Isaiah 13:18 (King James Bible) their eye shall not spare children
As discussed under 2 Nephi 13:8–9, the Book of Mormon text prefers plurals when referring to the eyes, tongues, and hearts of people. Thus the text here in 2 Nephi 23:18 has eyes rather than the singular eye of the King James Bible. The original manuscript is not extant for this verse, but nearby verses are extant and are in the hand of Oliver Cowdery.
David Calabro points out (personal communication) that the plural eyes could be the result of mishearing eye shall as eyes shall—that is, the initial /¸s/ of shall would have made it difficult for Oliver to have heard the difference between /ai ¸sæl/ and /aiz ¸sæl/. Even so, the critical text will maintain the plural eyes because the other examples listed under 2 Nephi 13:8–9 show that the Book of Mormon often favors the plural when the King James Bible uses the singular, especially in reference to parts of the body.
Summary: Maintain the plural eyes in 2 Nephi 23:18 (“their eyes shall not spare children”), even though the plural here may be a mishearing on the part of Oliver Cowdery, the scribe for this part of the original manuscript.