This study compared surgically induced astigmatism (SIA) following small incision cataract surgery using superior, supero-temporal, and temporal incisions. 150 eyes were randomly assigned to undergo surgery with one of the three incision types. Post-operative astigmatism and SIA were significantly lower in the supero-temporal and temporal groups compared to the superior group at 1 day, 7 days, and 45 days post-op. The supero-temporal and temporal approaches also resulted in better best corrected visual acuity compared to the superior approach. The study concludes that temporal and supero-temporal incisions provide better visual outcomes due to less induced astigmatism than superior incisions for small

1. A COMPARATIVE STUDY OF SURGICALLY
INDUCED ASTIGMATISM IN SUPERIOR,
SUPERO-TEMPORAL AND TEMPORAL
INCISION IN SMALL INCISION CATARACT
SURGERY IN A RURAL HOSPITAL
Presented by: Co-author:
Dr Madhumita Prasad Dr Sachin Daigavane

2. INTRODUCTION
• Cataract is the main and biggest cause of curable blindness in
India and worldwide. The annual incidence of cataract in India
has been estimated to be 3.8 million[1] and 1.8 million sight-
restoring operations are performed every year.[2]
• Cataract surgery has become one of the most common and
successful procedures in ophthalmology.
• Small incision manual extracapsular techniques (SICS) - the
first choice alternative to phacoemulsification as it retains
most of the advantages of "phaco" giving visual results
equivalent to phacoemulsification at lower cost.
• Minimal postoperative astigmatism, rapid visual rehabilitation
and the best corrected visual acuity possible are the aims of
modern cataract surgery. The axiom today in rehabilitation of
a patient of cataract is “Small is beautiful”[3].

3. AIMS AND OBJECTIVES:
• To compare between the surgically induced astigmatism(SIA) in
small incision cataract surgery(SICS) by superior incision , temporal
incision and supero-temporal incision.
• To evaluate change in preoperative and postoperative astigmatism.
• To study the effect of three different incision sites on post-
operative best corrected visual acquity.

4. MATERIAL AND METHODS
• This was a randomized prospective comparative study.
• A total of 150 eyes of patients attending the Ophthalmology OPD were
studied.
• The patients were randomly assigned to any of three groups. Each group
had 50 patients. The patient in group A underwent SICS with superior
tunnel incisions. Patients in group B underwent SICS with supero-
temporal tunnel incisions and patients in group C underwent SICS with
temporal tunnel incisions.
• INCLUSION CRITERIA: The patients with nuclear and cortical cataracts
ranging from grade 1 to hypermature cataracts and posterior Sub-
capsular cataracts and giving consent.
• EXCLUSION CRITERIA:The patients with any intraocular pathologies of
anterior segment and posterior segment and not giving consent.
• The patients were examined on the 1st
, 7th
and 45th
post-operative days
for best corrected visual acuity, under slit lamp and also auto-
refractometer and keratometry were done.
• The mean SIA were calculated at the 45th
post-operative day. All the
surgically induced astigmatism (SIA) were calculated by Vector Analysis
method.

5. OBSERVATIONS:
TABLE 1: DISTRIBUTION OF PRE-OPERATIVE CORNEAL
ASTIGMATISM IN 3 GROUPS
KERATOMETRIC
ASTIGMATISM IN
DIOPTERS(D)
GROUP A
n(%)
SUPERIOR
INCISION
GROUP B
n(%)
SUPERO-
TEMPORAL
INCISION
GROUP C
n(%)
TEMPORAL
INCISION
0-0.5D 22 20 26
0.75-1.00 D 13 17 15
>1.00 D 15 13 9
Total 50 50 50
In group A ,mean preoperative
astigmatism was 1.52±1.02. In
group B, mean preoperative
astigmatism was 1.38±1.03. In
group C, mean preoperative
astigmatism was 1.26±1.01.
2-value – 2.87, P value- 0.57, non-
significant.

6. TABLE 2: DISTRIBUTION OF POST-OPERATIVE
CORNEAL ASTIGMATISM IN 3 GROUPS AT DAY 1
KERATOMETRIC
ASTIGMATISM IN
DIOPTERS(D)
GROUP A
n(%)
SUPERIOR INCISION
GROUP B
n(%)
SUPERO-TEMPORAL
INCISION
GROUP C
n(%)
TEMPORAL INCISION
0-0.5D 10(20) 23(46) 15(30)
0.75-1.00 D 19(38) 18(36) 24(48)
>1.00 D 21(42) 9(18) 11(22)
Total 50 50 50
2-value – 12.44, p value- 0.014,
significant.

7. TABLE 3: DISTRIBUTION OF POST-OPERATIVE
CORNEAL ASTIGMATISM IN 3 GROUPS AT 7TH
DAY
KERATOMETRIC
ASTIGMATISM IN
DIOPTERS(D)
GROUP A
n(%)
SUPERIOR INCISION
GROUP B
n(%)
SUPERO-TEMPORAL
INCISION
GROUP C
n(%)
TEMPORAL INCISION
0-0.5D 9(18) 24(48) 14(28)
0.75-1.00 D 17(34) 19(38) 24(48)
>1.00 D 24(48) 7(14) 12(24)
Total 50 50 50
2-value – 19.40,
p value- 0.0007, significant.

8. TABLE 4: DISTRIBUTION OF POST-OPERATIVE
CORNEAL ASTIGMATISM IN 3 GROUPS AT 45TH
DAY
KERATOMETRIC
ASTIGMATISM IN
DIOPTERS(D)
GROUP A
n(%)
SUPERIOR INCISION
GROUP B
n(%)
SUPERO-TEMPORAL
INCISION
GROUP C
n(%)
TEMPORAL INCISION
0-0.5D 8(16) 25(50) 16(32)
0.75-1.00 D 18(36) 17(34) 23(46)
>1.00 D 24(48) 8(16) 11(22)
Total 50 50 50
The mean post operative astigmatism
was – 0.41±1.15 in group A.
In group B, the mean post operative
astigmatism was 1.56±1.23.
In group C, the mean post operative
astigmatism was 1.64±1.30.
2-value – 20.02, p value- 0.0005,
significant.

9. TABLE 5: DISTRIBUTION OF POST-OPERATIVE
SURGICALLY INDUCED ASTIGMATISM IN 3 GROUPS AT
45TH
DAY
(VECTOR ANALYSIS METHOD)
SURGICALLY INDUCED
ASTIGMATISM IN
DIOPTERS(D)
GROUP A
n(%)
SUPERIOR INCISION
GROUP B
n(%)
SUPERO-TEMPORAL
INCISION
GROUP C
n(%)
TEMPORAL INCISION
-1-0 D 10 27 23
1.00-2.00 D 15 14 15
>2.00 D 25 9 12
Total 50 50 50
2-value – 17.38, p value- 0.0016 ,
significant.
The mean SIA in group A was, -2.05±1.19.
The mean SIA in group Bwas, 0.53±0.51.
The mean SIA in group C was, 0.46±0.43.

10. TABLE 6: POST OPERATIVE BEST CORRECTED VISUAL
ACQUITY IN 3 GROUPS AT 45TH
DAY
POST-OPERATIVE
BCVA AT 45TH
DAY
GROUP A
n(%)
SUPERIOR INCISION
GROUP B
n(%)
SUPERO-TEMPORAL
INCISION
GROUP C
n(%)
TEMPORAL INCISION
6/6-6/9 19 20 22
6/12-6/18 17 30 18
6/24-6/60 13 0 9
<6/60 1 0 1
TOTAL 50 50 50
2-value – 18.15,
p value- 0.005 , significant.

11. TABLE 7: PRE, POST AND SURGICALLY INDUCED
ASTIGMATISM IN 3 GROUPS
GROUP A
n(%)
SUPERIOR
INCISION
GROUP B
n(%)
SUPERO-
TEMPORAL
INCISION
GROUP C
n(%)
TEMPORAL
INCISION
P VALUE
Mean
preoperative
astigmatism(D)
1.52±1.02 1.38±1.03 1.26±1.01 P>0.57
Mean
postoperative
astigmatism(D)
– 0.41±1.15 1.56±1.23 1.64±1.30 P<0.0005
Mean SIA
astigmatism(D)
-2.05±1.19 0.53±0.51 0.46±0.43 P<0.0016
SICS which is done with a temporal and a supero-temporal
approach provides a better quality of vision due to a significantly
less SIA than the superior approach.

12. REFERENCES
1. Minassian DC, Mehra V. 3.8 million blinded by cataract each year:
Projections from the first epidemiological study of incidence of
cataract blindness in India. Br J OphthalmoI1990;74:341-3.
2. Jose R, Bachani D. World Bank-assisted Cataract Blindness Control
Project. IndianJ Ophthalmoll995 ;43:35-43.
3. Naeser K. Assessment of surgically induced astigmatism; call for an
international standard [letter] J Cataract Refract Surg. 1997;
23:1278–1280 8. Naeser K. Assessment of surgically induced
astigmatism; call for an international standard [letter] J Cataract
Refract Surg. 1997; 23:1278–1280