Determination of the time of refractive stability after uneventful phacoemulsification in Indian eyes

Table 1 Demographic details

Parameters	Axial length, n (%)			Overall	P value1
	Hypermetropia	Emmetropia	Myopia
Age in yr					0.337
< 55	8 (14.5)	21 (10.8)	2 (40)	31 (12.2)
55–65	22 (40)	83 (42.8)	2 (40)	107 (42.1)
> 65	25 (45.5)	90 (46.4)	1 (20)	116 (45.7)
Sex					0.036a
Male	20 (36.4)	105 (54.1)	1 (20)	126 (49.6)
Female	35 (63.6)	89 (45.9)	4 (80)	128 (50.4)
Eye					0.861
Right eye	29 (52.7)	101 (51.3)	2 (40)	132 (51.4)
Left eye	26 (47.3)	96 (48.7)	3 (60)	125 (48.6)
K1-reading (1 wk)1
mean ± SD	43.8 ± 1.7
Range	(39-47.5)
K1-reading (6 wk)1
mean ± SD	43.8 ± 1.7
Range	(39-47.8)
K2-reading (1 wk)1
mean ± SD	44.5 ± 1.7
Range	(39.5-49.5)
K2-reading (6 wk)1
mean ± SD	44.6 ± 1.7
Range	(40-49)

^aP value < 0.05, Chi-square/Fisher’s exact test.

¹Paired t-test/Wilcoxon Sign rank test.

K: Keratometry.

Table 2 Refractive stability at two follow up visits of 1 wk and 6 wk

Parameters	Post-operative visits			P value1
	1st wk	6th wk	Difference
Sphere				0.851
mean ± SD	0.04 ± 0.4	0.01 ± 0.3	0.1 ± 0.2
Median (IQR)	0 (0-0)	0 (0-0)	0 (0-0)
Range	-1.5 to 1	-0.75 to 1.5	0 to 1.5
Cylinder				0.695
mean ± SD	-0.3 ± 0.7	-0.2 ± 0.6	0.3 ± 0.4
Median (IQR)	-0.5 (-0.75 to 0.5)	-0.5 (-0.75 to 0.5)	0.25 (0 to 0.25)
Range	-3.5 to 1.5	-1.5 to 1.5	0 to 2.75
Spherical equivalent				0.277
mean ± SD	-0.05 ± 0.4	-0.07 ± 0.4	0.2 ± 0.2
Median (IQR)	0 (-0.25 to 0)	0 (-0.25 to 0)	0.12 (0 to 0.25)
Range	-1.75 to 1.37	-1 to 1.75	0 to 1.5

¹Wilcoxon Sign rank test to compare refractive error between 1^st wk and 6^th wk post-operative.

IQR: Interquartile range.

Table 3 Refractive stability by age distribution

Parameters	1-wk post-operative			6-wk post-operative			P value1	P value2	P value3
	Age in yr			Age in yr
	< 55	55-65	> 65	< 55	55-65	> 65
Sphere							0.392	0.451	> 0.99
mean ± SD	-0.05 ± 0.4	0.1 ± 0.4	0.01 ± 0.4	-0.12 ± 0.3	0.03 ± 0.4	0.04 ± 0.3
Median (IQR)	0 (0-0)	0 (0-0)	0 (0-0)	0 (-0.5 to 0)	0 (0-0)	0 (0-0)
Range	-0.75 to 1	-0.8 to 1	-1.5 to 1	-0.75 to 0.75	-0.75 to 1.5	-0.5 to 1
Cylinder							0.769	0.408	0.717
mean ± SD	-0.6 ± 0.1	-0.2 ± 0.7	-0.3 ± 0.7	-0.5 ± 0.3	-0.1 ± 0.6	-0.4 ± 0.7
Median (IQR)	-0.5 (-0.75 to -0.5)	-0.5 (-0.5 to 0.5)	-0.5 (-0.75 to 0.5)	-0.5 (-0.5 to 0.5)	-0.5 (-0.5 to 0.5)	-0.5 (-0.75 to 0.5)
Range	-0.75 to 0.5	-3.5 to 1	-1.5 to 1.5	-1 to 0.5	-0.75 to 1.25	-1.5 to 1.5
Spherical equivalent							0.173	0.894	0.249
mean ± SD	-0.1 ± 0.4	-0.01 ± 0.4	-0.1 ± 0.4	-0.2 ± 0.3	-0.01 ± 0.4	-0.1 ± 0.3
Median (IQR)	0 (-0.37 to 0)	0 (-0.25 –0.25)	0 (-0.25 –0)	0 (-0.31– 0)	0 (-0.25 –0.25)	0 (-0.25 –0)
Range	-0.87 to 1	-1.75 to 1	-1.5 to 1.37	-1 to 0.5	-1 to 1.75	-1 to 0.87
P value4	0.358			0.287			-
P value5	0.052			0.013
P value6	0.246			0.057

¹Wilcoxon Sign rank test to compare the patients with age < 55 yr between 1^st wk and 6^th wk post-operative.

²Wilcoxon Sign rank test to compare the patients with age 55 yr to 65 yr between 1^st wk and 6^th wk post-operative.

³Wilcoxon Sign rank test to compare the patients with age > 65 yr between 1^st wk and 6^th wk post-operative. Boldface indicates statistical significance.

⁴Kruskal-Wallis test for comparing age and spherical power.

⁵Kruskal-Wallis test for comparing age and cylindrical power.

⁶Kruskal-Wallis test for comparing age and spherical equivalent.

IQR: Interquartile range.

Table 4 Refractive stability by sex wise distribution

Parameters	1 wk postoperative			6 wk postoperative			P value1	P value2
	Male	Female	P value3	Male	Female	P value3
Sphere			0.523			0.281	0.698	0.933
mean ± SD	0.06 ± 0.4	0.03 ± 0.4		0.05 ± 0.4	-0.03 ± 0.3
Median (IQR)	0 (0-0)	0 (0-0)		0 (0-0)	0 (0-0)
Range	-1.5 to 1	-0.75 to 1		-0.5 to 1.5	-0.75 to 1
Cylinder			0.979			0.585	0.788	0.783
mean ± SD	-0.3 ± 0.6	-0.3 ± 0.7		-0.3 ± 0.6	-0.2 ± 0.6
Median (IQR)	-0.5 (-0.8 to 0.5)	-0.5 (-0.8 to 0.5)		-0.5 (-1.5 to 1)	-0.5 (-0.5 to 0.5)
Range	-1.5 to 1.25	-3.5 to 1.5		-1.5 to 1	-1 to 1.5
Spherical equivalent			0.651			0.724	0.419	0.464
mean ± SD	-0.04 ± 0.4	-0.1 ± 0.4		-0.1 ± 0.4	-0.1 ± 0.4
Median (IQR)	0 (-0.25 to 0)	0 (-0.25 to 0)		0 (-0.25 to 0)	0 (-0.25 to 0)
Range	-1.5 to 1.12	-1.75 to 1.37		-0.87 to 1.75	-1 to 1

¹Wilcoxon Sign rank test to compare the male between 1^st wk and 6^th wk post-operative.

²Wilcoxon Sign rank test to compare the female between 1^st wk and 6^th wk post-operative.

³Mann Whitney U test.

IQR: Interquartile range.

Table 5 Refractive stability by axial length wise distribution

Parameters	1 wk post operative			6 wk postoperative			P value1	P value2	P value3
	Axial length in mm			Axial length in mm
	< 22	22-25	> 25	< 22	22-25	> 25
Sphere							> 0.99	0.989	0.317
mean ± SD	0.1 ± 0.4	0.1 ± 0.4	-0.2 ± 0.4	0.04 ± 0.3	0.01 ± 0.3	-0.2 ± 0.3
Median (IQR)	0 (0-0)	0 (0-0)	0 (-0.75 to 0)	0 (0-0)	0 (0-0)	0 (-0.5 to 0)
Range	-0.75 to 1	-1.5 to 1	-0.75 to 0	-0.75 to 1	-0.75 to 1.5	-0.5 to 0
Cylinder							0.765	0.783	0.782
mean ± SD	-0.1 ± 0.7	-0.3 ± 0.6	-1.6 ± 1.7	-0.2 ± 0.6	-0.2 ± 0.7	-0.8 ± 0.4
Median (IQR)	-0.5 (-0.6 to 0.5)	-0.5 (-0.75 to 0.1)	-0.75 (-3.5 to -0.5)	-0.5 (-0.5 to 0.5)	-0.5 (-0.75 to 0.5)	-0.75 (-1.2 to -0.5)
Range	-1.5 to 1.25	-1.5 to 1.5	-3.5 to 0.5	-1.25 to 0.75	-1.5 to 1. 5	-1.25 to 1.5
Spherical equivalent							0.982	0.19	0.477
mean ± SD	-0.01 ± 0.4	-0.1 ± 0.4	-0.6 ± 0.7	-0.04 ± 0.3	-0.1 ± 0.4	-0.4 ± 0.3
Median (IQR)	0 (-0.25 to 0.25)	0 (-0.25 to 0)	-0.37 (-1 to 0)	0 (-0.25 to 0.25)	0 (-0.25 to 0)	-0.37 (-0.62 to 0)
Range	-1 to 1	-1.5 to 1.37	-1.75 to 0	-1 to 1	-1 to 1.75	-0.75 to 0
P value4	0.559			0.657			-
P value5	0.123			0.226
P value6	0.091			0.164

¹Wilcoxon Sign rank test to compare the patients with axial length < 22 mm between 1^st wk and 6^th wk post-operative.

²Wilcoxon Sign rank test to compare the patients with axial length 22 to 25 mm between 1^st wk and 6^th wk post-operative.

³Wilcoxon Sign rank test to compare the patients with axial length > 25 mm between 1^st wk and 6^th wk post-operative.

⁴Kruskal-Wallis test for comparing axial length and spherical power.

⁵Kruskal-Wallis test for comparing axial length and cylindrical power.

⁶Kruskal-Wallis test for comparing axial length and spherical equivalent.

IQR: Interquartile range.