Alteration of pulse configuration affects the pain response during diode laser photocoagulation.
OBJECTIVE
The shape of the treatment pulse of the diode laser (810 nm) can be easily altered electronically in contrast to ion laser photocoagulators. We investigated whether changes in laser pulse shape influenced the subjective pain responses in patients undergoing retinal photocoagulation when only topical anesthesia was used.


METHODS
Twenty consecutive patients required peripheral retinal photocoagulation for proliferative diabetic retinopathy or extensive retinal breaks. Three diode pulse waveforms including a square wave, shaped-wave, and an envelope of micropulses were compared to one another. Power was adjusted so that each waveform delivered the same total energy. The patients subjectively ranked the intensity of any pain they experienced for each group of lesions. Responses were compared to one another using an analysis of variance.


RESULTS
40% of patients found the standard square wave pulse to be significantly more painful (P < 0.05) than the shaped pulse mode and 30% found the square wave significantly more painful (P < 0.05) than the micropulse mode.


CONCLUSIONS
Modification of the laser pulse waveform may ameliorate pain induced by diode laser photocoagulation of the retinal periphery.
Friberg
T R
TR
Department of Ophthalmology, University of Pittsburgh, Pennsylvania 15213, USA.
Venkatesh
S
S
D000704:Analysis of Variance; D000772:Anesthesia, Local; D000779:Anesthetics, Local / Q000008:administration & dosage; D003930:Diabetic Retinopathy / Q000601:surgery; D004582:Electronics, Medical; D006801:Humans; D007431:Intraoperative Complications / Q000517:prevention & control*; D007536:Isomerism; D017075:Laser Coagulation / Q000009:adverse effects / Q000379:methods*; D009887:Ophthalmoscopy; D010146:Pain / Q000517:prevention & control*; D011430:Propoxycaine / Q000008:administration & dosage; D012160:Retina / Q000601:surgery*; D012167:Retinal Perforations / Q000601:surgery
D000779:Anesthetics, Local; C005717:proxymetacaine; D011430:Propoxycaine