Aim: To evaluate & compare the surgically induced astigmatism (SIA) in superior & supero-temporal scleral incision in small incision cataract surgery.

Methods: This is a prospective comparative study done on a total number of 400 patients with senile cataract. 200 cases were randomly assigned superior scleral group & other 200 cases were allotted to supero-temporal scleral incision. Small incision cataract surgery with posterior chamber intraocular lens implantation were performed. Patients were examined post operatively 1^stday, 1^stweeks, 6^th weeks & 12 weeks. Postoperative best-corrected visual acuity & astigmatism measured.

Results: The mean surgically induced astigmatism (SIA) in superior scleral incision is 1.35± 0.44, in super temporal group is 0.95± 0.44. In superior group mostly “against the rule astigmatism” & in supero-temporal group it is “with the rule astigmatism”.

Conclusion: Supero-temporal small incision cataract surgery associated with modest astigmatism & with the rule astigmatism contrary to superior group (against the rule astigmatism), earlier stabilization of refraction, better visual acuity.

Keywords: Astigmatism, superior incision (SI), supero-temporal incision (STI), small incision cataract surgery (SICS), With The Rule Astigmatism (WTR), Against The Rule Astigmatism (ATR), Surgically Induced Astigmatism (SIA), Visual Acuity (VA), No Astigmatism (NA).

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2. Merriam JC, Zheng L, Merriam JE, Zaider M, Lindstrom B. The effect of incisions for cataract on corneal curvature. Ophthalmology. 2003 sep; 110(9): 1807-13.
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6. Burgansky Z, Isakov I, Avizemer H, Bartov E. Minimal astigmatism after sutureless, planned extracapsular cataract extraction. J Cataract Refract Surg2002; 28:499-503.
7. Merriam JC, Zheng L, Urbanowicz J, Zaider M. Change on the horizontal & vertical meridians of the cornea after cataract surgery. Trans Am Ophthalmol Soc.2001;99:187-95.
8. Kimura H, Kuroda S, Mizoguchi N, Terauchi H, Matsumura M, Nagata M. Extracapsular cataract extraction with a sutureless incision for dense cataracts. J Cataract Refract Surg 1999; 25:1275-9.
9. Gokhale NS, Sawhney S. Reduction in the astigmatism in manual small incision cataract surgery through change of incision site. Indian Journal of Ophthalmology; sept 2005;3:201.
10. Miller SJ, Parson’s Diseases of Eye, Edinburgh: Butterworth Heinmann International Edition, 18^th edition 1990; 63-69.
11. Merriam JC, Zheng L, Merriam JE, Zaider M, Lindstrom B. The effect of incisions for cataract on corneal curvature. Ophthalmology. 2003 sep; 110(9): 1807-13.
12. Koch PS. The structural analysis of cataract incision construction. J Cataract Refract Surg1991; 17(suppl): 661-67.
13. Armeniades CD, Boriek A, Knodle GE Jr. Effect of incision length, location, & shape on local corneoscleral deformation during cataract surgery. J Cataract Refract Surg, 1990; 16(1): 83-87.
14. Holladay JT, Dudeja DR, Koch DD. Evaluating & reporting astigmatism for individual & aggregate Data. J Cataract Refract Surg 1998;24:57-65 (PUBMED).
15. Burgansky Z, Isakov I, Avizemer H, Bartov E. Minimal astigmatism after sutureless, planned extracapsular cataract extraction. J Cataract Refract Surg2002; 28:499-503.
16. Merriam JC, Zheng L, Urbanowicz J, Zaider M. Change on the horizontal & vertical meridians of the cornea after cataract surgery. Trans Am Ophthalmol Soc.2001;99:187-95.
17. Kimura H, Kuroda S, Mizoguchi N, Terauchi H, Matsumura M, Nagata M. Extracapsular cataract extraction with a sutureless incision for dense cataracts. J Cataract Refract Surg 1999; 25:1275-9.
18. Gokhale NS, Sawhney S. Reduction in the astigmatism in manual small incision cataract surgery through change of incision site. Indian Journal of Ophthalmology; sept 2005;3:201.

Dr Suresh Chandra Swain, MS

Associate Professor of Ophthalmology, S.C.B. Medical College, Cuttack, Odisha