Table 4.

Clinical and Topographic Parameters According to Age

	<20		20–24		25–29		≥ 30		Total
	Mean	SD	Mean	SD	Mean	SD	Mean	SD	Mean	SD	P-value
BCVAa	0.7	0.3	0.7	0.3	0.7	0.3	0.6	0.3	0.7	0.3	0.249
Sphere	−0.7	2.0	−0.7	1.6	−1.6	2.4	−1.8	3.3	−1.2	2.5	0.000
Cylinder	−2.6	1.5	−2.7	1.7	−3.0	1.7	−3.0	1.6	−2.8	1.6	0.223
Cornea thinnest location	460.0	48.7	460.9	50.7	454.9	63.1	459.3	46.8	458.8	52.8	0.828
K meanb	47.5	5.0	47.6	5.2	47.6	4.6	47.9	5.9	47.7	5.2	0.955
K maxc	53.6	7.6	54.9	8.8	54.3	8.2	54.5	9.7	54.4	8.7	0.757

Notes: ^aBest-corrected visual acuity; ^bkeratometry mean; ^ckeratometry maximum.