The maximum focal length of the eye-lens for a person with myopia is less than 2.5 cm because myopia causes the far point of the eye to shift closer, reducing the lens's ability to focus on distant objects.
Final Answer: The maximum focal length of the eye-lens is \( \mathbf{< 2.5 \, \text{cm}} \), which corresponds to option \( \mathbf{(1)} \).