This paper outlines the problems of photocoagulating the extreme fundus periphery. It describes two new contact lenses which permit precise visualization for examination, photography, and photocoagulation of the extreme periphery. They can also be used for examination and photography of the anterior chamber angle. Photographs of the peripheral fundus, the ciliary body, and the anterior chamber angle are taken through the new contact lenses with a hand fundus camera (Kowa).
Lee P, Pomerantzeff O, Schepens CL. New Contact Lens for Peripheral Fundus Examination and Photocoagulation. Arch Ophthalmol. 1970;84(5):650-654. doi:10.1001/archopht.1970.00990040652019