss from a homonymous hemianopia. Most of these solutions are based on the concept that the patient should focus into the prism for detecting / viewing objects in the blind field. This has proven to be rather problematic, and none of the solutions has been successful.

If the prism is placed in the peripheral field of view instead, it works better. Since the purpose of the prism is to detect objects or movement in it and then move the eye / head to view it properly, the image quality is not essential. This means that instead of thick prisms, it is possible to use Fresnel Prisms. The use of Fresnel prism also means that higher prism powers could be used.

The pioneer within this field is Dr Eli Peli, who developed the Peli Lens that is distributed in the US.

In co-operation with Dr Eli Peli, we can now present Multilens version of this lens for the European market. We call our version of the lens for ML Peli Prism.

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ML Peli Prism

 
Power Range

Spherical +/- 4, Cylinder -2 (only Single Vision)

Press-On Prism

40 PRD (about 20 degrees expanded field of vision)

ML Optio Prism

40 PRD (about 20 degrees expanded field of vision) 
or 57 PRD (about 26 degrees)

Segment

PeliSeg, single or double

Material CR39, index 1.5

 

MULTIPLEXING

ML Peli Prism is based on the concept ”multiplexing”. Multiplexing means that the person with hemianopsia don’t focus their vision through the PeliSeg, but uses it for detecting movements and obstacles in the peripheral view. This means that we can make the segment using Fresnel Prism, since the optical quality and exact refractive correction are not crucial.

ONE OR TWO PRISM SEGMENTS

ML Peli Prism may be ordered with one or two prism segments (double segment). The double segment has one prism at the upper part of the lens and one at the lower, with a distance of 12 mm between the segments. The unique shape of the segment in our ML Peli Prism lenses we call PeliSeg. Our Press-On segments have a pointed end in the direction of the prism base to ease correct placement. The choice of one or two segments depends primarily on the needs of the patient. The expanded field of view sideways are obviously bigger with two segments, but at the same time the field of view upwards will be limited.

40 OR 57 PRD

ML Peli Prism lenses may be ordered with 40 or 57 PRD, whilst the ML Peli Prism Press-On segment may be ordered with 40 PRD (in packs of 10). What to choose is individual and should be tried out, but in most cases 40 PRD are sufficient.

CHOICE OF FRAME

ML Peli Prism lenses may be mounted in most frames as long as the frame height is at least 26 mm (one segment) or 38 mm (two segments) ML Peli Prism combined with our frame HangOn gives a solution where the patient easily can switch between using ML Peli Prism and not. The frame is designed to be put on top of the patients normal glasses, so as soon as the patient put the frames on, he / she will have ML Peli Prism segments positioned in the correct positions.

OUR DIFFERENT ML PELI PRISM PRODUCTS

The following ML Peli Prism products are available: ML Peli Prism as an ML Optio lens An “ML Optio Lens” means that the segment is mounted in a milled hole in the main lens. This gives the best possible optics in both the main lens and the segment. The main lens has normal optics and the segment is made of a Fresnel lens.

  • ML Peli Prism lens with one segment at the upper part
    A PeliSeg at the upper part with 40 or 57 PRD
  • ML Peli Prism lens with one segment at the lower part
    A PeliSeg at the lower part with 40 or 57 PRD
  • ML Peli Prism lens with double Segment
    PeliSeg both at the upper and lower part with 40 or 57 PRD.

STRAIGHT FORWARD FITTING

Fitting of ML Peli Prism is easily performed with our ML Peli Prism Test set. The test set includes a test frame (our frame HangOn) equipped with plano lenses. Furthermore, there are 10 ML Peli Prism Press-On segments, of which one or two are put on the right place on the test frame in relation to the patient’s pupil using the included template.
The patient may then use the test frame for as long as he / she needs to evaluate the function. The test set also includes a detailed fitting guide.

ML Peli Prism as a Press-On segment
A Press-On segment with an adhesive back side that stick to flat surfaces such as the lenses in a pair of glasses. The purpose of our Press-On segments is mainly designed for test, but may of course also be used permanently.

  • ML Peli Prism Press-On Segments Delivered in pack of 10.