68 lenses in single-diopter steps for precise resolution (+38 to -30)
Coaxial optics produce a shadow-free spot, easier entry into undilated pupils, and a larger field of view versus standard ophthalmoscopes
18 aperture/filter combinations for greater versatility: micro, small, and large spot sizes, cobalt blue filter for corneal exams, fixation target, or slit aperture can be combined with red-free filter, polarizing filter, or unfiltered Halogen HPX illumination