When cirrostratus clouds are disturbed by planes or strong winds, the droplets can freeze instantly or evaporate, the latter of which will form the hole.

At that time, walking out the little house, we stood in the cool air, which could freeze one's ears. How like the hares just coming out from its hole we were.

The simple method to treat retinal detachment with macular hole is introduced by this article, i. e. freeze and fluid-air exchage.