Histological and morphometric analysis of the effects of argon laser epilation

To analyse the location and extent of tissue damage induced after argon laser epilation.

Laser burns were applied to the lid margins of four patients before excision for entropion ("live tissue") and the lid margin of one patient was lasered after an excision for ectropion ("dead tissue"). The laser burns were directed towards the lash follicle and between 10 and 50 burns were applied with an argon blue-green laser set at power 0.9-1.0 W, at 0.1-0.2 second duration and a 100 micro m spot size. The tissues were processed for conventional histology. Serial sections were obtained and used for area measurements and three dimensional reconstructions of the burns to determine the volume and location of tissue destruction.

The laser created a cone-shaped region of tissue ablation with surrounding coagulative necroses. Maximum burn depth was 1.2 mm in dead tissue and 0.8 mm in live tissue. Maximum necrosis depth was 1.4 mm in dead tissue and 0.9 mm in live tissue. Follicle depth ranged from 0.8 mm to 1.9 mm. Some of the burns had been misdirected in the dermis leaving target hair follicles intact, despite being of adequate depth.

The argon laser has some potential for ablation of lash follicles, but accurate placement of the burn is essential and energy levels greater than those currently recommended should be applied. The treatment is ineffective in patients unable to remain immobile.