We can always choose thoughts to focus on.

Mary Baker Eddy says on P392 of her book Science and Health

“Stand porter at the door of thought.”

We need to watch our thoughts and be sure they are worthy of God.

Eddy says on P14
”Become conscious for a single moment that Life and intelligence are purely spiritual, — neither in nor of matter, — and the body will then utter no complaints. If suffering from a belief in sickness, you will find yourself suddenly well. Sorrow is turned into joy when the body is controlled by spiritual Life, Truth, and Love. Hence the hope of the promise Jesus bestows:

‘He that believeth on me, the works that I do shall he do also; . . . because I go unto my Father,’ — [because the Ego is absent from the body, and present with Truth and Love.] The Lord’s Prayer is the prayer of Soul, not of material sense.”

Eddy says on P393
“When Jesus declares that “the light of the body is the eye,” he certainly means that light depends upon Mind, not upon the complex humors, lenses, muscles, the iris and pupil, constituting the visual organism.”