The relation between superior phacoemulsification incision and steep axis on astigmatic outcomes

Abstract

To evaluate the relation between superior phacoemulsification incision and different steep axis on astigmatism outcomes. This prospective, randomized study comprised three groups each with 24 eyes with age-related cataracts and underwent 3.0 mm superior clear corneal incision (CCI). The three groups of the patients were divided by the location of the steep axis. The steep axis was between 0 and 30° in group 1, 31-60° in group 2, 61-90° in group 3. The degree was accepted as the distance from the steep axis to the distal aspect of the wound. Outcome measures were including the changes in mean total astigmatism, surgically-induced astigmatism (SIA), axis deviation, uncorrected visual acuity (UCVA), and best corrected visual acuity (BCVA). Astigmatism was measured by manuel keratometry readings before surgery and day-1, week-1, week-2, week-4 and week-8 postoperatively. The surgically-induced astigmatism was calculated by the vector analysis using the Holladay-Cravy-Koch method. The magnitude of mean total astigmatism was lowest in group 1 and highest in group 3 at 8th week. Surgically-induced astigmatism was 0.52 diopter (D), 0.88 D, 1.03 D in group 1, group 2, and group 3 respectively. The change in SIA was significant in group 1 (P < 0.05). The change in the astigmatic axis deviation was highest in group 1 (31.5 ± 31.3, P < 0.05). The mean UCVA and BCVA were not significant pre and postoperatively between groups (P > 0.05). Axis deviation and SIA were stable after the week-1 and week-2 examinations respectively. Cataract surgery with CCI on or near the steep axis is resulted in decreased SIA and increased axis deviation.