Published: 2017-01-17

Comparison of surgically induced astigmatism in corneo-scleral and clear corneal incision in phacoemulsification

Latha N.V, Risha Ravindran, Asha A.V, Twinkle Ann George


Background: The objective of the study was to determine and compare the surgically induced astigmatism in patients who have undergone phacoemulsification with clear corneal and corneoscleral incisions made superiorly and temporally.

Methods: Study was conducted in 100 patients who underwent cataract surgery from a period of November 2012 to July 2014. They were evaluated pre and post-operatively. Pre-op and Post-op Vision, retinoscopy and keratometry were analysed and surgically induced astigmatism was calculated using Vector method.

Results: Surgically induced astigmatism calculated with SIA Calculator using Holladay’s method was as follows; Superior corneoscleral 0.79 D,  Temporal corneoscleral  0.52 D, Superior clear corneal 0.60 D, Temporal clear corneal 0.73 D. A higher incidence of against the rule astigmatism was seen pre-operatively (45%) and post-operatively (42%).

Conclusions: From our study, we have concluded that no significant difference was seen in the surgically induced astigmatism following phacoemulsification in all four incisions though the least SIA value was obtained with Temporal corneo-scleral. To conclude, temporal corneo-scleral incisions being farther away from the visual axis has minimal effect on the corneal curvature with near astigmatic neutrality. 



Surgically induced astigmatism, Clear corneal incision, Corneo-scleral incision, Keratometry

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