The Diamond 20D Aspehric Lens features 3.13x magnification with a 46 degree field of view. 
 
The lens is made of high quality optical glass and is finished with a professional anti-reflection coating. 
 
As an aspherical indirect diagnostic lens with a wide angle, it can be used with a slit lamp or binocular ophthalmoscope to diagnose the rear and bottom of the eye's vitreous body. 
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When used with a slit lamp or ophthalmoscope the retina, nerve fibre, optic disc, macula and capillary vessel can be observed easily with a wide field of view.