OBJECTIVES The aim was to evaluate the effectiveness of topical cyclopentolate following pterygium surgery for post-operative ocular pain. METHODS All participants had nasal pterygium and underwent pterygium excision and conjunctival autografting with fibrin glue. Participants were randomised into two groups. Participants in group 1 received one per cent cyclopentolate eye drops and artificial tears upon completing surgery and were prescribed self-administered drops three times daily for three days, while participants in group 2 received a control (artificial tears) in a manner identical to group 1. Data were gathered regarding post-operative pain intensity experienced during each of the three days. Pain was graded from zero to 10 according to a visual analogue scale, in which zero signified no pain and 10 signified severe, unbearable pain. RESULTS This study analysed data regarding 38 participants in group 1 and 40 participants in group 2. Results were defined as median with interquartile range (IQR); median of the pain scores at days one, two and three were as follows, respectively: 4 (IQR 2), 2.5 (IQR 1) and 2 (IQR 1.25) for group 1 and 5 (IQR 1), 3 (IQR 1.75) and 3 (IQR 1) for group 2. Pain scores were significantly lower for group 1 compared with group 2 at days one, two and three (p < 0.05). CONCLUSIONS Topical cyclopentolate seems to be effective and well tolerated following pterygium surgery for post-operative ocular pain.