Vol.13
No. 1, October 2003
MANAGING ASTIGMATISM
IN PHACOEMULSIFICATION
Dr.
S.V. Singh, Dr. Ved Pal, Dr. C. S. Dhull
INTRODUCTION
Surgically
induced astigmatism remains a concern in every cataract
surgery even after present day of phacoemulsification.
The factor affecting the amount of postoperative astigmatism
include incision size, type, site and preexisting astigmatism.
In patients having no astigmatism, one should plan
astigmatically neutral incision and in those having
preoperative astigmatism one should plan astigmatically
beneficial incision. We have carried out this study to
know benefits of location of incision in correcting
preoperative astigmatism in patients undergoing
phacoemulsification through clear corneal 3.2 mm incision with
foldable PCIOL implantation.
MATERIAL
AND METHODS
Present
study included 100 patients with immature senile cataract
undergoing phacoemulsification with foldable PCIOL
implantation. Patients having previous history of
intraocular surgery, trauma and collagen vascular disease were
not included in this study. Thorough preoperative
examination including slit lamp examination, fundus
examination and BCVA was done.
Preoperative
keratometry was done and corneal astigmatism was recorded.
All surgeries were done by same surgeon.
Phacoemulsification was done through 3.2 mm clear corneal
incision which was placed on steepest corneal meridian.
In eyes having no astigmatism incision was placed
superotemprally. Follow up was done at 1 week.
Postoperative keratometry was done and astigmatism was
recorded by simple subtraction method.
OBSERVATIONS
Mean
age of patients was 62±6.75 years. There were 56 males
and 44 females. 30 eyes had w-t-r astigmatism. 42%
patients had a-t-r and 2% had oblique astigmatism. Rest
26% patients had no astigmatism. Mean keratometric
astigmatism was 0.84±1.24D ( range 0.25D to 3.75D) by simple
subtraction technique.
At
first week follow up, mean keratometric astigmatism was 0.42±1.04D.
In most of the patients flattening of the meridian of incision
was noticed. At 6 weeks, this flattening further
increased and mean astigmatism was 0.22±1.02D. A mean
reduction of 1.25±0.52 from preoperative stage was noticed.
62% patients had no keratometric astigmatism now. 15
patients had a-t-r and 13 had w-t-r astigmatism.
DISCUSSION
Surgically
induced astigmatism is of great concern in present era of
astigmatism free cataract surgery. When the incision is
given in the clear cornea and left unsutured, it has a
relaxing effect on the meridian in which it has been given.1
To reduce preoperative astigmatism of 0.5D to 1.25D a clear
corneal 3.2 mm incision should given in the steepest corneal
meridian.2 We have observed the same results
in our study. Thus postoperative corneal astigmatism can
be significantly reduced if incision is placed on the steepest
meridian.
REFERENCES
-
Roman
S, Ullern M. Astigmatism caused by superior and
temporal corneal incisions in cataract surgery. J Fr
Ophthalmol 1997; 20(4): 277-83.
-
Matsumoto
Y, Hara T, Chiba K, Chikuda M. Optimal incision sites to
obtain an astigmatism free cornea after cataract surgery
with a 3.2 mm sutureless incision. J Cataract Refract Surg
2001; 27(10): 1615-9.
Department
of Ophthalmology,
Post Graduate
Institute of Medical Sciences, Rohtak
