Surgically induced astigmatism is an unwanted variable that can lead to poorer visual and refractive outcomes in patients undergoing vitrectomy. The study evaluates the changes in regular corneal astigmatism after transconjunctival sutureless vitrectomy (25-gauge or 23-gauge) and 20-gauge conventional vitrec tomy.


The study is a retrospective comparative case series of vitrectomies performed by two surgeon. There were a total of 43 patients, 18 who underwent the 20 gauge, and 25 who had the small gauge procedure (7 eyes receiving 23-gauge and 18 eyes receiving 25-gauge). Inclusion criteria were that patients only received pars plana vitrectomy, no previous ophthalmic surgical treatment within 1 year. Patients were excluded for combine surgery with cataract extraction, large variation of five refractive value, any identified corneal pathology/opacity and/or conjunctival disease and/or eyelid disease, previous refractive surgery, previous ocular traumas and any other new onset ocular pathology during a 6 month-follow-up. Refraction powers were obtained by auto-refractors (Auto-refractor Topcon RM-8800) preoperatively, 1 month, 3 months, and 6 months postoperatively.


The absolute values of change differences in astigmatism power and axis were analyzed. Statistically significant difference were observed in the change of corneal astigmatism power in post-operative 1 month follow-up measurement (p < 0.001, Wilcoxon Rank Sum test, W RST), whereas no statistically significant difference in axis change(P=0.46,WRST). There is no statistically significant difference in change of corneal astigmatism power and axis in post-operative 3 (P=0.79,WRST) or 6 months(P=0.73,WRST) follow-up measurement. There is no statistically significant difference in surgical outcomes (improvement of vision, P=0.72,WRST, and change of intraocular pressure, P=0.78,WRST) and incidence of postoperative complications.


Small gauge transconjunctival sutureless vitrectomy induces less change and exerts little influence on astigmatism compare with 20-gauge vitrectomy in the post-operative 1 month measurement. However, this difference of changes in astigmatism between the two groups is no longer statistically significant after 3 months.

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