Journal List > J Korean Ophthalmol Soc > v.50(3) > 1008491

J Korean Ophthalmol Soc. 2009 Mar;50(3):353-358. Korean.
Published online March 18, 2009.
Copyright © 2009 The Korean Ophthalmological Society
Comparisons of Corneal Topographic Change Between 20-Gauge and 23-Gauge Pars Plana Vitrectomy
Young Min Park, MD, Ji Eun Lee, MD and Boo Sup Oum, MD
Department of Ophthalmology, College of Medicine, Pusan National University, Pusan, Korea.

Address reprint requests to Boo Sup Oum, MD. Department of Ophthalmology, Pusan National University Hospital #10 1ga Ami-dong, Seo-gu, Pusan 602-739, Korea. Tel: 82-51-240-7326, Fax: 82-51-242-7341, Email:
Received June 05, 2008; Accepted November 04, 2008.



To compare the changes in corneal topography between 23 gauge (G) pars plana vitrectomy (PPV) and 20 G PPV.


Forty-three eyes of 42 patients who underwent PPV were divided into 2 groups: 20G PPV (Group I, n=18) and 23 G PPV (Group II, n=25). Both groups were followed up over 3 months postoperatively. ORBSCAN II was performed to compare the corneal topographic change of 20 G PPV and 23 G PPV.


In a 5 mm zone, significant postoperative change in the mean corneal surface cylinder was found between the 1st day and the 1st month in Group I, while no significant change was found in Group II. Postoperatively, the increase in the mean corneal surface cylinder in Group I was significantly higher than in Group II between the 1st day and the 1st month. Clinically significant astigmatism, induced by surgery, was found only in Group I one week after the operation. In a 3 mm zone, there was no significant change in the mean corneal surface cylinder in both groups postoperatively. The difference in the mean corneal surface cylinder between the 2 groups at the postoperative periods showed no significant change. Surgically induced astigmatism was significantly higher in Group I than in Group II between the 1st day and the 1st month postoperatively.


PPV with the 23 G system is a sutureless transconjunctival surgery, which appears to be more effective due to insignificant corneal surface and astigmatic changes in the early postoperative period.

Keywords: Corneal topography; Vector analysis; 23 G Vitrectomy


Figure 1
Changes in mean astigmatism (in 5-mm zone) after 20-gauge and 23-gauge pars plana vitrectomy.

*Statistically significant change between preoperative and each postoperative periods; Statistically significant change between Group I and Group II at each time interval.

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Figure 2
Changes in mean astigmatism (in 3-mm zone) after 20-gauge and 23-gauge pars plana vitrectomy. Significant changes of mean astigmatism were not found in both groups postoperatively.
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Table 1
Methods of surgery
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Table 2
Changes of mean corneal power
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Table 3
Changes of anterior chamber depth
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Table 4
Surgically induced astigmatism after 20-gauge and 23-gauge pars plana vitrectomy in 5-mm zone
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