Comparison of Surgically Induced Astigmatism and Visual Outcome Following Manual Small-incision Cataract Surgery 6.5 mm and Phacoemulsification 3.2 mm Corneal Wound - การเปรียบเทียบสายตาเอียงที่เกิดจากการผ่าตัดและสายตาหลังผ่าตัด ระหว่างการผ่าตัด ต้อกระจกแผลเล็กและการสลายต้อกระจก

Abstract

             The objective of the restrospective analytic study was to compare surgical induced astigmatism  and visual outcome of Manual Small Incision Cataract Surgery (MSICS), with that of Phacoemulsification and to determine the appropriate width of corneal wound for bisected lens nuclear fragment removal in MSICS. Samples were patients who underwent cataract surgery as recorded during October 2006 - December 2006. Keratometry and visual acuity were performed pre-operatively and at 1, 4, 8, 12 weeks postoperatively. Surgically induced astigmatism was calculated. The distribution of number of eyes of each post operative visual acuity value in both groups were compared by chi-square. Width of corneal wound and difficulty in nuclear fragment removal were analysed. Cataract surgery was done in 116 eyes, 70 eyes underwent MSICS through 6.5 mm corneal wound with 5.5 mm non-foldable intraocular lens, and 46 eyes underwent phacoemulsification through 3.2 mm corneal wound with foldable intraocular lens. Surgical induced corneal astigmatism in MSICS and phacoemulsification were between 0.00 to -1.75 diopter (mode-1.25 D.) and +0.25 to - 0.50 diopter (mode 0.00 D.) respectively. The post operative visual acuity was not defferent in both groups (p >0.05). Uncorrected and best corrected visual acuity equal to or better than 6/18 were 81 percent and 94 percent respectively in the MSICS group. The appropriate width of clear corneal wound to remove bisected nuclear fragment in MSICS was 6.0-6.5 mm (87% of eyes). No serious complications was found in this study. The MSICS had more surgical induced astigmatism than phacoemulsification. Its visual result was comparable with that of phacoemulsification. The appropriate width of corneal wound for bisected lens nuclear fragment removal in MSICS was 6.0-6.5 mm.

Key words: MSICS, surgical induced astigmatism, phacoemulsification