A major disadvantage of excimer laser photorefractive keratectomy (PRK) is pain and discomfort after the surgery, which is thought to be due to damage to corneal sensory nerve fibres or local release of inflammatory substances. Pain only resolves once corneal re-epithelialisation is complete. Previous studies have shown that topical nonsteroidal anti-inflammatory drugs (NSAIDS) can cause corneal complications when used excessively and for long time periods. The aim of this prospective RCT was to determine the role of topical diclofenac in the management of post PRK pain. Sixty-eight adults undergoing bilateral PRK for myopia with or without astigmatism were included. All patients were given 100mg of extended release oral diclofenac at 9pm the evening before surgery and at 9am on the day of surgery. The case group (n=38) were given diclofenac 0.1% drop, one drop 2h preoperatively and one drop four times a day postoperatively for three days. The control group (n=30) were given artificial tears. All patients were examined two days after the procedure. Results showed no significant difference between the reported pain (measured on a scale graded between 0-10) experienced between the case and control groups. Other subjective symptoms, including photophobia and functional activity, were also not different between the two groups. Eyelid oedema and conjunctival injection levels were significantly higher in the control group. The authors conclude that the administration of topical diclofenac in addition to oral diclofenac to treat post PRK pain is unnecessary.