SINGAPORE—Lee Kuan Yew, Singapore's first and longest-serving prime minister, is fighting a neurological disease that makes it difficult for him to walk, his daughter wrote in a newspaper column on Sunday.

Lee Wei Ling, who is also director of Singapore's National Neuroscience Institute, wrote in Singapore's Sunday Times that her 88-year-old father has sensory peripheral neuropathy, a condition that has impaired the conduction of sensation from his legs to his spinal cord.

"This...