• Non-prescription version:
• Used when the telescope is for near vision only.
• When astigmatism is low.
• Version for a prescription lens:
• The lens is held in place with double-sided adhesive.
• Used to obtain afocal vision.
• To correct significant astigmatism.
• In binocular vision, to balance vision.

1. For a high prescription:

• Do it yourself: a template is supplied for the tracer.
• Order a pre-calibrated lens, edge to Ø20 mm.
• Contact LESA FRANCE.

• No correction needed.

Galilean system - Principle:

• The Galilean monocular is an afocal magnifier, meaning that the image is formed at infinity.
• The point of this system is therefore simply to magnify in distance vision.
• For near vision, just add an add-on lens to the front.
• Note that its power determines the working distance, which equals its focal length.

Monocular:

• Anodised aluminium body, very stable.
• Very light.
• Achromatic telescope.
• Wide field of view: 24° for the 1.8x
  
• Anti-reflective coated.
  

• You can:
• Buy a trial case with 3 monoculars that fit the optician's standard trial frame
• Rent a trial case, for a one-off sale.

Our add-on lens holder, used with its trial box, lets the optician find the wearer's optimal magnification.

• It is universal: all you need is one telescope with a trial ring.

• No more need for excessive stock.
• Placed on the trial frame, the patient's prescription can be added to assess the benefit with correction.
• The trial is done in real-life conditions.
• With a reading chart or a newspaper.
• On a computer screen.
• At intermediate distance, a television screen.
• To find the focal power of the add-on lens, divide 100 by the eye-to-object distance (in centimetres).
• Choose a large "panto" style frame.
• The optical centre must be the near-vision centre.
• The distance from the optical centre to the frame must be at least 19mm.
• Mark the optical centre (near vision) and check it.

• For a monocular fitting, order:

1. The chosen 1.8x, 2.1x or 2.5x telescope (Code BV20.Gxx ?).
2. The add-on lens determined with its trial box. Code (BV20.Axx ?)

• Option: pre-calibrated ophthalmic lens to be edged to 21mm.

1. 2 chosen 1.8x, 2.1x or 2.5x telescopes (Code BV20.Gxx ?).
2. 2 add-on lenses determined with the trial box. Code (BV20.Axx ?)

• Option: 2 pre-calibrated ophthalmic lenses to be edged to 21mm.

• Or simply mark the near-vision optical centre on the spectacles and LESA FRANCE takes care of everything..............Code BV20.MONT

• Simple, isn't it?........

How do you choose the telescope magnification?

• Look at the table above.

1. Suppose the patient achieves useful acuity with a 1.8x Galilean and a 12D add-on lens: the working distance is 8cm.
2. With a 2.1x telescope, the working distance increases from 8cm to 10cm for the same magnification (±≈).
3. With a 2.5x telescope, the working distance increases from 8cm to 12cm for the same magnification (±≈).