International Journal of Ophthalmology (Jun 2015)

Surgical induced astigmatism correlated with corneal pachymetry and intraocular pressure:transconjunctival sutureless 23-gauge versus 20-gauge sutured vitrectomy in diabetes mellitus

  • Yan Shao,
  • Li-Jie Dong,
  • Yan Zhang,
  • Rayaz A Malik,
  • Bo-Jie Hu,
  • Ju-Ping Liu,
  • Xiao-Rong Li

DOI
https://doi.org/10.3980/j.issn.2222-3959.2015.03.16
Journal volume & issue
Vol. 8, no. 3
pp. 528 – 533

Abstract

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AIM: To determine the difference of surgical induced astigmatism between conventional 20-gauge sutured vitrectomy and 23-gauge transconjunctival sutureless vitrectomy, and the influence of corneal pachymetry and intraocular pressure (IOP) on surgical induced astigmatism in diabetic patients.METHODS:This retrospective, consecutive case series consisted of 40 eyes of 38 diabetic subjects who underwent either 20-gauge or 23-gauge vitrectomy. The corneal curvature and thickness were measured with Scheimpflug imaging before surgery and 1wk; 1, 3mo after surgery. We compared the surgical induced astigmatism (SIA) on the true net power in 23-gauge group with that in 20-gauge group. We determined the correlation between corneal thickness change ratio, IOP and SIA measured by Pentacam.RESULTS: The mean SIAs were 1.082±0.085 D (mean±SEM), 0.689±0.070 D and 0.459±0.063 D at postoperative 1wk; 1, 3mo respectively in diabetic subjects. The vitrectomy induced astigmatisms were declined significantly with time (F2,36=33.629, P=0.000) postoperatively. The 23-gauge surgery group induced significantly less astigmatism than 20-gauge surgery group (F1,37=11.046, P=0.020). Corneal thickness in diabetes elevated after surgery (F3,78=10.532, P=0.000). The linear regression analysis at postoperatively 1wk went as:SIA=-4.519+4.931 change ratio (Port3) +0.026 IOP (R2=0.46, P=0.000), whereas the rate of corneal thickness change and IOP showed no correlation with the change of astigmatism at postoperatively 1 and 3mo.CONCLUSION: There are significant serial changes in both 20-gauge and 23-gauge group in diabetic subjects. 23-gauge induce less astigmatism than 20-gauge and become stable more rapidly than 20-gauge. The elevation of corneal thickness and IOP was associated with increased astigmatim at the early postoperative stage both in 23-gauge and 20-gauge surgery group.

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