• The effects of an incision through the pars plana ciliaris for open-sky subtotal vitrectomy were evaluated in four groups of monkeys, with incisions ranging from 170° to 240°. The nasal long ciliary artery and nerve and the anterior ciliary arteries from the inferior and medial recti were left intact in all cases. Follow-up observation ranging from three to 24 months indicates that the 170° incision and the longer incisions in which the temporal ciliary artery and nerve were sacrificed do not cause severe anterior segment necrosis. The advantages of the incision through the pars plana ciliaris are (1) easier approach to the vitreous cavity, (2) preservation of the crystalline lens and an intact iris, and (3) circumvention of the corneal and chamber angle complications sometimes associated with the transcorneal approach.
Liu H, Tolentino FI, Schepens CL, Freeman HM. Experimental Vitreous SurgeryXIII. Open-Sky Partial Vitrectomy Through Pars Plana Incision. Arch Ophthalmol. 1975;93(10):1023-1029. doi:10.1001/archopht.1975.01010020801013