Final answer:
Benign bilateral schwannomas of the acoustic nerve result from mutations in the NF2 gene, which are unrelated to changes in the lens of the eye. Bilateral hemianopia, involving loss of lateral peripheral vision, is associated with a pituitary gland growth pressing on the optic chiasm, not schwannomas.
Step-by-step explanation:
Benign bilateral schwannomas of the acoustic nerve occur due to mutations in the neurofibromatosis type 2 (NF2) gene. This condition can lead to issues such as hearing loss if left untreated, but it is important to note that the question seems to mix up two distinct medical conditions. Schwannomas related to NF2 do not directly affect the lens of the eye; instead, the described impact on vision, specifically the loss of lateral peripheral vision or bilateral hemianopia, is associated with a pituitary gland growth pressing on the optic chiasm. The axons projecting to the same side of the brain remain unaffected in this scenario, and thus, only the vision to the far right and left sides is compromised.