He couldn't find his eyeglasses and now can't read the words in the book clearly.

eyeglasses 是由 eye（眼睛）和 glasses（眼镜）组成的复合名词，指"眼镜"这种矫正视力的工具。glasses 本身是复数形式，因为传统眼镜由两个镜片组成。