Table 2. Cox proportional hazards model in Motor Failure and Persistent Head Tilt.

Predictor	Motor failurea			Persistent head tilt
	HR	Standard deviation	P-value	HR	Standard deviation	P-value
Group
Present group
Absent group	3.0	0.8	0.157	1.6	0.7	0.490
Age at the operation	0.6	0.2	0.009*	0.7	0.1	0.022*
Head tilt angle	1.1	0.0	0.074	1.1	0.0	0.038*

Cox proportional hazards model with firth's correction.

Asterisk * indicates statistical significance.

^a: Motor failure was defined as the undercorrection and recurrence of ipsilateral hypertropia after the inferior oblique myectomy.