The Competency of Pars Plana Vitrectomy Incisions: A Comparative Histologic and Spectrophotometric Analysis
Accepted 18 August 2008. published online 23 October 2008.
Purpose
To compare the relative competency of pars plana vitrectomy (PPV) sclerotomies.
Design
Laboratory investigation.
Methods
PPV was performed in human cadaveric eyes using 20-gauge (20 G), 23-gauge (23 G), and 25-gauge (25 G) instrumentation. India ink was applied over a sclerotomy site while the intraocular pressure was varied. The presence of India ink particles (IIPs) along incisions was evaluated by histologic analysis. Spectrophotometric absorbance levels of vitreous aspirates were measured.
Results
PPV was performed in a control eye and two eyes, each using standard 20 G, standard 23 G, perpendicular 25 G, and beveled 25 G instrumentation incisions. IIPs were not detected in the 20 G incisions either on histology or by spectrophotometry. IIPs were detected along the entire incision length in one of two eyes with 23 G sclerotomies and confirmed by spectrophotometry. IIPs were detected along the entire incision length in one of two eyes with 25 G perpendicular sclerotomies and confirmed by spectrophotometry in both eyes. IIPs were noted partially along the length in one of the two beveled 25 G eyes, but not detected in either eye by spectrophotometry.
Conclusions
During the early postoperative period, sutureless vitrectomy incisions may allow entry of ocular surface fluid. These findings may provide a pathophysiologic mechanism for the reported increased risk of endophthalmitis in small-gauge vitrectomy surgery.
aRetina Service, Wills Eye Institute, Thomas Jefferson University, Philadelphia, Pennsylvania
bPathology Department, Wills Eye Institute, Thomas Jefferson University, Philadelphia, Pennsylvania
cDepartment of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania
Inquiries to Joseph I. Maguire, The Retina Service of Wills Eye Institute, Thomas Jefferson University, 840 Walnut Street, Suite 1020, Philadelphia, PA 19107
ABSTRACT