A procedure is described for open-sky vitrectomy through a 170°pars plana incision. This approach permits direct visualization of the vitreous cavity and about 75% of the total fundus. It allows a more direct access to the vitreous cavity, greater surgical precision, and affords better protection to the anterior segment than the transcorneal approach. Experimental results in monkey eyes indicate that open-sky surgery through such a large incision is clinically feasible. It may be considered as an alternative procedure when extensive removal of diseased vitreous is indicated, either independently or as an adjunct to retinal surgery.
Lee P, Constable IJ, Hamada S, Schepens CL. Experimental Vitreous Surgery in MonkeysIX. Pars Plana Approach in Open-Sky Techinque. Arch Ophthalmol. 1974;92(2):139-141. doi:10.1001/archopht.1974.01010010145013