The is an ideal lens for doctors who regularly cater to populations prone to glaucoma and other posterior pole abnormalities. The double aspheric design and field of view offered by a 78D offers clear and large views of the central mid-retinal regions. This lens offers a high magnification without cutting down too drastically on the field of view. This lens is a popular choice as a general diagnosis lens among doctors who prefer a larger ring size than the more common and smaller profile of the 90D. Dilation is required to obtain optimum retinal imaging with the 78D. Field of View – 81? / 97? Image Magnification – 0.93x Laser Spot Magnification – 1.08x Working Distance – 08 mm