1. In cases of the following specified injuries, in the absence of proof to the contrary, the disability caused thereby shall be deemed total and permanent:
(a) The total and permanent loss of sight of both eyes.
(b) The loss by separation of both legs at or above the knee.
(c) The loss by separation of both arms at or above the elbow.
(d) An injury to the spine resulting in permanent and complete paralysis of both legs or both arms, or one leg and one arm.
(e) An injury to the skull resulting in incurable imbecility or insanity.
(f) The loss by separation of one arm at or above the elbow, and one leg by separation at or above the knee.
2. The enumeration in subsection 1 is not exclusive, and in all other cases permanent total disability must be determined by the insurer in accordance with the facts presented.