Multi-Stage Semi-Markov Models for Recovery Process

Some models for the recovery process of cataract patients after surgery are presented. The use of semi-Markov modeling approach is adapted in a multi-stage process involving acuity levels of patients. The parametric and nonparametric methods of estimation were used for maximum likelihood estimation of the sojourn time distribution. The stationary or long run distribution of the recovery pattern of patients in the Semi-Markov process (SMP) reveals that state G (6/18) is the best corrected acuity with 0.3485 proportions of patients. The distance in meters that the patient can stand and read certain alphabets is 6 and 18m is for a normal person, hence the acuity level of 6/18.