The patented Welch Allyn Coaxial Vision System facilitates ophthalmoscopy by enabling easier entry into the eye, a larger field of view, and reduced glare compared to standard ophthalmoscopes.

Welch Allyn website for more information on the 3.5V Coaxial Ophthalmoscope:
https://www.welchallyn.com/en/products/categories/physical-exam/eye-exam/ophthalmoscopes--traditional-direct/35v_coaxial_ophthalmoscope.html