I worked with an 18 month old esotropic girl whose eyes were so crossed I thought she had convergence fixus. However when I held her at arms length and turned my body through 360 degrees her vestibulars took over and her eyes straightened and she showed nystagmus. At each of the three visits I increased the plus to take home. She has of course continued to be straight eyed. Wild monkeys have low hyperopia or emmetropia and no myopia.
Caged monkeys have less hyperopia and much more myopia.
Because the evidence for emmetropization is so strong, I suggest a couple of approaches on how to emmetropize young hyperopes. Only prescribe as much plus as needed to keep the eyes straight. At most the Rx should only be about half of the retinoscopic Rx and then reduced in power as the eyes change. With esotropia, more plus power may be needed at first to establish normal binocular vision, after which treatment of hyperopia may proceed. Alternatively for esotropia, the no Rx, binasal approach, see below, is highly recommended.