For fixed c, Prolate Spheroidal Wave Functions (PSWFs), denoted by ψ n,c , form an orthogonal basis with remarkable properties for the space of band-limited functions with bandwith c. They have been largely studied and used after the seminal work of D. Slepian and his co-authors. In several applications, uniform estimates of the ψ n,c in n and c, are needed. To progress in this direction, we push forward the uniform approximation error bounds and give an explicit approximation of their values at 1 in terms of the Legendre complete elliptic integral of the first kind. Also, we give an explicit formula for the accurate approximation the eigenvalues of the Sturm-Liouville operator associated with the PSWFs.2010 Mathematics Subject Classification. Primary 42C10, 65L70. Secondary 41A60, 65L15. Key words and phrases. Prolate spheroidal wave functions, asymptotic and uniform estimates, eigenvalues and eigenfunctions, Sturm-Liouville operator.