Induced astigmatism after cataract surgery - a retrospective analysis of cases from the University of Port Harcourt Teaching Hospital, Nigeria

Abstract

Visual rehabilitation after cataract surgery may often be disappointing due to induction of corneal astigmatism following issues in realigning, point to point, the corneal wound margin in the process of surgery despite biometry and use of the appropriateintraocular lens. The purpose of this study is to determine the amount of surgically induced astigmatism after sutured cataract extraction-extracapsular cataract extraction (ECCE) and intracapsular cataract extraction (ICCE) and intraocular lens (IOL)implantation in the University of Port Harcourt Teaching Hospital, Port Harcourt, Nigeria. Folders of all cataract patients operated on in the eye theatre of the aforenamed tertiary facility between2002 and 2006 were considered.  Relevant patient details and intraoperative and postoperative management were examined and reported upon. One hundred and fourteen eyes (114) of one hundred patients who had cataract surgeries done within the five-year period of this study were examined. ECCE + IOL implantation were examined in the period under review. The post-operative refraction objectively and subjectively was retrieved from the records of each patient. The post-operative cylinderpower (total astigmatism) was recorded.Of 114 eyes, only 83 eyes (72.8%) had refraction results postoperatively due to loss of fol-low-up. The total number with astigmatism was 57(68.7%). Forty-two had against-the-rule (73.7%), twelve (21.1%) with-the-rule, while five (0.09%) were oblique. The mean post-operative astigmatism was 1.85 D. The surgically induced corneal astigmatism was highest with ECCE with PCIOL. Astigmatism less than 2 D was highest in this group (ECCE with IOL) while ICCE with ACIOL had the highest number with astigmatism in the range between 2 D and 4 D. The total astigmatism which was mainly with-the-rule (vertical plus cylinder) did not seem to impair severely the post-operative visual acuity of the patients.In conclusion, surgically induced astigmatism affected almost 75% of the patients operated and refracted within the period under review. This can be reduced with better operating skills using small incision suture-less techniques. Existing postoperative astigmatism can be reduced by suture cutting at specific periods particularly if there is follow-up at the critical periods. (S Afr Optom 2011 70(2)75-80)