Inter-Ocular Asymmetry in Anterior Corneal Aberrations Using Placido Disk-Based Topography

Figures & data

Table 1 Descriptive Statistics of Refractive and Corneal Astigmatism for Control, Myopia, and Hypermetropia Groups

	Control Group		Myopia Group		Hypermetropia Group
	Refractive Astigmatism (RE)	Refractive Astigmatism (LE)	Refractive Astigmatism (RE)	Refractive Astigmatism (LE)	Refractive Astigmatism (RE)	Refractive Astigmatism (LE)
Mean	−0.26	−0.24	−0.72	−0.74	−0.56	−0.58
SD	0.37	0.38	0.69	0.78	0.66	0.64
Maximum	0.75	0.75	0.00	0.00	0.00	0.00
Minimum	−1.50	−1.50	−2.75	−4.00	−3.75	−3.75
	Corneal Astigmatism (RE)	Corneal Astigmatism (LE)	Corneal Astigmatism (RE)	Corneal Astigmatism (LE)	Corneal Astigmatism (RE)	Corneal Astigmatism (LE)
Mean	−0.71	−0.73	−0.87	−0.94	−0.65	−0.64
SD	0.40	0.49	0.58	0.73	0.52	0.67
Maximum	0.00	0.57	0.00	0.92	0.60	0.80
Minimum	−1.90	−2.37	−2.75	−3.38	−3.07	−3.95

Note: Results are presented as mean ± SD, maximum and minimum for RE and LE, in diopter unit.

Table 2 Mean High-Order Aberrations for Control, Myopia, and Hypermetropia Groups

High-Order Aberrations, µm	Control Group					Myopia Group					Hypermetropia Group
	RE		LE		P	RE		LE		P	RE		LE		P
	Mean	SD	Mean	SD		Mean	SD	Mean	SD		Mean	SD	Mean	SD
RMS 3 mm	0.14	0.05	0.15	0.07	0.10	0.16	0.08	0.17	0.10	0.05	0.16	0.09	0.16	0.07	0.80
RMS 5 mm	0.49	0.20	0.53	0.26	0.06	0.55	0.28	0.67	0.85	0.13	0.56	0.33	0.53	0.30	0.62
RMS 7 mm	1.57	1.14	1.60	0.88	0.81	1.63	1.03	1.84	2.20	0.32	1.68	1.95	1.64	1.40	0.86
Vertical Trefoil	0.11	0.10	0.11	0.10	0.96	0.10	0.09	0.13	0.31	0.37	0.14	0.15	0.14	0.13	0.96
Oblique Trefoil	0.07	0.07	0.07	0.09	0.78	0.06	0.08	0.09	0.23	0.23	0.08	0.09	0.07	0.06	0.62
Vertical Coma	0.12	0.12	0.12	0.12	0.65	0.12	0.14	0.14	0.44	0.62	0.13	0.16	0.11	0.12	0.33
Horizontal Coma	0.12	0.07	0.14	0.08	<0.001	0.09	0.06	0.11	0.10	0.02	0.12	0.07	0.15	0.08	<0.001
Primary Spherical	0.17	0.07	0.18	0.07	0.72	0.17	0.07	0.20	0.30	0.31	0.18	0.11	0.19	0.09	0.69

Notes: Results are presented as mean ± SD for RE and LE, and the outcome of the Student t test for matched pairs for each group is also shown. P values in bold denote statistically significant interocular differences.

Abbreviation: RMS, root mean square for pupil entry of 3 mm, 5 mm, and 7 mm.

Table 3 P values of High-Order Aberrations for All Groups Using Post Hoc Bonferroni Test for Right and Left Eyes

High-Order Aberrations, µm	P
RMS 3 mm (RE)	0.13
RMS 3 mm (LE)	0.90
RMS 5 mm (RE)	0.30
RMS 5 mm (LE)	0.27
RMS 7 mm (RE)	1
RMS 7 mm (LE)	0.85
Vertical Trefoil (RE)	0.11
Vertical Trefoil (LE)	0.83
Oblique Trefoil (RE)	0.30
Oblique Trefoil (LE)	1
Vertical Coma (RE)	1
Vertical Coma (LE)	1
Horizontal Coma (RE)	0.01
Horizontal Coma (LE)	0.01
Primary Spherical (RE)	0.03
Primary Spherical (LE)	0.03

Notes: Results are presented as Post Hoc Bonferroni Test for RE and LE for each group shown. P values in bold denote statistically significant interocular differences at alpha level of 0.05.

Abbreviation: RMS, root mean square for pupil entry of 3 mm, 5 mm, and 7 mm.

Table 4 Absolute Interocular Differences in High-Order Aberrations in Mean ± SD (95% CI) for Control, Myopia, and Hypermetropia Groups

Absolute Interocular Difference in High Order Aberrations (µm)	Control Group				Myopia Group				Hypermetropia Group				P
	Mean	SD	95% CI		Mean	SD	95% CI		Mean	SD	95% CI
RMS 3 mm	−0.01	0.06	−0.02	0.00	−0.01	0.07	−0.03	0.00	0.00	0.10	−0.02	0.02	0.38
RMS 5 mm	−0.04	0.22	−0.09	0.00	−0.12	0.73	−0.27	0.04	0.03	0.38	−0.06	0.12	0.19
RMS 7 mm	−0.03	1.06	−0.24	0.19	−0.22	2.12	−0.65	0.22	0.03	1.70	−0.38	0.43	0.61
Vertical Trefoil	0.00	0.10	−0.02	0.02	−0.27	0.28	−0.08	0.03	0.00	0.16	−0.04	0.04	0.60
Oblique Trefoil	0.00	0.10	−0.24	0.18	−0.03	0.24	−0.08	0.02	0.01	0.10	−0.02	0.03	0.34
Vertical Coma	−0.01	0.15	−0.04	0.02	−0.02	0.40	−0.10	0.06	0.02	0.18	−0.02	0.06	0.66
Horizontal Coma	−0.02	0.10	−0.04	−0.01	−0.03	0.11	−0.05	0.00	−0.02	0.07	−0.04	−0.01	0.98
Primary Spherical	0.00	0.06	−0.01	0.01	−0.03	0.31	−0.10	0.03	−0.01	0.11	−0.03	0.02	0.52

Notes: The results of the nonmatched pairs Student t test are shown.

Abbreviations: CI, confidence interval; RMS, root mean square for pupil entry of 3 mm, 5 mm, and 7 mm.

Table 5 Percentile Distribution of Interocular Differences (Right Eye Minus Left Eye) in High-Order Aberrations (µm) for Control, Myopia, and Hypermetropia Groups

High-Order Aberrations (µm)	Control Group		Myopia Group		Hypermetropia Group
	Percentiles
	2.5th	97.5th	2.5th	97.5th	2.5th	97.5th
RMS 3 mm	−0.17	0.14	−0.24	0.13	−0.19	0.27
RMS 5 mm	−0.78	0.42	−1.36	0.55	−0.98	1.08
RMS 7 mm	−2.65	2.84	−4.22	3.72	−3.81	6.19
Vertical Trefoil	−0.25	0.20	−0.36	0.24	−0.31	0.42
Oblique Trefoil	−0.25	0.18	−0.52	0.10	−0.19	0.37
Vertical Coma	−0.53	0.37	−0.36	0.39	−0.35	0.49
Horizontal Coma	−0.21	0.19	−0.16	0.20	−0.17	0.13
Primary Spherical	−0.14	0.12	−0.22	0.15	−0.22	0.40

Note: The results of the 2.5th and 97.5th percentiles of interocular difference tolerance limits for the control, myopia, and hypermetropia groups.

Abbreviation: RMS, root mean square for pupil entry of 3 mm, 5 mm, and 7 mm.