S. Rauz et al., VARIATION IN ASTIGMATISM FOLLOWING THE SINGLE-STEP, SELF-SEALING CLEAR CORNEAL SECTION FOR PHACOEMULSIFICATION, Eye, 11, 1997, pp. 656-660
Purpose: A single-step, self-sealing, 3.2 mm clear corneal section is
described and the incidence and variation of surgically induced astigm
atism following phacoemulsification over a period of 3 months is deter
mined. Methods: Twenty-two patients who underwent uncomplicated 3.2 mm
clear corneal phacoemulsification with foldable Allergan silicone int
raocular lens implantation were autorefracted pre-operatively and on d
ay 1, week 1, week 6 and at 3 months. The variation in induced astigma
tism was analysed using the subtraction method and vector analysis. Th
e change in direction of the cylindrical axis was examined. Results: T
he induced astigmatism represented by the total vector on day 1 was 1.
17 D and vector decomposition ratio, ATR:WTR (against-the-rule:with-th
e-rule), was 21.05:78.95. The total vector increased by 0.5 D in the f
irst week and then stabilised. Vector decomposition showed an against-
the-rule astigmatic drift so that by 3 months the ATR:WTR was 40.49:59
.91. There was a tendency of the axis of the negative cylinder to swin
g towards the corneal section meridian on day 1 and to oscillate aroun
d that meridian at week 1 and week 6. By 3 months the direction revert
ed to that pre-operatively, in most cases. Conclusions: The single-ste
p, self-sealing clear corneal section is mechanically stable and, thou
gh there is some variability in the measured astigmatism, there is an
acceptable functional result throughout the post-operative period.