Twenty-eight eyes of 22 patients (20 [71.43%] men and 8 [28.57%] women) who underwent FLACS with primary IOL implantation were included in this study. The mean age at surgery was 4.67 ± 1.54 years. All measurements were performed preoperatively. Table 1 shows the characteristics of the eyes in the study population.
Table 1: Characteristics of patients’ eyes.
Variables
|
Mean ± SD
|
Median
|
Range
|
Age at surgery (y)
AL (mm)
ACD (mm)
K1 (D)
K2 (D)
PCD (mm)
|
4.67 ± 1.54
22.33 ± 1.71
3.17 ± 0.51
42.36 ± 2.08
44.52 ± 1.67
4.47 ± 0.13
|
4.54
22.12
3.33
42.13
44.31
4.40
|
2.08, 6.92
20.14, 27.82
1.57, 3.93
37.50, 46.37
41.98, 48.21
4.20, 4.80
|
K1, flat keratometry; K2, steep keratometry; ACD, anterior chamber depth; AL, axial length; PCD, programmed capsulorhexis diameter; SD, standard deviation; y, years
Anterior capsulorhexis was performed with femtosecond laser. No patient developed an anterior capsule tear. IOL implantation was successfully performed in all 28 cases. Tecnis ZCB00 (Abbott Medical Optics, United States), which is a hydrophobic acrylic 1-piece IOL with 6.0-mm optic diameter and 13.0-mm overall diameter, was implanted into the capsular bag. Posterior capsulotomy was successfully performed with anterior vitrectomy in all cases without any posterior capsule ruptures. Capsulorhexis enlargement occurred in all 28 cases (Figure 2).
Table 2 shows the PCD, AACD, and “E” for each patient. “E” was estimated to be 1.211±0.039 (standard deviation [SD]; range, 1.122–1.284).
Table 2: Clinical data of patients.
Patient
|
Case
|
Eye
|
Age at Surgery (y)
|
Femtosecond Laser Capsulorhexis
|
PCD
|
AACD
|
E
|
Patient 1
|
1
|
L
|
6.83
|
4.5
|
5.48
|
1.218
|
Patient 2
|
2
|
L
|
4.50
|
4.5
|
5.47
|
1.216
|
Patient 3
|
3
|
R
|
6.00
|
4.6
|
5.57
|
1.211
|
Patient 4
|
4
|
L
|
5.00
|
4.6
|
5.55
|
1.207
|
Patient 5
|
5
|
R
|
6.75
|
4.8
|
5.72
|
1.192
|
Patient 6
|
6
|
R
|
3.50
|
4.6
|
5.64
|
1.226
|
7
|
L
|
3.50
|
4.4
|
5.26
|
1.195
|
Patient 7
|
8
|
R
|
5.92
|
4.6
|
5.54
|
1.204
|
Patient 8
|
9
|
R
|
6.83
|
4.6
|
5.61
|
1.220
|
10
|
L
|
6.83
|
4.6
|
5.59
|
1.215
|
Patient 9
|
11
|
R
|
3.25
|
4.6
|
5.67
|
1.233
|
12
|
L
|
3.33
|
4.4
|
5.48
|
1.245
|
Patient 10
|
13
|
L
|
4.08
|
4.4
|
5.20
|
1.182
|
Patient 11
|
14
|
L
|
3.00
|
4.4
|
5.47
|
1.243
|
15
|
R
|
3.00
|
4.4
|
5.46
|
1.241
|
Patient 12
|
16
|
L
|
2.08
|
4.5
|
5.78
|
1.284
|
Patient 13
|
17
|
L
|
6.92
|
4.5
|
5.45
|
1.211
|
Patient 14
|
18
|
R
|
4.83
|
4.4
|
5.17
|
1.175
|
Patient 15
|
19
|
R
|
5.50
|
4.4
|
5.14
|
1.168
|
Patient 16
|
20
|
R
|
2.75
|
4.4
|
5.45
|
1.239
|
Patient 17
|
21
|
R
|
4.33
|
4.4
|
4.95
|
1.125
|
22
|
L
|
4.58
|
4.4
|
5.02
|
1.141
|
Patient 18
|
23
|
L
|
3.92
|
4.4
|
5.60
|
1.273
|
Patient 19
|
24
|
L
|
6.33
|
4.5
|
5.05
|
1.122
|
Patient 20
|
25
|
L
|
2.25
|
4.4
|
5.38
|
1.223
|
Patient 21
|
26
|
R
|
3.33
|
4.4
|
5.55
|
1.261
|
Patient 22
|
27
|
L
|
5.75
|
4.2
|
5.10
|
1.214
|
28
|
R
|
5.83
|
4.2
|
5.17
|
1.231
|
AACD, actual achieved capsulorhexis diameter; PCD, programmed capsulorhexis diameter; y, years; L, left; R,
Correlations among the different parameters and “E”
Simple correlation analysis showed “E” was negatively related to the age at surgery (r=−0.417, p=0.027) (Figure 3) and ACD (r=−0.558, p=0.002) (Figure 4).
Results of partial correlation analysis showed that “E” value correlated significantly with ACD (r=−0.469, p=0.021) and AL (r=0.452, p=0.027), but showed only a weak correlation with the age at surgery (r=−0.343, p=0.100), K1 (r=−0.253, p=0.232) and K2 (r=0.072, p=0.737).
Multiple Linear Regression
Multiple linear regression was performed using the age at surgery, AL, ACD, K1 and K2; the results showed that “E” correlated positively with AL, whereas it correlated negatively with ACD (Table 3).
Table 3. Multiple linear regression for “E.”
Variables
|
Beta
|
SE
|
p value
|
ACD
AL
Constant
|
−0.052
0.009
1.177
|
0.014
0.004
0.038
|
0.001
0.046
<0.001
|
PCD, programmed capsulorhexis diameter; ACD, anterior chamber depth; AL, axial length; SE, standard error;
The multiple linear regression model was based on the following equation: Predicted E = 1.177−0.052×ACD+0.009×AL, R2 = 0.346 (F=4.396, p=0.046). Furthermore, the predicted PCD formula (Equation 1) was obtained from the “predicted E” equation