Journal List > J Korean Ophthalmol Soc > v.56(10) > 1010106

Park, Park, and Kim: Surgically Induced Posterior Corneal Astigmatism in 2.2 mm Microcoaxial Cataract Surgery Versus 2.85 mm Coaxial Conventional Cataract Surgery

Abstract

Purpose

To compare the surgically induced posterior astigmatism of microcoaxial cataract surgery using a 2.2 mm incision and conventional cataract surgery using a 2.85 mm incision.

Methods

This study included 56 eyes that underwent phacoemulsification and intraocular lens insertion. Subjects were divided into 2 groups: 26 eyes receiving a microcoaxial cataract surgery using a 2.2 mm incision (MCCS group) and 30 eyes receiving a conventional cataract surgery using a 2.85 mm incision (CCS group). Anterior, posterior and total corneal astigmatism was measured. The surgically induced anterior astigmatism, surgically induced posterior astigmatism and surgically induced total as-tigmatism were compared between MCCS and CCS groups. Corneal astigmatism was measured using a Pentacam® device (Oculus, Wetzlar, Germany), uncorrected visual acuity, best corrected visual acuity and corneal aberrations of front and rear side was measured preoperatively and at 1 day, 1 month and 2 months postoperatively.

Results

There was no difference in surgically induced posterior astigmatism between CCS and MCCS groups, however, surgi-cally induced anterior astigmatism and surgically induced total astigmatism were significantly lower in the MCCS group than in the CCS group ( p = 0.005 and, p = 0.036, respectively). There was a significant positive linear correlation between surgically in-duced posterior astigmatism and surgically induced total astigmatism in the CCS group ( p = 0.01, r = 0.563). There was also a significant positive linear correlation between surgically induced anterior astigmatism and surgically induced total astigmatism in both CCS and MCCS groups (CCS group: p = 0.00, r = 0.855; MCCS group: p = 0.039, r = 0.407).

Conclusions

There was no significant difference in the surgically induced posterior astigmatism between the MCCS and CCS groups. However, surgically induced posterior astigmatism significantly affected surgically induced total astigmatism in the CCS group but not in the MCCS group. Considering both anterior and posterior astigmatism of the cornea, microcoaxial cataract sur-gery using a 2.2 mm incision affects surgically induced total astigmatism less than conventional cataract surgery.

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Figure 1.
Double-angle plots of surgically induced astigmatism (SIA) using Pentacam® (Oculus, Wetzlar, Germany) at 2 months af-ter surgery, in CCS group (A) and MCCS group (B). CCS = conventional cataract surgery; MCCS = microcoaxial cataract sur-gery; SIA-A = surgically induced astigmatism-anterior; SIA-P = surgically induced astigmatism-posterior; SIA-T = surgically in-duced astigmatism-total.
jkos-56-1534f1.tif
Figure 2.
Correlation of magnitude of SIA-A, SIA-P and SIA-T in CCS group (A,B) and MCCS group (C,D). SIA-A = surgically induced astigmatism-anterior; SIA-P = surgically induced astigmatism-posterior; SIA-T = surgically induced astigmatism-total; CCS = conventional cataract surgery; MCCS = microcoaxial cataract surgery.
jkos-56-1534f2.tif
Figure 3.
Change in corneal higher order aberrations on front side in CCS group (A) and MCCS group (B) and on rear side in CCS group (C) and MCCS group (D). CCS = conventional cataract surgery; MCCS = microcoaxial cataract surgery; RMS = root mean square; HOA = high order abberation; LOA = lower order aberrations; Pre-op = preoperative; Post-op 2 m = postoperative 2 months. * p-value by Paired t-test ( p < 0.05).
jkos-56-1534f3.tif
Table 1.
Demographic factor CCS group vs. MCCS group
Variables CCS group (n = 30) MCCS group (n = 26) p-value
Laterality (OD:OS) 9:21 13:13 0.126*
Sex (male:female) 7:23 7:19 0.757*
Age (years) 60.0 ± 11.26 60.92 ± 5.53 0.192
Pachymetry (μ m) 553.6 ± 37.49 556.62 ± 31.95 0.479
Endothelial cell count (cell/mm2) 2,846.6 ± 348.37 2,750.42 ± 346.90 0.307
Axial length (mm) 24.58 ± 2.41 23.65 ± 1.27 0.073
Anterior chamber depth (mm) 2.81 ± 0.43 2.58 ± 2.53 0.089
SE (diopter) -1.84 ± 4.73 -1.67 ± 3.87 0.882
UCVA (log MAR) 0.66 ± 0.48 0.52 ± 0.36 0.243
BCVA (log MAR) 0.26 ± 0.15 0.24 ± 0.18 0.900
Pre-op anterior astigmatism (diopter) 0.63 ± 0.30 0.61 ± 0.29 0.757
Pre-op posterior astigmatism (diopter) 0.30 ± 0.14 0.30 ± 0.14 0.857
Pre-op total astigmatism (diopter) 0.78 ± 0.27 0.77 ± 0.55 0.932

Values are presented as mean ± SD unless otherwise indicated. CCS = conventional cataract surgery; MCCS = microcoaxial cataract surgery; OD = oculus dexter; OS = oculus sinister; SE = spherical equivalent; UCVA = uncorrected visual acuity; BCVA = best corrected visual acuity; Pre-op = preoperative.

* p-valued on Chi-Square test;

p-valued on Student's t-test.

Table 2.
Data summary of UCVA and BCVA
CCS group MCCS group p-value*
Post-op 1 day
 UCVA (log MAR) 0.20 ± 0.22 0.15 ± 0.11 0.256
 BCVA (log MAR) 0.10 ± 0.10 0.09 ± 0.03 0.475
Post-op 1 month
 UCVA (log MAR) 0.19 ± 0.21 0.11 ± 0.08 0.036
 BCVA (log MAR) 0.09 ± 0.10 0.07 ± 0.05 0.258
Post-op 2 months
 UCVA (log MAR) 0.18 ± 0.16 0.12 ± 0.10 0.112
 BCVA (log MAR) 0.07 ± 0.07 0.06 ± 0.05 0.779

Values are presented as mean ± SD unless otherwise indicated. UCVA = uncorrected visual acuity; BCVA = best corrected visual acuity; CCS = conventional cataract surgery; MCCS = microcoaxial cata-ract surgery; Post-op = postoperative.

* p-valued on Student's t-test.

Table 3.
Comparisons of SIA-A, SIA-P and SIA-T between CCS group and MCCS group (arithmetic mean)
CCS group MCCS group p-value*
Post-op 1 day SIA-A (D) 0.80 ± 0.60 SIA-A (D) 0.38 ± 0.21 0.001
SIA-P (D) 0.23 ± 0.18 SIA-P (D) 0.23 ± 0.16 0.997
SIA-T (D) 1.23 ± 1.02 SIA-T (D) 0.77 ± 0.60 0.043
Post-op 1 month SIA-A (D) 0.73 ± 0.62 SIA-A (D) 0.37 ± 0.19 0.005
SIA-P (D) 0.16 ± 0.15 SIA-P (D) 0.12 ± 0.07 0.201
SIA-T (D) 0.75 ± 0.49 SIA-T (D) 0.45 ± 0.33 0.012
Post-op 2 months SIA-A (D) 0.78 ± 0.58 SIA-A (D) 0.44 ± 0.26 0.005
SIA-P (D) 0.18 ± 0.16 SIA-P (D) 0.14 ± 0.06 0.257
SIA-T (D) 0.75 ± 0.63 SIA-T (D) 0.51 ± 0.34 0.049

Values are presented as mean ± SD unless otherwise indicated. CCS = conventional cataract surgery; MCCS = microcoaxial cataract surgery; SIA-A = surgically induced astigmatism-anterior; SIA-P = surgically induced astigmatism-posterior; SIA-T = surgically induced astigmatism-total; Post-op = postoperative.

* p-valued on Student's t-test.

Table 4.
Comparisons of SIA-A, SIA-P and SIA-T between CCS group and MCCS group from WTR group at 2 months after surgery
CCS group (n = 10) MCCS group (n = 15) p-value*
SIA-A (D) 0.86 ± 0.53 0.38 ± 0.22 0.019
SIA-P (D) 0.11 ± 0.07 0.13 ± 0.07 0.341
SIA-T (D) 0.77 ± 0.34 0.40 ± 0.28 0.004

Values are presented as mean ± SD unless otherwise indicated. SIA-A = surgically induced astigmatism-anterior; SIA-P = surgically induced astigmatism-posterior; SIA-T = surgically induced astigma-tism-total; CCS = conventional cataract surgery; MCCS = microcoaxial cataract surgery; WTR = within the rule.

* p-valued on Mann Whitney U-test.

Table 5.
Comparisons of SIA-A, SIA-P and SIA-T between CCS group and MCCS group from ATR group at 2 months after surgery
CCS group (n = 20) MCCS group (n = 11) p-value*
SIA-A (D) 0.66 ± 0.67 0.45 ± 0.27 0.072
SIA-P (D) 0.19 ± 0.18 0.11 ± 0.07 0.087
SIA-T (D) 0.75 ± 0.56 0.53 ± 0.40 0.261

Values are presented as mean ± SD unless otherwise indicated. SIA-A = surgically induced astigmatism-anterior; SIA-P = surgically induced astigmatism-posterior; SIA-T = surgically induced astigma-tism-total; CCS = conventional cataract surgery; MCCS = microcoaxial cataract surgery; ATR = against the rule.

* p-valued on Mann Whitney U-test.

Table 6.
Postoperative changes of corneal aberrations on the rear side
Pre-op Post-op 1 day Post-op 1 month Post-op 2 months
RMS total (μ m) CCS group 0.835 ± 0.156 1.216 ± 0.498 0.881 ± 0.178 0.848 ± 0.172
MCCS group 0.798 ± 0.198 1.108 ± 0.353 1.124 ± 1.980 0.842 ± 0.144
p-value* 0.343 0.359 0.332 0.884
RMS HOA (μ m) CCS group 0.230 ± 0.126 0.428 ± 0.0191 0.273 ± 0.126 0.235 ± 0.061
MCCS group 0.231 ± 0.120 0.436 ± 0.228 0.458 ± 0.968 0.262 ± 0.071
p-value* 0.990 0.883 0.304 0.138
RMS LOA (μ m) CCS group 0.758 ± 0.190 1.113 ± 0.467 0.828 ± 0.209 0.813 ± 0.170
MCCS group 0.744 ± 0.202 1.011 ± 0.298 1.114 ± 1.731 0.795 ± 0.152
p-value* 0.438 0.239 0.319 0.683
Spherical abberation CCS group -0.142 ± 0.035 -0.220 ± 0.192 -0.152 ± 0.031 -0.148 ± 0.029
Z (4, 0) (μ m) MCCS group -0.175 ± 0.215 -0.165 ± 0.046 -0.168 ± 0.131 -0.144 ± 0.033
p-value* 0.415 0.165 0.521 0.652
Oblique trefoil RMS CCS group -0.009 ± 0.085 0.046 ± 0.131 -0.009 ± 0.105 -0.048 ± 0.105
Z (3, -3) (μ m) MCCS group -0.035 ± 0.123 0.022 ± 0.197 -0.032 ± 0.090 -0.054 ± 0.080
p-value* 0.309 0.591 0.379 0.720
Horizontal trefoil RMS CCS group -0.002 ± 0.063 -0.009 ± 0.172 -0.097 ± 0.082 0.008 ± 0.056
Z (3, 3) (μ m) MCCS group -0.001 ± 0.075 -0.085 ± 0.213 -0.085 ± 0.325 -0.008 ± 0.107
p-value* 0.933 0.147 0.288 0.483
Trefoil (μ m) CCS group 0.087 ± 0.059 0.182 ± 0.122 0.113 ± 0.072 0.105 ± 0.071
MCCS group 0.100 ± 0.109 0.231 ± 0.190 0.177 ± 0.300 0.117 ± 0.081
p-value* 0.588 0.254 0.261 0.564
Vertical coma RMS CCS group 0.014 ± 0.035 -0.052 ± 0.159 0.010 ± 0.061 0.017 ± 0.049
Z (3, -1) (μ m) MCCS group 0.032 ± 0.064 0.017 ± 0.104 0.049 ± 0.082 0.043 ± 0.074
p-value* 0.224 0.061 0.045 0.035
Horisontal coma RMS CCS group -0.009 ± 0.037 -0.029 ± 0.139 -0.071 ± 0.076 -0.021 ± 0.059
Z (3, 1) (μ m) MCCS group 0.008 ± 0.043 -0.017 ± 0.178 0.029 ± 0.148 0.011 ± 0.065
p-value* 0.150 0.785 0.134 0.052
Coma (μ m) CCS group 0.046 ± 0.026 0.183 ± 0.121 0.082 ± 0.056 0.067 ± 0.044
MCCS group 0.044 ± 0.041 0.183 ± 0.090 0.133 ± 0.117 0.093 ± 0.046
p-value* 0.882 0.939 0.037 0.039

Values are presented as number or mean ± SD. CCS = conventional cataract surgery; MCCS = microcoaxial cataract surgery; Z = zernike coefficients; RMS = root mean square; HOA = high order abberation; LOA = lower order aberrations; Pre-op = preoperative; Post-op = postoperative.

* p-valued on Student's t-test;

Trefoil =  ;

Coma =  .

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