Vol.14
No. 1, Januray, 2004
SICS An
Alternative to Phaco
RC Nagpal, Manisha Rathi, Sumit Sachdeva
INTRODUCTION
Modern cataract surgery, in which the cataract is actually
extracted from the eye, was introduced by Jacques Daviel in
Paris in 1748. Daviel advocated a form of extracapsular
surgery in which the inner lens contents were removed from the
eye, but a portion of the lens capsule or outer covering and
the zonules that attached to it were left in place.
Samuel Sharp of London introduced the concept of intracapsular
cataract surgery in 1753 by using pressure with his thumb to
remove the entire lens intact through an incision. Small
suction cups (erysiphakes) were introduced for this purpose in
1902 as well as various capsular forceps to grasp the lens for
removal.1
The techniques
and materials historically developed for cataract surgery, in
particular the rapid improvements of recent decades, have made
possible the miracle of modern cataract surgery. Today,
patients can have their cataracts safely removed as an
outpatient procedure, under local anesthesia, with the
implantation of a sophisticated intraocular lens calculated to
correct their vision, and can resume their normal activities
in a matter of days.1
While the
conventional cataract surgery had disadvantages like large
incision, multiple sutures, and induced astigmatism, newer
techniques like phacoemulsification and small incision
cataract surgery come into vogue. The scleral tunnel
incision was introduced in early eighties in an attempt to
provide better wound healing with less surgically induced
astigmatism. This has become the most favoured incision
technique in the recent past for suture less, small incision,
non-phaco cataract surgery. Although the length of external
incision in this techniques varies from 5mm to 7mm, it is
still called small incision cataract surgery (SICS) since the
architectural design of SICS renders a suture less, self
sealing property to this incision. The incision of ECCE
in contrast to SICS is approximately 12mm at the posterior
limbus and requires a number of sclerocorneal stitches.2
Surgery has
evolved from being just a small incision technique for
cataract extraction to being a sutureless way of ending the
procedure, thereby causing minimal distortion to the corneal
curvature. So, all the vital parameters that go into the
creation of a reproducible, leak proof and atigmatically
neutral incision have assumed great importance today.2
METHODS
This study is a retrospective review of 120 cases operated by
a single surgeon. All the patients had immature senile
cataract and underwent Manual SICS through superior scleral
tunnel incision. The group was followed up for a period
of two months. The surgery was evaluated in terms of
ease of operation, per-operative and post-operative
complications, visual outcome, and astigmatism.
SURGICAL
TECHNIQUE
Under full asepsis, peribulbar anaesthesia was given. A
superior rectus bridle suture and an eye speculum was applied.
A fornix based conjunctival flap was raised. A 5.5 mm
frown shaped incision was made and scleral tunnel was made
superiorly was to help of a crescent knife. The anterior
chamber was entered with a 3 mm keratome, and formed with
sterile air. 2 drops of trypan blue dye was instilled
under the air bubble in the chamber to stain the anterior
capsule. The dye and the air were washed out and the
chamber formed with 2% methylcellulose. Continuous
curvilinear capsulorrhexis was formed using a 30 G bent
needle and hydrodissection and hydrodelineation was done.
The nucleus was rotated and prolapsed into the anterior
chamber, and then delivered using an irrigating wire vectis (viscoexpression).
The remaining cortical matter was aspirated using a 2-way
I&A cannula. A rigid PCIOL was implanted in the
capsular bag. Conjunctiva was reposited back and wet
field cautery done to anchor it in its position.
POSTOPERATIVE
EVALUATION
Post operative evaluation was done at 1 day, 1 week, 4 weeks
and 8 weeks and included a detailed examination including
vision. keratometry, slit lamp biomicroscopy, and intraocular
pressure mesurement.
The cylinder
was taken to be the difference of vertical and horizontal
K-readings (pre-operative and post- operative) was calculated,
and the axis was of the higher K-reading. This was then
converted to Cartesian coordinates using the following formula3.
x=
Cylinder*cos(2*axis)
y=
Cylinder*sine(2*axis)
Pre-operative
Cartesian coordinates were subtracted from the post operative
values, and this difference was taken as X and Y respectively.
To convert the Cartesian coordinates back to standard polar
notation for astigmatism, we used the following formula:
Cylinder = Ö
X2 + Y2
Angle=1/2* Arc tan (Y/X)
If X & Y>0, then axis =
angle
If X<O, then axis=angle+90o
If X>O & Y<O, then
axis = angle + 180o
RESULT AND DISCUSSION
The data was analyzed and it was observed that out of 120
patients who were taken up for this study, 70 patients had
against the rule astigmatism of 1.57D, and 50 patients had
with a rule astigmatism of 1.25 D at the end of 2 months.
There was no significant per-operative complication. In
3 patients, premature entry into the anterior chamber occurred
while forming the tunnel, and in one patient there occurred a
rent in the posterior capsule. Post operatively, striate
keratitis was observed in 25% patients, which resolved within
1-2 days. Most of the patients (98.3%) had a
post-operative visual acuity from 6/12 to 6/6.
CONCLUSION
We have found that the Manual SICS is a very safe, effective
and economical alternative to phacoemulsification with
comparative results in terms of visual acuity, astigmatism,
and wound stability, without having the inherent drawbacks of
the latter, namely, high cost of surgery, relatively lesser
margin of safety, and a steep learning curve.
REFERENCES
-
Cataract
surgery in modern era [online]] [cited September 4].
Available from: URL: http://www.eyecareamerica.org/eyecare/museum/exhibits/online/cataract/modern.cfm
-
Kamaljeet
Singh. History of cataract surgery, Surgical aspects Un
Small incision cataract surgery (Manual Phaco) 1sted.,
Jaypee Brothers, 2002, 4-8, 75-83.
-
Holladay
JT, Dudeja Dr. Koch DO. Evaluating and reporting
astigmatism for individual and aggregate data. J cataract
refract Surg 1998;24: 57-65.
Address
for Correspondence
Dr. R.C. Nagpal, Deptt. of Ophthalmology,
Pt. BD Sharma, PGIMS, Rohtak.
