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Entonox as an analgesic agent during panretinal photocoagulation
  1. H L Cook1,
  2. R S B Newsom1,
  3. E Mensah1,
  4. M Saeed1,
  5. D James2,
  6. T J ffytche1
  1. 1Department of Ophthalmology, St Thomas’s Hospital, London, UK
  2. 2Department of Anaesthesia, St Thomas’s Hospital, London, UK
  1. Correspondence to: Helen L Cook, Moorfields Eye Hospital, City Road, London EC1V 2PD, UK; HelenLCook{at}


Background/aims: Panretinal photocoagulation (PRP) reduces the risk of visual loss in proliferative diabetic retinopathy but some patients cannot tolerate PRP because of pain. Inhaled Entonox was evaluated as an analgesic during PRP.

Methods: A randomised, crossover, double masked pilot study was performed. Patients inhaled either air or Entonox and half the PRP was applied. The treatment was completed with the alternate inhaled gas. Patients graded pain experienced during both stages of the treatment using a visual analogue scale. Pain scores were compared using a paired t test.

Results: 20 patients participated. Mean pain scores from the Entonox and air treatments were 2.94 (SD 2.73) versus 3.73 (SD 3.20) respectively (p<0.03).

Conclusion: Entonox can be used as a safe and effective analgesic agent during PRP treatment.

  • diabetic retinopathy
  • analgesia
  • Entonox
  • panretinal photocoagulation

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  • There were no proprietary interests.

  • This work was presented at a free paper session at the Royal College of Ophthalmologists’ Annual Congress in Birmingham in May 2001.