Abstract
Purpose: :
To compare postoperative intraocular pressure (IOP) fluctuation after pars plana vitrectomy with 25-gauge (Ga) oblique transconjunctival incision versus 25-Ga or 20-Ga straight (perpendicular) incision.
Methods: :
A retrospective, consecutive, interventional case series was designed to evaluate all consecutive eyes that underwent surgical repair for stage II, III, or IV full-thickness macular hole with standard 3-port pars plana vitrectomy. The study only enrolled eyes that met the criteria of anatomically successful macular hole repair, as determined by optical coherence tomography (OCT), without any documented intraoperative complications. All eyes were required to have a minimum follow-up period of 3 months with documented IOP measurements at each postoperative follow-up visit (day 1, week 1, month 1, and month 3).
Results: :
A total of 155 eyes operated from January 2004 to December 2008 were enrolled. Forty-nine eyes received 20-Ga straight (perpendicular) incisions (Group A), 45 eyes received 25-Ga straight incisions (Group B), and 61 eyes received 25-Ga oblique incisions (Group C) during pars plana vitrectomy. Mean postoperative IOP fluctuation was significantly greater in Group A versus Group B (13.2 ± 8.0 to 10.3 ± 7.5 mmHg, p = 0.035), and Group A versus Group C (13.2 ± 8.0 to 8.4 ± 6.6, p < 0.01). Mean IOP fluctuation was greater in Group B than Group C, but this did not reach statistical significance. Mean postoperative IOP at all four follow-up periods was significantly higher in Group A versus each 25-Ga group (Group B and Group C). There was no statistically significant difference in mean IOP at any follow-up period between Group B and Group C. In Group B, 48.9% of eyes required starting new topical IOP-lowering medications for IOP spikes (IOP ≥ 25 mmHg), versus only 27.9% of eyes in Group C (p = 0.027). Two eyes developed episodes of hypotony (IOP ≤ 5 mmHg) in Group B (4.4%), versus no hypotony reported in Group C.
Conclusions: :
Straight and oblique 25-Ga incisions resulted in lower mean IOP and less IOP fluctuation than traditional straight 20-Ga incisions after macular hole repair with pars plana vitrectomy. Oblique 25-Ga incisions resulted in similar postoperative IOP as straight 25-Ga incisions. However, among the 25-Ga groups, oblique incisions resulted in fewer eyes requiring the addition of IOP-lowering medications and fewer episodes of postoperative hypotony than straight incisions.
Keywords: vitreoretinal surgery • macular holes • intraocular pressure