Table 4.

Relationship between Refractive error regression after PRK Surgery and preoperative variables in people with both eyes regressed and both eyes non-regressed

Variables	People whose both eyes were non regressed after surgery			People whose both eyes were regressed after surgery
	Right eye N = 107	Left eye N = 107	Test	Right eye N = 20	Left eye N = 20	Test
	Mean ± SD	Mean ± SD	P value§	Mead(min-max)	Mead(min-max)	P value®
Thickness (μm)	536.7 ± 32.6	537.6 ± 34.7	0.84	537.5 (499–572)	531 (501–575)	0.49
Irregularity5(mm)	1.33 ± 0.31	1.36 ± 0.38	0.55	1.35 (1.00–2.70)	1.25 (0.9–2.6)	0.45
Astigmatism(D)	0.99 ± 0.70	1.07 ± 0.73	0.43	1.62 (0–3.75)	1.87 (0–4.25)	0.43
Sphere (D)	3.17 ± 1.69	3.12 ± 1.70	0.84	6.25 (0.25–12)	7.87 (0–11.50)	0.41
SimK (D)	0.97 ± 0.49	1.04 ± 0.51	0.30	1.25 (0.25–2.90)	1.50 (0.50–2.90)	0.92

PRK Photorefractive keratectomy, Sim k astigmatism: simulated keratometry astigmatism, P value: ^§: Independent sample t. test ®; Mann –Whitney U independent sample test