Table 3.

Mesh sensitivity analysis for the changes in the apical displacements and the apical FPS relative to numbers of degrees of freedom.

RK	Number of degree of freedom	413,432	683,791	828,576	1,266,756
	Linear error	1.10E-09	1.10E-09	6.90E-10	6.00E-10
	Relative cange in apical disp.	—	3.27%	1.78%	1.93%
	Relative cange in apical FPS	—	4.40%	0.77%	0.05%
PRK	Number of degree of freedom	231,494	363,701	717,906	1,009,708
	Linear error	5.80E-10	4.50E-10	3.90E-10	2.60E-10
	Relative cange in apical disp.	—	0.02%	0.02%	0.08%
	Relative cange in apical FPS	—	0.04%	0.06%	0.06%
LASIK	Number of degree of freedom	309,585	464,395	642,852	1,013,765
	Linear error	8.90E-10	6.30E-10	2.80E-10	2.90E-10
	Relative cange in apical disp.	—	0.03%	0.00%	0.10%
	Relative cange in apical FPS	—	0.51%	0.10%	0.05%
SMILE	Number of degree of freedom	253,242	405,396	464,395	995,119
	Linear error	7.60E-10	3.70E-10	6.30E-10	3.10E-10
	Relative cange in apical disp.	—	0.17%	0.10%	0.10%
	Relative cange in apical FPS	—	0.17%	0.19%	0.02%